Processing Cassava for Food, Feed, and Industry

#### **Chapter 8**

## Cassava and Microalgae Use in the Food Industry: Challenges and Prospects

*Ardiba Rakhmi Sefrienda, Dedy Kurnianto, Jasmadi Jasmadi and Andri Frediansyah*

#### **Abstract**

Cassava is a good source of carbohydrates and a staple diet in many countries. It has a high-calorie count but a low protein and fat content. Microalgae biomass is increasingly being used in the food business industry due to its ease of production, low carbon requirements, and small footprint. The usage of microalgae in combination with cassava is becoming more common as it can boost the amount of nutrients in processed cassava products. In this chapter, we discuss the development of cassava products that combine cassava with microalgae. Furthermore, cassava waste contains carbohydrates, which can be used as a carbon source for the development of microalgae. Cassava starch, when modified to become cationic cassava starch, has the potential to be used as a flocculant agent for the separation of microalgal biomass. Cassava starch is also well-known for being a low-cost source of bioplastics. This chapter also addresses the possibilities for microalgae and cassava to be used as bioplastics in the same way.

**Keywords:** cassava, microalgae, cationic, food, bioplastics

#### **1. Introduction**

Cassava is cultivated in more than one hundred countries and is a primary source of nutrition for millions of people living in tropical areas of Africa, Asia, and America. The average amount of cassava that can be harvested from one hectare in Nigeria is 10.6 tons, making the country the largest cassava producer in the world [1]. Cassava, in addition, is considered to be one of the staple foods in Indonesia. After Nigeria and Thailand, Indonesia has emerged as one of the world's leading producers of cassava, making it one of the top three countries in this regard. Up to 53% of cassava production is used for food items, with the remaining amount being used for animal feed and as sources of bioethanol. Cassava-based food items such as boiled or fried cassava, chips, fermented cassava (*tape, peyeum*), *gatho*t, and *tiwul* are examples of these.

About 70% of the cassava root is water. If the roots are not treated within 2–3 days, they will fully oxidize. Therefore, the drying procedure is a necessary post-harvest

treatment for preserving the quality of the roots. Roots of cassava that have been peeled, then cut into chips, and then dried in the sunlight. Cassava flour can be produced by grinding dried cassava chips in a mill. The locals of Java, Indonesia refer to it as "gaplek" flour. In addition to drying the roots directly, we can alter the cassava by soaking the chips in water containing bio-starter after it has been chopped. This is done after the root has been dried. There will be a three-day period of fermentation. After being fermented, the cassava chips were exposed to the sun to finish drying. In Indonesia, this type of flour is referred to as "mocaf." The acronym mocaf stands for "modified cassava flour," which is the full meaning of the term "mocaf" [2]. Mocaf flour is already being put to use as a gluten-free alternative to regular flour. It can be used as a wheat flour replacement in gluten-free baking, as well as in the preparation of gluten-free noodles and snacks. The non-food industry relies heavily on cassava flour and starch as its primary raw materials. Paper, textiles, plywood, glue, and biofuels are just some of the products that can be made with them. The gelatinization temperature of cassava starch is lower than that of other types of starch, and it also has a higher water-binding capacity and viscosity than other types of starch. These characteristics make it valuable in the culinary, chemical, and pharmaceutical industries [3]. These days, one of the components utilized in the production of biodegradable packaging is cassava starch, which is obtained from the root of the cassava plant [4].

Cassava roots have a significant amount of dietary fiber, which helps to improve heart health and eliminate atherosclerosis and the associated concerns, such as heart attacks and strokes. Cassava is also beneficial to digestive health. It contains vitamins and minerals such as vitamins C and K, as well as potassium, calcium, iron, copper, and zinc [5]. Despite the fact that cassava roots are a source of carbs, they are quite low in protein and fat content [6]. To meet the nutritional requirements for consumption, cassava root products must be coupled with foods that provide a source of protein. A protein source derived from microalgae is one of the forms of protein that are compatible with cassava food products and can be integrated with them. Microalga *Spirulina* sp. is a widespread type of microalgae that is frequently combined with foods that people consume on a regular basis, such as cookies, chocolates, energy drinks, crackers, and instant noodles [7–10]. The cassava cake and the cassava doughnut are the two cassava items that have been reported to combine with *Spirulina* sp. [11, 12]. After the addition of *Spirulina* sp., all the research revealed an increase in the product's protein content [11, 12].

The relationship between cassava and microalgae goes beyond food products. Cassava starch that has been modified to make it cationic cassava starch can be used effectively as a flocculant agent in the microalgae harvesting process [13]. Waste products from cassava processing can be used for the cultivation of microalgae seeds or for fermentation. Achi, et al. [14] reported that waste products from the processing of cassava are a significant source of pollution. Cassava peels are a significant source of waste, and in most areas, 91% of them are piled up in trash landfills [15]. Additionally, Zhang et al. [16] found that the physical and chemical properties of waste cassava were comparable to those of biomass derived from woody plants. This made waste cassava an interesting option for bioconversion into products with additional value [17]. These results imply that the waste generated during cassava processing is a significant contributor to environmental pollution and that cassava waste has the potential to be converted into value-added products. However, additional research is needed to determine whether it is possible to generate value-added commodities from cassava waste.

One example of a sustainable cycle is the integration of the cassava industry with microalgae biorefinery. It could reduce the amount of cassava wasted and the cost of microalgae biorefinery. Microalgae as a protein source has the potential to be a staple dietary fortification against malnutrition. There is also the prospect of developing cassava-microalgae bioplastics as a long-lasting, functional, and environmentally beneficial packaging material.

#### **2. Foods derived from cassava and microalgae**

Cassava production in Indonesia can reach 20 million tons per year, allowing cassava to become one of the staple foods in Indonesia. Cassava, on the other hand, is unpopular as a food source due to its stigma as a meal for marginalized people [2]. In order to increase consumer acceptance of cassava, innovation in the processing of products based on cassava is required. There have been a number of advancements made in the processing of cassava flour into food products. These include the modification of the structure of the cassava flour through the use of fermentation, as well as the transformation of well-known dishes such as cookies, cheese sticks, and noodles using cassava flour [18–21].

Cassava is a source of carbs and contains a negligible amount of protein [6]. The nutritional value of processed food products made from cassava can be improved by the incorporation of various protein sources into their composition. Microalgae are a potential source of protein that might be added to this cassava product after it has been processed. *Spirulina* sp. is by far the most common type of microalgae used.

• Product using cassava flour

Cassava flour has been used to replace wheat flour in doughnut recipes. The microalga *S. platensis* has been utilized to boost the nutritional value of cassava doughnuts. The compositions of the formulation's proximal, sensory, and technical components were assessed. When *S. platensis* was introduced to doughnuts, the protein, lipid, and fiber content increased linearly by 2.59, 3, 4, 5, and 5.41% (w/w). It also increases shearing force, making the doughnut more resistant to deformation and more difficult to chew. However, the doughnut with the highest *S. platensis* inclusion is still acceptable by the consumer, according to the acceptance test. As a result, this product can be utilized to provide improved nutrition to patients suffering from celiac disease [12].

Cassava flour can also be used to make cassava cake. Microalga *S. platensis* was introduced to compensate for the absence of protein in cassava products. The addition of *S. platensis* at 1% and 2% boosted the protein content without affecting consumer acceptance [11].

• Product using modified cassava flour (mocaf)

Food products made from modified cassava flour are becoming increasingly popular in Indonesia. The usage of mocaf can replace the use of wheat flour, which is still imported. Furthermore, an increasing number of people are concerned about glutenfree foods. The fermentation procedure used to create modified cassava flour influenced the physical quality but not the protein content. The protein content of mocaf and cassava flour is 1.2% [22]. The use of *Spirulina* sp. is one approach to boosting the protein content of these products. Commercially available mocaf and *Spirulina*based products include 'Nasamie' mocaf *Spirulina* noodles and "Garmil" mocaf sticks as shown in **Figure 1**. In Nasamie, the addition of *Spirulina* sp. to mocaf noodles

**Figure 1.**

*From left to the right: Mocaf noodles (https://nasamie.co.id/En), pie [22], and stick enriched with* Spirulina *sp. (https://albitec.co.id/product/garmil-dari-stick-spirulina/).*

could elevate the protein level up to 8 g in an 80 g serving size (data from 'Nasamie's nutrition fact'). Therefore, in Garmil, the protein content is 3 g per 25 g serving size (data from 'Garmil Spirulina' nutrition facts) after the addition of *Spirulina* sp. to a mocaf-based stick. Furthermore, the protein content of Garmil mocaf *Spirulina* sp. sticks was higher than that of mocaf sticks reported by Kusumaningrum, Miftakhussolikhah, Herawati, Susanto, and Ariani [18]. This indicates that the addition of *Spirulina* sp. improves the nutritional quality of mocaf sticks. Al-Baarri, et al. [23] reported that the combination of 2% *Spirulina* sp. and 5% basil leaf can reduce the level of mocaf noodle hardness by as much as 50%.

Pie susu as shown in **Figure 1**, a Balinese culinary icon, is another example. It was a short pastry dough with milk and topping. Pastry dough made with a 1:2 ratio of flour and mocaf mocaf and flour. *Spirulina* sp. addition is 0.5% of the total dough. It is the maximum amount of *Spirulina* sp. that can meet the pastry requirement [22].

• Product using cassava starch (tapioca)

Tapioca is widely used in Indonesian cuisine, particularly in a variety of dishes. *Pempek, cireng, cimol, bika ambon, ongol-ongol, kue lapis*, and *cenil* are just some of the delectable dishes that are traditionally prepared in Indonesia with tapioca as one of the main ingredients. Tapioca pearls are among the most well-known foods that are generated from tapioca, and their use can be found all over the world. Tapioca in the form of balls, with a diameter of 2–8 mm [6]. Tapioca is commonly used as a topping in desserts and beverages. Frutea, a Colombian bubble tea maker, has launched Espirulitea, a bubble tea variety. Tea, milk, tapioca, and *Spirulina* sp. are among the ingredients. A franchise café in the United States created a dessert with phycocyanin extract from *Spirulina* sp., also known as blue spirulina. They create a sorbet out of coconut, pineapple, and blue spirulina. Toppings included strawberry tapioca pearls, crunchy honey GF granola, banana, strawberries, and kiwi (**Figure 2**).

Cassava products are grown in over 100 countries and feed millions of people in Africa, Asia, and some part of America. Nigeria is the world's largest cassava producer, with an average yield per hectare of 10.6 tons per acre [1]. The top three countries in terms of cassava production are Nigeria, Thailand, and Indonesia [24]. However, because of its low protein content, cassava necessitates the development of new methods of processing in order to improve its nutritional value and make it suitable for consumption as a food source in the fight against stunting. In order to

*Cassava and Microalgae Use in the Food Industry: Challenges and Prospects DOI: http://dx.doi.org/10.5772/intechopen.110518*

**Figure 2.**

*Tapioca pearls using as drink and dessert enriched with spirulina sp. (https://frutea.com.co/p/espirulitea/; https://beyondjuiceryeatery.com/boba-blue-bowl/).*

boost the nutritional value of cassava, one of the supplementary substances that may be used is microalgae, which is abundant in both protein and antioxidants.

#### **3. Bioplastics from cassava and microalgae**

Currently, the world faces global plastic waste contamination. Innovation is required to reduce this pollution. In contrast, plastics derived from fossil fuels have dropped. Bioplastics were utilized as an alternative to polymers derived from fossil fuels. Bioplastics are a type of plastic that can be derived from natural materials like starches and vegetable oil. The use of plant-based bioplastics is anticipated to reduce petroleum use by 15–20% by 2025, with Asia and Europe holding the biggest market share for bioplastics [25].

Bioplastics can be categorized into three groups: those made from recycled materials, those modified from naturally occurring polymers, and those made from synthetic biobased monomers. Biopolymers can be made from a wide variety of renewable but non-biodegradable raw materials, such as bio-polyethylene (Bio-PE), biobased polyethylene terephthalate (PET), and polytrimethylene terephthalate (PTT), as well as biodegradable but non-renewable materials, such as polybutylene adipate-coterephthalate (PBAT), polybutylene succinate (PBS), and polycaprol. Starch-based polymers are the most prevalent bioplastics polymers worldwide [26]. Indonesia has mass-produced cassava starch and tapioca, for bioplastics under the brand name Telobag as shown in **Figure 3**. A Telobag is a bag constructed from telo-cassava.

Furthermore, microalgae-based bioplastics have been developed. The production of microalgal bioplastics could involve the use of microalgal biomass, bio- or petroleum-based polymers, and additives. The alternate method depends on the

**Figure 3.** *Bioplastics from cassava (www.telobag.com).*


#### **Table 1.**

*Development of microalgae-based bioplastics.*

*Cassava and Microalgae Use in the Food Industry: Challenges and Prospects DOI: http://dx.doi.org/10.5772/intechopen.110518*

intracellular synthesis of biopolymers in microalgae cells, such as polyhydroxybutyrates (PHBs) and starch (**Table 1**) [26].

Although the production of cassava-microalgae-based bioplastics is feasible, no research on cassava bioplastics based on microalgae has been reported. Nevertheless, Cardoso, et al. [40] have developed biobased films from cassava bagasse and *Spirulina platensis.* This biofilm has a total solid content of 7%, with 4% cassava starch, 1% glycerol, and 2% cassava bagasse/*S. platensis*/gelatin mixture. The greatest elongation value was discovered in a mixture of cassava bagasse: *S. platensis*: gelatin (0.34:1.32:0.34). The inclusion of *S. platensis* raised the color (the value of *a\*)* and opacity, but the addition of cassava bagasse increased the viscosity. The films' green color makes them perfect for packing meals of the same color.

The study reported that the biobased films made from cassava bagasse and *S. platensis* are applied to Cambuci peppers (*Capcisum* sp.). For 14 days, the peppers are stored at room and refrigerator temperatures. At room temperature, peppers coated with cassava bagasse-*S. platensis* biobased films lose less bulk. The temperature of the refrigerator delays the maturity of the peppers. In addition, cambuci peppers' shelf life can be extended by combining coating with low temperature [41].

#### **4. Cassava wastewater as a substrate for microalgae**

The cassava industry generates a large number of byproducts and leftovers that are rich in organic matter and particulate debris [42]. In addition, cassava processing generates a lot of effluents. It should be noted that processing one ton (1000 kg) of cassava roots may result in between 250 and 600 kilos of wastewater [43]. de Carvalho, et al. [44] reported that cassava wastewater has high quantities of numerous mineral nutrients. The ash level of cassava waste ranges between 2.5% and 3.5% [17]. The biological oxygen demand (BOD), chemical oxygen demand (COD), and total suspended solids (TDS) found in cassava wastewater are all above average [45, 46]. Wastewater's excessive TDS, BOD, and COD levels are directly correlated to the organic matter and chemical content of the water, which poses serious threats to the environment and the well-being of living things [47].

Microalgae are dependent on the chemical composition and organic matter of cassava wastewater. COD reflects the quantity of oxygen that can be consumed by reactions in a measured solution. The biological oxygen demand (BOD), also known as biological oxygen need, is the amount of dissolved oxygen required by aerobic biological organisms to decompose organic material present in a given water sample at a particular temperature over a certain time period. BOD and COD can be utilized to assess the effectiveness of wastewater treatment plants [48]. Nitrogen is an important factor in the growth of microalgae. Nitrogen is essential for the formation of DNA, proteins, and pigments [49]. Phosphorus is also an essential component of numerous metabolic activities, such as the transfer of energy across cell membranes and cells, the production of nucleic acids, and the encouragement of cell growth and photosynthetic activity [50].

Microalgae can naturally absorb nutrients from the water in order to grow. Thus, laboratory studies have shown that nutrient removal via microalgae cultivation is possible [51]. Microalgae can be autotrophic or heterotrophic. If they are autotrophic, they obtain their carbon from inorganic molecules. Autotrophs are classified into two types: chemolithotrophic and photoautotrophic (photolithotrophic). Photoautotrophs use light as an energy source, whereas chemoautotrophs (chemolithotrophs)

oxidize inorganic substances for energy. Furthermore, heterotrophic microalgae employ organic molecules for growth. Heterotrophs are classified into two groups: photoheterotrophs (photoorganotrophs) and heterotrophs (chemoorganotrophs). Photoheterotrophs use light as an energy source, whereas chemoheterotrophs (chemoorganotrophs) oxidize organic substances for energy. Furthermore, heterotrophic microalgae can absorb complete food particles into food vesicles for processing. They may, on the other hand, be osmotrophic, absorbing dissolved nutrients through the plasma membrane. Some photosynthetic algae are mixotrophic (facultatively heterotrophic). They rely on organic chemicals found in the media [52]. Sorgatto, Soccol, Molina-Aulestia, de Carvalho, de Melo Pereira, and de Carvalho [53] reported that microalgae grew faster in cassava wastewater and produced lipids similar to synthetic mixotrophic cultures. Another research by Nwanko and Agwa (2021) showed that the optimal ratio of cassava peel water to cassava wastewater (CP:CW) for growth was 160:40.

Nutrients in cassava wastewater can be removed using microalgae. For wastewater treatment, the microalgal genera Chlorella, Haemotococcus, Arthrospira, and Dictyosphaerium have been studied [45, 47, 54–57]. Chai, et al. [58] reported that microalgae are effective at removing nitrogen, phosphate, and toxic metals from wastewater. de Faria Ferreira Carraro, Loures, and de Castro [46] demonstrated cyanide removal efficacy approaching 99% and average CO2 biofixation of 0.19 g L−1 from cassava wastewater. The efficacy of wastewater treatment varies according to the species as shown in **Table 2**.

Microalgae-treated wastewater has the potential to be used in pollution removal, agriculture, aquaculture, biogas production, bioproducts, and biomaterials [58, 60]. One method for producing biomass and metabolites at a cheaper cost is to cultivate


#### **Table 2.**

*Microalgae waste removal efficiency.*


**Table 3.**

*Metabolites formed during the processing of cassava waste.*

microalgae in wastewater [53, 61]. **Table 3** depicts the cassava wastewater treatment product based on microalgae. Wastewater from cassava processing can be utilized to cultivate microalgae, which can be used to produce biodiesel or biogas [44, 63]. Microalgae can also be used as a bio stabilizer to boost biogas production from cassava starch effluent [64]. The use of cassava wastewater can also increase astaxanthin accumulation and reduce the toxicity caused by this agro-industrial effluent in *H. pluvialis* [56].

#### **5. Cationic cassava starch as flocculants for microalgae harvesting**

The most difficult challenge in collecting biomass for subsequent usage is efficiently collecting microalgae biomass from their growth substrate. According to Al-Hattab, et al. [65], it accounted for 20–30% of overall biomass production expenses. We are aware that harvesting using filtration techniques is one of the most cost-effective methods available, despite the fact that it is limited to microalgae with a large size, such as *Arthrospira* sp. This method is widely used, even in industrial production. Indeed, microalgae harvesting strategies consider species characteristics, size, density, downstream biomass processing, and sometimes medium recycling needs [66–68]. The greater the size or length of the microalgae, the greater the number of potential screening options available. In actuality, single-cell and small-sized microalgae predominate in our environment, and we constantly interact with them. These factors encourage the development of harvesting systems that are sustainable, cost-effective, suited for industrial production, and safe based on the final product's intended use.

Researchers have studied various methods of harvesting microalgae biomass, including filtration with specific treatments, centrifugation, dispersed air flotation, sedimentation, flocculation, bioflocculation, coagulation, and fluidic oscillation [67, 69–71]. The previously researched bioflocculation harvesting method was regarded as a viable approach for gathering microalgal biomass since it was acceptable with regard to sustainability, large-scale production, low-cost energy, and environmental friendliness [47]. When bioflocculant is utilized, however, microbially contaminated biomass products may be produced [72]. In contrast to microbial-based flocculants, plant-based coagulants enable the harvesting of microalgal biomass that is biodegradable and less contaminated by microorganisms, as mentioned previously. Apart from *Moringa oleifera*, neem, cactus, orange (peels),

pomegranate (peels), banana (peels), *Canavalia ensiformis*, *Strychnos potatorum*, and *Azadirachta indica*, a cassava starch-based coagulant has previously been examined for microalgal harvesting [73–77]. Moreover, considering biodegradability, renewability, and cost-effectiveness, it becomes attractive to use cassava starch as a natural flocculant [78].

The flocculation harvesting concept is driven by the fact that most microalgae cells have a negative surface wall charge; hence, their stability in suspension is a result of their mutual repulsion [74]. With a positive charge, flocculant The so-called cationic flocculant can absorb and react with the naturally negatively charged microalgae, which results in charge cancelation and cell agglomeration, also known as charge neutralization [79, 80]. Natural flocculants that are positively charged are presumably able to agglomerate the microalgae cells in suspension by means of the mechanism [81]. Moreover, another flocculation mechanism, namely bridging, occurs when natural flocculants with long polymers and a large molecular weight are unable to build polymer bridges with negatively charged ions [82]. Charged cationic biopolymers are also using the mechanism to construct the bridge between the cell walls by means of neutralization of the charge or through electrostatic path agglomeration [83]. Bioflocculant mechanisms are illustrated in **Figure 4**.

