**7. Drying by spray drying**

Microencapsulation is a technique that aims to protect the assets, from possible causes that produce their instability, such as oxidation, humidity, and photolysis, among others. For this purpose, the sample is surrounded by a polymeric layer that was denominated an encapsulating agent [13]. Therefore, there are several works in this area, which aim to guarantee and/or increase the stability of phenolic compounds present in tropical fruit by-products, including cocoa, cupuassu, pracaxi, and tucumã [13, 28, 56, 57].

Thus, the spray drying technique was chosen for drying and obtaining microencapsulated extract of CA, CP, PX, and TM by-products, in order to protect the phenolic compounds against oxidation and environmental factors. For the drying of the materials, different conditions of inlet temperature (IT) and feed flow (FF) were used, in addition to the encapsulating agents.

To confirm the encapsulation, from the microencapsulated dry extract, the total polyphenol (TP) and total flavonoid (TF) contents were determined, besides their polyphenol (YTP) and flavonoid (YTF) microencapsulation yields, as well as the antioxidant activity by the ABTS+ method. Analysis of scanning electron microscopy (SEM) of microparticles from microencapsulated extracts of Amazonian fruit by-products was performed.

**Table 6** shows the results obtained in the drying of cocoa, cupuassu, pracaxi, and tucumã extracts. Maltodextrin was the encapsulating agent for drying all extracts of fruit by-products, and a percentage of 5.0% was used. For CA extract, chitosan was also used in a percentage of 0.5%. Chitosan was used as a polymer for encapsulation as the microparticles formed with the cocoa extract by-product because it was used in pisciculture, since maltodextrin is readily soluble in water [32]. For the CA and CP extracts, FF = 2.5 and 5.0 mL/min were used, respectively, while for both, IT was 170°C. For PX and TM extracts, the FF value was 10 and 7.5 mL/min, and the IT was 160 and 100°C, respectively.

The TM extract showed the highest values for all methods used in relation to the other extracts. It was observed that the higher TP content influenced a higher antioxidant activity for all extracts, where the TM extract had the highest content of polyphenols and, consequently, higher antioxidant activity by the ABTS+ method. Despite the difference in the TP contents for the extracts of CA (80.44 ± 2.84 mgGAE/g) and CP (38.93 ± 1.24 mgGAE/g), the two presented values of YPT close to 64.87 ± 0.16% and 67.20 ± 1.90%, respectively.

The CP and TM extracts showed better microencapsulation yields (YPT and YFT), being above 50%. The YPT of the CP and TM extracts were close, where 96.50 ± 0.10 and 93.95 ± 2.62% of the polyphenols were present in the microparticles of the extracts, respectively, suggesting that they were not affected by the high temperatures used.

All extracts presented higher antioxidant activities in relation to the studies performed by Rezende et al. (129.16–155.24 μM Trolox/g) in the drying of acerola byproduct extract; this may be due to use of gum arabic, along with maltodextrin, as an encapsulation agent, besides the plant material used and drying parameters [28, 59].


*\* Results expressed as a mean of triplicate ± standard deviation.*

*\*\*mgQE/g for microencapsulated CA, PX, and TM extracts; mgCE/g for microencapsulated CP extracts.*

*ME = microencapsulated extracts; TP = total polyphenols; TF = total flavonoids; YPT and YFT = microencapsulation yields of polyphenols and flavonoids, respectively.*

#### **Table 6.**

*Values of microencapsulated extracts of CA [13], CP [10], PX [14], and TM [15] obtained by spray drying.*

*Agro-industrial By-Products from Amazonian Fruits: Use for Obtaining Bioproducts DOI: http://dx.doi.org/10.5772/intechopen.91174*

#### **Figure 7.**

*Photomicrograph (SEM) of the microencapsulated extract of Amazonian fruit by-products. a) CA [13]; b) CP [10]; c) PX [14], magnification in 1.000x; d) TM, magnification in 5.000x [15].*

With the drying results of the raw extracts of the Amazonian fruit by-products, it was observed that all of them maintained the presence of bioactive compounds and also showed antioxidant activity, using maltodextrin as an encapsulating agent.

There are a variety of polymers that can be used in microencapsulation; maltodextrin is of natural origin and is used as a wall material for encapsulation of various plant extracts because it has advantages such as biocompatibility, biodegradability, low toxicity, and reduced moisture in the wall of the microparticle [60].

The SEM analysis was performed for all four by-products in order to verify the formation of microparticles after spray drying. In the microencapsulated extract of the cocoa by-product (**Figure 7a**), the microparticles did not present any type of cracks and were not very grouped, besides not being rough. For the microencapsulated extract of the cupuassu by-product, the microparticles exhibited a very regular spherical structure, with low agglomeration, few ruptures, and heterogeneous size (**Figure 7b**), indicating poor structure deformation.

**Figure 7c** shows the photomicrographs of the microparticles present in the extract of the pracaxi by-product, where it is possible to verify that in general, the particles presented a spherical shape and rough surface characteristic of particles obtained by the spray drying method, which occurred probably during the drying and cooling process [56]. The presence of heterogeneous sizes and aggregate formation was also observed.

