**5. Innovative strategies for rice postharvest loss reduction in Africa**

Innovative production is a concept that describes an on-going re-engineering process with the major aims of evolving products and production engineering from prevalent trends based on advances in research for development [34]. Innovative rice postharvest loss reduction trends in Africa is being re-engineered by evolving new value added products based on prevalent research trends. Since production innovation strengthens the productivity and resource use efficiency of production system, recent trends in Africa in the field of rice postharvest system development is the innovative approach to the utilization of rice processing by-products as a strategy to strengthen the productivity of rice and resource use efficiency. The following sections describes the innovative strategies currently used in Africa to reduce postharvest through efficient postharvest system management.

#### **5.1 Utilization of broken rice fractions for rice flour production**

Fissuring cause by poor postharvest handling of paddy results in broken kernels upon milling, and consequently lost in quality and economic values of milled rice [35]. However, recent increase in the use of rice flour has promoted interest in broken rice fractions utilization as raw materials in many foods especially snacks, porridges and others [36]. Rice flour has been used traditionally for the production of traditional stiff dough (*tuwo*) in Nigeria and many West African countries [20]. Its application in the production of high quality flour that could be used in baking has been hampered by lack of improved rice flour production process that produces flour of particles sizes that could be considered suitable as baking flour and improved functionality [21].

Chiang and Yeh [37] proposed wet milling of rice kernels to produce flour of desirable functionality. As a strategy to valorised broken rice fractions resulting from poor milling processes and rice of low grain quality characteristics, broken rice fractions are processed through wet milling process to produce high quality rice flour that has appreciably acceptable baking quality [21]. The innovative technique which is being commercialized in Africa, involves repeated wet grinding of soaked broken rice fractions and sieving through a fine cloth mesh until virtually all the slurries are made to pass through the sieve. The filtrate is allowed to stand for 3–4 hours depending on the variety and water temperature and decanted to obtain smooth sediment at the bottom. The solid sediment is broken into pieces and dried in an oven before pulverizing and sieving (200 μm) to obtain rice flour (**Figure 2**). The United States Code of Federal Regulation (CFR) state that for a product of milling of grains to be considered as flour, not less than 98% of the particles of the milling process must pass through a sieve having opening not larger than 212 μm [38]. Flour of this particle size characteristics has been demonstrated to impact positively on the end-use application [21, 38–40] studied the physicochemical and functional properties of flours from some common Nigerian rice varieties and concluded that these properties are promising for their application in food systems.

Production of flour from broken rice fraction has been shown to improve the economic value of broken rice kernels by 38% and significant consumer preference for snacks and other baked products. This has significantly reduced qualitative losses incurred during rice processing and improved income of smallholder food processors. The high quality rice flour is also blended with legume based flour (**Figure 3**) to improve protein content and quality to enhance nutrition and product specifications [21] which is an innovative production system.

*Recent Advances in Rice Research*

nutrition security in SSA.

**4. Constraints and need for innovative loss reduction strategies**

The continues increase in rice consumption together with minimal increase in domestic production coupled with high postharvest losses, high rice import cost and glaring impacts of climate change and conflicts in Africa, research and development organizations are working together under a coordinated strategy lead by Africa Rice Centre (Africa*R*ice) to provide innovative approach for improving productivity and food and nutrition security through postharvest loss reduction. The rapid advances in small and intermediate technology development, formulation and production of new value added products from low grade broken rice fractions and other rice processing by-products demonstrated the ability to improve food and nutrition security in Africa through novel postharvest loss reduction strategies [10, 16, 21, 28]. Until recently, rice research for development has focused on yield improvement without much emphasis on postharvest practices especially as it relates to loss reduction, quality improvement and marketability. But Nguyen and Ferrero [29] opined that in near future, the possibility of expanding rice production area will remain limited in SSA due to high cost of developing new land suitable for rice production combined with water scarcity for rice production and urban and industrial expansion, implying that loss at any point of the value chain need to minimized to save food and