Cassava starch has been reported as a flocculant in numerous applications, including kaolin suspension, water treatment, water purification, and wastewater treatment [84–88]. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) characterizations and chemical analysis confirmed that double helix configurations in cassava starch result from the amorphous crystalline distribution of starches and influence the growth of flocs and, thus, sedimentation [89, 90]. Cassava starch with a range of unique modified structures has been used to harvest valuable microalgae from their culture medium due to its promising application. When applied to *Chlorella* sp., the harvesting efficiency of cationic cassava starch in composite magnetic form was able to reach 98.09% with 1.67 g microalgae per g flocculant harvesting capacity [78]. In addition, according to Chittapun, Jangyubol, Charoenrat, Piyapittayanun, and Kasemwong [13], a 1000 mg/L dose of

#### **Figure 4.**

*Mechanisms of bioflocculants that interact with microalgae cells: A. charge neutralization mechanism; B. bridging mechanism (reconstructed according to Ogbonna and Nwoba [47]).*


#### *Cassava and Microalgae Use in the Food Industry: Challenges and Prospects DOI: http://dx.doi.org/10.5772/intechopen.110518*


## **Table 4.**

*Characteristics of cassava and other bioflocculants for algae harvesting.*


*Cassava and Microalgae Use in the Food Industry: Challenges and Prospects DOI: http://dx.doi.org/10.5772/intechopen.110518*

> **Table 5.**

*Application of cassava flocculants for microalgae harvesting.*

commercial cationic starch enabled harvesting of the same species of microalgae at the maximum harvesting capacity of 92.86% (**Table 4**). For comparison, potato starch, on the other hand, has been applied for *Scenedesmus dimorphus* flocculation. Cationic starch was used to precipitate more than 95% of the microalgae. Cationic starch was generated using N-(3-chloro-2-hydroxypropyl) trimethyl ammonium chloride (CHPTAC), and epoxide equivalent 2,3-epoxypropyl trimethyl ammonium chloride (EPTC) was used to make cationic starch [91]. While Anthony and Sims [92] investigated different forms of potato starch flocculant using 3-methacryloyl aminopropyl trimethyl ammonium chloride (MAPTAC) and discovered disparate results as shown in **Table 4**. This research has already demonstrated the effects of dose, pH, and degree of substitution on the efficiency of cassava starch as a harvesting aid for microalgae. Additionally, the ionic strength of the medium, hydrophobicity and net charge, phase of cellular growth, CO2 concentration, particle size, and zeta potential will influence flocculation processes [93, 94].

The use of cassava starch as a microalga harvesting agent has already been tested in the laboratory as shown in **Table 5**. The volume of microalgae cultures that have been employed in numerous industries (food, feed, and cosmetics). According to FAO [95], 56,456 tons of microalgae were produced, with 99.56% coming from *Spirulina* (Arthrospira) and the remaining 248 tons derived from other single-celled microalgae such as *Haematococcus pluvialis, Chlorella vulgaris*, *Tetraselmis* spp., and *Dunaliella salina*. One of the reasons for the low production of other single-celled macroalgae could be the inefficiency of the harvesting technique. In light of this, it appears that studies on flocculation harvesting techniques, including the use of cassava starch as a natural material-based flocculant agent, are still in great demand. However, laboratory research on cassava starch as a harvesting agent for microalgae is still limited to microalgae and cassava species. Only two literatures, namely Jangyubol, Kasemwong, Charoenrat and Chittapun [78] and Chittapun, Jangyubol, Charoenrat, Piyapittayanun, and Kasemwong [13] have intensively investigated cassava starch as a flocculant agent. Some additional research is required, such as increasing microalgae volume levels, toxicity analysis, marine microalgae species utilization, end product nutrient analysis, and until microalgae production is economically feasible. Cassava starch's economic worth, renewable availability, and biodegradability have attracted industrial levels despite the fact that starch is only the planet's second most plentiful natural polymer [13].

#### **6. Future prospective**

The integration of the cassava industry and the microalgae biorefinery is a promising and sustainable technology. Using cassava waste to grow microalgae can help to reduce the environmental impact of the cassava flour industry. Additionally, using cassava waste as a substrate for microalgae can reduce manufacturing costs. Microalgae can generate useful products comprising protein, lipids, antioxidants, and vitamins. In addition, harvesting microalgae with cassava starch is highly effective and minimizes the cost of producing microalgae biomass. In addition, the development of fortified staple foods is necessary for the future improvement of public health. Trends in health and fitness increase demand for microalgae and cassava products. Microalgae can be added to cassava products to improve their nutritional value. The addition of microalgae to cassava products can help the sustenance of the community. Furthermore, the addition of microalga to baby food items helps prevent

#### *Cassava and Microalgae Use in the Food Industry: Challenges and Prospects DOI: http://dx.doi.org/10.5772/intechopen.110518*

infant stunting. Moreover, biomass derived from microalgae and cassava can be used to produce plant-based proteins. The development of high-protein and mineral-rich plant-based proteins is primarily motivated by the desires of vegetarian and vegan societies.

In conclusion, the integration of the cassava industry with microalgae biorefinery has numerous environmental and social benefits. It contributes to the implementation of clean technology within the cassava industry. Additionally, it adds to the nourishment of the population. Responsible consumption and production, ending hunger, protecting terrestrial and marine ecosystems, and preserving biodiversity are just a few of the Sustainable Development Goals that benefit from this work.

### **Author details**

Ardiba Rakhmi Sefrienda, Dedy Kurnianto, Jasmadi Jasmadi and Andri Frediansyah\* Research Center for Food Technology and Processing (PRTPP), National Research and Innovation Agency (BRIN), DI. Yogyakarta, Indonesia

\*Address all correspondence to: andr042@brin.go.id

© 2023 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

### **References**

[1] Parmar A, Sturm B, Hensel O. Crops that feed the world: Production and improvement of cassava for food, feed, and industrial uses. Food Security. 2017;**9**(5):907-927

[2] Frediansyah A. Microbial Fermentation as Means of Improving Cassava Production in Indonesia. 2018

[3] Li S, Cui Y, Zhou Y, Luo Z, Liu J, Zhao M. The industrial applications of cassava: Current status, opportunities and prospects. Electronic. The Journal of the Science of Food and Agriculture. London: SCI by John Wiley & Sons Ltd. 2017:1097-1110

[4] Savitri S. Cassava-based packaging for a better future. Available from: https:// www.industrysourcing.com/article/ Cassava-based-packaging-for-a-betterfuture (27 November)

[5] Tsige TZ, Basa B, Herago T. Medicinal, nutritional and anti-nutritional properties of cassava (Manihot esculenta): A review. 2019:34-46

[6] Shigaki T. In: Caballero B, Finglas PM, Toldrá FB T-Eo F a H, editors. Cassava: The Nature and Uses. Oxford: Academic Press; 2016. pp. 687-693

[7] Şahin OI. Effect of spirulina biomass fortification for biscuits and chocolates. In: Turkish Journal of Agriculture - Food Science and Technology. 2019

[8] Abd El-Salam AM, Morsy OM, Abd El Mawla EM. Production and evaluation crackers and instant noodles supplement with spirulina algae. Current Science International. Pakistan. 2017;**6**:908-919

[9] Barakat EH, El-Kewaisny NM, Salama AA. Chemical and nutritional evaluation of fortified biscuits with dried spirulina algae. Journal of Food and Diary Sciences. 2016;**7**:167-177

[10] Freitas BCB, Santos TD, Moreira JB, Zanfonato K, Morais MG, Costa JAV. Novel foods: A meal replacement shake and a high-calorie food supplemented with spirulina biomass. International Food Research Journal. 2019;**26**:59-65

[11] Navacchi M, Carvalho JC, Takeuchi K, Danesi E. Development of cassava cake enriched with its own bran and Spirulina platensis. Acta Scientiarum Technology. 2012;**34**:465-472

[12] Rabelo S, Lemes A, Takeuchi K, Frata M, Carvalho JC, Danesi E. Development of cassava doughnuts enriched with Spirulina platensis biomass. Brazilian Journal of Food Technology. 2013;**16**:42-51

[13] Chittapun S, Jangyubol K, Charoenrat T, Piyapittayanun C, Kasemwong K. Cationic cassava starch and its composite as flocculants for microalgal biomass separation. International Journal of Biological Macromolecules. 2020;**161**:917-926

[14] Achi CG, Coker AO, Sridhar MKC. In: Ghosh SK, editor. Cassava Processing Wastes: Options and Potentials for Resource Recovery in Nigeria, Utilization and Management of Bioresources, Singapore. Singapore: Springer Singapore; 2018. pp. 77-89

[15] Olukanni DO, Olatunji TO. Cassava waste management and biogas generation potential in selected local government areas in Ogun state, Nigeria. Recycling. 2018;**3**(4):58

[16] Zhang L, Chen L, Wang J, Chen Y, Gao X, Zhang Z, et al. Attached *Cassava and Microalgae Use in the Food Industry: Challenges and Prospects DOI: http://dx.doi.org/10.5772/intechopen.110518*

cultivation for improving the biomass productivity of Spirulina platensis. Electronic. 2015:1873-2976

[17] Veiga JPS, Valle TL, Feltran JC, Bizzo WA. Characterization and productivity of cassava waste and its use as an energy source. Renewable Energy. 2016;**93**:691-699

[18] Kusumaningrum A, Solikhah M, Herawati ERN, Susanto A, Ariani D. Gluten-free snacks cheese stick based on mocaf (modified cassava) flour: Properties and consumer acceptance. IOP Conference Series: Earth and Environmental Science. 2019;**251**(1)

[19] Putri DP, Yulianti LE, Afifah N. Accelerated shelf life testing of mocatilla chip using critical moisture content approach and models of sorption isotherms. IOP Conference Series: Materials Science and Engineering. 2021;**1011**:1-8

[20] Sefrienda AR, Ariani D, Fathoni A. Karakteristik Mi berbasis tepung ubi kayu termodifikasi (MOCAF) yang Diperkaya Ekstrak Wortel (Daucus Carota). Jurnal Riset Teknologi Industri. 2020;**14**(2):133-141

[21] Setiaboma W, Kristanti D, Afifah N. Pendugaan Umur Simpan Kukis Mocaf dengan metode akselerasi berdasarkan kadar air kritis. Jurnal Riset Teknologi Industri. 2020;**14**(2):167-167

[22] Ariani RP, Ekayani IAPH, Masdarini L. Processing MOCAF into pie susu with the addition of super food 'spirulina'. Journal of Physics: Conference Series. 2021;**1810**(1):012078

[23] Al-Baarri A, Widayat W, Aulia R, Prahasiwi E, Mawarid A, Pangestika W, et al. The hardness analysis of noodles made from modified cassava flour, spirulina (Spirulina platensis) and

basil leaves extract (Ocimum sanctum L.). IOP Conference Series: Earth and Environmental Science. 2021;**653**:12051

[24] Verma R, Chauhan N, Singh B, Chandra S, Author C, Sengar R. Cassava processing and its food application: A review. The Pharma Innovation Journal. 2022;**SP-11**(5):415-422

[25] Ashter SA. Introduction. In: Ashter SA, editor. Introduction to Bioplastics Engineering. Oxford: William Andrew Publishing; 2016. pp. 1-17

[26] Onen Cinar S, Chong ZK, Kucuker MA, Wieczorek N, Cengiz U, Kuchta K. Bioplastic production from microalgae: A review. Electronic. 2020:1660-4601

[27] Ismail D, Gozan M, Noviasari C. The effect of glycerol addition as plasticizer in Spirulina platensis based bioplastic. E3S Web of Conferences. 2018;**67**:03048

[28] Ismail D, Khalis SA. The effect of compatibilizer addition on Chlorella vulgaris microalgae utilization as a mixture for bioplastic. E3S Web of Conferences. 2018;**67**:03047

[29] Otsuki T, Zhang F, Kabeya H, Hirotsu T. Synthesis and tensile properties of a novel composite of chlorella and polyethylene. Journal of Applied Polymer Science. 2004;**92**:812-816

[30] Torres S, Navia R, Campbell Murdy R, Cooke P, Misra M, Mohanty AK. Green composites from residual microalgae biomass and poly(butylene adipate-co-terephthalate): Processing and plasticization. ACS Sustainable Chemistry & Engineering. 2015;**3**(4):614-624

[31] Fabra MJ, Martínez-Sanz M, Gómez-Mascaraque LG, Gavara R, López-Rubio A. Structural and physicochemical characterization of thermoplastic corn starch films containing microalgae. Electronic. 2018:1879-1344

[32] Zeller MA, Hunt R, Jones A, Sharma S. Bioplastics and their thermoplastic blends from spirulina and chlorella microalgae. Journal of Applied Polymer Science. 2013;**130**(5):3263-3275

[33] Ciapponi RA-OX, Turri S, Levi M. Mechanical reinforcement by microalgal biofiller in novel thermoplastic biocompounds from plasticized Gluten. Materials. 2019:1476. DOI: 10.3390/ ma12091476

[34] Zhu N, Ye M, Shi D, Chen M. Reactive compatibilization of biodegradable poly(butylene succinate)/spirulina microalgae composites. Macromolecular Research. 2017;**25**(2):165-171

[35] Wang K, Mandal A, Ayton E, Hunt R, Zeller MA, Sharma S. Chapter 6 - Modification of protein rich algal-biomass to form bioplastics and odor removal. In: Singh Dhillon G, editor. Protein Byproducts. Canada: Academic Press; 2016. pp. 107-117

[36] Mathiot C, Ponge P, Gallard B, Sassi JF, Delrue F, Le Moigne N. Microalgae starch-based bioplastics: Screening of ten strains and plasticization of unfractionated microalgae by extrusion. Electronic. 2019:1879-1344

[37] Sabathini HA, Windiani L, Ismail D, Gozan M. Mechanical physical properties of chlorella-PVA based bioplastic with ultrasonic homogenizer. E3S Web of Conferences. 2018;**67**:03046

[38] Zhang C, Wang C, Cao G, Wang D, Ho SH. A sustainable solution to plastics pollution: An eco-friendly bioplastic film production from high-salt contained

Spirulina sp. residues. Electronic. 2020:1873-3336

[39] Abdo SM, Ali GH. Analysis of polyhydroxybutrate and bioplastic production from microalgae. Bulletin of the National Research Centre. 2019;**43**(1):97

[40] Cardoso T, Esmerino LA, Bolanho BC, Demiate IM, Danesi EDG. Technological viability of biobased films formulated with cassava by-product and Spirulina platensis. In: Journal of Food Process Engineering. Vol. 42. USA: John Wiley & Sons, Ltd; 2019. p. e13136

[41] Cardoso T, Demiate I, Danesi E. Biodegradable films with Spirulina platensis as coating for Cambuci peppers (capsicum sp.). American Journal of Food Technology. 2017;**12**:236-244

[42] Zhang M, Xie L, Yin Z, Khanal SK, Zhou Q. Biorefinery approach for cassava-based industrial wastes: Current status and opportunities. Bioresource Technology. 2016;**215**:50-62

[43] Oghenejoboh KM, Orugba HO, Oghenejoboh UM, Agarry SE. Value added cassava waste management and environmental sustainability in Nigeria: A review. Environmental Challenges. 2021;**4**:100127

[44] de Carvalho JC, Borghetti IA, Cartas LC, Woiciechowski AL, Soccol VT, Soccol CR. Biorefinery integration of microalgae production into cassava processing industry: Potential and perspectives. Bioresource Technology. 2018;**247**:1165-1172

[45] Melo JM, Telles TS, Ribeiro MR, de Carvalho Junior O, Andrade DS. Chlorella sorokiniana as bioremediator of wastewater: Nutrient removal, biomass production, and potential profit. Bioresource Technology Reports. 2022;**17**:100933

#### *Cassava and Microalgae Use in the Food Industry: Challenges and Prospects DOI: http://dx.doi.org/10.5772/intechopen.110518*

[46] de Faria Ferreira Carraro C, Loures CCA, de Castro JA. Microalgae technique for bioremediation treatment of cassava wastewater. Water, Air, & Soil Pollution. 2021;**232**(7):281

[47] Ogbonna CN, Nwoba EG. Bio-based flocculants for sustainable harvesting of microalgae for biofuel production. A review. Renewable and Sustainable Energy Reviews. 2021;**139**:110690

[48] Li K, Liu Q, Fang F, Luo R, Lu Q, Zhou W, et al. Microalgae-based wastewater treatment for nutrients recovery: A review. Bioresource Technology. 2019;**291**:121934

[49] Markou G, Angelidaki I, Georgakakis D. Microalgal carbohydrates: An overview of the factors influencing carbohydrates production, and of main bioconversion technologies for production of biofuels. Applied Microbiology and Biotechnology. 2012;**96**(3):631-645

[50] Liyanaarachchi VC, Nishshanka GKSH, Premaratne RGMM, Ariyadasa TU, Nimarshana PHV, Malik A. Astaxanthin accumulation in the green microalga Haematococcus pluvialis: Effect of initial phosphate concentration and stepwise/ continuous light stress. Biotechnology Reports. 2020;**28**:e00538

[51] Nguyen TDP, Le TVA, Show PL, Nguyen TT, Tran MH, Tran TNT, et al. Bioflocculation formation of microalgaebacteria in enhancing microalgae harvesting and nutrient removal from wastewater effluent. Bioresource Technology. 2019;**272**:34-39

[52] Sluiman H. Phycology. In: Lee RE, editor. Edinburgh Journal of Botany. 4th ed. United Kingdom: Trustees of the Royal Botanic Garden Edinburgh; 2009. p. 66

[53] Sorgatto VG, Soccol CR, Molina-Aulestia DT, de Carvalho MA, de Melo Pereira GV, de Carvalho JC. Mixotrophic cultivation of microalgae in cassava processing wastewater for simultaneous treatment and Production of lipid-rich biomass. In Fuels. 2021;**2**:521-532

[54] Araujo GS, Santiago CS, Moreira RT, Dantas Neto MP, Fernandes FAN. Nutrient removal by Arthrospira platensis cyanobacteria in cassava processing wastewater. Journal of Water Process Engineering. 2021;**40**:101826

[55] Liu J, Zheng QJ, Ma QX, Gadidasu KK, Zhang P. Cassava genetic transformation and its application in breeding. Journal of Integrative Plant Biology. 2011;**53**:552-569

[56] Coutinho Rodrigues OH, Itokazu AG, Rörig L, Maraschin M, Corrêa RG, Pimentel-Almeida W, et al. Evaluation of astaxanthin biosynthesis by Haematococcus pluvialis grown in culture medium added of cassava wastewater. International Biodeterioration & Biodegradation. 2021;**163**:105269

[57] Padri M, Boontian N, Teaumroong N, Piromyou P, Piasai C. Co-culture of microalga Chlorella sorokiniana with syntrophic streptomyces thermocarboxydus in cassava wastewater for wastewater treatment and biodiesel production. Bioresource Technology. 2022;**347**:126732

[58] Chai WS, Tan WG, Halimatul Munawaroh HS, Gupta VK, Ho S-H, Show PL. Multifaceted roles of microalgae in the application of wastewater biotreatment: A review. Environmental Pollution. 2021;**269**:116236

[59] Padri M, Boontian N, Teaumroong N, Piromyou P, Piasai C. Application of two indigenous strains of microalgal

Chlorella sorokiniana in cassava biogas effluent focusing on growth rate, removal kinetics, and harvestability. Water. 2021;**13**:1-21

[60] Al-Jabri H, Das P, Khan S, Thaher M, AbdulQuadir M. Treatment of wastewaters by microalgae and the potential applications of the produced biomass—A review. Water. 2021;**13**:1-26

[61] Ren Z, Jia B, Zhang G, Fu X, Wang Z, Wang P, et al. Study on adsorption of ammonia nitrogen by iron-loaded activated carbon from low temperature wastewater. Chemosphere. 2021;**262**:127895

[62] Liu L, Chen J, Lim P-E, Wei D. Enhanced single cell oil production by mixed culture of Chlorella pyrenoidosa and Rhodotorula glutinis using cassava bagasse hydrolysate as carbon source. Bioresource Technology. 2018;**255**:140-148

[63] Neves C, Maroneze MM, dos Santos AM, Francisco ÉC, Wagner R, Zepka LQ, et al. Cassava processing wastewater as a platform for third generation biodiesel production. In Scientia Agricola. 2016;**73**:412-416

[64] Budiyono B, Kusworo T. Microalgae for stabilizing biogas Production from cassava starch wastewater. International Journal of Waste Resources (IJWR). 2012;**2**

[65] Al-Hattab M, Ghaly A, Hammouda A. Microalgae harvesting methods for industrial production of biodiesel: Critical review and comparative analysis. Journal of Fundamentals of Renewable Energy and Applications. 2015;**5**:1-26

[66] Uduman N, Qi Y, Danquah MK, Forde GM, Hoadley AFA. Dewatering of microalgal cultures: A major

bottleneck to algae-based fuels. Journal of Renewable and Sustainable Energy. 2010;**2**:1

[67] Rawat I, Ranjith Kumar R, Mutanda T, Bux F. Dual role of microalgae: Phycoremediation of domestic wastewater and biomass production for sustainable biofuels production. Applied Energy. 2011;**88**(10):3411-3424

