**7. Conclusion**

*Recent Advances in Rice Research*

snacks are well-liked by consumers.

**6. Utilization of rice husk for energy**

postharvest handling for sustainable environment.

cooking in rice processing communities of Africa.

Cold forming extrusion (40–70°C, 60–90 bar) of pre-gelatinized rice flour blended legume flour is used for the production of rice-based 3G snacks. Adjusting extrusion temperature, residence time and initial ingredient moisture facilitate complete gelatinization of starch component of the ingredients before frying [57, 59, 60]. Extruded snacks from rice will significantly take some market share as more and more countries in Africa are increasingly improving their rice production and more consumers are becoming more interested in non-gluten baked snacks. Badau *et al.* [61] state that the addition of 30% cowpea to rice flour for the production of traditional Nigeria snack (*Garabia*) significantly improves protein content, metabolizable energy and vitamin B2, while consumer rating based on 9-point hedonic scales was above 6.0 indicating that with the addition of cowpea, the

In 2014, it was estimated that Sub-Saharan Africa produces about 22.1 million tonnes of paddy, which represent about 4.6% of the total global production [5]. Structurally, paddy consists of about 72% kernel, 5–8% bran and 20–22% husk [62]. Therefore, when 22.1 million tonnes of paddy are subjected to milling, it produces about 4.8 million tonnes of husk [11]. With the increased production of paddy in Africa over the last 2 decades, the annual production of rice husk has also proportionally increased. The utilization of rice husk for economic purposes hitherto in Africa especially SSA is very low even though by-products such as rice husk is suitable raw material for energy generation and bran is a nutritive ingredient for food formulation [11, 63]. The high amount of silica in rice husk even when mixed with bran as obtained from village mills (Engelberg type mill) is not suitable for animal feeding purposes. In SSA, significant proportion of rice husk produced is disposed of by burning in open fields or abandoned around rice milling facilities [11]. These practices have resulted in the pollution of air, land and water through the generation of greenhouses gases and particles in water and air [64]. This situation calls for urgent and innovative technique to economically utilize the husk and improve rice

Rice husk, a by-product of rice milling is about 20% by weight of paddy and chemically contains about 20% SiO2. Gasification technique for rice husk as energy for rice parboiling and household cooking has been recently developed and is being commercialized across the continent of Africa [65]. Five different rice husk top-lit updraft (TLUD) gasifier household cooking stoves for use in rice processing clusters of Africa has been evaluated under a study to select technically feasible rice husk stove for rural and semi urban household cooking and artisanal rice processing in Africa. Ndindeng, *et al*. [65] study demonstrated that fan-assisted cook stoves especially PO150 recorded better thermal and emission indices and are safer to use than the natural draft gasifiers stove and is therefore recommended for household

Gasification is the process of converting biomass such as rice husk into a combustible gas through thermo-chemical reaction of oxygen in the air and carbon available in the biomass during combustion. In other to gasify rice husk therefore, about 4.7 kg of air per kg of rice is needed [66, 67] and has resulted in the development of several models of fan-assisted rice husk gasifier [65]. The energy obtained are environmentally friendly and the technology easy to use by rural households. Using biomass such as rice husk in Africa for energy generation offers several advantages, including the mitigation of gaseous emissions such as CO2, SOx, and NOX [68]. This is probably due to low amount of sulphur and nitrogen present in

**218**

Significant improvement has been made in Africa in terms of rice production mainly as a results of the development of new improved varieties, expansion of area under rice cultivation and huge public and private sector investments. This increased production has resulted in increased by-products such as broken rice fractions and husk. Poor utilization of the broken fractions resulted in reduction of productivity of rice and the husks have become of huge environmental and health changes. The high postharvest losses recorded in Africa has become of great concern to research and development experts, and new innovative methodologies were developed to use broken rice fractions for the production of high quality rice flour that could be used to produce high nutrients and consumer acceptable value added products that improve income and food security of smallholder rice value chain actors. The utilization of rice husk for energy generation has also become a fast moving technology where fan-assisted cooking stoves are developed and provide efficient alternative to fossil fuel. Both qualitative and quantitative postharvest losses in rice are being aggressively managed as a strategy to improve food and nutrition security, environmental sustainability and overall productivity of rice production system. Stakeholder including policy-makers, environmental experts, among others, should as a matter of urgency priority consider the use of biomass as sources of energy for home cooking to reduce over dependence on forest woods and popularize the fan-assisted cooking stove among rural dwellers especially among populations in the Sahel region of Africa where desert is moving fast. Utilization of broken rice fraction as raw materials for flour, snacks, porridges and other foods should be encouraged as means of improving food and nutrition security as well as the socioeconomic development of rural areas.
