CHAPTER ONE
1.0     INTRODUCTION
1.1   Background of the Study
Proteins are essential nutrients for the human body (Hermann, 2002). They are one of the building block of the body tissue, and also serve as a fuel source. As a fuel, protein contain 4kcal 7kj) per gram, just like carbohydrates and unlike lipids, which contain 9kcal (37kj) per gram. The most important aspect and defining characteristics of protein from a nutritional stand point is its amino acid composition (Laurence, 2000).
Proteins are polymer chains made of amino acids linked together by peptide bonds. During human digestion, proteins are broken down in the stomach to smaller polypeptide chain via hydrochloric acid and protease actions. This is crucial for the synthesis of the essential amino acids that cannot be biosynthesized by the body (Genton, 2010). There are nine essential amino acids which humans must obtain from their diet in order to prevent protein-energy malnutrition. They are phenylalanine, valine, lysine, leucine, threonine, tryptophan, methionine, isoleucine and histidine (Laurence, 2000). There are five dispensable amino acids which humans are able to synthesize in the body. These five are alanine, aspartic acid, sernine, asparagines and glutamic acid. There are six conditionally essential amino acids whose synthesis can be limited under special pathophysiological conditions, such as prematurity in the infant or individuals in severe catabolic distress (Laurence, 2000). These six are argnine, cysteine, glycine, glutamine, proline and tryrosine (Laurence, 2000). Sources of protein include grains, legumes and nuts, as well as animal sources such as meats, dairy products, fish and eggs (Young, 1994).
African breadfruit (Treculia Africana Decne) belongs to the mulberry family. Moracceae, which is of African origin but now grown in the most tropical and sub-tropical countries (Agu and Nwabueze, 2007). African breadfruit or wild jack fruit in some areas, is a neglected and under exploited tropical tree (Osuji and Owei, 2010).
According to Okonkwo and Ubani (2012), it is a common forest tree called various names among different tribes in Nigeria, such as “Ukwa” (Igbo), “afon” (Yoruba), “eyo” (Igala), “barafuta” (Hausa), “Ize” (Benin) and “edikang” (Efik). The tree crop is widely grown in the southern state of Nigeria where it serves as low cost meat substituent for poor families in some communities (Badifu and Akuba, 2001; Ugwu, et al, 2001). the plant produced large, usually round, compound fruit covered with pointed outgrowths and the seeds are buried in the spongy pulp of the fruits (Nwokolo, 1996). the seeds are seldom eaten raw but can be baked, roasted or fried before consumption, or they can be ground into flour in bakery products (Agu et al, 2007; Ijeh et al, 2010). African breadfruit seeds are highly nutritious and constitute a cheap source of vitamins, minerals, proteins, carbohydrates and fats.
Brown beans (Phaseolus Vulgaris) is a herbaceous annual plant grown worldwide for its edible dry seeds (Known as just ‘Beans”) or unripe fruit (Green beans). It’s leaf is also occasionally used as a vegetable and the straw as fodder. It’s botanical classification, along with other phaseolus species, is as a member of the legume family fabaceae, most of whose members acquire the nitrogen they require through association with rhizoidal, a species of nitrogen-fixing bacteria (Edet, 1982). Beans are grown in every continent except Antarctica. Brazil and India are the largest producers of dry beans, while china produces by far, the largest quantity of brown beans. Worldwide, 23 million tones of dry common beans and 17.1 billion tones of green were grown in 2010 (Philips, 2010). Similar to other beans, the brown beans is high in starch, protein and dietary fiber, and is an excellent source of iron, selenium, potassium, molybdenum, thiamine, vitamin B6 and folate (Paul, 1998) .