[68] Amaro HM, Guedes AC, Malcata FX. Advances and perspectives in using microalgae to produce biodiesel. Applied Energy. 2011;**88**(10):3402-3410

[69] Kim L, Kwon K, Oh Y. Effects of harvesting method and growth stage on the flocculation of the green alga Botryococcus braunii. Letters in Applied Microbiology. 1998;**27**(1):14-18

[70] Pittman JK, Dean AP, Osundeko O. The potential of sustainable algal biofuel production using wastewater resources. Bioresource Technology. 2011;**102**(1):17-25

[71] Letelier-Gordo CO, Holdt SL, De Francisci D, Karakashev DB, Angelidaki I. Effective harvesting of the microalgae i via bioflocculation with cationic starch. Bioresource Technology. 2014;**167**:214-218

[72] Barros AI, Gonçalves AL, Simões M, Pires JCM. Harvesting techniques applied to microalgae: A review. Renewable and Sustainable Energy Reviews. 2015;**41**:1489-1500

[73] Teixeira C, Teixeira P. Evaluation of the flocculation efficiency of Chlorella vulgaris mediated by Moringa oleifera seed under different forms: Flour, seed cake and extracts of flour and cake. Brazilian Journal of Chemical Engineering. 2017;**34**:1

[74] Behera B, Balasubramanian P. Natural plant extracts as an economical *Cassava and Microalgae Use in the Food Industry: Challenges and Prospects DOI: http://dx.doi.org/10.5772/intechopen.110518*

and ecofriendly alternative for harvesting microalgae. Bioresource Technology. 2019;**283**:45-52

[75] Díaz-Santos E, Vila M, de la Vega M, León R, Vigara J. Study of bioflocculation induced by Saccharomyces bayanus var. uvarum and flocculating protein factors in microalgae. Algal Research. 2015;**8**:23-29

[76] Abdul Razack S, Duraiarasan S, Santhalin Shellomith AS, Muralikrishnan K. Statistical optimization of harvesting Chlorella vulgaris using a novel bio-source, Strychnos potatorum. Biotechnology Reports. 2015;**7**:150-156

[77] Ali M, Mustafa A, Saleem M. Comparative study between indigenous natural coagulants and alum for microalgae harvesting. Arabian Journal for Science and Engineering. 2019;**44**(7):6453-6463

[78] Jangyubol K, Kasemwong K, Charoenrat T, Chittapun S. Magnetic– cationic cassava starch composite for harvesting chlorella sp. TISTR8236. Algal Research. 2018;**35**:561-568

[79] Salim S, Bosma R, Vermuë MH, Wijffels RH. Harvesting of microalgae by bio-flocculation. Journal of Applied Phycology. 2011;**23**(5):849-855

[80] Salim S, Kosterink NR, Tchetkoua Wacka ND, Vermuë MH, Wijffels RH. Mechanism behind autoflocculation of unicellular green microalgae Ettlia texensis. Journal of Biotechnology. 2014;**174**:34-38

[81] Aljuboori AHR, Idris A, Abdullah N, Mohamad R. Production and characterization of a bioflocculant produced by aspergillus flavus. Bioresource Technology. 2013;**127**:489-493

[82] Aljuboori AHR, Uemura Y, Osman NB, Yusup S. Production of a bioflocculant from aspergillus Niger using palm oil mill effluent as carbon source. Bioresource Technology. 2014;**171**:66-70

[83] Vandamme D, Foubert I, Muylaert K. Flocculation as a low-cost method for harvesting microalgae for bulk biomass production. Trends in Biotechnology. 2013;**31**(4):233-239

[84] Razali MAA, Ariffin A. Polymeric flocculant based on cassava starch grafted polydiallyldimethylammonium chloride: Flocculation behavior and mechanism. Applied Surface Science. 2015;**351**:89-94

[85] Villabona-Ortíz A, Tejada-Tovar C, Millán-Aníbal M, Granados-Conde C, Ortega-Toro R. Reduction of turbidity in waters using cassava starch as a natural coagulant. PRO. 2021;**19**:1

[86] Lugo-Arias J, Lugo-Arias E, Ovallos-Gazabon D, Arango J, de la Puente M, Silva J. Effectiveness of the mixture of nopal and cassava starch as clarifying substances in water purification: A case study in Colombia. Heliyon. 2020;**6**(6):e04296

[87] Jiraprasertkul W, Nuisin R, Jinsart W, Kiatkamjornwong S. Synthesis and characterization of cassava starch graft poly(acrylic acid) and poly[(acrylic acid)-co-acrylamide] and polymer flocculants for wastewater treatment. Journal of Applied Polymer Science. 2006;**102**:2915-2928

[88] Meshram MW, Patil VV, Mhaske ST, Thorat BN. Graft copolymers of starch and its application in textiles. Carbohydrate Polymers. 2009;**75**(1):71-78

[89] Chávez-Salazar A, Bello-Pérez LA, Agama-Acevedo E, Castellanos-Galeano FJ, Álvarez-Barreto CI, Pacheco-Vargas G.

Isolation and partial characterization of starch from banana cultivars grown in Colombia. International Journal of Biological Macromolecules. 2017;**98**:240-246

[90] Ashri A, Yusof MSM, Jamil MS, Abdullah A, Yusoff SFM, Arip MNM, et al. Physicochemical characterization of starch extracted from Malaysian wild yam (Dioscorea hispida Dennst.). Emirates Journal of Food and Agriculture. 2014;**26**(8)

[91] Hansel PA, Guy Riefler R, Stuart BJ. Efficient flocculation of microalgae for biomass production using cationic starch. Algal Research. 2014;**5**:133-139

[92] Anthony R, Sims R. Cationic starch for microalgae and total phosphorus removal from wastewater. Journal of Applied Polymer Science. 2013;**130**(4):2572-2578

[93] Papazi A, Makridis P, Divanach P. Harvesting Chlorella minutissima using cell coagulants. Journal of Applied Phycology. 2010;**22**(3):349-355

[94] Shelef G, Sukenik A, Green M. Microalgae Harvesting and Processing: A Literature Review. Haifa, Israil: Technion Research and Development Foundation ltd.; 1984

[95] FAO Fishery and Aquaculture Statistics. Available from: www.fao.org/ fishery/statistics/software/fishstatj/en

## **Chapter 9** Use of Cassava in Chicken Diet

*Tagesse Tadesse*

#### **Abstract**

Chicken production has negatively been affected by continuous increment in conventional energy-source feed ingredients due to the competition between human beings and animals globally. Cereal crops, their byproducts, and leftovers from households are among the frequently accessible sources of chicken feed. Poultry industry has been affected by a shortage and increasing cost of conventional feed resources. Various non-conventional feed resources have been reported to solve this problem. Tuber and root crops are among the alternative feed resources and can be substituted at varying quantities in chickens' diets. Among the root and tuber crops that can be included in the diet of chickens is cassava. The tuber of cassava can be cut into chunks, dried, milled, or pelletized and added to the diet of chickens. It can also be added to the diet of broilers, and it can substitute 50% of the maize in their diet without negatively impacting their performance. Adding 40% cassava flour or 20% cassava peel meal to the diet of layer chickens is also beneficial for their ability to lay eggs. Generally, different parts of cassava can be included at different amounts in the diets of chickens.

**Keywords:** cassava, chicken, feed intake, non-conventional feed, substitution

#### **1. Introduction**

African chicken production survives by scavenging and, other than the occasional feeding of household garbage to the chickens and under other circumstances, with the addition of grain to the feed. Due to low input levels and numerous issues with village chicken production, the entire standard of chicken production in developing nations like Ethiopia is primarily of the scavenging type and is typically inefficient [1]. Chickens are a simple way to generate family income and opportunities for job creation with relatively low resource investment and readily available family labor because of their tendency to adapt to most regions of the world, their rapid growth rate, their quick breeding rate compared to most other livestock, or the short generation span. When compared to other domestic animals, chicken is an incredible resource for chicken farming and for household usage as a protein-rich source of animal food for human consumption [2]. The production of chicken is challenged by various factors. The major problem that affects the poultry industries in the tropics is the increasing cost of feed ingredients, such as maize and soya bean meal. The seasonal instability in the supply of conventional feed ingredients requires alternative energy sources to be explored to ensure optimum performance of the chickens [3].

The main challenges for livestock production in the tropics and sub-tropical countries are inadequate feed sources and low quality of existing feed resources [4]. Due to insufficient production of conventional feedstuffs for livestock feeding, the majority of developing nations struggles to provide their animals with enough to feed. Both humans and animals compete over the few amounts of concentrated feedstuffs they produce each year. As a result, the production of livestock in these nations frequently faces a significant problem due to the lack of feed resources [5]. The use of non-conventional feedstuffs in animal feeding can help to solve this problem. In this regard, alternative feed ingredients have been used in animal feeding, including cassava root meal [6, 7] and sweet potato meal [8–12]. The use of cassava as an alternative to conventional energy feed stuffs like maize could help to reduce feed costs [13].

#### **2. Cassava (***Manihot esculenta***) in chicken diet**

Crops with starchy roots, tubers, rhizomes, corms, or stems are known as root and tuber crops. They are mostly utilized to make animal feed, human food (either raw or processed), starch, alcohol, and fermented drinks like beer. A root is an organ that grows from the root tissue and is a small, frequently enlarged storage organ with hairy stalks. A root is also a tuber. It grows from a rhizome, or a prolonged stem tissue; therefore, it is probably an enlarged storage organ. Consequently, a plant may also be a root, whereas a tuber is a root crop. For instance, potatoes, sweet potatoes, and yams are edible tubers, whereas carrots and cassava are root vegetables. There are differences between the growth patterns of edible tubers and edible root crops or plants. Since the plant's edible tubers and root vegetables are what fuel its above-ground growth, they are rich in starchy nutrients. While most vegetables grow above ground, root and tuber vegetables are the components of the plant that grow below the soil or on the soil surface. Rhizomes that grow underground can run parallel to or just below the soil's surface and can also run horizontally. Simply, a swelling portion of one of these rhizomes makes up the tuber. It may be possible to extract nutrients from these bloated chunks. In order for the plants to create healthy new growth in the spring, they want to store nutrients for them [14].

Cassava (*Manihot esculenta*) is grown for its underground starchy tuberous roots in tropical and subtropical regions. Over 800 million people worldwide eat mostly cassava roots, commonly known as cassava tubers [15]. Cassava roots are low in protein but abundant in calories because they are mostly constituted of starch and soluble carbohydrates. It is anticipated that more than 60% of the cassava grown in Africa will be consumed, with the other third being used to make secondary products [16]. The rising and expensive cost of feed ingredients has been a hindrance to global chicken production for many years. The majority of the time, different cereal crops are used as a conventional feed source for chickens. The competition between human and animal food and feed, as well as the use of these components in other industries, may be to blame for the ongoing increase in these feed ingredients. As a result, a substitute for the conventional energy and protein elements in chicken feed must be affordable and easily accessible and have an adequate nutritious composition and should have no discernible impact on chickens. Accordingly, Cassava (*Manihot esculenta*) is one such alternative. A common root tuber known as cassava is high in calcium, vitamins B and C, vital minerals, and carbohydrates, making it a viable substitute for maize in the diets of chickens. Cassava's low protein content, imbalanced amino acid profile, dustiness, and presence of anti-nutritional elements, however,

#### *Use of Cassava in Chicken Diet DOI: http://dx.doi.org/10.5772/intechopen.110309*

limit its utilization in chicken diets. However, these flaws can be solved through proper processing and the inclusion of feed additives in the diet [17].

Different parts of cassava can be supplemented into diets of chickens. As a result, cassava tubers can be consumed boiled, mashed, deep-fried, and so on, and there are many food products based on cassava such as tapioca (cassava starch), a worldwide food ingredient; fufu (cassava flour boiled in water); and garri (fermented cassava mash), the two last popular foods in West and Central Africa [18]. The basic cassava products used in animal feeding are chips and pellets, which can partially or completely substitute the cereal grain in poultry feed [19]. The finger-like leaves, which are consumed as vegetables or used as animal feed, as well as different byproducts from the cassava processing industries, such as pomace and peels from starch, ethanol, and cassava food production, which can be used as livestock feed, are examples of other cassava products. Cassava flour, which should not be consumed by humans, can be used to make livestock feed [20]. Livestock feeding accounts for more than a third of the cassava crop's production [21]. Before being powdered or pelletized for use in commercial livestock feed, cassava tubers are first cut into slices and dried. Cassava chips can be made using basic household or village procedures as well as on a big, mechanized scale, and the processes utilized at various sizes of chip and pellet manufacturing are connected. The amount of cassava that needs to be processed, the cost of labor and capital, as well as the accessibility of relatively cheap energy, all influence the technology that is selected [22]. The availability of a better source of protein and the inclusion of enough methionine in the diet to meet both body requirements and cyanide detoxification are two factors that will determine whether utilizing cassava powder as a maize alternative in poultry feed is feasible [23]. While attempts have been made to reduce the dirtiness with the addition of oil and supplementation with suitable amounts of methionine and lysine amino acids, it has been beneficially observed that cassava root meal can replace up to 30% of maize in a broiler ration [24]. In a layer's diet, cassava root meal can completely replace maize [25]. Compared to chicken-fed rations with cassava chips or maize, broiler chicken-fed rations containing cassava pellets exhibited improved feed consumption [26]. For growing Japanese quail, about 35% cassava meal-based ration is suggested [27]. Cockerel starter birds can tolerate only about 28% level of cassava sievate in their ration [28]. Cassava root sievate and wet maize milling waste [29] can successfully replace maize by up to 35% without impacting the growth and feed utilization of finisher broilers.

The majority of research findings demonstrates that adding cassava to chickens' diets results in attractive responses in their behavior. For instance, substituting a 4:1 mixture of cassava root meal and leaves for maize in the diet of chickens can lower feed costs without affecting the layers' ability to gain weight or produce eggs [30]. Feeding broilers cassava chips supplemented with Moringa oleifera leaf meal at levels of 5 and 10% showed that cassava chips replacing maize at levels of 55.56% and 83.33%, respectively, in the diets had no negative effects on production and blood parameters [31]. Depending on dry matter consumption and growth performance of broilers, cassava root chips can completely substitute maize grain in broiler rations as an energy feed source [32]. On the other hand, based on the results of yields of major edible meat parameters, cassava root chips could replace maize grain by less than 50% in broilers diet, and 50% cassava root chips or 5% Moringa olifera meal, or a mixture of both can successfully be used in the ration of layers, substituting maize grain and soybean meal. The final body weight gain, total body weight gain, and daily body weight gain of broiler chickens were enhanced by substitution of noug seed cake with

cassava leaf meal at a 4% substitution level. Thus, cassava leaves can be a good protein source to substitute the expensive Noug seed cake in the broiler ration [33].

#### **3. Limitations on using cassava meal**

The physical properties of cassava root meal, such as dustiness, poor pelleting quality, and poor pigmentation, tend to also limit the use of cassava as a feed ingredient in animal diets, in addition to the antinutritional factors and nutrient deficiencies inherent in raw and unprocessed cassava root. It has been noted that these physical restrictions, particularly in poultry, can lower feed intake and have an impact on body weight gain and feed conversion ratio. Animals fed a diet based on cassava that does not contain oil or that is fed as mash have also been shown to exhibit crop impaction and respiratory system irritation [34].

A cassava-based diet's dustiness is typically correlated with the form in which the feed is given to the animal. High levels of cassava meal in mash feed often produce dusty feed. Through proper pelleting, dustiness problems in cassava-based mash diets might be resolved, which would increase feed consumption and poultry performance. Pelletizing a cassava-based diet produces a diet that is denser, more homogeneous, and less dusty [35]. Diets based on cassava are about one-third less bulky after pelleting, which solves the dustiness problem. However, methods like the addition of oil or molasses can be used to address difficulties with dustiness in unpelleted chicken feed on farms without pelleting machinery.

To reduce dustiness, wet mashed feed can also be given to the birds; however, moist mashed feed should not be kept for an extended period of time to prevent contamination and deterioration. Lack of pigmentation is a further physical characteristic that restricts the use of cassava as a feed element for animals, particularly poultry. The color of cassava root meal is white (it does not have any pigmentation). It has been noted that feeding layers and broilers large amounts of cassava root meal causes pale meat and egg yolks, respectively. Due of minimal consumer appeal, it has been stated that these eggs and chicken flesh are sold for low prices.

When using a lot of cassava meal, the product quality should be improved by adding leaf meal or other pigmenting agents to the diet. Cassava root meal's lack of pigmentation can be avoided by adding at least 30–50 g of leaf meal per kg of poultry food. Leaf meals including those from young grass, ipil-ipil (leucaena) leaves, sweet potato leaves, and cassava leaves have been shown to be successful [35].

#### **4. Methods to raise the nutritional value of cassava**

Various processing techniques have been employed for many years to improve the nutritional content of cassava for use by humans and fowl. All of these techniques aim to remove different ANFs that are present in raw cassava, including hydrogen cyanide, phytate, saponin, and alkaloids [36]. These processing techniques have also been utilized to address physical issues like dustiness and a lack of pigmentation that tend to decrease performance and product quality and raise mortality when unprocessed cassava is used as a food or feed ingredient, as well as nutrient shortages. There are two types of cassava processing techniques: traditional [37] and modern [38]. Traditional cassava processing techniques include drying; boiling; parboiling/ cooking; steaming; frying; roasting; addition of oil, molasses, and leaf meal; and

#### *Use of Cassava in Chicken Diet DOI: http://dx.doi.org/10.5772/intechopen.110309*

utilization of natural fermentation processes in order to improve the nutritional composition and decrease the anti-nutrient content. HCN losses from these procedures range from 25 to 98% [39]. The addition of feed additives, such as nutrient supplements with amino acids, vitamins, and minerals; the addition of pigmentation agents; pelleting; the addition of synthetic enzymes; the microbial fermentation of cassava roots; and the genetic modification of the cassava plant are examples of contemporary methods of cassava processing [40].

#### **5. Conclusion**

Feed resources for chickens mainly come from activities directed toward human food production. The potential sources of feed for chicken production are mainly cereal crops and their byproducts. Shortage of conventional feed resources and continuous increment in its cost have been challenging chicken production in the tropics. Utilization of alternative feed resources is mandatory to overcome this challenge in the poultry sector. Root and tuber crops can be added in chicken diets. Cassava is among the root crops and can be included in chickens' ration. Thus, the tuber of cassava can be included in broilers diet and substitute up to 50% maize in the ration without harming the performances of both broiler and layer chickens. The use of cassava in chicken diet is limited by the presence of some anti nutritional factors. These factors can be reduced by different methods. In conclusion, cassava can be included in chickens' diet without causing negative impact on the performances of chickens.