The microparticles of the microencapsulated extract of the tucumã by-product (**Figure 7d**) showed morphologies with low deformation in their structures and heterogeneity. Its external surfaces were without cracks and thus does not lead to rupture, which is essential to ensure greater protection of the asset. In general, they exhibit regular spherical shapes, although some are rounded, without strong agglomeration that may be due to the repulsion of loads, with varied size and presence of roughness.

### **8. Industrial application**

The reuse of vegetable waste (by-products) is a viable alternative to contribute to the production chain segment, reduce costs, and contribute to the reduction of environmental contamination [32]. In this context, they have a wide spectrum of use in the food, pharmaceutical, cosmetic and veterinary industries.

The use of residues of certain fruits as raw material in the food industry in place of synthetic antioxidants and in the production of food that can be included in human food, such as biscuits, breads, cereal bars, cakes, and pastes among other products is of great economic interest and has represented an important segment in industries [26]. By-products have been used in innovative biotechnological processes to obtain enzymes with proteolytic and keratinolytic properties [57].

The exploration of by-products of fruit and vegetable processing, as a source of functional compounds and their application in cosmetics, is a promising field, used in personal, perfumery, and cosmetics hygiene products [25]. Animal feed supplementation is one of the most frequent applications for plant by-products. Its indications on the market are pisciculture, poultry, cattle, and pigs [23, 58]. The use of nutraceuticals in diets is adopted by improving the development, performance, and immunity of the animal. In this segment, enzymes, nucleotides, chitin, chitosan, vitamins, antioxidants, and plant extracts stand out in this segment [59].

The application is possible, thanks to the levels of nutrients that they possess, because they have an expressive amount of protein, nutrients, minerals, and bioactive compounds and ensure good digestibility [33, 60] contributing to generate a low-cost product with promising characteristics for its use.

The use of elements with a low-cost and easy access enables the use of byproducts from industrial processing as a strategy to optimize the entire course of the productive stage [61]. Several studies use by-products of vegetable origin as a raw material for industrial reuse [39, 62]. These matrices present nutrient contents significantly interesting for total or partial use in fish feed supplementation [63]. Within this perspective, the cocoa and pracaxi extracts from the by-product present all the prerequisites to be applied in this market [13, 14].

In this perspective, the elaboration and characterization of flours, from fruit byproducts, have been the object of numerous studies, which point to good nutritional characteristics and potential for their application as ingredients in food [33]. Due to their nutritional characteristics, cupuassu and tucumã flours emerge as a highly desirable food ingredient to enrich other foods [33, 64].

The market is made up of niches of consumers of natural foods (energy products), such as athletes, sportsmen, children, and workers who need to eat caloric foods [65]. As a result of the growing interest of consumers for more nutritious natural foods, with good intake of carbohydrates, proteins, vitamins, minerals, fibers, and an adequate balance of calories, the market for cereal bars has been increasing [64].

In view of the above, the extracts obtained from the by-products of cupuassu and tucumã can be used in this segment. The by-product of cupuassu can be used in the enrichment of multimixture flour, which is incorporated in the feeding of children in a state of infant malnutrition, a project already applied by the Sociedade Bíblica do Brasil in partnership with the Pastoral da Criança [33] and the by-product of tucumã in the preparation of bakery products (in the form of bread and cookies) and pasta in the production of cereal bars explored as functional food [15, 64].

### **9. Conclusions**

The cocoa, cupuassu, pracaxi, and tucumã seed by-products presented concentrations of macronutrients such as proteins, fibers, total fats, and carbohydrates as ingredients potentially to be used as food or animal feed. In addition, these extracts showed significant antioxidant activity, and phenolic compounds (including protocatechuic acid, gallic acid, caffeic acid, and *p*-coumaric acid) and flavonoids (quercetin, glucosylated quercetin, epicatechin, catechin, and epigallocatechin-3-gallate) *Agro-industrial By-Products from Amazonian Fruits: Use for Obtaining Bioproducts DOI: http://dx.doi.org/10.5772/intechopen.91174*

were the most abundant compounds in these extracts. By means of the response surface methodology, it was determined that the optimal conditions for the microencapsulation of cocoa, cupuassu, and pracaxi seeds by-product extract are: IT = 170°C, FF = 2.5 mL/min, and MD = 5.0%; IT = 170°C, FF = 5.0 mL/min, and MD = 5.0%; IT = 160°C, FF = 10.0 mL/min and MD = 5.0%, respectively, and optimal conditions for microencapsulation of tucumã seeds IT = 100°C, FF = 7.5 mL/ min, and MD = 5.0%. Under these conditions, the microparticles were obtained with good stability and some heterogeneity, with spherical structure, confirming the efficiency of the microencapsulation process with the use of maltodextrin as a drying adjuvant.

Therefore, it is suggested that the microencapsulated extracts of cocoa, cupuassu, pracaxi, and tucumã seed by-products can be used in the food, cosmetic, pharmaceutical, and veterinary industries And used as a potential source of nutrients to be deployed as an integrator of alternative human food or animal feed, an opportunity in which they acquire economic value and at the same time reducing the environmental impact related to their disposal in the environment.
