1.0 Introduction
1.1 Background to the study
Infants and young children suffer from malnutrition in most developing countries. The growth of infant in the first and second year of life is very rapid and breast milk alone cannot meet the child's nutritional requirements. The infant needs supplementary feeding starting from 46 months (Achinewhu, 1987; Ijarotimi and Famurewa, 2006). Many brands of preparatory foods have been developed and marketed; however these brands are too expensive and therefore are beyond the economics of low income families. The high price of proprietary weaning food and animal proteins combined with faulty feeding practices are mostly responsible for aggravating malnutrition among children (Dutra-de —Olivera, 1991).
Protein energy malnutrition (PEM) generally occurs during the crucial transitional phase when children are weaned from liquid to semi solid or fully adult foods. Children therefore require nutritionally balanced calorie-dense supplementary foods in addition to mother's milk (Berggren, 1982; Cameroon and Hafvander, 1971). Several studies have reported that most of the weaning foods consumed by children in many parts of developing nations are deficient in essential macro and micro nutrients (Levin et al., 1993; Brabin and Coulter, 2003; Milward and Jackson, 2004). In view of this nutritional problem, several strategies have been used to formulate weaning food (Lalude and Fashakin, 2006; Ijarotimi and Ashipa, 2006; Ijarotimi and Bakare, 2006) through a combination of locally available under-ultilized food crops that complement each other.
Tigernut (Cyperus esculentus) is an underutilized readily available crop in Nigeria. It belongs to the family of Cyperaceae, which produce rhizomes from the base and are somewhat spherical. The tubers contain significant amount of protein, fat, minerals and vitamins (Alobo and Ogbogo, 2007; Oladele and Aina, 2007). In addition, tigernut tubers could be used for the treatment of flatulence, indigestion, diarrhea, dysentery and excessive thirst (Chevallier, 1996). The use of such readily available underexploited crop to complement with legumes such as soybeans in developing a simple household low cost weaning food hold promise in alleviation of infant malnutrition. The challenge therefore is to develop a nutrient dense supplementary infant food from locally available underutilized crops that could be adoptable at the household level.
1.2 Uses of Soybeans
When the farmer sells soybeans to a grain dealer, the beans may then go to a number of ultimate destinations. When processed, a 60-pound bushel will yield about 11 pounds of crude soybean oil and 47 pounds of soybean meal. Soybeans are about 18% oil and 38% protein. Because soybeans are high in protein, they are a major ingredient in livestock feed. Soybeans are processed for their oil (see uses below) and meal (for the animal feed industry). A smaller percentage is processed for human consumption and made into products including soy milk, soy flour, soy protein, tofu and many retail food products. Soybeans are also used in many non-food (industrial) products.
Some soybeans are needed to produce another crop each year. High quality soybeans are grown, harvested and purchased by the seed industry to be used as seed for the next year's crop. Researchers in the seed industry focus on developing new soybean varieties with outstanding characteristics including high yield, lodging resistance, nematode resistance, herbicide tolerance, and many other desirable characteristics.
Food for Humans
Nearly all soybeans are processed for their oil. Soy processors (such as Cargill & ADM) take the raw soybeans and separate the oil from the meal. The oil may be refined for cooking and other edible uses, or sold for biodiesel production or industrial uses. The processors bake the high-protein fiber that is left after the oil is removed and sell it for animal feed.
Soybean oil is used in cooking and frying foods. Margarine is a product made from soybean oil. Salad dressings and mayonnaises are made with soybean oil.
Some foods are packed in soybean oil (tuna, sardines, etc.) Baked breads, crackers, cakes, cookies and pies usually have soybean oil in them.
Feed for Animals
The high-protein fiber (that which remains after processing has removed the oil) is toasted and prepared into animal feed for poultry, pork, cattle, other farm animals and pets. The poultry and swine industries are major consumers of soybean meal. Over half of the soybeans processed for livestock feed are fed to poultry, about one-quarter is fed to swine, and the rest is used for beef cattle, dairy cattle and pet food.
Soy protein is increasingly found in fish food, both for home aquariums and for the fish grown for eating. Most marine species were fed fish meal at one time, but the scarcity and increasing cost of fish meal has led producers to switch to high protein soymeal for a variety of marine species. Around the world, soy protein may be found in feed for most animals.