#### **Author details**

Tagesse Tadesse Department of Animal Science, College of Agricultural Sciences, Wachemo University, Hossana, Ethiopia

\*Address all correspondence to: tagessetadesse76@gmail.com

© 2023 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

### **References**

[1] Dessie T, Ogle B. Village poultry production systems in the central highlands of Ethiopia. Tropical Animal Health and Production. 2001;**33**(6):521-537

[2] Solomon D. Growth performance of local and white Leghorn chicken under intensive management system. Journal Science. 2004;**27**:161-164

[3] Fafiolu AO, Oduguwa OO, CON I, Onwuka CFI, Adebule MA. Performance and egg quality assessment of laying hens fed malted sorghum sprouts base diets. In: Proceedings of the 9th Annual Conference of Animal Science Association of Nigeria. Abakaliki, Nigeria: Ebonyi State University; 2004. pp. 33-35

[4] Boufennara, Lopez S, Bousseboua H, Bodas R, Bouazza L. Chemical composition and digestibility of some browse plant species collected from Algerian arid rangelands. Spanish Journal of Agricultural Research. 2012;**10**(1):88-98

[5] Aregheore EM. Chemical composition and nutritive value of some tropical by-product feedstuffs for small ruminants—In vivo and in vitro digestibility. Animal Feed Science and Technology. 2000;**85**(1-2):99-109

[6] Sultana F, Khatun MF, Ali MA. Effect of dietary cassava tuber meal on egg production and egg quality of laying hen. Int J BioRes. 2011;**2**:1-4

[7] Sultan F, Ali MA, Jahan I. Growth performance meat yield and profitability of broiler chickens fed diets incorporating cassava tuber meal. Journal of Environmental Science & Natural Resources. 2012;**5**(1):47-53

[8] Agwunobi LN. Performance of broiler chickens fed sweet potato meal (*Ipomea batatas* L.) diets. Tropical Animal Health and Production. 1999;**31**:383-389

[9] Ayuk EA, Essien A. Growth and haematological response of broiler chicks fed graded levels of sweet potato (Ipomoea batata) meal as replacement for maize. International Journal of Poultry Science. 2009;**8**:485-488

[10] Beckford RC, Bartlett JR. Inclusion levels of sweet potato root meal in the diet of broilers I. Effect on performance, organ weights, and carcass quality. Poultry Science. 2015;**94**:1316-1322

[11] Maphosa T, Gunduza KT, Kusina J, Mutungamiri A. Evaluation of sweet potato tuber (*Ipomea batatas* l.) as a feed ingredient in broiler chicken diets. Livestock Research for Rural Development. 2003;**15**:Article #3

[12] Mozafari O, Ghazi S, Moeini MM. The effects of different levels of edible potat (Solanumtubresum) replacing maize on performance, serum metabolite and immune system of broiler chicks. Iranian Journal of animal Science. 2013;**3**(3):583-588

[13] Ukachukwu SN. Studies on the nutritive value of composite cassava pellets for poultry: Chemical composition and metabolizable energy. Livestock Research for Rural Development. 2005;**17**(11)

[14] Gardner K. The Difference between Tubers & Root Crops. 2019. Available from: https://www.gardenguides. com/13407021-thedifference-betweentubers-root-crops.html

[15] Ecocrop. Ecocrop Database. FAO;2011

*Use of Cassava in Chicken Diet DOI: http://dx.doi.org/10.5772/intechopen.110309*

[16] Scott G, Best R, Rosegrant MW, Bokanga M. Roots and tubers in the global food system—A vision statement to the year 2020. CIAT-CIP-IFPRI-IITA - IPGRICIP. 2000;**45**

[17] Ravindran V. Poulty Feed Availability and Nutrition in Developing Countries. Alternative Feedstuffs for Use in Poultry Feed Formulations. Poultry Development Review. Rome: FAO; 2013. pp. 60-63

[18] Kuiper L, Ekmecki B, Hamelink C, Hettinga W, Meyer S, Koop K. Bioethanol from cassava. In: Project Number: PBIONL062937. Ecofys Netherlands BV: Utrecht; 2007

[19] Iji PA, Bhuiyan MM, Chauynarong N, Barekatain MR, Widodo AP. Improving the nutritive value of alternative feed ingredients for poultry. In: Proceedings of the Recent Advanced in Animal Nutrition; Australia. 2011. pp. 115-122

[20] Boscolo WR, Hayashi C, Meurer F. Apparent digestibility of the energy and nutrients of conventional and alternative foods for Nile tilapia (Oreochromis niloticus). Revista Brasileira de Zootecnia. 2002;**31**(2):539-545

[21] FAO. FAOSTAT. Food and Agriculture Organization of the United Nations; 2011

[22] Hahn SK, Reynolds L, Egbunike GN. Cassava as livestock feed in Africa. In: Proc. IITA/ILCA/Univ. of Ibadan Workshop on the Potential Utilization of Cassava as Livestock Feed in Africa; 14-18 November 1988; Ibadan, Nigeria. 1992

[23] Okereke CO, Ukachukwu SN. Effect of dietary inclusion of composite cassava meal on egg production charateristics of laying hens [student thesis]. Micheal Okpara University. Department of

Non Ruminant Animal Nutrution and Biochemistry; 2005. pp. 1-38

[24] Tekalegn Y, Etalem T, Getnet A. Poultry feed resources and coping mechanisms of challenges in Sidama zone, southern Ethiopia. 2017

[25] Akinola LAF, Oruwari BM. Response of laying hens total dietary replacement of maize with cassava. Nigerian Journal of Animal Production. 2007;**34**(2):196-202

[26] Bhuiyan MM, Iji PA. Energy value of cassava products in broiler chicken diets with or without enzyme supplementation. Asian-Australasian Journal of Animal Sciences. 2015;**28**(9):1317-1326

[27] Edache JA, Musa U, Karsin PD, Esilonu DO, Yisa A, Okpala EJ, et al. The feeding value of cassava meal diets for growing Japanese quail (Coturnix coturnix japonica). Nigerian Journal of Animal Production. 2007;**34**(1):77-82

[28] Nwokoro SO, Orheruata AM, Paul IO. Replacement of maize with cassava sievates in cockerel starter diets; some blood metabolic. In: Proceeding of 25th Annual Conference with NSAP. 2000. pp. 234-236

[29] Onwujiariri EB, Onyekwere MU, Okoronkwu MO, Okechukwu S. Evaluation of wet maize milling waste and cassava root sievaite as a replacement for maize in broiler finisher diets. In: Proc 42nd Annual Conference, Agricultural Society of Nigeria (ASA). October 19th-23rd 2008 Ebonyi State University Abakilike Nigeria. 2000. pp. 669-671

[30] Tewe OO, Bokanga M. Research Highlights Cassava Utilization, 2001. Ibadan, Nigeria: International Institute of Tropical Agriculture; 2001

[31] Olugbemi TS, Mutayoba SK, Lekule FP. Effect of Moringa (Moringa oleifera) inclusion in cassava based diets fed to broiler chickens. International Journal of Poultry Science. 2010;**9**:363-367

[32] Etalem T, Getachew A, Mengistu U, Tadelle D. Nutritional value of cassava root chips and Moringa Oleifera leaf meal in broiler and layer rations [PhD dissertation]. 2013

[33] Melesse A, Masebo M, Abebe A. The substitution effect of Noug seed (*Guizotia abyssinica*) cake with cassava leaf (*Manihot escutulata* C.) meal on feed intake, growth performance, and carcass traits in broiler chickens. Journal of Animal Husbandry and Dairy Science. 2018, 2018;**2**(2):1-9

[34] Okechuku SN. Studies on the nutritive value of composite cassava pellets for poultry: Chemical composition and metabolizable energy. Livestock Research for Rural Development. 2005;**17**:125. Available from: http://www. lrrd.org/lrrd17/11/ukac17125.htm

[35] Food and Agricultural Organisation (FAO). Better Farming Series 46: Use of Cassava and Sweet Potatoes in Animal Feeding. 1995. p. 47

[36] Kemdirim OC, Chukwu OA, Achinewhu SC. Effect of traditional processing of cassava on the cyanide content of gari and cassava flour. Plant Foods and Human Nutrition. 1995;**48**(4):335-339

[37] Padmaja G. Cyanide detoxification in cassava for food and feed uses. Critical Reviews in Food Science and Nutrition. 1995;**35**(4):299-339

[38] Siritunga D, Sayre R. Transgenic approaches for cyanogen reduction in cassava. Journal of Association of Official Analytical Chemists International. 2007;**90**(5):1450-1455

[39] Zvauya R, Muzondo MI. Reduction of cyanide levels in cassava during sequential sun drying and solid state fermentation. International Journal of Food Science and Nutrition. 1995;**46**(1):13-16

[40] Liu J, Zheng Q, Ma Q, Gadidasu KK, Zhang PJ. Cassava genetic transformation and its application in breeding. Integrated Plant Biology. 2011;**53**(7):552-569

#### **Chapter 10**

## Advances in Cassava Trait Improvement and Processing Technologies for Food and Feed

*Kariuki Samwel Muiruri and Anwar Aliya Fathima*

#### **Abstract**

Cassava is an important staple crop globally; its roots and leaves are directly consumed as food or undergo secondary processing in food industries or as animal feed. Inherent biological challenges in cassava affect the quality and quantity of food and feed. Although trait consolidation has been explored, the diversity in cassava food products has led to stratification of target crop characteristics. Among the traits targeted, crop improvement for food includes: yield and starch quality for different applications such as pounding, resistant starch, waxy starch, and even post-harvest deterioration. The presence of the antinutritional compound cyanide reduces the quality of food and feed, and efforts to reduce cyanide levels are continuously explored. In this Chapter, we review biological and technological research efforts in cassava geared toward improving the quality/quantity of cassava for food and feed. These efforts cut across target trait improvement efforts to new bioprocessing technologies.

**Keywords:** food, feed, traits, cassava, agro-processing, improvement, starch, quality, quantity

#### **1. Introduction**

Cassava is a major staple food crop cultivated for its starchy roots and sometimes its leaves. It ranks among the top five crops as a food source and is consumed by over 700 million people globally [1]. Cassava not only plays a critical role in food security but also serves as a trading commodity in most rural areas where it is grown [2]. In most cassava growing regions, for example, cassava trade entails the sale of fresh or recently harvested roots. In the recent past, cassava has gained additional importance owing to its increased use in animal feeds, bio-energy, and processed food industry [3–5]. Cassava is increasingly being used to partially or fully replace grains in livestock [5] and chicken [6] feed without negative effects [7]. Cassava is better adapted to drought and reduced soil fertility compared to cereal crops (mostly maize) used in animal feeds [8]. Cassava, therefore, serves to a greater extent as an appropriate animal feed alternative during the unpredictable conditions being experienced with changes in climate. Cassava biomass is already being used for nonfood and nonfeed applications [9, 10] and the uses are still rising. The utility of cassava as food, feed, and agro-processing is challenged by intrinsic and extrinsic threats. Among many challenges, low productivity impacts cassava use, resulting from a wide range of factors including cultivar type [11], agricultural management practices [12], pests and diseases [13], and environmental conditions [14]. Postharvest physiological deterioration (PPD), a loss in quality of harvested cassava roots due to physiological and biochemical processes, is another major challenge in cassava use as food and feed [15]. The PPD results in the darkening of harvested roots rendering them unusable as food and feed. Another major drawback in cassava utility is the presence of cyanide in the roots, which have antinutritional properties. Consumption of cyanide-laden cassava or constant exposure in a cassava processing industry can cause neurological disorders and even immediate death [16, 17]. Poor nutritive value of cassava roots is yet another challenge, particularly in areas where cassava is consumed regularly as a staple. Cassava roots are generally low in proteins [18] and minerals like iron and zinc [19]. These among other challenges compromise the quantity and quality of cassava produce and approach to overcome them have been extensively explored.

Cassava roots contain up to 80% starch on a dry-weight basis [20]. Starch polymers contain amylose and amylopectin, which are interconnected α-1,4 linear chains and β-1,6 branched chains of glucose monomers. Amylose is insoluble in water at low temperatures whereas amylopectin dissolves easily in water. The heating and cooling of native starch cause retrogradation, a condition in which the amylose and amylopectin chains realign to form a more crystalline structure. High amylose content in native starch can promote retrogradation [21] and subsequently, the starch polymer expels water, a process called syneresis, and becomes unfavorable for food applications [22]. Other constraints include water absorption and swelling behavior that influences the consistency of the product in certain baking applications and this is dependent on the amylose content, size, and structural integrity of starch granules [23].

Approaches aimed at overcoming challenges affecting cassava use as food and feed can be broadly grouped into two: 1) those that modify the biology of the plant with the ultimate goal of improving its performance in quality and quantity [24, 25]. These methods include conventional breeding and biotechnologies such as genetic engineering and genome editing. 2) Processing and bioprocessing methods that modify cassava product profiles [26, 27]. These include addition of missing but critical compounds that enhance cassava product quality or removal of unwanted and harmful metabolites. In addition, methods that change cassava products' profiles to fit intended use are grouped into this second category. This chapter reviews these different approaches used in addressing challenges affecting use of cassava and its products in food and feed industries.

#### **2. Improvement of cassava crop for food and feed**

#### **2.1 Targeting cassava for yield improvement**

The quantity of cassava harvested is important in both food and feed industries. Yield in cassava is influenced by, among other factors, genetics, environment, and the corresponding interactions [28]. The selection of cassava cultivars for increased yield breeding using crop physiology as the basis entails simple yield parameters that include harvest index (HI), biomass, and root dry matter content (DMC) [29]. In cassava, HI is the ratio of root wet weight to the total plant biomass whereas dry matter content is the percentage of fresh root weight that is dry matter. The higher variability in the fresh weight of the harvested cassava necessitated the use of HI as a cassava yield indicator. High levels of HI heritability have been observed even early on in cassava growth

*Advances in Cassava Trait Improvement and Processing Technologies for Food and Feed DOI: http://dx.doi.org/10.5772/intechopen.110104*

making it a crucial yield prediction trait in cassava [30]. A positive correlation between fresh root eating qualities and DMC exists [31]. Majority of processing in the cassava food industry involves drying of the roots. The DMC and HI equally determine a key target trait in improving cassava yield and have consistently been used in breeding programs in Brazil [11, 32], Uganda [33], Nigeria [34], and Thailand [35] among others.

#### **2.2 Early bulking for faster harvest**

The increase in cases of drought occasioned by climate change makes predictability of harvest time a herculean task. This in turn makes predictable food and feed production from cassava difficult, especially for varieties that take long time to mature [36]. Planting of early maturing cassava varieties is a clear strategy for adapting to climate change and ensuring a quick return on investment in both cassava food and feed industries. Early bulking (thickening of storage roots due to starch accumulation) is a genotype-dependent trait that can be used in breeding for quicker harvesting and, consequently, faster food provision [37]. Bulking in cassava is thought to occur when vegetative requirements of photoassimilates are less than the ones being generated [38]. Early bulking varieties are thought to be ready for harvest 6—8 months postplanting [39]. Early bulking varieties among pro-vitamin A cassava genotypes have been selected with the goal of ensuring early harvesting [40]. Early cassava bulking has also been achieved in efforts to breed drought-tolerant varieties [37, 41].

#### **2.3 Crop improvement for increased levels of pro-vitamin A carotenoids**

Vitamin A deficiency is common, particularly in areas where one type of food naturally low in pro-vitamin A is consumed as a staple. Most of the cassava varieties cultivated in regions where it is a staple food tend to be low in vitamin A [42]. Fortification of cassava is used as a strategy for enriching cassava produce, particularly flour with β-carotene [43, 44]. Fortification can be a costly option compared to biofortification, where cassava varieties naturally produce pro-vitamin A [45]. Cassava varieties able to accumulate pro-vitamin A carotenoids in the roots have been developed using biotechnology [45] and conventional approaches [46]. Overexpression of the deoxy-d-xylulose-5-phosphate synthase (DXS) and bacterial phytoene synthase (crtB) genes resulted in enhanced levels of β-carotene in the roots through biotechnology approaches. Breeding for improved β-carotene requires first screening for varieties with this trait and working upwards to enhance it [47]. Varieties with higher levels of β-carotene have been identified and bred into the major cassava lines [48–50]. In addition to β-carotene, varieties with increased pro-vitamin A have longer shelf life, albeit at the expense of low dry matter content [45].

#### **2.4 Improvement of cassava against post-harvest physiological deterioration (PPD)**

Post-harvest physiological deterioration results in cassava roots turning blue, black, or brown in color one to five days post-harvest. The discoloration is accompanied by a bitter taste rendering the roots unusable [51]. The PPD has been associated with both plant genetics as well as environment, particularly storage conditions. In Indonesia, different cassava genotypes were observed to have a range of 10 to more than 20% deterioration and were classified as having low, medium, and high susceptibility to PPD [51]. Similar variations have also been observed in cassava from Africa and South America [52–54]. The genes responsible for PPD and the associated quantitative trait loci (QTLs) have

already been mapped in the cassava genome [55, 56]. In Nigeria, where extensive breeding for tolerance to PPD has been done, four major tolerance sources have been identified and include interspecific hybrids, gamma irradiated mutants where a gene involved in PPD is silenced, clones with high β-carotene, and an amylose-free waxy starch mutant [29, 57]. In addition to conventional breeding, genetic engineering strategies have also been applied in addressing the PPD challenge. Overexpression of reactive oxygen species (ROS) scavenging genes has shown promising results in reducing PPD [58]. One major challenge observed in silencing some of the genes associated with reduced PPD is loss in dry matter content and reduced starch storage [59]. Therefore, appropriate genes that minimize PPD while still retaining desirable traits like starch deposition and dry matter accumulation should be explored.

#### **2.5 Improvement of cassava for specific starch profile**

Cassava is prepared for food in different ways including boiling and pounding to make foods like "fufu" common in west Africa, and even in drinks, the most famous being bubble tea. The physicochemical qualities of cassava starch determine the culinary uses of the roots and associated products [60]. Cassava starch contains amylopectin and amylose, the former being longer and more branched and the latter linear. The levels of complexity in branching differentiate amylopectin's physical and chemical characteristics [61].

The variations in physical and chemical properties of starch in cassava are dependent on the genotype. There are four cassava genotype classes categorized on the basis of amylose levels: The waxy type contains a maximum of 2% amylose, semi-waxy with a maximum of 15%, normal-regular with a maximum of 35%, and high category with more than 35% amylose cumulative root starch yield [61]. Most varieties are grown for food fall within the normal-regular category. However, waxy varieties that completely lack amylose have been observed to exist as natural variants [62–64]. Naturally, waxy scratch variants have been observed to carry a mutation in the *granule-bound starch synthase (GBSS)* gene that renders it non-functionally [65]. Silencing of the GBSS gene through transgenic approaches has also resulted in waxy starch genotypes [66]. Cassava waxy starch is extensively used as a stabilizer in food storage because it does not have syneresis making it first among other starches in food stabilization.

Other than waxy starch, resistant starch, which is starch less amenable to enzymatic breakdown in the human stomach and reduced absorption in the small intestine, has been considered for a product profile [67]. The difficulty in breakdown of the RS bears resemblance to dietary fiber in being indigestible. The indigestibility of RS in the small intestine lowers the pH in the large intestine consequently increasing the fecal bulk, and consequently reducing the risks associated with cancer of the colon [68].

#### **2.6 Developing cassava with reduced cyanide levels**

The presence of cyanogenic glycosides in cassava roots risks its use for food and feed in both humans and animals. Development of cassava varieties with reduced cyanide levels is considered a viable approach to safe use of cassava root [69, 70]. To reduce the levels of cyanide in cassava a combination of both biotechnological and conventional approaches is being implemented. Through biotechnology, targeting cassava *CYP79D1* and *CYP79D2* genes resulted in a cyanogenic cassava, especially in the leaves [69, 70]. Low cyanogenic glucoside cassava varieties have been identified and selected for use in food production [71]. Combined, biotechnological, and

#### *Advances in Cassava Trait Improvement and Processing Technologies for Food and Feed DOI: http://dx.doi.org/10.5772/intechopen.110104*

conventional approaches to cyanide reduction can be used to enhance usability of both the raw and processed products from cassava roots for both food and feed (**Table 1**).


#### **Table 1.**

*Summary of research on trait and bioprocessing approaches aimed at enhancing cassava quality and quantity for food and feed.*

#### **3. Cassava bioprocessing for improved food and feed quality**

Cassava is a source of commonly used ingredients in the food industry, which, when processed, result in functionally unique value-added products [87]. Owing to the high carbohydrate content and gluten-free status of cassava products, their demand has increased. The increase in demand has necessitated the development of economically viable processing methods [19, 88]. The quality of processed cassava products is largely determined by the quality of starch. The starch quality is dependent on factors such as (i) method of extraction (ii) physicochemical characteristics and (iii) nutritive quality. Bioprocessing methods have been widely used to alter the properties of native cassava starch to be made suitable for the food and feed industry.

#### **3.1 Improving cassava starch content**

Conventionally, cassava starch is extracted from root tubers using maceration at optimum temperatures to produce pulp. To recover starch, the pulp containing 50–60% w/w of starch [89] is resuspended in 10 fold w/v of water followed by filtration, settling, decanting, and drying [90]. This method results in starch recovery t ranging from 18–25% per fresh cassava tuber weight. This makes the method laborious and time-consuming with minimal returns. Several modifications in the extraction methods have shown enhanced starch yield. The maceration of cassava tissues to produce pulp, for example, was improved by addition of microbial enzymes such as pectinases and polygalacturonase [91]. Recently, ultrasound-assisted extraction (UAE) was used to extract starch trapped inside cellulose fibers in cassava. The method produced the highest yield of 56.57% with a starch purity of 88.36% [92]. The limitations with starch losses in commercial-scale production units have been notably challenging and can be minimized by optimizing operation, design, and feed variables [93]. These processes have been further improved by addition of sulfur for improved starch granular stability and separation of the native starch from bound proteins and other impurities during the extraction process [94, 95].

#### **3.2 Improving functional properties of cassava starch**

The native starch can be processed to improve the physicochemical properties that maximize the use of cassava in the food and feed industry. The cassava processing methods involve either physical, chemical, enzymatic, or biological pre-treatments that modify starch content, nutrient content, texture, swelling power, solubility, pasting property, viscosity, gelatinization, crystallinity, and anti-nutrient content of the modified starch [96].

Physical modification of starch includes thermal or nonthermal methods. Thermal modifications such as pre-gelatinization, heat and moist treatment, dry heating, annealing, and microwaving involve the treatment of starch at various temperatures and pressures [97]. These methods have been very effective in deformation of granular structure of starch and in reducing crystallinity. Nonthermal modifications such as ball milling, cold plasma technology, hydrostatic pressure, microfluidization, pulse electric field, and ultrasound require no heat treatment, and, therefore, reduce energy consumption [98]. These modifications have shown the ability to maintain the granular integrity and increase surface activity of starch consequently improving pasting and swelling properties of cassava starch [98]. Recently, a combination of methods utilizing dry heat and ozone treatment has been shown to affect starch molecule size, structural properties, and gelatinization [99].

