PASTING AND FUNCTIONAL PROPERTIES OF FLOUR BLENDS MADE FROM AFRICAN YAM BEAN AND CORN

The problem of malnutrition due to deficiency of protein and calories is common in Nigeria. Protein and calories from plant sources have been proposed as a solution to this problem (Idowu, 2015).Corn (Zea mays L.) also known as maize is commonly used as an inexpensive source of calories in Nigeria and some other countries. Corn is the third most important cereal in the world after rice and wheat and ranks fourth after millet, sorghum and rice in Nigeria (Kumar and Jhariya, 2013; Enyisi et al., 2014). Corn is considered an important source of nutraceuticals known to enhance health and prevent diseases, including phenolics, carotenoids, anthocyanins, phlobaphenes, insoluble and soluble dietary fiber and polar and nonpolar lipids (Serna-Saldivar, 2016; ŽIlić et al., 2017). Corn is extensively used in making ogi, tuwo, donkunnu, masa, popcorn, aadunand kokoro in Nigeria (Ekpa et al., 2019).Some of these products are made from corn flour, which is rich in carbohydrate (Idowu, 2015).These products are widely consumed especially among the low income community thus necessitating its fortification with an inexpensive protein from plant source.

African yam bean (Sphenostylis stenocarpa) is an underutilized tropical legume with high nutritional value (Baiyeri et al., 2018).African yam bean seeds are an important food sources that can be exploited, particularly in the developing countries where there is shortage of animal protein(Baiyeri et al., 2018).Seeds of African yam bean possess lysine, histidine, arginine, aspartic acid, threonine, serine, glutamic acid, proline, glycine and methionine (Okorie, 2018).Although it contains anti-nutritional factors such as haemagglutinins, tannins and oligosaccharides (Okeola and Machuka, 2011), processing destroys most of these factors and the processed products do not give serious health problems (Idowu, 2014).

Pasting property is one of the most important properties that influence quality and aesthetic considerations in the food industry since they affect texture and digestibility as well as the end use of starch-based food commodities (Ajanaku et al., 2012). It is an index for predicting the ability of a food to form a paste when subjected to heat applications (Iwe et al., 2016). Pasting property includes peak viscosity, trough viscosity, breakdown viscosity, final viscosity, setback viscosity, peak time and pasting temperature (Iwe et al., 2017).

Functional properties are the fundamental physio-chemical properties that reflect the complex interaction between the composition, structure, molecular conformation and physio-chemical properties of food components together with the nature of environment in which these are associated and measured (Siddiq et al., 2009). According to Fitzpatrick and Ahrné (2005), the behaviour of flour during food processing is based on their functional properties. Examples of functional properties includes but not limited to bulk density, water absorption capacity, oil absorption capacity, gelatinization temperature and so on (Nwanekezi et al., 2010).

Composite flour is crucial for production of numerous food products. It has various advantages which includes but not limited to reduction of wheat flour importation, encouragement of the use of locally grown crops as flour (Hasmadi et al., 2014) and saving some foreign exchange which could be used to develop other areas of the economy (Nwanekezi, 2013).Assessment of functional and pasting properties of composite flour from African yam bean and corn is a means of determining their applicability in food system. 

Food insecurity is one of the most pressing problems in developing countries. Food insecurity exists when people lack sustainable access to adequate, safe, nutritious, and socially acceptable food for a healthy and productive life, thus, resulting to chronic hunger and malnutrition (Ilaboya et al., 2012).Globally, protein energy malnutrition continues to be a major health burden in developing countries and the most important risk factor for illnesses and death especially among young children (Ejaz and Latif, 2010). Protein energy malnutrition is associated with a number of co-morbidities such as lower respiratory tract infections including diarrhea (Ejaz and Latif, 2010).The World Health Organization estimates that about60% of all deaths occurring among children aged less than five years in developing countries such as Nigeria could be attributed to protein energy malnutrition (Faruque et al., 2008). This necessitates utilization of nutritious and locally available crops in food system. Nigeria is one of the producers of corn and African yam bean seeds which serve for both domestic and industrial consumption. However, despite their relative high production, Nigeria depends on importation of flour. This importation makes flours from locally available staples to go into extinction. This, no doubt, is depleting Nigeria’s external currency earnings and reserve. Therefore, this study aims at evaluating the functional and pasting properties of flour blends made from nutritious and locally available raw materials (African yam bean and corn).

The main objective of the study is to evaluate the functional and pasting properties of flour blends made from corn (Zea mays)and African yam bean seeds (Sphenostylis stenocarpa).

The specific objectives are to:

Increase utilization of flour blends of African yam bean and corn in food systems is one of the practical means of curbing food insecurity in developing countries such as Nigeria. This will reduce the reliance on imported flour leading to saving of Foreign exchange. It will also create awareness of the potentials of African yam bean, thus, preventing it from going into extinction. Evaluation of the functional and pasting properties of flour produced from African yam bean and corn blends will enhance their food and industrial application. Data obtained in this study will be of great benefit to food industries and households that utilize local staples in food production like biscuits, chin chin, cakes, dough nut and other bakery products. Nutritionists and dieticians in developing countries such as Nigeria will find composite flours developed in this study highly valuable in management of protein energy malnutrition.