User talk:Krishna Industries

Introduction

Soybean (Glycine max) is a leguminous plant. Majority of nonvegetarian people do not consume animal products on a daily basis in quantities sufficient to provide the recommended amount of protein. Soybeans are a rich source of good quality protein. Besides nutritional benefits soybeans provide several therapeutic benefits too. Soybean is one of the very few plants that provide high quality protein. Soybeans contain all the major macronutrients required for good nutrition, as well as fiber, vitamins, minerals. Soybean protein provides all the essential amino acids in the amounts needed for human health. Soybean meal is the supplemental protein source most widely used in animal feeds. Soybean meal is an excellent source of protein, because nearly 480 g/kg of the Dry Matter (DM) is protein and the protein quality is high [1]. Soybeans have almost 40% protein, making soybeans higher in protein than any other legumes and many animal products. The quality of soy protein is virtually equivalent in quality to that of milk and egg protein. The composition of soybean seed not only affects the soymilk and soy paneer quality but also its yield [2]. Unlike many other good sources of protein, soybean not only has higher percentage of oil but also quality fatty acid profile. It has low saturated fat content with high amount of essential fatty acids. Soybean oil obtained from the soybean is also a good source of omega-3 and 6 fatty acids similar to those found in fish oils and are cholesterol-free. Soybeans are an excellent source of dietary fiber with both soluble and insoluble fiber.

Soymilk is a creamy, milk-like product made by soaking and grinding soybeans in water. However the water absorption of soybeans in soaking is directly related to the changes in textural characteristics and grinding properties of soybeans for processing [3]. Soybean or soymilk has always been a rich source of protein which is inexpensive [4] and abundantly available. Soymilk is used in various food products such as tofu, fruit flavored puddings, calcium and protein rich soymilk. Soy milk (also called soymilk, soybean milk) 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 besides being rich in protein, vitamins and minerals. Soy milk is an intermediate product in the manufacture of soy paneer. It is often used in confections, meat fillers, beverages, and as part of infant formulas for children allergic to dairy milk [5]. Soymilk is very economical, lactose free, highly digestible and nutritious alternative of dairy and meat centered diet. It is cholesterol free product, has a very low fat content and is rich in polyunsaturated fatty acids of phospholipids. Generally soymilk contains around 7-8% TSS in it. Adding 3-4% sugar and about 0.05% salt brings it to a sugar, salt and total solid level approximately identical to toned (2% fat) cow’s milk, i.e. about 12-13% TSS. It can be made into yogurt (curd) or tofu (paneer) or used directly in cooking. In addition to that blends of the soymilk with cow/buffalo milk have been successfully tried for the preparation of different varieties of soy paneer. Soymilk contains some anti-nutritional constituents also. Soymilk is good source of calcium and helps to avoid osteoporosis. Soluble fiber in soymilk controls blood sugar. It is good for pregnant women and lactating mothers. Soymilk reduces menopausal symptoms and bone deformities. Soya foods contain calcium, magnesium and phosphorus, which help to strengthen teeth and prevent nerve disorder. Soybean consumption on regular basis delays the ageing process.

Soy paneer is known for its extraordinary nutritional benefits, as well as its versatility. Soy paneer is a soft cheese-like food made by curdling soya milk with a coagulant. To improve the texture and increase the yield of tofu, researchers has been engaged to find better coagulation methods, concentration of coagulants and optimum temperature of coagulation. Researchers [6] studied the effect of two different coagulants calcium sulphate and modified nigari (Japanese name for magnesium chloride), three stirring speeds (137, 207 and 285 rpm), and six stirring times (5, 10, 15, 20, 25 and 30 sec) on yield and textural properties of soft tofu. They found that tofu made by the highest stirring speed (285 rpm) had a lower yield, but higher brittleness force, hardness and elasticity than tofu made at 207 rpm. Other factors that affected yield of tofu were whole soybean (higher yield) versus soybean flakes [7], heating method where steam injected cooker system had higher yield as compared to steam jacketed kettle system [8]. Soy is easily digestible from of protein, and is the only complete protein food source in the plant Kingdom. Other health benefits of soy include calcium, iron, B vitamins and naturally occurring phyto-estrogens. The effect of soybean storage affects the textural properties of the soy paneer developed from it [9]. Soy paneer is usually packaged in water and should be refrigerated and kept in water until used. Soy paneer can be frozen for up to three months. It is dense and can be cubed and stir-fried, grilled, scrambled, pickled, smoked, baked, barbecued or served in soups. Different yogurt-like products were prepared from the combination of skim milk and soymilk [10]. The present study was selected to develop Soy paneer from soymilk and blend of soymilk and skimmed milk and to evaluate the sensory and physico-chemical properties of the product.

Materials and Methods

Soybean seeds of the variety “Pooja” were procured from the local market. The coagulant used in the experiment was citric acid.

Preparation of soymilk

Soy bean seeds were soaked in water (1:3 w/v) for 14-16 hrs. The soaked water was decanted and the seeds were washed with fresh water. Hundred grams of soaked soybean seeds per litre of water was used for grinding i.e. 1:10 (w/v). The resulting suspension was filtered through a double layered muslin cloth. The muslin cloth was wrapped around the bean pulp, okara and squeezed till all the liquid was extracted. The filtrate obtained was boiled in water bath at 80°C. The soymilk was then cooled and refrigerated for 3 days [11].

Preparation of soy paneer

Soy paneer is one of the most popular soy-products and is prepared by coagulating soymilk. Soypaneer has been reported as low-calorie food and is rich source of iron, calcium, low in saturated fat and as a source of isoflavones which can mimic human estrogens and can have beneficial effects on human health [12]. Soy paneer was prepared in the laboratory at Department of Food Technology, University of Kashmir (India) using 1L of soymilk for each experimental trial. A solution of 1.5% citric acid was used to coagulate soymilk. Soymilk samples were heated to coagulation temperatures of 80°C. The coagulant was added into soymilk slowly with gentle and continuous stirring. After complete coagulation, stirring was stopped and contents were left undisturbed at room temperature of 300C for 15 min. Whey was then removed by straining through a muslin cloth. The coagulum (soy paneer) obtained was pressed. It was removed and soaked in cold water for 30 min [11]. Then it was taken out and the free water on the surface was removed by wrapping paneer blocks on a clean muslin cloth. The method adopted in the preparation of soy paneer is shown in Figure 2. The soy paneer yield was expressed as kg soy paneer per kg of raw dry beans [13]. Tofumaking procedures generally include soaking and grinding of soybeans in water, filtering, boiling and coagulation of soymilk, and molding and pressing of bean curds. Tofu is usually sold in the form of a wet cake with a creamy white color, smooth texture, and bland taste