Preparation of Soyabean Milk and Its Comparision with Natural Milk

Soy milk (also called soya milk, soymilk, soybean milk, or soy juice and sometimes referred to as soy drink/beverage) is a beverage made from soybeans. A traditional staple of Asian cuisine, it is a stable emulsion of oil, water, and protein. It is produced by soaking dry soybeans and grinding them with water. Soy milk contains about the same proportion of protein as cow’s milk: around 3. 5%; also 2% fat, 2. 9% carbohydrate, and 0. 5% ash. Soy milk can be made at home with traditional kitchen tools or with a soy milk machine.Despite the terminology used by consumers, it is illegal to sell soy milk under that name in the European Union, where – with certain exceptions – EC Regulation (1898/87) has restricted the term ‘milk’ to mammary secretions since 1987; in such countries the term ‘soy drink’ is commonly used. [1][2] The coagulated protein from soy milk can be made into tofu, just as dairy milk can be made into cheese. Preparation of soya milk Soy milk can be made from whole soybeans or full-fat soy flour.The dry beans are soaked in water overnight or for a minimum of 3 hours or more depending on the temperature of the water.Heating at or near the boiling point is continued for a period of time, 15–20 minutes, followed by the removal of an insoluble residue (soy pulp fiber or okara) by filtration.There is a simple yet profound difference between traditional Chinese and Japanese soy milk processing: the Chinese method boils the filtrate (soy milk) after a cold filtration, while the Japanese method boils the slurry first, followed by hot filtration of the slurry. The latter method results in a higher yield of soy milk but requires the use of an anti-foaming agent or natural defoamer during the boiling step. Bringing filtered soy milk to a boil avoids the problem of foaming. It is generally opaque, white or off-white in color, and approximately the same consistency as cow’s milk.For all raw soybean protein products, heat is necessary to destroy the activity of the protease inhibitors naturally present in the soybean. The pancreas naturally secretes proteases to digest a protein meal. Eating raw soybeans on a regular basis causes the pancreas to hypersecrete, leading to benign tumors of the pancreas. When soybeans absorb water, the endogenous enzyme, Lipoxygenase (LOX), EC 1. 13. 11. 12 linoleate:oxidoreductase, catalyzes a reaction between polyunsaturated fatty acids and oxygen {hydroperoxidation}. LOX initiates the formation of free radicals, which can then attack other cell components.Soybean seeds are the richest known sources of LOXs. It is thought to be a defensive mechanism by the soybean against fungal invasion. In 1967, experiments at Cornell University and the New York State Agricultural Experiment Station at Geneva, NY led to the discovery that paint-like, off-flavors of traditional soy milk can be prevented from forming by a rapid hydration grinding process of dehulled beans at temperatures above 80 °C. The quick moist heat treatment inactivates the LOX enzyme before it can have a significant negative effect on flavor.All modern bland soy milks have been heat treated in this manner to destroy LOX. In 1969, Mattick and Hand[16] at Cornell University made the important discovery that most of the so-called beany flavor in soybeans was not inherent in the beans themselves but was produced by the enzyme lipoxygenase when the split beans came in contact with water. Lipoxygenase could be inactivated and most of the beany flavor removed by either dropping unsoaked soybeans directly into boiling water or by removing any cracked or split beans prior to soaking, then carefully dropping the soaked beans into boiling water.Normal mature soybeans actually contain three LOX isozymes (SBL-1, SBL-2, and SBL-3) important for undesirable flavor development. One or more of these isozymes have recently (1998) been removed genetically from soybeans yielding soy milk with less cooked beany aroma and flavor and less astringency. An example of a triple LOX-free soybean is the American soybean named “Laura”. The University of Illinois has developed a soy milk that makes use of the entire soybean. What would normally constitute “insolubles” are ground so small by homogenization as to be in permanent suspension. [17] Natural milk.Milk is a white liquid produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals before they are able to digest other types of food. Early-lactation milk contains colostrum, which carries the mother’s antibodies to the baby and can reduce the risk of many diseases in the baby. It also contains many other nutrients. [1] As an agricultural product, milk is extracted from mammals and used as food for humans. Worldwide, dairy farms produced about 730 million tonnes of milk in 2011. [2]India is the world’s largest producer and consumer of milk, yet neither exports nor imports milk.New Zealand, the European Union’s 27 member states, Australia, and theUnited States are the world’s largest exporters of milk and milk products. China and Russia are the world’s largest importers of milk and milk products. [3][4] Throughout the world, there are more than 6 billion consumers of milk and milk products. Over 750 million people live within dairy farming households. Milk is a key contributor to improving nutrition and food security particularly in developing countries. Improvements in livestock and dairy technology offer significant promise in reducing poverty and malnutrition in the world.[5] Project Aim: Preparation of soya bean milk and its comparison with the natural milk with respect to curd formation, effect of temperature and taste. Theory: Natural milk is an opaque white fluid secreted by the mammary glands of female mammal. The main constituents of natural milk are proteins, carbohydrates, minerals, vitamins, fats and water and are a complete balanced diet. Fresh milk is sweetish in taste. However, when it is kept for a long time at a temperature of 35 ± 50C it becomes sour because of bacteria present in air. These bacteria convert lactose of milk starts separating out as a precipitate.When the acidity in milk is sufficient and temperature is around 360C, it forms semi-solid mass, called curd. Soya bean milk is made from soya beans. It resembles natural milk. The main constituents of soya bean milk are proteins, carbohydrates, fats, minerals and vitamins. It is prepared by keeping soya beans dipped in water for sometime. The swollen soya beans are then crushed to a paste which is then mixed with water. The solution is filtered and filtrate is soya bean milk. Materials required: Beakers, pestle and mortar, measuring cylinder, glass-rod, tripod-stand, thermometer, muslin cloth, burner.Soya beans, buffalo milk, fresh curd, distilled water. Procedure: Soak about 100 g of soya beans in sufficient amount of water for 24 hours. Take out swollen soya beans and grind them to a very fine paste with a pestle-mortar. Add about 250 ml of water to this paste and filter it through a muslin cloth. Clear white filtrate is soya bean milk. Compare its taste with buffalo milk. Take 50 ml of buffalo milk in three beakers and heat the beakers to 300, 400 and 500 C respectively. Add spoonful curd to each of the beakers and leave the beakers undisturbed for 8 hours and curd is ready.Similarly, take 50 ml of soya bean milk in three other beakers and heat the beakers to 300,400 and 500 C respectively. Add 1 spoonful curd to each of these beakers. Leave the beakers 4 undisturbed for 8 hours and curd is formed. Type of milk Beaker no Temperature Quality of curd Taste of curd Buffalo milk 1 300C 2 400C 3 500C 4 300C Soya bean milk 5 400C 6 500C Result: For buffalo milk, the best temperature for the formation of good quality and tasty curd is… oC and for soya bean milk, it is …. oC. Read more at: http://projects. icbse. com/chemistry-277.