In 2008, the SSA countries were faced with significant hike in food price [30]. Milled rice in the international market grow by almost 400% and combined with about 40% rice deficit in SSA, it become highly vulnerable to global rice prize shock and probably was the major cause of 'food riot' in 2008 in countries such as Burkina Faso, Cameroon, Cote d'Ivoire, Mauritania and Senegal [31, 32]. The riot of 2007–2008 [32] triggered renewed focus and investments in rice production together with postharvest operations in many African countries. Nigeria, Ghana, Togo, Cote d'Ivoire, The Gambia, Senegal and Burkina Faso developed a national strategic plan to attain rice self-sufficiency in medium and long time by increasing public and private sector investment into rice sub-sector of their economy, but quality and postharvest losses are least emphasised [33]. In 2011, Africa*R*ice lead a consortium of research organizations in major rice producing countries of Africa to implement and innovative postharvest loss reduction model 'enhancing food security in Africa through the improvement of rice postharvest handling, marketing and development of new rice-based products'. The project emphases the utilization of flour from low grade broken rice fractions to prepare value added food products such as snacks, biscuits, and porridges. This innovative uses of rice can catalyse rural enterprises and raise income, especially for women farmers and processors in Africa [33]. The project also developed innovative technology to utilize rice husk for energy as a strategy to add value to rice husks which are hitherto stockpiled and dumped near mills where they rot and produces methane (a potential greenhouse

gas) or burned in the open fields, thus causing pollution.

By improving harvest and postharvest system of rice value chain in Africa, small holder farmer's income will be enhanced through time saving on processing, reduction in qualitative and quantitative postharvest losses which will translate to higher income and better quality of locally milled rice which may compete favourably with imported brands and fetch better price, thereby enhancing the incomes of various actors along the value chain. New rice products containing high nutrients will improve nutrition security and provide employment for women and youths and the overall industrial development of rural communities. The utilization of rice husks for energy will certainly reduce deforestation which is currently threatening

significant number of countries of Africa, especially the Sahel region.

**212**

#### **Figure 2.**

*Flow chart for the production of high quality rice flour from broken rice fractions. Danbaba et al. [21].*

#### **Figure 3.**

*High quality rice flour from broken rice fractions (left), branded rice flour (centre) and rice flour blended with cowpea flour for the production of high protein baked products [21].*

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**Figure 4.**

*Advances in Rice Postharvest Loss Reduction Strategies in Africa through Low Grade Broken Rice…*

Recent changes in social life of many population across the world and the development of middle class worker in developing countries of Africa has resulted in high population of people who are inclined to eat 'ready-to-eat' food, because of its convenience, easy to consume, low to moderate price with minimal need for further processing. Extruded snacks are example of such products and their consumption is growing by day. Extrusion cooking technology is a continuous mixing, cooking and shaping process carried out at high temperatures over short times [41]. It is a very versatile, low-cost and highly energy efficient technology for snack or expanded foods production. Extrusion of cereal-based flours or other starchy raw materials is widely used in the food industry in developed countries to produce snack foods [42]. Little of extrusion cooking is being practiced in Africa especially as it relates to value added rice processing, but recent advances in rice postharvest science has introduce the use of low grade broken rice fractions as raw material for the

However, when starchy raw materials such as rice are subjected to extrusion cooking, there is a chemical and structural transformation such as starch gelatinization, protein denaturation, complex formation between amylose, lipids and/or proteins, and degradation of pigments and vitamins [44]. Under the Africa-Wide Taskforce on Rice Processing and Value Addition of Africa Rice Centre and its national partners, low grade broken rice fractions from different milling operations have been tested and validated for the production of snacks that are high in protein and acceptable to consumers [21, 43]. Through process modelling and optimization, optimum moisture content, barrel temperature and level of legume flour for extrusion have been established for the blends of broken rice fractions with cowpea, bambara groundnut and soybean, keeping other extrusion parameters within range [21, 28, 43]. This optimized process conditions produces extruded snacks with smooth outer-surface (**Figure 4**) and uniform air spaces with regular shape, this

Because extrusion cooking process allows for the production of low-fat snacks and induces the formation of resistant starch, which makes no caloric contribution

*Photographic images (longitudinal section) of the physical state of rice-cowpea blend extruded snacks.*

according Ryu et al., [45] are features of good quality extrudates.

**5.2 Development of ready-to-eat (RTE) high protein extruded snacks and** 

*DOI: http://dx.doi.org/10.5772/intechopen.94273*

**porridges from broken rice fractions**

production of extruded snack foods [10, 43].

*Advances in Rice Postharvest Loss Reduction Strategies in Africa through Low Grade Broken Rice… DOI: http://dx.doi.org/10.5772/intechopen.94273*