#### *Advances in Cassava Trait Improvement and Processing Technologies for Food and Feed DOI: http://dx.doi.org/10.5772/intechopen.110104*

The commonly used chemical treatments include acid hydrolysis, cross-linking, and oxidation [100]. The functional groups in chemicals react with hydroxyl groups in native starch to produce modified starch. The modification of cassava starch at various concentrations of hydrochloric acid and temperatures has been shown to alter the fraction of amylose and amylopectin and crystallinity of native starch [101]. Acid hydrolysis improves water holding capacity and water absorption, which can alter pasting properties of starch [102]. The treatment of native starch with weak organic acids such as citric acid is advantageous in culinary applications because it reportedly improves granular starch yield and avoids depolymerization. Citric acid has also been used for cross-linking of native starch [103]. Cross-linking introduces covalent interactions and reinforces the hydrogen bonds between starch molecules and prevents movement of polymer chains thereby reducing retrogradation and providing resistance to shearing and thermal decomposition during storage [104]. Moreover, natural organic acids such as lactic acid, malic acid, and citric acid are safe for consumption and generally have applications in the food industry as acidity regulators, flavoring agents, etc. Some of the studies highlighted here have highlighted a combination of modifications that improve properties of native starch [105]. Post-acid treatment of lactic acid hydrolyzed native starch by drying under UV irradiation resulted in the depolymerization of native starch and improved its baking expansion [96]. Lactic acid hydrolysis combined with microwave heating or fermentation and esterification in the presence of ethanol have shown better properties of modified starch for use in food coatings [106]. Other cross-linking agents that are commonly used are adipic and acetic acid mixed anhydrides, phosphorus oxychloride, sodium trimetaphosphate, sodium hydroxide, and ethylene glycol diacrylate epichlorohydrin (EPI) [107–109]. Acetylation and esterification improved water retention and reduced retrogradation tendency in cassava starch compared to sorghum and potato starch [110, 111].

The starch processing approaches discussed have their pros and cons. Chemical processes, for example, can be high starch-yielding but are prone to residual by-products of the chemical reactions. Physical processes are considered clean and sustainable in comparison with chemical starch processing/modifying approaches. However, physical modification techniques involving prolonged heating may reduce starch viscosity and stability and are moderately effective in reducing the amylose content making the starch less suitable for baking [112]. Alternative enzymatic treatments and fermentation methods of starch modification alter amylose content by addition of hydrolyzing enzymes or treatment with microorganisms that can break down amylose [113]. Retting is a traditional process that allows microbial activity on plant materials to dissolve cell wall polysaccharides such as cellulose and pectin by immersion in water [114]. The pasting properties can be influenced by the combination of microbes used for retting [115]. Starch modifying and starch converting enzymes mainly perform hydrolysis, transglycosylation, or cleavage of α-1, 4 linked glucan and α-1, 6 linked branches, extensively reviewed for their use in baking applications by Mikolo et al. [116].

#### **3.3 Bioprocessing to improve nutritive quality of cassava starch**

The consumption of starch containing high amounts of amylose (resistant starch) has several health benefits [117]. Like previously noted, resistant starch (RS) escapes digestion in the small intestine and is fermented by the gut microbiota in the large intestine [118]. The fermentation end-products such as short-chain fatty acids, acetic acid, and butyric acid have been found to reduce the effects of chronic inflammatory health

conditions and also improve growth of beneficiary gut microbes [119]. Chemical modification of cassava starch using octenyl succinic anhydride has been shown to improve resistant starch content in cassava [120]. The most common and highly resistant starch-yielding methods use enzymatic debranching of native starch using isoamylase or pullulanase followed by autoclaving and/or high-pressure annealing [121, 122].

Cassava has a high energy content and is widely regarded as a good source of dietary fiber, minerals, and vitamins. However, the protein content of cassava roots is significantly low compared to cassava leaves [123]. Pre-processing of cassava roots through drying and fermentation improved protein, fiber, and shelf-life of cassava products [124]. Co-fermentation with legumes has been shown to enrich protein content in cassava [125]. Alternatively, cassava-based industries have developed high-quality cassava flour (HQCF) from processed cassava roots without fermentation, no-off odor, and appealing taste [126]. HCQF can replace wheat flour by addition of protein-rich mushroom flour to HQCF, which makes it a suitable food commodity [127, 128].

Research has been focused on developing different processing methods to reduce cyanide content [129]. The use of cassava as food and feed is primarily limited by high cyanide content and antinutrients that reduce nutrient availability as discussed in the previous sections [130, 131]. The edible parts of cassava including root tubers and leaves have been found to contain toxic cyanogenic glycosides (CNglcs) namely linamarin and lotaustralin [132]. Prolonged consumption of cassava can increase risk of cyanide poisoning in humans and animals [133]. During tissue damage, the released glycosides come in contact with enzymes (linamarase) and form acetone cyanohydrin, a less stable intermediate that is either spontaneously or enzymatically (hydroxynitrile lyase) converted to volatile and toxic hydrogen cyanides (HCN) [134]. Previously, processing techniques such as pounding cassava tubers and soaking the paste in cold water, wilting, drying, boiling, ensiling, and fermentation removed most of the cyanides [135, 136]. During cassava root retting, microbial strains have been found to naturally evolve with ability to produce enzymes that degrade CNglcs and have been proven to reduce cyanides efficiently during the process of fermentation [137–139]. Alternatively, the application of enzymes that degrade plant cell wall polysaccharides such as cellulases and hemicellulases may indirectly trigger release of linamarin due to tissue damage caused by these enzymes [140]. In another study, cassava leaves were washed, dried, and treated with bicarbonate to efficiently reduce the cyanide contents [141]. Bicarbonate treatment was most efficient in reducing cyanide levels in cassava leaves in comparison to thermal, enzymatic, and ultrasonic methods but significantly reduced nutritive components such as ascorbic acid [142]. The other antinutrients present in cassava leaves including polyphenols, nitrates, and phytates significantly reduce absorption of proteins and essential minerals [143, 144]. Fermentation of cassava leaves has been the most promising method to reduce antinutrients and concomitantly retain the nutritive value of cassava and flavors [145, 146]. Other potential methods include boiling, steaming, dry-roasting, and microwaving [147].

#### **4. Conclusion**

Cassava has been identified as an exemplary crop for developing a sustainable food system due to its hardiness, relatively better adaptation to abiotic stress, particularly drought and higher productivity. Challenges inherent in the crop have necessitated crop improvement and bioprocessing efforts to improve its use for food, feed, and bioenergy sectors. Some of these methods as highlighted in this

#### *Advances in Cassava Trait Improvement and Processing Technologies for Food and Feed DOI: http://dx.doi.org/10.5772/intechopen.110104*

chapter have progressively been implemented to enhance the quality of cassava food products in terms of palatability and dietary benefits and ensure transformation of cassava as a potential raw material to produce economic and high-value livestock and poultry feed. Crop improvement approaches as summarized in this chapter have been employed to produce varieties with increased essential micro-nutrients and pro-vitamin A to address malnutrition and adopt cassava as a biofortified crop. Protein supplementation of cassava flour has promoted cassava as an ideal choice for high-quality diet that can replace conventional food crops. The utility of cassava has been undoubtedly increased through modern technologies making cassava versatile to serve nontraditional subsistence roles with enhanced market value.

#### **Author details**

Kariuki Samwel Muiruri1 \* and Anwar Aliya Fathima2

1 Kenyatta University, School of Plant Sciences, Nairobi, Kenya

2 Department of Bioinformatics, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Chennai, India

\*Address all correspondence to: muiruri.samwel@ku.ac.ke

© 2023 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

### **References**

[1] FAOSTAT [Internet]. [cited 2022 Nov 10]. Available from: https://www.fao.org/ faostat/en/

[2] Rozi F, Krisdiana R, Sutrisno I. Pattern of cassava demand as the promising commodity in the future. In: 1st International Conference on Sustainable Agricultural Socio-economics, Agribusiness, and Rural Development (ICSASARD 2021). France: Atlantis Press; 2021. pp. 31-36

[3] Li S, Cui Y, Zhou Y, Luo Z, Liu J, Zhao M. The industrial applications of cassava: Current status, opportunities and prospects. Journal of the Science of Food and Agriculture. 2017 Jun;**97**(8):2282-2290

[4] Yulianto A, National Laboratory for Starch Technology, Agency for the Assesment and Application of Technology, Lampung, Indonesia, Kayati FN, et al. The effect of extrusion temperature on changes of characteristics of partially pregelatinized Cassava starch. International Journal of Chemical Engineering and Applications. 2020;**11**:67-70. DOI: 10.18178/ ijcea.2020.11.2.782

[5] Aso SN, Teixeira AA, Achinewhu SC. Cassava residues could provide sustainable bioenergy for cassava producing nations. In: Cassava. London: IntechOpen. 2018;**2018**:219. DOI: 10.5772/intechopen.72166

[6] Zheng Y, Zhao Y, Xue S, Wang W, Wang Y, Cao Z, et al. Feeding value assessment of substituting Cassava (*Manihot esculenta*) residue for concentrate of dairy cows using an in vitro gas test. Animals. 2021;**11**:307. DOI: 10.3390/ani11020307

[7] Chang EP, Abdallh ME, Ahiwe EU, Mbaga S, Zhu ZY, Fru-Nji F, et al. Replacement value of cassava for maize in broiler chicken diets supplemented with enzymes. Journal of Animal Science. 2020;**33**(7):1126-1137

[8] Muiruri SK, Ntui VO, Tripathi L, Tripathi JN. Mechanisms and approaches towards enhanced drought tolerance in cassava (*Manihot esculenta*). Current Plant Biology. 2021;**28**:100227. DOI: 10.1016/j.cpb.2021.100227

[9] Okudoh V, Schmidt S, Trois C. Biogas Production in Africa: Benefit Potentials of Cassava Biomass. London: LAP Lambert Academic Publishing; 2015. p. 84

[10] Nuwamanya E, Chiwona-Karltun L, Kawuki RS, Baguma Y. Bio-ethanol production from non-food parts of cassava (Manihot esculenta Crantz). Ambio. 2012;**41**(3):262-270

[11] de Andrade LR, Sousa MBE, Oliveira EJ, de Resende MD, Azevedo CF. Cassava yield traits predicted by genomic selection methods. PLoS One 2019;**14**(11):e0224920

[12] Kintché K, Hauser S, Mahungu NM, Ndonda A, Lukombo S, Nhamo N, et al. Cassava yield loss in farmer fields was mainly caused by low soil fertility and suboptimal management practices in two provinces of the Democratic Republic of Congo. European Journal of Agronomy. 2017;**89**:107-123. DOI: 10.1016/j. eja.2017.06.011

[13] Uke A, Tokunaga H, Utsumi Y, Vu NA, Nhan PT, Srean P, et al. Cassava mosaic disease and its management in Southeast Asia. Plant Molecular Biology. 2022;**109**(3):301-311

[14] Yabuta S, Fukuta T, Tamaru S, Goto K, Nakao Y, Khanthavong P, et al. The Productivity of Cassava (*Manihot esculenta* Crantz) in Kagoshima, Japan, *Advances in Cassava Trait Improvement and Processing Technologies for Food and Feed DOI: http://dx.doi.org/10.5772/intechopen.110104*

Which Belongs to the Temperate Zone. Agronomy. 2021;**11**:2021. DOI: 10.3390/ agronomy11102021

[15] Djabou ASM, Carvalho LJCB, Li QX, Niemenak N, Chen S. Cassava postharvest physiological deterioration: A complex phenomenon involving calcium signaling, reactive oxygen species and programmed cell death. Acta Physiologiae Plantarum. 2017;**39**(4):91

[16] Dhas PK, Chitra P, Jayakumar S, Mary AR. Study of the effects of hydrogen cyanide exposure in cassava workers. Indian Journal of Occupational Environmental Medicine. 2011;**15**(3):133-136

[17] Akintonwa A, Tunwashe OL. Fatal cyanide poisoning from cassavabased meal. Human & Experimental Toxicology. 1992;**11**(1):47-49

[18] Stephenson K, Amthor R, Mallowa S, Nungo R, Maziya-Dixon B, Gichuki S, et al. Consuming cassava as a staple food places children 2-5 years old at risk for inadequate protein intake, an observational study in Kenya and Nigeria. Nutrition Journal. 2010;**9**:9

[19] Morgan NK, Choct M. Cassava: Nutrient composition and nutritive value in poultry diets. Animal Nutrition. 2016;**2**(4):253-261

[20] Olomo V, Ajibola O. Processing factors affecting the yield and physicochemical properties of starch from cassava chips and flour. Starch/Stärke. 2003;**55**(10):476- 481. DOI: 10.1002/star.200300201

[21] Biduski, Bárbara, Wyller Max Ferreria da Silva, Rosana de Colussi, Shanise Lisie, Loong-Tak Lim, Álvaro Renato Guerra Dias, and Elessandra Rosa Zavareze. "Starch hydrogels: The influence of the amylose content and gelatinization method." International

Journal of Biological Macromolecules. 2018;**113**:443-449

[22] Mizrahi S. Syneresis in food gels and its implications for food quality. In: Chemical Deterioration and Physical Instability of Food and Beverages. Sawston, CA: Woodhead Publishing; 2010. pp. 324-348

[23] Arya S, Sadawarte P, Ashish W. Importance of damaged starch in bakery products-a review. 2019. Retrieved April 1 2015

[24] Mbanjo EGN, Rabbi IY, Ferguson ME, Kayondo SI, Eng NH, Tripathi L, et al. Technological innovations for improving cassava production in sub-Saharan Africa. Frontiers in Genetics. 2020;**11**:623736

[25] Fathima AA, Sanitha M, Tripathi L, Muiruri S. Cassava (*Manihot esculenta*) dual use for food and bioenergy: A review. Food and Energy Security. 2022;**12**(1):e380. DOI: 10.1002/fes3.380

[26] Omede AA, Ahiwe EU, Zhu ZY, Fru-Nji F, Iji PA. Improving cassava quality for poultry feeding through application of biotechnology. Cassava. 2018:214-264. DOI: 10.5772/ intechopen.72236

[27] Padmaja G. Cyanide detoxification in cassava for food and feed uses. Critical Reviews in Food Science and Nutrition. 1995;**35**(4):299-339

[28] Phoncharoen P, Banterng P, Vorasoot N, Jogloy S, Theerakulpisut P, Hoogenboom G. Growth rates and yields of cassava at different planting dates in a tropical Savanna climate. Scientia Agricola. 2019;**76**:376-388. DOI: 10.1590/1678-992x-2017-0413

[29] Ceballos H, Hershey C, Iglesias C, Zhang X. Fifty years of a public cassava breeding program: Evolution of breeding objectives, methods, and decisionmaking processes. Theoretical and Applied Genetics. 2021;**134**(8):2335-2353

[30] Kawano K, Narintaraporn K, Narintaraporn P, Sarakarn S, Limsila A, Limsila J, et al. Yield improvement in a multistage breeding program for Cassava. Crop Science. 1998;**38**:325-332. DOI: 10.2135/cropsci1998.0011183x0038 00020007x

[31] Kawano K, Fukuda WMG, Cenpukdee U. Genetic and environmental effects on dry matter content of cassava root. Crop Science. 1987;**27**:69-74. DOI: 10.2135/cropsci1987. 0011183x002700010018x

[32] Sagrilo E, Filho PSV, Pequeno MG, Gonçalves-Vidigal MC, Kvitschal MV. Dry matter production and distribution in three cassava (Manihot esculenta Crantz) cultivars during the second vegetative plant cycle. Brazilian Archives of Biology and Technology. 2008;**51**:1079-1087. DOI: 10.1590/ s1516-89132008000600001

[33] Manze F, Rubaihayo P, Ozimati A, Gibson P, Esuma W, Bua A, et al. Genetic gains for yield and virus disease resistance of cassava varieties developed over the last eight decades in Uganda. Frontiers in Plant Science. 2021;**21**(12):651992

[34] Jiwuba L, Danquah A, Asante I, Blay E, Onyeka J, Danquah E, et al. Genotype by environment interaction on resistance to cassava green mite associated traits and effects on yield performance of cassava genotypes in Nigeria. Frontiers in Plant Science. 2020;**11**:572200

[35] Maraphum K, Saengprachatanarug K, Wongpichet S, Phuphuphud A, Sirisomboon P, Posom J. Modified specific gravity method for estimation of

starch content and dry matter in cassava. Heliyon. 2021;**7**(7):e07450

[36] Okogbenin E, Fregene M. Genetic analysis and QTL mapping of early root bulking in an F1 population of noninbred parents in cassava ( Manihot esculenta Crantz). Theoretical and Applied Genetics. 2002;**106**(1):58-66

[37] Chipeta MM, Shanahan P, Melis R, Sibiya J, Benesi IRM. Early storage root bulking index and agronomic traits associated with early bulking in cassava. Field Crops Research. 2016;**198**:171-178. DOI: 10.1016/j.fcr.2016.09.004

[38] el Sharkawy MA. Cassava biology and physiology. Plant Molecular Biology. 2003;**53**:621-641. DOI: 10.1023/b:plan.0000019109.01740.c6

[39] Amelework AB, Bairu MW. Advances in genetic analysis and breeding of cassava ( Crantz): A review. Plants. 2022;**20**:12. DOI: 10.3390/ plants11121617

[40] David Badewa O, Gana Saba A, Kolo Tsado E, Dele TK. Selection of early bulking performance among pro vitamin A cassava genotypes based on selective indices of fresh storage root yield and harvest index. International Journal of Genetic Genome. 2020;**8**(1):11

[41] Campos H, Caligari PDS. Genetic Improvement of Tropical Crops. Newyork: Springer; 2017. p. 320

[42] Belalcazar J, Dufour D, Andersson MS, Pizarro M, Luna J, Londoño L, et al. High-throughput phenotyping and improvements in breeding cassava for increased carotenoids in the roots. Crop Science. 2016;**56**:2916-2925. DOI: 10.2135/ cropsci2015.11.0701

[43] Mosha TC, Laswai HS, Mtebe K, Paulo AB. Control of vitamin A

*Advances in Cassava Trait Improvement and Processing Technologies for Food and Feed DOI: http://dx.doi.org/10.5772/intechopen.110104*

deficiency disorders through fortification of cassava flour with red palm oil: A case study of Kigoma district, Tanzania. Ecology of Food and Nutrition. 1998;**37**:569-593. DOI: 10.1080/03670244.1998.9991566

[44] Wang S. The alleviation of vitamin a deficiency through staple food fortification in ghana. Review of Agricultural and Applied. 2018;**21**:94-102. DOI: 10.15414/ raae.2018.21.02.94-102

[45] Beyene G, Solomon FR, Chauhan RD, Gaitán-Solis E, Narayanan N, Gehan J, et al. Provitamin A biofortification of cassava enhances shelf life but reduces dry matter content of storage roots due to altered carbon partitioning into starch. Plant Biotechnology Journal. 2018;**16**(6):1186-1200

[46] Oluba OM, Oredokun-Lache AB, Odutuga AA. Effect of vitamin A biofortification on the nutritional composition of cassava flour (gari) and evaluation of its glycemic index in healthy adults. Journal of Food Biochemistry. 2018;**42**:e12450. DOI: 10.1111/jfbc.12450

[47] Njoku DN, Vernon G, Egesi CN, Asante I, Offei SK, Okogbenin E, et al. Breeding for enhanced β-carotene content in cassava: Constraints and accomplishments. Journal of Crop Improvement. 2011;**25**:560-571. DOI: 10.1080/15427528.2011.594978

[48] Nduwumuremyi A, Melis R, Shanahan P, Theodore A. Genetic inheritance of pulp colour and selected traits of cassava (Manihot esculenta Crantz) at early generation selection. Journal of the Science of Food and Agriculture. 2018;**98**(8):3190-3197. DOI: 10.1002/jsfa.8825

[49] Moorthy SN, Jos JS, Nair RB, Sreekumari MT. Variability of β-carotene content in cassava germplasm.

