Soybeans are cracked, their moisture content is adjusted, they are rolled into flakes and then solven-extracted with commercial hexane to produce soybean oil. The oil is then refined, blended for different applications, and sometimes hydrogenated. Soybean oils, both liquid and partially hydrogenated, are exported as vegetable oil, for use in cooking and in a variety of processed foods.
Soybean oil is very popular because it is cheap, healthful and has a high smoke point. Soybean oil does not contain much saturated fat. Like all other oils of vegetable origin, soybean oil contains no cholesterol. However, it is often hydrogenated to increase its shelf life or to produce a more solid product. In this process, unhealthy trans fats are produced, which may raise blood cholesterol levels and increase the risk of heart disease. Food manufacturers are now trying to remove trans fats from their products.
How to select
• Soybean oil is sold bottled or in plastic pouches for cooking use.
• Look for light golden coloured oil free from any discoloration, cloudiness or granules.
• Since soybean oil is almost tasteless and odourless, it is a good choice for baking.
• Soybean oil is used in the manufacture of pickles.
• It is commonly used as a salad oil, and in the preparation of salad dressings, sandwich spreads, margarine, bread, mayonnaise, non-dairy coffee creamers, crumb coatings, baking mixes and snack foods.
• The high smoke point of soybean oil allows it to be used as frying oil.
How to store
• Store the soy oil in a cool and dark place.
• Avoid reusing the left over oil from deep frying as reheating oil again and again may affect the chemical composition and rancidity quotient of the oil.
• Unopened bottles or metal containers, can be kept for about a year.
• Once opened, it should be used within two months, after which, it may turn rancid and should not be consumed.
• If possible, transfer the oil from the can into a glass bottle to avoid metallic tasting oil; plastic containers shouldn't be used because they may impart a "plastic" taste to the oil.
• Soybean contains natural antioxidants which remain in the oil even after extraction. These antioxidants help to prevent the oxidative rancidity.
• The major unsaturated fatty acids in soybean oil triglycerides are 7% alpha-Linolenic acid (C-18:3); 51% linoleic acid (C-18:2); and 23% oleic acid (C-18:1). It also contains saturated fatty acids, namely, 4% stearic acid and 10% palmitic acid.