Chemistry Project

Chemistry Project

Study of Comparison on Soya Milk (Soymilk) and Natural Milk

Submitted To: Submitted BY:

Rohit Kumar

Soy 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 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. The coagulated protein from soy milk can be made into Tofu, just as dairy milk can be made into cheese.

Nutrition and health information Nutrients in 8 ounces (250ml) of plain soymilk: Regular Soymilk Calories (gm) 140 Protein (gm) 10.0 Fat (gm) 4.0 Carbohydrate (gm) 14.0 Sodium (mg) 120.0 Iron (mg) 1.8 Riboflavin (mg) 0.1 Calcium (mg) 80.0

Lite Soymilk (reduced fat) 100 4.0 2.0 16.0 100.0 0.6 11.0 80.0

Preparation 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. The rehydrated beans then

undergo wet grinding with enough added water to give the desired solids content to the final product. The ratio of water to beans on a weight basis should be about 10:1. The resulting slurry or purée is brought to a boil in order to improve its nutritional value by heat inactivating soybean trypsin inhibitor, improve its flavor and to sterilize the product. 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. 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.

Commercial products labeled "soy drink" are often derivatives of soy milk containing more water or added ingredients.

Preparation of curd from soya bean milk To 2400 kg of soy bean milk were added 71 kg of calcium hydroxide-sucrose complex solution, 30 kg of 10% saline water and 30 kg of 5% sodium hexametaphosphate solution. To the resulting mixture were further added 81 kg of 10% - aqueous solution of citric acid and 170 kg of water for forcing the soy bean milk through the pipeline. The pH value of the resulting mixture was adjusted to 7.1. With use of the VTIS device manufactured by Alfalaval Inc., the resulting mixture was subjected to a high temperature sterilizing treatment for 30 seconds at 140° C. by the VTIS method, followed by cooling and further mixing with 36 kg of 10% - aqueous solution of citric acid. The pH value of the resulting mixture was then adjusted to 5.75. Then, with use of the aseptic charging device manufactured by Tetra Pack Co., the mixture was conventionally charged into a container under germ-free conditions as the opening of the container was sealed. The product thus obtained was charged into a

heating and coagulating tank and coagulated by treatment at 85° C. for 40 minutes to give the product soy bean curd. The resulting curd formed a highly satisfactory gel with less water oozing and with a mild creamy texture. The calcium contents in the product amounted to 100 mg % as calcium so that the curd provided to be an excellent calcium-enriched foodstuff. It is noted that the soy bean milk used in the present Example is composed of 12.0 percent of total solid contents, 5.8 percent of protein and 30 mg % as calcium, and the solution of the calcium hydroxide-sucrose complex is a solution in 43.0 ky of water of 5.0 kg of calcium hydroxide and 23.3 kg of succrose.

Soya Curd

Soya Curd, (Soya yoghurt in British English) also referred to as is curd prepared using soy milk, Curd bacteria, mainly Lactobacillus bulgaricus and Streptococcus thermophilus and sometimes additional sweetener, like fructose, glucose, or raw sugar . It is suitable for vegans, as the bacteria for shop-bought Soya Curd are usually not grown on a dairy base. Soya Curd can be prepared at home using the same method as dairy Curd . One tablespoon of sugar per 1 liter of unsweetened soy milk may be added to promote bacterial fermentation. Soy milk on its own lacks the lactose (milk sugar) that is the basic food for the Curd bacteria. Soya Curd may have a slight beany soy taste when made directly from freshly prepared soymilk, but this is less pronounced in shop-bought Soya Curd and in Soya Curd made from commercial soy milk. Soya Curd contains less fat than Curd made with whole milk. This amounts to about 2.7% (the same percentage as soy milk), versus 3.5% in dairy Curd. However, dairy Curd can be made with 2%, 1%, or fat-free milk, and these cases; it is lower in fat than Soya Curd.

Buffalo curd(Natural milk Curd)

A pot of water buffalo curd with coconut honey. Buffalo curd (in Hindi - "Dahi") is a traditional and nutritious dairy product prepared by buffalo milk and it is popular throughout the south Asian countries such as India, Sri Lanka, Nepal, etc. Buffalo milk is traditionally better than cow milk for curd due to its higher fat content making a thicker curd. Mostly clay pots are used as packaging material for Buffalo curd. Buffalo curds is obtained by curdling (coagulating) buffalo milk using microbial activities. In this process lactose in buffalo milk is converted in to lactic acid using several micro-organisms. Several micro-organism species are involved in the fermentation such as Streptococcus lactis, Streptococcus diacetylactis, Streptococcus cremoris, Lactobacillus bulgaricusand and Streptococcus thermophillus. Buffalo curd has a higher nutritional value of protein, fat, lactose, minerals and vitamins. It should have 7.5% of milk fat, 8.5% of milk solids and 4.5%

of Milk acid (lactic acid). Quality of the curd is totally depend on the starter culture. Fermentation also develops the characteristic flavor and colour of the product. Buffalo curd can be made in both traditional and industrial forms. Traditionally buffalo milk is filtered and boiled, the scum is removed and it is cooled to room temperature. A few spoonfuls of a previous batch of curd are added and it is then mixed well and poured into clay pots. These are sealed by wrapping a piece of paper over the pot and allowing it to stand for 12 hours.

EXPERIMENT Preparation of soyabean milk and its comparison with the natural milk with respect to curd formation, effect of temperature and taste.

REQUIREMENTS Beakers, pestle and mortar, measuring cylinder, glass rod, tripod-stand, thermometer, muslin cloth, burner. Soyabeans, buffalo milk, fresh curd and distilled water.

PROCEDURE

1)

Soak about 150g of Soya beans in sufficient amount of water so that they are completely dipped in it.

2) Take out swollen Soyabeans and grind them to a very fine paste 3)

Take out swollen Soyabeans and grind them to a very fine paste and filter it through a muslin cloth. Clear white filtrate is soyabean milk. Compare its taste with buffalo milk.

4)

Take 50 ml of soyabean milk in three other beakers and heat the beakers to 30°, 40°and 50°C respectively. Add ¼ spoonful curd to each of these beakers. Leave the beakers undisturbed for 8 hours and curd is formed.

5)

Similarly, take 50 ml of buffalo milk in three beakers and heat the beakers to 30°, 40° and 50°C respectively. Add ¼ spoonful curd to each of these beakers. Leave the beakers undisturbed for 8 hours and curd is formed.

RESULT: 1. Natural milk is sweet in taste while soya bean milk is not. 2. The curd formation is take place at a faster rate with increase and both type of milk. 3. In natural milk, fermantation take place faster at a higher temperature, leading to formation of larger amount lactic Acid which imparts of sour taste.