Food Chemistry. 1990;**36**:233-236. DOI: 10.1016/0308-8146(90)90058-c

[50] Athanase N, Rob M. Gene action and heterosis in F1 clonal progenies of cassava for β-Carotene and farmers' preferred traits. Heliyon. 2019;**5**:e01807. DOI: 10.1016/j.heliyon.2019.e01807

[51] Rachmawati RS, Khumaida N, Ardie SW, Sukma D, Sudarsono S. Effects of harvest period, storage, and genotype on postharvest physiological deterioration responses in cassava. Biodiversitas Journal of Biological Diversity. 2021;**23**(1):100-109. DOI: 10.13057/biodiv/d230113

[52] Venturini MT, Santos LR, Vildoso CIA, Santos VS, Oliveira EJ. Variation in cassava germplasm for tolerance to post-harvest physiological deterioration. Genetics and Molecular Research. 2016;**15**(2). DOI: 10.4238/ gmr.15027818

[53] Tumuhimbise R, Melis R, Shanahan P. Genetic variation in cassava for postharvest physiological deterioration. Archives of Agronomy and Soil Science. 2015;**61**:1333-1342. DOI: 10.1080/03650340.2014.995641

[54] Moyib KO, Mkumbira J, Odunola OA, Dixon AG, Akoroda MO, Kulakow P. Genetic variation of postharvest physiological deterioration susceptibility in a cassava germplasm. Crop Science. 2015;**55**:2701-2711. DOI: 10.2135/ cropsci2014.11.0749

[55] Reilly K, Bernal D, Cortés DF, Gómez-Vásquez R, Tohme J, Beeching JR. Towards identifying the full set of genes expressed during cassava post-harvest physiological deterioration. Plant Molecular Biology. 2007;**64**:187-203. DOI: 10.1007/s11103-007-9144-0

[56] Beeching JR, Han Y, Gómez-Vásquez R, Day RC, Cooper RM. Wound and Defense responses in cassava as related to post-harvest physiological deterioration. Phytochemical Signals and Plant—Microbe Interactions. 1998;**1998**:231-248. DOI: 10.1007/978-1-4615-5329-8\_12

[57] Chávez AL, Sánchez T, Ceballos H, Rodriguez-Amaya DB, Nestel P, Tohme J, et al. Retention of carotenoids in cassava roots submitted to different processing methods. Journal of the Science of Food and Agriculture. 2007;**87**:388-393. DOI: 10.1002/jsfa.2704

[58] Xu J, Duan X, Yang J, Beeching JR, Zhang P. Enhanced reactive oxygen species scavenging by overproduction of superoxide dismutase and catalase delays postharvest physiological deterioration of cassava storage roots. Plant Physiology. 2013;**161**(3):1517-1528

[59] Beyene G, Chauhan RD, Gehan J, Siritunga D, Taylor N. Cassava shrunken-2 homolog MeAPL3 determines storage root starch and dry matter content and modulates storage root postharvest physiological deterioration. Plant Molecular Biology. 2022;**109**(3):283-299

[60] Nuwamanya E, Baguma Y, Kawuki RS, Rubaihayo PR. Quantification of starch physicochemical characteristics in a cassava segregating population. African Crop Science Journal. 2010;**16**(3):191-202. DOI: 10.4314/acsj.v16i3.54380

[61] Chisenga SM. Primary quality control parameters for cassava raw materials. Cassava. 2021:151-167. DOI: 10.5772/intechopen.97879

[62] do Carmo CD, MBE S, Dos Santos Silva PP, Oliveira GAF, Ceballos H, de Oliveira EJ. Identification and validation of mutation points associated with waxy phenotype in cassava. BMC Plant Biology. 2020;**20**(1):164

[63] do Carmo CD, Sousa MB, Brito AC, de Oliveira EJ. Genome-wide association studies for waxy starch in cassava. Euphytica. 2020;**216**(5). DOI: 10.1007/ s10681-020-02615-9

[64] Toae R, Sriroth K, Rojanaridpiched C, Vichukit V, Chotineeranat S, Wansuksri R, et al. Outstanding characteristics of Thai Non-GM bred waxy cassava starches compared with normal cassava starch, waxy cereal starches and stabilized cassava starches. Plants. 2019;**24**(8):11. DOI: 10.3390/ plants8110447

[65] Ceballos H, Sánchez T, Morante N, Fregene M, Dufour D, Smith AM, et al. Discovery of an amylose-free starch mutant in cassava (Manihot esculenta Crantz). Journal of Agricultural and Food Chemistry. 2007;**55**(18):7469-7476

[66] Bull SE, Seung D, Chanez C, Mehta D, Kuon JE, Truernit E, et al. Accelerated ex situ breeding of - and -edited cassava for modified starch. Science Advances. 2018;**4**(9):eaat6086

[67] Sánchez T, Dufour D, Moreno IX, Ceballos H. Comparison of pasting and gel stabilities of waxy and normal starches from potato, maize, and rice with those of a novel waxy cassava starch under thermal, chemical, and mechanical stress. Journal of Agricultural and Food Chemistry. 2010;**58**(8):5093-5099

[68] Charles AL, Chang YH, Ko WC, Sriroth K, Huang TC. Influence of amylopectin structure and amylose content on the gelling properties of five cultivars of cassava starches. Journal of Agricultural and Food Chemistry. 2005;**53**(7):2717-2725

[69] Jørgensen K, Bak S, Busk PK, Sørensen C, Olsen CE, Puonti-Kaerlas J, et al. Cassava plants with a depleted

*Advances in Cassava Trait Improvement and Processing Technologies for Food and Feed DOI: http://dx.doi.org/10.5772/intechopen.110104*

cyanogenic glucoside content in leaves and tubers. Distribution of cyanogenic glucosides, their site of synthesis and transport, and blockage of the biosynthesis by RNA interference technology. Plant Physiology. 2005;**139**(1):363-374

[70] Juma BS, Mukami A, Mweu C, Ngugi MP, Mbinda W. Targeted mutagenesis of the CYP79D1 gene via CRISPR/Cas9-mediated genome editing results in lower levels of cyanide in cassava. Frontiers in Plant Science. 2022;**13**:1009860. DOI: 10.3389/ fpls.2022.1009860

[71] Mbah EU, Nwankwo BC, Njoku DN, Gore MA. Genotypic evaluation of twenty-eight high- and low-cyanide cassava in low-land tropics, Southeast Nigeria. Heliyon. 2019;**5**(6):e01855

[72] Ihemere U, Arias-Garzon D, Lawrence S, Sayre R. Genetic modification of cassava for enhanced starch production. Plant Biotechnology Journal. 2006;**4**(4):453-465

[73] Boonna S, Rolland-Sabaté A, Lourdin D, Tongta S. Macromolecular characteristics and fine structure of amylomaltase-treated cassava starch. Carbohydrate Polymers. 2019;**205**:143-150

[74] Chandanasree D, Gul K, Riar CS. Effect of hydrocolloids and dry heat modification on physicochemical, thermal, pasting and morphological characteristics of cassava (*Manihot esculenta*) starch. Food Hydrocolloids. 2016;**52**:175-182. DOI: 10.1016/j. foodhyd.2015.06.024

[75] Zhou W, Zhao S, He S, Ma Q, Lu X, Hao X, et al. Production of very-highamylose cassava by post-transcriptional silencing of branching enzyme genes. Journal of Integrative Plant Biology. 2020;**62**(6):832-846

[76] Remya R, Jyothi AN, Sreekumar J. Effect of chemical modification with citric acid on the physicochemical properties and resistant starch formation in different starches. Carbohydrate Polymers. 2018;**202**:29-38

[77] Zhang P, Jaynes JM, Potrykus I, Gruissem W, Puonti-Kaerlas J. Transfer and expression of an artificial storage protein (ASP1) gene in cassava (Manihot esculenta Crantz). Transgenic Research. 2003;**12**(2):243-250

[78] Begum R, Rakshit SK, Mahfuzur Rahman SM. Protein fortification and use of cassava flour for bread formulation [internet]. International Journal of Food Properties. 2011;**14**:185- 198. DOI: 10.1080/10942910903160406

[79] Rosales-Soto MU, Gray PM, Fellman JK, Scott Mattinson D, Ünlü G, Huber K, et al. Microbiological and physico-chemical analysis of fermented protein-fortified cassava (*Manihot esculenta* Crantz) flour. LWT - Food Science and Technology. 2016;**66**:355- 360. DOI: 10.1016/j.lwt.2015.10.053

[80] Kobawila SC, Keleke S. Reduction of the cyanide content during fermentation of cassava roots and leaves to produce bikedi and ntoba mbodi, two food products from Congo. African Journal of Biotechnology. 2005;**4**:689-696. DOI: 10.5897/ ajb2005.000-3128

[81] Bradbury JH, Cliff J, Denton IC. Uptake of wetting method in Africa to reduce cyanide poisoning and konzo from cassava. Food and Chemical Toxicology. 2011;**49**(3):539-542

[82] Wang W, Hostettler CE, Damberger FF, Kossmann J, Lloyd JR, Zeeman SC. Modification of cassava root starch phosphorylation enhances starch functional Properties. Frontiers in Plant Science. 2018;**9**:1562

[83] Ačkar Đ, Grec M, Grgić I, Gryszkin A, Styczyńska M, Jozinović A, et al. Physical properties of starches modified by phosphorylation and high-voltage electrical discharge (HVED). Polymers. 2022;**14**(16):3359. DOI: 10.3390/polym14163359

[84] Ahmed AS, Igbo UE, Igwe CC. Evaluation of the physico-chemical properties of acid thinned cassava starch. Nigerian Food Journal. 2005;**23**(1):85-90. DOI: 10.4314/nifoj.v23i1.33603

[85] Leite TD, Nicoleti JF, Penna ALB, Franco CML. Effect of addition of different hydrocolloids on pasting, thermal, and rheological properties of cassava starch. Food Science and Technology. 2012;**32**:579-587. DOI: 10.1590/s0101-20612012005000074

[86] Liu S, Zainuddin IM, Vanderschuren H, Doughty J, Beeching JR. RNAi inhibition of feruloyl CoA 6′-hydroxylase reduces scopoletin biosynthesis and postharvest physiological deterioration in cassava (Manihot esculenta Crantz) storage roots. Plant Molecular Biology. 2017;**94**(1-2):185-195

[87] Udoro EO, Anyasi TA, Jideani AIO. Process-induced modifications on quality attributes of cassava (*Manihot esculenta* Crantz) flour. Processes. 2021;**9**:1891. DOI: 10.3390/pr9111891

[88] Garske RP, Mercali GD, Thys RCS, Cladera-Olivera F. Cassava starch and chickpea flour pre-treated by microwave as a substitute for gluten-free bread additives. Journal of Food Science and Technology. 18 Sep 2022;**60**(1):53-63. DOI: 10.1007/s13197-022-05586-y

[89] Bunterngsook B, Laothanachareon T, Natrchalayuth S, Lertphanich S, Fujii T, Inoue H, et al. Optimization of a minimal synergistic enzyme system for hydrolysis of raw cassava pulp. RSC Advances. 2017;**7**:48444-48453. DOI: 10.1039/ c7ra08472b

[90] Kaur K, Ahluwalia P, Singh H. Cassava: Extraction of starch and utilization of flour in bakery products. International Journal of Food Fermentation Technology. 2016;**6**(2):351

[91] Martos MA, Zubreski ER, Combina M, Garro OA, Hours RA. Isolation of a yeast strain able to produce a polygalacturonase with maceration activity of cassava roots. Food Science and Technology. 2013;**33**:332-338

[92] Setyaningsih W, Karmila FRN, Cahyanto MN. Process optimization for ultrasound-assisted starch production from cassava (Manihot esculenta Crantz) using response surface methodology. Agronomy. 2021;**11**(1):117

[93] Saengchan K, Nopharatana M, Songkasiri W. Recovery of tapioca starch from pulp in a conical basket centrifuge– effects of rotational speed and liquid to solid (L/S) ratio on cake formation and starch–pulp separation efficiency. Separation and Purification Technology. 2014;**127**:192-201

[94] Lim ST, Lee JH, Shin DH, Lim HS. Comparison of protein extraction solutions for rice starch isolation and effects of residual protein content on starch pasting properties. Starch. 1999;**51**:120-125. DOI: 10.1002/ (sici)1521-379x(199904)51:4<120::aidstar120>3.0.co;2-a

[95] Sriroth K, Wanlapatit S, Piyachomkwan K, Oates CG. Improved cassava starch granule stability in the presence of sulphur dioxide. Starch. 1998;**50**:466-479. DOI: 10.1002/(sici)1521- 379x(199812)50:11/12<466::aidstar466>3.0.co;2-0

[96] Sumardiono S, Jos B, Pudjihastuti I, Sari RJ, Kumala WDN, Cahyono H. Effect of chemical modification, drying *Advances in Cassava Trait Improvement and Processing Technologies for Food and Feed DOI: http://dx.doi.org/10.5772/intechopen.110104*

method, and drying temperature on baking expansion and the physicochemical properties of cassava starch. Journal of Food Processing and Preservation. Jan 2022;**46**(1). DOI: 10.1111/jfpp.16111

[97] Che LM, Li D, Wang LJ, Chen XD, Mao ZH. Micronization and hydrophobic modification of cassava starch. International Journal of Food Properties. 2007;**10**:527-536. DOI: 10.1080/10942910600932982

[98] Maniglia BC, Castanha N, Rojas ML, Augusto PED. Emerging technologies to enhance starch performance. Current Opinion in Food Science. 2021;**37**:26-36. DOI: 10.1016/j.cofs.2020.09.003

[99] Lima DC, Maniglia BC, Matta Junior MD, Le-Bail P, Le-Bail A, Augusto PED. Dual-process of starch modification: Combining ozone and dry heating treatments to modify cassava starch structure and functionality. International Journal of Biological Macromolecules. 2021;**167**:894-905

[100] Wang Z, Mhaske P, Farahnaky A, Kasapis S, Majzoobi M. Cassava starch: Chemical modification and its impact on functional properties and digestibility, a review. Food Hydrocolloids. 2022;**129**:107542. DOI: 10.1016/j. foodhyd.2022.107542

[101] Beninca C, Colman TAD, Lacerda LG, Filho MAS, Bannach G, Schnitzler E. The thermal, rheological and structural properties of cassava starch granules modified with hydrochloric acid at different temperatures. Thermochimica Acta. 2013;**552**:65-69. DOI: 10.1016/j. tca.2012.10.020

[102] Babu AS, Parimalavalli R, Jagannadham K, Rao JS. Chemical and structural properties of sweet potato

starch treated with organic and inorganic acid. Journal of Food Science and Technology. 2015;**52**(9):5745-5753

[103] Utomo P, Nizardo NM, Saepudin E. Crosslink modification of tapioca starch with citric acid as a functional food. In: Proceedings of the 5th International Symposium on Current Progress in Mathematics and Sciences (ISCPMS2019). Newyork: AIP publishing; 2020. DOI: 10.1063/5.0010364

[104] Shah N, Mewada RK, Mehta T. Crosslinking of starch and its effect on viscosity behaviour. Reviews in Chemical Engineering. 2016;**32**(2):265-270. DOI: 10.1515/revce-2015-0047

[105] Khurshida S, Das MJ, Deka SC, Sit N. Effect of dual modification sequence on physicochemical, pasting, rheological and digestibility properties of cassava starch modified by acetic acid and ultrasound. International Journal of Biological Macromolecules. 2021;**188**:649-656

[106] Sumardiono S, Pudjihastuti I, Jos B, Taufani M, Yahya F. Modification of cassava starch using combination process lactic acid hydrolysis and micro wave heating to increase coated peanut expansion quality. In: AIP Conference Proceedings. AIP Publishing LLC; 24 May 2017;**1840**(1):060005. DOI: 10.1063/1.4982285

[107] Marques PT, Pérégo C, Le Meins JF, Borsali R, Soldi V. Study of gelatinization process and viscoelastic properties of cassava starch: Effect of sodium hydroxide and ethylene glycol diacrylate as cross-linking agent. Carbohydrate Polymers. 2006;**66**:396- 407. DOI: 10.1016/j.carbpol.2006.03.028

[108] Méndez PA, Méndez ÁM, Martínez LN, Vargas B, López BL. Cassava and banana starch modified with maleic anhydride-poly (ethylene glycol) methyl

ether (Ma-mPEG): A comparative study of their physicochemical properties as coatings. International Journal of Biological Macromolecules. 2022;**205**:1-14

[109] Jyothi AN, Moorthy SN, Rajasekharan KN. Effect of cross-linking with epichlorohydrin on the properties of cassava (*Manihot esculenta* Crantz) Starch. Starch. 2006;**58**:292-299. DOI: 10.1002/star.200500468

[110] Palavecino PM, Penci MC, Ribotta PD. Effect of sustainable chemical modifications on pasting and gel properties of sorghum and cassava starch. Food and Bioprocess Technology. 2020;**13**:112-120. DOI: 10.1007/ s11947-019-02381-0

[111] Mbougueng PD, Tenin D, Scher J, Tchiégang C. Influence of acetylation on physicochemical, functional and thermal properties of potato and cassava starches. Journal of Food Engineering. 2012;**108**:320-326. DOI: 10.1016/j. jfoodeng.2011.08.006

[112] Lin CL, Lin JH, Lin JJ, Chang YH. Properties of high-swelling native starch treated by heat–moisture treatment with different holding times and iterations. Molecules. 2020;**25**:5528. DOI: 10.3390/ molecules25235528

[113] Dolas KA, Ranveer RC, Tapre AR, Nandane AS, Sahoo AK. Effect of starch modification on physicochemical, functional and structural characterization of cassava starch (*Manihot esculenta* Crantz). Food Research. 2020;**4**:1265-1271. DOI: 10.26656/fr.2017.4(4).075

[114] Ngolong Ngea GL, Guillon F, Essia Ngang JJ, Bonnin E, Bouchet B, Saulnier L. Modification of cell wall polysaccharides during retting of cassava roots. Food Chemistry. 2016;**213**: 402-409

[115] Ze NN, Ndjouenkeu R, Ngang JJE. Effect of accelerated retting process on physiochemical and pasting Properties of cassava (Manihot esculenta Crantz) flours. Asian Food Science Journal. 2020;**2020**:45-52. DOI: 10.9734/ afsj/2020/v15i430160

[116] Park SH, Na Y, Kim J, Kang SD, Park KH. Properties and applications of starch modifying enzymes for use in the baking industry. Food Science and Biotechnology. 2018;**27**(2):299-312

[117] Shi YC, Maningat CC. Resistant Starch: Sources, Applications and Health Benefits. New Jersey: John Wiley & Sons; 2013. p. 312

[118] Tan FPY, Beltranena E, Zijlstra RT. Resistant starch: Implications of dietary inclusion on gut health and growth in pigs: A review. Journal of Animal Science and Biotechnology. 2021;**12**(1):124

[119] Jia L, Dong X, Li X, Jia R, Zhang HL. Benefits of resistant starch type 2 for patients with end-stage renal disease under maintenance hemodialysis: A systematic review and meta-analysis. International Journal of Medical Sciences. 2021;**18**(3):811-820

[120] Zhang B, Mei JQ, Chen B, Chen HQ. Digestibility, physicochemical and structural properties of octenyl succinic anhydride-modified cassava starches with different degree of substitution. Food Chemistry. 2017;**229**:136-141

[121] Abioye VF, Adeyemi IA, Akinwande BA, Kulakow P, Maziya-Dixon B. Effect of autoclaving on the formation of resistant starch from two Nigeria Cassava (*Manihot esculenta*) varieties. Food Research. 2018;**2**:468-473. DOI: 10.26656/fr.2017.2(5).205

[122] Lertwanawatana P, Frazier RA, Niranjan K. High pressure intensification *Advances in Cassava Trait Improvement and Processing Technologies for Food and Feed DOI: http://dx.doi.org/10.5772/intechopen.110104*

of cassava resistant starch (RS3) yields. Food Chemistry. 2015;**181**:85-93

[123] Montagnac JA, Davis CR, Tanumihardjo SA. Nutritional value of cassava for use as a staple food and recent advances for improvement. Comprehensive Reviews in Food Science and Food Safety. 2009;**8**(3):181-194

[124] Onyango SO, Abong GO, Okoth MW, Kilalo DC, Mwang'ombe AW. Effect of pre-treatment and processing on nutritional composition of cassava roots, millet, and cowpea leaves flours. Frontiers in Sustainable Food Systems. 2 Jun 2021;**5**:625735. DOI: 10.3389/ fsufs.2021.625735

[125] Agbon CA, Ngozi EO, Onabanjo OO. Production and nutrient composition of Fufu made from a mixture of cassava and cowpea flours. Journal of Culinary Science & Technology. 2010;**8**:147-157. DOI: 10.1080/15428052.2010.511096

[126] TECA, FAO. Production of high quality cassava flour. Accessed December 9, 2022. https://teca.apps.fao.org/teca/fr/ technologies/4574

[127] Ekunseitan OF, Obadina AO, Sobukola OP, Omemu AM, Adegunwa MO, Kajihausa OE, et al. Nutritional composition, functional and pasting properties of wheat, mushroom, and high quality cassava composite flour. Journal of Food Processing and Preservation. 2017;**41**:e13150. DOI: 10.1111/jfpp.13150

[128] Ayandipe DO, Adebowale AA, Obadina O, Sanwo K, Kosoko SB, Omohimi CI. Optimization of high-quality cassava and coconut composite flour combination as filler in chicken sausages. Journal of Culinary Science & Technology. 2022;**20**:1-32. DOI: 10.1080/15428052.2020.1799280

[129] Montagnac JA, Davis CR, Tanumihardjo SA. Processing techniques to reduce toxicity and Antinutrients of cassava for use as a staple food. Comprehensive Reviews in Food Science and Food Safety. 2009;**8**:17-27. DOI: 10.1111/j.1541-4337.2008.00064.x

[130] Ravindran V. Cassava leaves as animal feed: Potential and limitations. Journal of the Science of Food and Agriculture. 1993;**61**:141-150. DOI: 10.1002/jsfa.2740610202

[131] Quinn AA, Myrans H, Gleadow RM. Cyanide content of cassava food products available in Australia. Foods. 11 May 2022;**11**(10):1384. DOI: 10.3390/ foods11101384

[132] Jørgensen K, Morant AV, Morant M, Jensen NB, Olsen CE, Kannangara R, et al. Biosynthesis of the cyanogenic glucosides linamarin and lotaustralin in cassava: Isolation, biochemical characterization, and expression pattern of CYP71E7, the oxime-metabolizing cytochrome P450 enzyme. Plant Physiology. 2011;**155**(1):282-292

[133] Cressey P, Reeve J. Metabolism of cyanogenic glycosides: A review. Food and Chemical Toxicology. 2019;**125**:225-232

[134] White WLB, Arias-Garzon DI, McMahon JM, Sayre RT. Cyanogenesis in cassava. The role of hydroxynitrile lyase in root cyanide production. Plant Physiology. 1998;**116**(4):1219-1225

