DETERMINATION OF AMINO ACID PROFILE , PROXIMATE COMPOSITION, MINERIALS, VITAMINS, PHYTOCHEMICAL OF SEMI CURDLED MILK USING ALUM AS COAGULANT

CHAPTER ONE 1.0 INTRODUCTION Awara is the curd formed by the coagulation of milk by rennet or enzymes in the presence of lactic acid produced by added micro-organisms (Johnson et al., 2001; Achachlouei et al., 2013). It is produced with a wide range of flavours, textures and forms by coagulation of the milk protein casein. Usually the milk of buffalo, goat, or sheep is used. During production, the milk is usually acidified by adding the enzyme rennet which causes coagulation. The solids produced are separated and pressed into the final form (Achachlouei et al., 2013). Awara (Tofu) is very nutritious due to the high protein quality (Butler et al., 2010; Ndife, 2016) and is also a good source of dietary calcium. Cheese has fewer digestive problems compared to other dairy products (Oboh and Omotsho, 2005; Onwuka, 2014). However, the high saturated fat content, from the nutritional quality point of view, poses a health challenge to consumer perception (Onwuka, 2014). Apart from Tofu being a popular snack among students of primary schools in northern Nigeria, awara has long been used as a substitute for meat and fish in a variety of home- cooked dishes. In some cases, awara fills the gap in terms of dietary requirements if traditional animal protein like meat and fish are out of reach because of budgetary constraints. Awara's nutritional benefits are immense (Adetunji and Babalobi, 2011). Besides protein, it contains nutrients like magnesium, calcium, fiber, unsaturated fatty acids, carbohydrates, vitamins B, C, and K, iron, and manganese. It is reported to aids in digestion and bowel movement, drives the immune system, strengthens blood vessels, reduces cholesterol, improves bone health, and is an easy choice for people with diabetes and lactose intolerance. It is a very good source of dietary protein that ranks high among the great world protein sources, which are meat, fish, eggs and milk (Liu, 1997). Soybean (Glycine max L) is a leguminous plant, which is a rich source of good quality protein (Giri et al., 2018), it also provides several therapeutic benefits because of its essential amino acids in the amounts needed for human health. It is also rich in phenolic compounds, isoflavones and antioxidants (Guzmán-Ortiz et al., 2017). Besides, soy products offer a considerable appeal for a growing segment of consumers with certain dietary and health concerns (Jooyandeh, 2011). Protein percentage in soybean is about 70% compared with that of whole egg protein (Crittenden, 2005). In tropics where animal protein is limited, expensive, and scarce, soybean meal is a good source of plant protein, it is available, and could be a supplement to cereal foods where lysine is limiting (Crittenden, 2005). Soy cheese is a nutritious meat substitute and it is prepared by curdling the milk extract from soybean. The coagulation of the milk obtained from the soy is influenced by cooking temperature, pH, solid contents; coagulant types, amount, concentration; mixing and adding methods, time etc. (Cai et al., 1998). Among the coagulant’s different salts like magnesium chloride, magnesium sulphate (Epsom salt), calcium sulphate etc. are used because they reduce the pH of the solution which helps to coagulate the proteins (Obatolu, 2008). These salts are also used to coagulate the milk obtained from other pulses (Cai et al., 2001). Tiger nut (Cyperus esculentus L.), also classified as a nut have been recognized as one of the best nutritional crop that can be used to augment the diet of human population (Afenu, 2008). Consumption of tiger nut is healthy and aids in preventing heart attacks, thrombosis and activates blood circulation; it also helps in preventing colon cancer and other cancers due to its high content of soluble glucose (Adejuyitan et al., 2009). Tiger nut is cultivated for both human and livestock consumption. The nuts can be eaten raw, baked or roasted or processed further into a drink. It can also be used as a flavouring agent for ice creams and biscuits (Bolarinwa et al., 2009) and can also be used as a substitute for almonds in confectionery. The nuts are valued for their highly nutritious starch content, dietary fibre, carbohydrate (mono, di and polysaccharides). The nut was reported to be rich in sucrose (17.4 to 20.0%), fat (25.50%), and protein (8%). 