[135] Tweyongyere R, Katongole I. Cyanogenic potential of cassava peels and their detoxification for utilization as livestock feed. Veterinary and Human Toxicology. 2002;**44**(6):366-369

[136] Nambisan B. Strategies for elimination of cyanogens from cassava for reducing toxicity and improving food safety. Food and Chemical Toxicology: An International Journal Published for the British Industrial Biological Research Association. 2011;**49**(3):690-693

[137] Obi CN, Okezie O, Ukaegbu T. Fermentation reduces cyanide content during the production of cassava flours from sweet and bitter cassava tuber varieties. Asian Food Science Journal. 2019;**2019**:1-10. DOI: 10.9734/afsj/2019/ v11i130050

[138] Iwuoha CI, Banigo EOI, Okwelum FC. Cyanide content and sensory quality of cassava (*Manihot esculenta* Crantz) root tuber flour as affected by processing. Food Chemistry. 1997;**58**:285-288. DOI: 10.1016/0308-8146(95)00184-0

[139] Nkoudou NZ, Essia JJN. Cyanides reduction and pasting Properties of cassava (Manihot Esculenta Crantz) flour as affected by fermentation process [internet]. Food and Nutrition Sciences. 2017;**08**:326-333. DOI: 10.4236/ fns.2017.83022

[140] Sornyotha S, Kyu KL, Ratanakhanokchai K. An efficient treatment for detoxification process of cassava starch by plant cell walldegrading enzymes. Journal of Bioscience and Bioengineering. 2010;**109**(1):9-14

[141] Mikolo B, Nakavoua AHW, Nkounga CK. Effects of cassava leaves detoxification processes on the physicochemical and sensory qualities of *Saka Saka*. American Journal of Applied Chemistry. 2021;**9**:109. DOI: 10.11648/j. ajac.20210904.13

[142] Zhong Y, Xu T, Ji S, Wu X, Zhao T, Li S, et al. Effect of ultrasonic pretreatment on eliminating cyanogenic glycosides and hydrogen cyanide in

cassava. Ultrasonics Sonochemistry. 2021;**78**:105742

[143] Wobeto C, Corrêa AD, de Abreu CMP, dos Santos CD, Pereira HV. Antinutrients in the cassava (Manihot esculenta Crantz) leaf powder at three ages of the plant. Ciência e Tecnologia de Alimentos. 2007;**27**:108-112. DOI: 10.1590/s0101-20612007000100019

[144] Delimont NM, Haub MD, Lindshield BL. The impact of tannin consumption on iron bioavailability and status: A narrative review. Current Developmental Nutrition. 2017;**1**(2):1-12

[145] Hawashi M, Altway A, Widjaja T, Gunawan S. Optimization of process conditions for tannin content reduction in cassava leaves during solid state fermentation using. Heliyon. 2019;**5**(8):e02298

[146] Terefe ZK, Omwamba M, Nduko JM. Effect of microbial fermentation on nutritional and antinutritional contents of cassava leaf. Journal of Food Safety. 2022;**42**(3). DOI: 10.1111/jfs.12969

[147] Ekpo UA, Baridia DF. Effect of processing on the chemical and antinutritional properties of cassava leaves (sweet and bitter varieties). ARC Journal of Nutrition and Growth. 2020;**6**(2):6-12

#### **Chapter 11**

## The Cyanogenic Potential of Certain Cassava Varieties in Uganda and Their Fermentation-Based Detoxification

*Benson Oloya, Christopher Adaku and Morgan Andama*

#### **Abstract**

Cassava is the leading staple food in the developing world, providing an essential diet for about half a billion individuals. However, cassava contains significantly toxic compounds, the cyanogenic glycosides. Ingestion of such toxins in large quantities can lead to acute cyanide poisoning and may cause death in both humans and animals. Therefore, cassava may present a potential health risk to consumers. Information regarding the cyanogenic glycoside content is vital in averting health risks associated with cassava consumption. Accordingly, the seven most common local cultivars in Zombo district and six improved cultivars were grown and later characterized based on their cyanogenic potential. Additionally, the root tubers of *Nyar-udota* and *Nyarpapoga* were fermented to detoxify them from the cyanogens. The cyanogenic glycoside levels in the selected cultivars surpassed the critical value of 10 ppm established by the World Health Organization. The improved cassava had lower and moderately identical concentrations of HCN, unlike the local varieties. Cyanogenic contents were highest at 8-10 months. Fermentation led to substantial detoxification of the cyanogens, and the decrease varied with the fermentation period. In making choices for the cultivation and consumption of cassava, it is crucial to consider the cultivar, period of harvesting, and detoxification by fermentation.

**Keywords:** cassava, cyanogenic potential, cyanogenic glycosides, cyanide poisoning, detoxification, fermentation, food safety, food security

#### **1. Introduction**

Cassava produced by 105 countries is the basic food for more than 600 million people worldwide [1]. Cassava is a very important food source in the tropics, ranking third after rice and maize [2, 3]. It is presently one of Uganda's most vital food crops, ranking second to bananas in terms of the area it occupies, per capita consumption, and total production [1]. About 275 million tons of cassava were produced globally in 2018, with the largest producer being Africa (contributing 61.1% of the total), followed by Asia (29.0%), the Americas (9.8%), and Oceania (0.1%) [4]. In 2020, cassava production globally exceeded 302 million tons, with more than half of the

production recorded in Africa [5]. Nigeria is the world's leading cassava producer, producing 35 million metric tons. In comparison, Uganda's cassava production is about 5 million metric tons each year, and the traditional cassava growing regions in Uganda include the North, West Nile, and Eastern parts of the country [1].

Cassava, a carbohydrate-rich crop, has many uses, including food for human consumption, animal feeds, fuel for producing biofuel & ethanol, and industrial raw material in making paper, citric acid, clothing, alcohol, medicine, and chemicals [4]. Cassava is easily grown and can produce better yields in good and even poor soils, subject to dry conditions. The roots are starchy and may be sweet or bitter, and the young leaves are a good source of protein [6]. Owing to the perceived agricultural advantages of cassava growing and the increasing demand for food as a result of population pressures, cassava usage has been extending to some parts of Africa and elsewhere where it was not formerly used [7]. Traditionally, cassava has been grown as a food security crop, a form of protection against drought and the failure of other staple crops. It is mainly planted in the first rainy season of the year rather than the second, and it is customarily intercropped with beans, maize, and sweet potatoes [8].

Africa's cassava production is mainly for domestic consumption. The cassava supports local food security as well as an economic activity for the farmers, with the main products being fresh cassava roots and processed cassava products [4]. In Uganda, cassava growing is mostly practiced by smallholder farmers covering 1–2 acres of land to ensure food security and generate income. However, there is an effort by the government of Uganda to encourage large-scale cassava production to cater for the ever-growing commercial uses of cassava in the baking industry, pharmaceutical industries, and the manufacture of paper board and starch, biofuel, and alcohol [1]. Most of the cassava is sold as dry cassava chips or cassava flour milled from the dried chips and as fresh cassava roots, especially in urban areas [1].

Unfortunately, all the cassava cultivars produce toxic compounds in the form of cyanogenic glycosides, such as linamarin and lotaustralin, in varying concentrations, ranging from around 10 mg/kg to over 500 mg/kg fresh weight basis [9]. The cyanogenic glycoside content in cassava roots is determined by the cultivar and the growth conditions [10]. These cyanogens are spread in all parts of the plant, with the highest amounts in the leaves and the root cortex (skin layer). The root parenchyma (interior) has comparatively smaller amounts of cyanogens. The so-called sweet cassava varieties have only a small amount of cyanogens in the parenchyma so that after peeling, these roots can be safely boiled and eaten [6]. Bitter cassava's bitter taste is primarily due to linamarin [11]. Cassava produces the two cyanogenic glycosides as a defence mechanism to prevent predator attacks.

The cyanogenic glycosides are nitrile-containing plant secondary compounds that produce cyanide (cyanogenesis) after their enzymatic breakdown. A cyanogenic glucoside is typically a D-glucose joined by a *β*-linkage to an acetone cyanohydrin derivative [12]. There are about 25 different types of cyanogenic glucosides; the only difference between them is the residual group attached to the end of the acetone cyanohydrin. Linamarin has a hydrogen atom, whilst lotaustralin has a methyl (-CH3) group.

Cassava produces the cyanogenic glucosides in a particular way. The first step is the conversion of L-valine into (*Z*)-2-methylpropanal oxime, which is catalysed by two similar cytochromes (P450s) which are encoded by the genes CYP79D1/D2 [13]. There are two of these genes since *M. esculenta* is an allopolyploid. In the next step (*Z*)-2-methylpropanal oxime reacts to acetone cyanohydrin, and in the final step, a glucose molecule is bound to the acetone derivative, forming linamarin.

*The Cyanogenic Potential of Certain Cassava Varieties in Uganda and Their Fermentation… DOI: http://dx.doi.org/10.5772/intechopen.110748*

**Figure 1.** *Cyanogenesis in cassava.*

The physiology and the biochemistry of cyanogenesis (**Figure 1**) in cassava have been well studied [14, 15]. Cyanogenesis in cassava starts when there is damage in the plant tissue. When the vacuole is raptured, linamarin is released, and it is hydrolyzed by a cell wall-associated *β*-glycosidase, linamarase [14]. Linamarin hydrolyzes producing an unstable hydroxynitrile intermediate, acetone cyanohydrin, and glucose. Acetone cyanohydrin spontaneously decomposes to form acetone and HCN at pH >5.0 or temperatures >35°C. Acetone cyanohydrin can also be broken down by the enzyme hydroxynitrile lyase (HNL) [16–20].

In Africa, consumption of poorly processed cassava, specifically by nutritionally compromised individuals, has led to several cyanide-associated health disorders [21]. The severity of these disorders is dependent on the quantity of the cyanogens consumed, the frequency of cyanogen exposure, and the consumer's health. The presence of toxins in cassava presents a health risk because inadequate preparation of cassava can leave sufficient quantities of residual cyanide in cassava products. The consumption of cassava and its products containing significant amounts of cyanogens causes cyanide poisoning with symptoms of dizziness, vomiting, headache, stomach pains, diarrhoea, weakness, nausea, and occasionally death [22, 23]. The HCN is very poisonous because it binds to the Fe2+ in haemoglobin, forming cyanohaemoglobin [24]. As a result, there is impediment of the respiratory cycle because the binding affinity of cyanide is much higher than the equivalent binding affinity of oxygen.

Ingestion of cyanide from cassava aggravates goitre and cretinism in areas deficient in iodine [25] and is almost undoubtedly the cause of konzo in central, eastern, and southern Africa. Konzo is an irreversible paralysis of the legs that starts suddenly, occurring mostly in children and women of childbearing age [26–28]. Tropical ataxic neuropathy (TAN) is a chronic condition of gradual onset and occurs in older people who consume a monotonous cassava diet. It causes loss of vision, deafness, weakness, and ataxia of gait [29–31].

The body's major defence in countering cyanide's toxic effects is converting it to thiocyanate mediated by the enzyme rhodanese [32]. Therefore, individuals with low protein and in particular low cysteine intake in their diets are more vulnerable to cyanide poisoning since detoxifying cyanide to thiocyanate by rhodanese requires cysteine as a substrate [32]. In addition, a number of minor reactions help in the detoxification of ingested cyanide. Firstly, cystine can react directly with the cyanide forming 2-iminothiazolidine-4-carboxylic acid, which is excreted in the saliva and urine [33]. Secondly, a small amount of the cyanide may be converted into formic acid and then excreted in urine [33]. Thirdly, cyanide can react with hydroxycobalamine (vitamin B12) to form cyanocobalamine, which is excreted in the urine and bile. Reabsorption of cyanocobalamine may also occur by the intrinsic factor mechanism in the ileum, permitting effective recirculation of vitamin B12 [33]. Fourthly, methaemoglobin effectively competes with cytochrome oxidase for cyanide, and its formation from haemoglobin, effected by sodium nitrile or amylnitrite, is exploited in the treatment of cyanide intoxication [33].

In Uganda and the West Nile sub-region in particular, excessive consumption of bitter cassava is responsible for disability amongst children. The region depends on cassava as

its primary food source. Dr. Tito Beyeza, an orthopaedic surgeon at Makerere University College of Health Sciences, reported that 10 out of 40 children who underwent surgery at Nebbi Hospital had cyanide, signifying a serious health hazard. He added that removing cyanide requires surgery, which is expensive. 'A surgery like this is ordinarily done in Mulago at Uganda Shillings 800,000', he said. The regional coordinator of the Uganda Society for Disabled Children, Mr. Stephen Eguma, also noted that several families are affected. 'It is an expensive disease to treat for our poor parents here. And they let the children just grow with the deformity and disability which affects the child's future' [34].

Nevertheless, in an attempt to deter thieves, animals, and pests, many farmers from cassava-growing countries oftentimes prefer the bitter varieties [35]. In some places, the more-toxic cassava varieties are a fallback resource (a 'food security crop') during famine [36]. Generally, higher cyanide content correlates with higher yields. During drought times, the cyanide content of both sweet and bitter cassava varieties rises [37]. Bitter cassava varieties are more readily available and cheaper during drought periods because they are more drought resistant. However, due to food shortages during drought, less time is sometimes available for the complete processing required, leaving sufficient quantities of the cyanogens in cassava [38].

Substantial reduction in the per capita cyanide intake could prevent the medical conditions caused by cyanide overload. It is, therefore, crucial to characterise cassava cultivars based on their cyanogenic potential so that cultivars with the lowest levels of toxins are recommended for household consumption. Also, to realise the full potential value of cassava, a lot has to be done at the processing level. Therefore, better and more effective processing methods, especially fermentation [39], have to be promoted and improved to reduce further the cyanide content in cassava flour to within acceptable limits (safe level) of 10 ppm, set by the World Health Organisation (WHO) [36].

#### **2. Materials and methods**

#### **2.1 Materials**

The materials used during this research included containers (basins), airtight polythene bags, a thermometer, a refrigerator, a distillation flask, a kitchen knife, a pH meter. Others included a reciprocating shaker, filter funnels, micro burette, 125 mL Erlenmeyer flasks, Filter paper (Whatman #42), disposable plastic vials, and distillation apparatus. The main reagents that were used during laboratory analysis were concentrated sulphuric acid, sodium hydroxide, potassium permanganate, 5% potassium iodide solution, 0.02 N silver nitrate, potassium dichromate, ferrous ammonium sulphate, and distilled water.

#### **2.2 Sample acquisition**

The cassava varieties used were obtained from the same garden in Agure village, Palei-west ward, Zombo Town council in Zombo district, Uganda.

#### *2.2.1 Cultivation of cassava*

A plot of land measuring 20 × 7 m was cleared manually, tilled, and 13 ridges measuring 18 × 0.6 m were made. The spacing between the ridges was 0.5 m. Stems of six improved cultivars of cassava (NASE 03, NASE 09, NASE 14, NASE *The Cyanogenic Potential of Certain Cassava Varieties in Uganda and Their Fermentation… DOI: http://dx.doi.org/10.5772/intechopen.110748*

19, TME 14, and TME 204) were obtained from National Agricultural Research Organisation (NARO) at Abii Farm, Arua district, whilst the seven local cassava cultivars ('*Bisimwenge*', '*Nyar-anderian',* '*Nyar-papoga*', '*Nyar-pamitu*', '*Nyar-matia*', '*Nyar-udota*', and '*Terengule*') were collected from local peasant farmers in Zombo district, Uganda.

The cuttings from each cultivar, measuring about 27 cm in length, were planted at about 45° on the crest of the ridges [40]. Care was taken to ensure that the buds were not inverted during planting in order to prevent delayed sprouting [40]. The planting distance was about 0.5 × 0.5 m. Weeding was done at 4, 8, and 12 weeks, respectively, after planting since the crop was planted as a sole crop [41].

#### *2.2.2 Collection and preparation of cassava samples*

For the determination of cyanogenic glycosides content variation with cassava age, the samples were collected and prepared monthly (on the 15th of each month) for cassava aged 7–13 months. For the comparative analysis of the cyanogenic glycosides content in the various cassava cultivars, the samples were obtained only at the age of 13 months.

Fresh cassava root samples were obtained directly from the garden using a hand hoe. The soils were removed and then the samples were transported home in polythene bags for preparation and then to the Government Analytical Laboratory for analysis. 40 g of each peeled and washed sample was mashed using a wooden pestle and mortar and weighed. The samples were then kept in a deep freezer at a temperature of - 4°C awaiting analysis within 24 hours.

For heap fermentation, cassava roots grown for thirteen (13) months were got from the garden and the peels were removed using a kitchen knife. The peeled root tubers were subjected to partial sun drying at a temperature range of 28 to 40°C and at varied periods (0, 1, 2, 3, and 4 hours). The dried root tubers were heaped together on dry banana leaves with polythene sheets underneath and then covered with dry banana leaves, followed by black polythene sheets. The root tubers were heaped to enable terrestrial fermentation by the growth of moulds, and it was carried out in a grass-thatched hut having a clay floor to afford steady warmth. The period of fermentation was varied by withdrawing some of the heaped cassava after 2, 3, 4, 5, and 7 days for *Nyar-papoga*, and 0, 2, 3, 4, 6, 8, and 10 days for *Nyar-udota* variety.

The moulds from the fermented cassava roots were removed by scrapping them with a blunt kitchen knife. The cassava was pounded and then subjected to sun-drying for around 8 hours at a temperature ranging from 28 to 40°C. The dried cassava was then milled and analysed at the Government Analytical Laboratory. As a control, fresh tubers that were not fermented but sun-dried as well as a fresh tuber that was not dried, were milled and analysed.

#### **2.3 Determination of level of cyanides in cassava**

The standard method of FAO [42] was used to analyse the cassava samples at the Government Analytical Laboratory (GE058/07) in Kampala. Briefly, in order to set free all the bound hydrocyanic acid, the sample (10 to 20 g) was placed in a distillation flask, and distilled water (about 200 ml) was added and left to stand for two to 4 hours. The mixture was distilled with steam and 150–200 ml of distillate was collected in a solution of 0.5 g of sodium hydroxide in 20 ml of water. The distillate was then diluted to a volume of 250 ml.

To 100 ml of distillate was added 8 ml of 5% potassium iodide solution and titrated with 0.02 N silver nitrate (1 ml of 0.02 N silver nitrate corresponds to 1.08 mg of hydrocyanic acid) using a micro burette. The endpoint was shown by a faint but permanent turbidity, which was easily recognised, particularly against a black background. When all the cyanide ions have reacted with the silver ions, any excess silver ions react with the iodide ions giving a precipitate of silver iodide.

$$\text{HCNV}\_{(aq)} + \text{AgNO}\_{3(aq)} \to \text{HNO}\_{3(aq)} + \text{AgCN}\_{(aq)}\tag{1}$$

$$\text{Ag}^{\cdot}\_{\text{(aq)}} \star I^{\cdot}\_{\text{(aq)}} \to \text{AgI}\_{\text{(s)}} \tag{2}$$

#### **2.4 Data analysis**

Graphs were generated using computer packages: SPSS 16 and Microsoft Excel from the results of laboratory analysis. Descriptive statistics for the overall HCN levels in each of the two cassava varieties (local and improved) were obtained. Student t test was used to compare the amount of HCN in the local and improved cassava varieties. Results were significant at 0.05 level. The experimental data were analysed using the two-way ANOVA for comparison of the effect of the duration of fermentation (days) and period of partial drying on the amount of hydrogen cyanide. The variation of HCN level with the duration of fermentation in *Nyar-udota* cassava cultivar was analysed using One-way ANOVA.

#### **3. Results and discussions**

#### **3.1 Effect of age of cassava on the levels of hydrogen cyanide**

The effect of the age of cassava on the levels of hydrogen cyanide was studied, and the result showing the trend is shown in **Figure 2**.

The level of hydrogen cyanide generally showed an increasing pattern from the 8th month up to the 10th month for varieties (NASE 9, TME 14, *Nyar-anderiano,* and *Bisimwenge*). Then it started decreasing until the 13th month, except for *Bisimwenge*, which showed a slight increase from the 12th month up to the 13th month. For *Nyar-Udota*, there was an increase from the 8th month up to the 9th month, after which the level of hydrogen cyanide started decreasing until the 13th month. By the 13th month, *Bisimwenge* had the highest amount of hydrogen cyanide (181.48 mg/kg), followed by NASE 9 (109.33 mg/kg), TME 14 (105.60 mg/kg), *Nyar-anderiano* (90.00 mg/kg), and finally *Nyar-udota* (88.50 mg/kg) with the lowest amount of the hydrogen cyanide.

This trend could be attributed to the following two opposing factors: Firstly, cyanogen synthesis, which is based on the expression of the gene CYP79D1/D2, takes place in the young shoots. After the synthesis, it is translocated to the roots [43]. This increases the level of cyanogen in the roots. Secondly, cyanogen re-assimilating based on the expression of the gene *β*-CAS, where they are exploited for the synthesis of amino acid [12] as well as the enzymes, linamarase and HNL, both of which take part in breaking down the cyanogens upon tissue rapture, based on their expression clustered together. Both cyanogen re-assimilation and the action of linamarase and HNL reduce the level of cyanogen in the roots.

*The Cyanogenic Potential of Certain Cassava Varieties in Uganda and Their Fermentation… DOI: http://dx.doi.org/10.5772/intechopen.110748*

#### **Figure 2.**

*A graph showing the variation of levels of hydrogen cyanide (HCN) with age in five cassava cultivars (NASE 9, TME 14, 'Nyar-anderiano', 'Nyar-udota', and 'Bisimwenge').*

When cyanogen synthesis outweighed, there was an increasing trend of the cyanide level (8–10 months). During the tender age of cassava, cyanogen synthesis is enhanced because of the increased number of young shoots sprouting, which is responsible for the synthesis of the cyanogens. This led to an overall increase in the cyanogen level.

Meanwhile, when cyanogen re-assimilation and action of linamarase and HNL outweighed cyanogen synthesis, there was a decreasing trend in the graph (10–13 months) except for *Nyar-udota* where the decrease was from the 9th month as in **Figure 2**. As the cassava matures, the number of young shoots being produced reduces drastically, leading to a decrease in the amount of cyanogen synthesised, as the rate of cyanogen re-assimilation and action of linamarase and HNL remains fairly constant. Thus, overall, the level of the cyanogens was reduced.

#### **3.2 Hydrogen cyanide levels in the cassava varieties at maturity**

The levels of hydrogen cyanide found in the different cassava varieties at maturity (13 months) are presented in **Figure 3**.

The levels of the hydrogen cyanide increased in the order; *Nyar-udota* < *Nyaranderiano* < NASE 19 < TME 14 < NASE 9 < TME 204 < NASE 3 < NASE 14 < *Terengule* < *Nyar-matia < Bisimwenge < Nyar-pamitu < Nyar-papoga.* In the improved cassava varieties, the HCN level was highest for NASE 14 (116.51 mg/ kg) and lowest for NASE 19 (101.84 mg/kg). Amongst the local cassava varieties considered in this study, the cyanide levels in *Nyarudota* (88.5 mg/kg) and *Nyaranderiano* (90.0 mg/kg) were the lowest, even much lower than for the improved varieties. This was in agreement with what was reported by Afoakwa et al. [44], who generally reported lower HCN in local varieties than in improved ones. The cyanide levels in the other four local cassava varieties were higher than those in the improved varieties (**Figure 3**), contrary to the findings of Afoakwa et al. [44]. Generally, the improved cassava varieties considered in this study have shown

**Figure 3.**

*A graph showing the levels of hydrogen cyanide (in mg/kg) in all the cassava varieties planted at maturity (13 months).*

significantly lower levels of hydrogen cyanide (mean value = 108.75) than the local cultivars (mean value = 201.65) (t = 2.331, p = 0.042). Furthermore, the cyanide level variation in the improved varieties (standard deviation was 5.31) was much lower than in the local cultivars (standard deviation 89.00).

Generally, this trend could be attributed to the fact that in the improved cassava cultivars, the linamarase gene, which is responsible for the disintegration of the cyanogens, has higher transcriptional activity than the bitter cultivars.

It is also possible that there is more inhibition of the cytochrome gene expression that catalyses the first step in the synthesis of linamarin in the improved cassava varieties than the local ones. According to Siritunga and Sayre [43], the linamarin content of cassava roots reduced by 99% in transgenic plants expressing the cytochrome P450 genes (CYP79D1 and CYP79D2) that catalyse the first step in the synthesis of linamarin.

Nonetheless, all the values lie within the cyanide range in cassava root parenchyma of 10–500 mg cyanide equivalents/kg dry weight [43, 45, 46].

#### **3.3 Variation of the level of hydrogen cyanide with fermentation days in**

#### *3.3.1 Nyar-papoga cassava variety*

The hydrogen cyanide level (mg/kg) dry weight was obtained for cassava samples subjected to varied hours of partial sun-drying and the number of days of fermentation. The trend is presented in the line graph in **Figure 4**.

The level of hydrogen cyanide was high after two (2) days of fermentation but kept reducing steadily until the seventh (7th) day of fermentation. The hydrogen cyanide level in the local cassava variety ('*Nyar-papoga*') varied significantly (F(4, 16) = 62.48, p = 1.49 × 10−9) with the number of days of fermentation.

*The Cyanogenic Potential of Certain Cassava Varieties in Uganda and Their Fermentation… DOI: http://dx.doi.org/10.5772/intechopen.110748*

#### **Figure 4.**

*A graph showing the variation of hydrogen cyanide level in a local cassava variety (Nyar-papoga) with hours of partial drying and fermentation days.*

#### *3.3.2 Nyar-udota cassava variety*

The hydrogen cyanide level in *Nyar-udota* cassava variety that was subjected to fermentation for a varying number of days was determined. The result is presented in the line graph in **Figure 5**.

The level of hydrogen cyanide in the unfermented (Day 0) dried *Nyar-udota* cassava variety was the highest (52.63 mg/kg). The level of the hydrogen cyanide then decreased steadily with fermentation days until the fourth day. Thereafter, it remained fairly constant until the 10th day of fermentation (18.58 mg/kg), although there was only a slight decrease in the level of hydrogen cyanide. Generally, the hydrogen cyanide level reduced significantly (F (1, 12) = 19.46, p = 8.49 × 10−4) with the period of fermentation, with a percentage reduction of about 65% on the 10th day of fermentation.

Fermentation probably causes more cells to rupture, easily bringing about contact between substrate cyanoglycosides and the enzymes, consequently leading to the breakdown of cyanoglycosides to release free HCN [39]. Moreover, heap fermentation generates heat that volatilizes free hydrogen cyanide [39]. However, Lambri et al. [47] and Bradbury [48] revealed that fermentation temperature was not significant because no consistent differences were exhibited between 30 and 35°C fermentation temperatures. However, the warmth generated by fermentation could progressively evaporate the free hydrogen cyanide, which is volatile at 25.7°C [39, 49].

According to Westby [49], the essential features of efficient processing of the cyanogens involve adequate tissue disruption to enable endogenous linamarase to

**Figure 5.** *A graph showing the variation of hydrogen cyanide level with fermentation period in Nyar-udota cassava variety.*

come into contact with linamarin and then favourable conditions for the breakdown of acetone cyanohydrin, or conditions that can facilitate spontaneous volatilisation of the compound. In the case of heap-fermented products, microbial growth reduces cyanide content by softening the cassava roots, which increases the contact between endogenous linamarin and linamarase [50].

A series of microorganisms in which the microbial groups, lactic acid bacteria (LAB), and yeasts predominate, characterise natural fermentation [51, 52]. The most frequent LAB species are *Lactobacillus manihotivorans* and *Lactobacillus plantarum* [53]. *L. manihotivorans* exists only during the first period of fermentation, when it may accelerate the rate of degrading starch [52], resulting into contact between linamarase and cyanogenic glycosides, thus, reducing the cyanide level as fermentation progresses. Meanwhile, *L. plantarum*, which is present during all the steps of the fermentative process, acidifies the substrate. Therefore, as the fermentation progresses, there is a gradual decrease in the number of microorganisms due to the increased acidity of the medium [54]. This slows down the fermentation process until it finally stops (**Figure 5**).

#### **4. Conclusions**

Improved cassava varieties have lower levels of hydrogen cyanide, and the level does not significantly vary amongst them. The local cassava varieties considered have high levels of hydrogen cyanide except *Nyar-Udota* and *Nyar-anderiano* and there is

*The Cyanogenic Potential of Certain Cassava Varieties in Uganda and Their Fermentation… DOI: http://dx.doi.org/10.5772/intechopen.110748*

significant variation of the cyanide levels amongst them. Generally, the improved cassava varieties considered have lower hydrogen cyanide levels than the local ones.

The hydrogen cyanide levels in the cassava cultivars studied were found to be highest at the ages of 8–10 months.

Fermentation reduces the hydrogen cyanide level significantly, and the decrease varies with the fermentation period.

#### **Acknowledgements**

The authors are grateful to Mr. Dan Lema of the Government Analytical Laboratory in Kampala, Uganda, for his technical guidance during the analysis of the samples for the cyanide content. The authors also thank the Management of Muni University, who provided the funds used for paying the Open Access publication fees of this Book Chapter.

#### **Conflict of interest**

The authors declare no conflict of interest.

#### **Author details**

Benson Oloya1 \*, Christopher Adaku<sup>2</sup> and Morgan Andama1

1 Muni University, Arua, Uganda

2 Mbarara University of Science and Technology, Mbarara, Uganda

\*Address all correspondence to: oloyabenson@gmail.com

© 2023 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

### **References**

[1] NAADS. Profit Margins on Cassava Production. Kampala; 2020. Available from: https://naads.or.ug/ profit-margins-on-cassava-production/

[2] Ano OA, Eke-Okoro NO, Egesi NC. Heavy metals (Cd, Ni and Pb) pollution effects on cassava (Manihot esculenta Crantz). International Journal of Biodiversity Conservation. 2013;**5**:640- 646. DOI: 10.5897/IJBC11.029

[3] Bayata A. Review on nutritional value of cassava for use as a staple food. Scientific Journal of Analytical Chemistry. 2019;**7**:83. DOI: 10.11648/j. sjac.20190704.12

[4] Sowcharoensuk C. Cassava industry, Thail. Ind. Outlook. 2018;**20**:1-8

[5] Adebayo K, Abdoulaye S. West Africa Competitiveness Programme Regional Investment Profile – Summary Cassava Value Chain. Geneva; 2022

[6] Bradbury JH, Holloway WD. Chemistry of Tropical Root Crops: Significance for Nutrition and Agriculture in the Pacific. Melbourne: Australian Centre for International Research; 1988

[7] Cardoso AP, Mirione E, Ernesto M, Massaza F, Cliff J, Haque MR, et al. Processing of cassava roots to remove cyanogens. Journal of Food Composition and Analysis. 2005;**18**:451-460. DOI: 10.1016/j.jfca.2004.04.002

[8] Otim-Nape GW, Bua A, Thresh JM, Baguma Y, Ogwal S, Ssemakula G, et al. The Current Pandemic of Cassava Mosaic Virus Disease in East Africa and Its Control. Chatham, UK: Natural Resources Institute (NRI); 2000

[9] O'Brien GM, Wheatley CC, Iglesias C, Poulter N. Evaluation, modification, and comparison of two rapid assays for cyanogens in cassava. Journal of the Science of Food and Agriculture. 1994;**65**:391-399

[10] Grace MR. Elaboration of Cassava. FAO Collection: Plant Protection and Protection. Rome, Italy; 1977

[11] King NLR, Bradbury JH. Bitterness of cassava: Identification of a new apiosyl glucoside and other compounds that affect its bitter taste. Journal of the Science of Food and Agriculture. 1995;**68**:223-230

[12] Jørgensen K, Bak S, Busk PK, Sørensen C, Olsen CE, Puonti-Kaerlas J, et al. Cassava plants with a depleted cyanogenic glucoside content in leaves and tubers. Distribution of cyanogenic glucosides, their site of synthesis and transport, and blockage of the biosynthesis by RNA interference technology. Plant Physiology. 2005;**139**:363-374. DOI: 10.1104/ pp.105.065904

[13] Andersen MD, Busk PK, Svendsen I, Møller BL. Cytochromes P-450 from cassava (Manihot esculenta Crantz) Catalyzing the first steps in the biosynthesis of the cyanogenic glucosides Linamarin and Lotaustralin. The Journal of Biological Chemistry. 2000;**275**:1966- 1975. DOI: 10.1074/jbc.275.3.1966

[14] McMahon JM, White WLB, Sayre RT. Cyanogenesis in cassava (Manihot esculenta Crantz). Journal of Experimental Botany. 1995;**46**:731-741

[15] Siritunga D, Sayre R. Transgenic approaches for cyanogen reduction in cassava. Journal of AOAC International. *The Cyanogenic Potential of Certain Cassava Varieties in Uganda and Their Fermentation… DOI: http://dx.doi.org/10.5772/intechopen.110748*

2007;**90**:1451-1455. DOI: 10.1093/ jaoac/90.5.1450

[16] Cutler J, Conn E, Grant S. The biosynthesis of cyanogenic glucosides in *Linum usitatissimum* (linen flax) in vitro. Archives of Biochemistry and Biophysics. 1981;**212**:468-474

[17] Yemm RS, Poulton JE. Isolation and characterization of multiple forms of Mandelonitrile from mature black cherry (Prunus serotina Ehrh.) seeds. Archives of Biochemistry and Biophysics. 1986;**247**:440-445

[18] Wajant H, Mundry K. Hydroxynitrile lyase from Sorghum bicolor: A glycoprotein heterodimer. Plant Science. 1993;**89**:127-133

[19] Wajant H, Riedel D, Bent S, Mundry K. Immunocytological localization of hydroxynitrile lyases from Sorghum bicolor L. and *Linum usitatissimum* L. Plant Science. 1994;**103**:145-154

[20] Zheng L, Poulton E. Jonathan, temporal and spatial expression of amygdalin hydrolase and (R) - (+)-Mandelonitrile Lyase in black cherry seeds. Plant Physiology. 1995;**109**:31-39

[21] Rosling H. Cassava Cyanide and Epidemic Spastic Paraparesis: A Study in Mozambique on Dietery Cyanide Exposure. Sweden: Uppsala University; 1974

[22] Akintonwa A, Tunwashe O, Onifade A. Fatal and non-fatal acute poisoning attributed to cassavabased meal. Acta Horticulturae. 1994;**375**:285-288

[23] Mlingi N, Poulter NH, Rosling H. An outbreak of acute intoxications from consumption of insufficiently processed cassava in Tanzania. Nutrition Research. 1992;**12**:677-687. DOI: 10.1016/ S0271-5317(05)80565-2

[24] Cereda MP, Mattos MCY. Linamarin: The toxic compound of cassava. Journal of Venome Animal Toxins. 1996;**2**. DOI: 10.1590/ S0104-79301996000100002

[25] Delange F, Ekpechi LO, Rosling H. Cassava cyanogenesis and iodine deficiency disorders. Acta Horticulturae. 1994;**375**:289-293

[26] Howlett WP, Brubaker GR, Mlingi N, Rosling H. Konzo, an epidemic upper motor neuron disease studied in Tanzania. Brain. 1990;**113**:223-235

[27] Cliff J, Nicala D, Saute F, Givragy R, Azambuja G, Taela A, et al. Konzo associated with war in Mozambique. Tropical Medicine & International Health. 1997;**2**:1068-1074

[28] Nzwalo H, Cliff J. Konzo: From Poverty, Cassava, and Cyanogen Intake to Toxico-Nutritional Neurological Disease. PLOS Neglected Tropical Diseases. 2017;**5**(2011):1-8. DOI: 10.1371/journal. pntd.0001051

[29] Osuntokun BO. Chronic cyanide intoxication of dietary origin and a degenerative neuropathy in Nigerians. Acta Horticulturae. 1994;**375**:311-321

[30] Howlett WP. Konzo; a new human disease entity. Acta Horticulturae. 1994;**375**:323-329

[31] Onabolu AO, Oluwole OSA, Bokanga M, Rosling H. Ecological variation of intake of cassava food and dietary cyanide load in Nigerian communities. Public Health Nutrition. 2001;**4**:871-876

[32] Lang K. Die Rhodanbildung im Tierkörper. Biochemische Zeitschrift. 1933;**259**(1933):243-256

[33] F. Standards. Cyanogenic Glycosides in Cassava and Bamboo Shoots: A Human Health Risk Assessment. Canberra, Australia/Wellington, New Zealand; 2005

[34] Editor. Bitter cassava to blame for children disability - expert, Dly. Monit 2013. https://www.monitor.co.ug/ uganda/news/national/bitter-cassavato-blame-for-children-disabilityexpert-1560918

[35] Linley C-K, Chrissie K, Ngoma J, Chipungu F, Mkumbira J, Simukoko S, et al. Bitter cassava and women: An intriguing response to food security. LEISA Mag. 2002;**18**

[36] FAO/WHO. Joint FAO/WHO Food Standards Programme. Rome, Italy; 1991

[37] Bokanga M, Essers S, Poulter N, Rosling H, Tewe O. International workshop on cassava safety (WOCAS). Acta Horticulturae. 1994:375

[38] Akintonwa A, Tunwashe OL. Fatal cyanide poisoning from cassavabased meal. Human & Experimental Toxicology. 1992;**11**:47-49. http://www. ncbi.nlm.nih.gov/pubmed/1354460

[39] Andama M, Lejju JB. Potential of fermentation in detoxifying toxic cassava root tubers. 2012;**2**:1-7

[40] Okigbo NB. Nutritional Implications of Projects Giving High Priority to the Production of Staples of Low Nutritive Quality: The Case of Cassava in the Humid Tropics of West Africa. Tokyo; 1980

[41] Melinfonwu A, James B, Achou K, Weise S, Awah E, Gbaguidi B. Weed Control in Cassava Farms. IPM Field Guide for Extension Agent. Cotonou, Benin: IITA; 2000

[42] FAO. Processing and Utilization of Root and Tuber Crops. Rome, Italy; 2000 [43] Siritunga D, Sayre RT. Generation of cyanogen-free transgenic cassava. Planta. 2003;**217**:367-373

[44] Afoakwa EO, Asiedu C, Budu AS, Chiwona-Karltun L, Nyirendah DB. Chemical composition and cyanogenic potential of traditional and high yielding CMD resistant cassava (Manihot esculenta crantz) varieties. International Food Research Journal. 2012;**19**:175-181

[45] Arguedas P, Cooke RD. Residual cyanide concentration during the extraction of cassava starch. Food Technology. 1982;**17**:251-261

[46] Dufour DL. Cyanide content of cassava (Manihot esculenta, Euphorbiaceae) cultivars used by Tukanoan Indians in Northwest Amazonia. Economic Botany. 1988;**42**:255-266. DOI: 10.1007/ BF02858929

[47] Lambri M, Fumi MD, Roda A, De Faveri DM. Improved processing methods to reduce the total cyanide content of cassava roots from Burundi, African. Journal of Biotechnology. 2013;**12**:2685-2691. DOI: 10.5897/ AJB2012.2989

[48] Bradbury JH. Simple wetting method to reduce cyanogen content of cassava flour. Journal of Food Composition and Analysis. 2006;**19**:388-393. DOI: 10.1016/j.jfca.2005.04.012

[49] Westby A. Cassava utilization, storage and small-scale processing. In: Cassava Biol. Prod. Util. UK: CABI Publishing; 2001. pp. 281-300. DOI: 10.1079/9780851995243.0281

[50] Essers AJA, Ebong C, van der Grift RM, Nout MJR, Otim-Nape W, Rosling H. Reducing cassava toxicity by heap-fermentation in Uganda. International Journal of Food Sciences *The Cyanogenic Potential of Certain Cassava Varieties in Uganda and Their Fermentation… DOI: http://dx.doi.org/10.5772/intechopen.110748*

and Nutrition. 1995;**46**:125-136. DOI: 10.3109/09637489509012540

[51] Figueroa C, Davila AM, Pourquié J. Lactic acid bacteria of the sour cassava starch fermentation. Letters in Applied Microbiology. 1995;**21**:126-130. DOI: 10.1111/j.1472-765X.1995.tb01023.x

[52] Ampe F, Sirvent A, Zakhia N. Dynamics of the microbial community responsible for traditional sour cassava starch fermentation studied by denaturing gradient gel electrophoresis and quantitative rRNA hybridization. International Journal of Food Microbiology. 2001;**65**:45-54. DOI: 10.1016/S0168-1605(00)00502-X

[53] Ben Omar N, Ampe F, Raimbault M, Guyot J-P, Tailliez P. Molecular diversity of lactic acid Bacteria from cassava sour starch (Colombia). Systematic and Applied Microbiology. 2000;**23**:285-291. DOI: 10.1016/ S0723-2020(00)80016-8

[54] Oyewole O. Characteristics and significance of yeasts' involvement in cassava fermentation for 'fufu' production. International Journal of Food Microbiology. 2001;**65**:213-218. DOI: 10.1016/S0168-1605(01)00431-7

### *Edited by Andri Frediansyah*

Cassava is a staple crop in many nations due to its adaptability to a wide range of climates. It has expanded across tropical Asia, sub-Saharan Africa, and Latin America. Cassava, noted for its high carbohydrate content, is third in carbohydrate content after rice and maize. *Cassava - Recent Updates on Food, Feed, and Industry* is the second edition of our previous book, *Cassava - Biology, Production, and Use*. This new edition has four sections. The first section discusses the perspectives of several countries on cassava, including food security and the circular economy. Due to the importance of cassava in many countries, the second section examines recent biotechnological advances as well as soil management and modifications in the improvement of cassava. The third section discusses disease management and control of cassava plants. Due to its widespread use and industrial importance, cassava has been subjected to biological and technological intervention for processing into food, feed, and other industrial matter, which is covered in the final section. We hope that this book will help readers gain advanced knowledge about cassava and learn from experts in the field with multiple perspectives.

Published in London, UK © 2024 IntechOpen © yuca / Pixabay

Cassava - Recent Updates on Food, Feed, and Industry

Cassava

Recent Updates on Food, Feed, and Industry

*Edited by Andri Frediansyah*