1.1 PROBLEM STATEMENT Dairy milk and dairy milk products are nutritious and highly consumed around the world but many people are also allergic and have lactose intolerance to dairy milk products. In developing countries, lack of sufficient protein in the diet of a large percentage of the population is becoming a major setback for human development (Liu, 2000). Also, the high saturated fat content, from the nutritional quality point of view, poses a health challenge to consumer perception (Onwuka, 2014). Efforts are aimed at finding alternative sources of protein from legume seeds in order to meet protein demands in places where animal protein is either grossly inadequate or relatively expensive. 1.2 JUSTIFICATION Soybeans is one of Nigeria’s most important agricultural products. It represents a form of preservation of milk in the solid state and contains high proteins content. As a result, it can be used to alleviate various forms of malnutrition, particularly protein-energy malnutrition, which is common in developing countries. Tiger nuts on the other hand are excellent sources of minerals such as phosphorus, potassium, vitamins E and C, starch, fat, sugars, protein (Belewu and Belewu, 2007). Incorporation of milk from these two crops into awara production will provide a rich product that is filled with nutrients. 1.3 AIMS AND OBJECTIVES a. To produce Soy-cheese (Awara) from Soybean milk and tigernut milk b. Determine the amino acid profile of Soy-cheese from Soybean and tigernut milk c. To evaluate the Phytochemical properties of Soy-cheese from Soybean and tigernut milk d. To determine the Proximate composition of Soy-cheese (Awara) from Soybean and tigernut milk CHAPTER TWO LITERATURE REVIEW 2.1 Awara is fermented milk-based food products, produced in a wide range of flavors and forms. They are commonly classified according to their texture, which varies with the degree of moisture. Tofu has a long history in the human diet. In ancient times, cheese was primarily a concentrated form of milk with the benefit of a prolonged shelf life. The high content of fat and protein in cheese made it an energy-rich and nutritious food that was suitable for our hardworking ancestors. Recent advances in nutrition science have highlighted the contribution of cheese to nutrition and health. Cheese is a rich source of essential nutrients; in particular, proteins, bioactive peptides, amino acids, fat, fatty acids, vitamins and minerals. Ripened cheese is free of lactose and therefore suitable for the nutrition of lactose-intolerant individuals. Nowadays, cheese consumption is widely spread throughout the world. The main reason for the consumption of cheese is not the prevention of hunger but the supply of important and essential nutrients, its manifold uses in the kitchen, and its enjoyment. Technological progress has led to a multitude of different types of cheese on the market, varying in texture and flavor. Nowadays, a shift is observable from the optimum in product quality to the optimum for the consumer. So research is no longer based on the production of high quality cheese but more and more on the commercialization of cheese as a functional food. Technology is needed for gentle processing to retain or even accumulate desired nutrients and to remove undesired compounds. Since more and more individuals would like to control their health via custom-made food, the worldwide market for Functional Food is one of the fastest- growing markets in the world. 2.1.1 COMPOSITION OF AWARA The various cheese types can be classified according to the milk used (cow, sheep, goat, buffalo), their manufacture (rennet, sour milk cheese, ultrafiltration), consistency (extra- hard, hard, semi-hard, semi-soft, soft, fresh cheese), fat content (double cream, cream, full fat, three-quarters fat, half fat, quarter fat cheese), fermentation type (lactic acid, lactic and propionic acid, butyric acid), surface (hard, soft, with smear, moulds) and interior (eyes, moulds). Additionally, they differ in flavor as well as some bioactive components, which are mainly created during the different stages of ripening when the main ingredients lactose, protein and fat are broken down by fermentation, proteolysis and lipolysis (Molimard and Spinnler, 1996). Thus, the varieties of cheese on the market are enormous, which is also reflected in the variability in the composition of the different types of cheese. In most of the countries with a high consumption of milk products the major part is produced from cow’s milk. 2.2 Proximate Composition of Awara According to Bintu et al. (2021), the percentage moisture, ash, protein and fat contents of non-fermented soybean awara was (4.95±0.04), (2.86±0.01), (1.59±0.01) and (14.37±0.00), respectively while fermented soybean awara had (18.92±0.01), (6.47±0.01), (3.75±0.01) and (17.13±0.01) respectively and these values were significantly (p