Time： 2019-06-06 00:00:00
Existing forms of soybean protein isolate
Soybean protein is a high molecular organic polymer composed of a series of amino acids through peptide bonds. It is mainly composed of albumin and globulin, of which albumin accounts for about 5% and globulin accounts for about 90%.
There are two ways to classify the existing forms of soybean protein isolates. One is based on the sedimentation index. After high-speed centrifugation, soybean protein is divided into four grades according to the centrifugal sedimentation index: 2S, 7S, 11S and 15s. 7S and 11S are the main components, which are also the main components of globulin, accounting for about 70% of the total protein. They play a very important leading role in the functional characteristics of soybean protein isolates.
The other is the classification based on immunological characteristics. It can be divided into four categories: a-globulin concentrate (about 15%), 13 globulin concentrate (about 28%), y-globulin concentrate (about 3%), and soluble globulin (about 40%).
Functional properties of soybean protein isolate
Soy protein isolate (SPI) is a surfactant, which can not only reduce the surface tension of water and oil, but also reduce the surface tension of water and air. Easy to form stable emulsion. In the production of baked food, frozen food and soup food, adding soy protein isolate as emulsifier can stabilize the state of products.
Soybean protein isolate contains many polar groups along its peptide chain skeleton, so it has water absorption, water retention and expansibility. The water absorption of protein isolate is much stronger than that of protein concentrate, and it is almost unaffected by temperature. The protein isolate also has the ability to maintain water during processing, and the maximum water retention capacity is 14g water /g protein.
When protein isolate is added to meat products, it can form emulsion and gel matrix to prevent fat from moving to the surface, so it plays a role in promoting fat absorption or fat combination, reducing the loss of fat and juice in the processing of meat products, and helping to maintain the stability of appearance. The oil absorption rate of protein isolate is 154%.
It makes the protein isolate have high viscosity, plasticity and elasticity. It can be used not only as a carrier of water, but also as a carrier of flavor agents, sugars and other complexes, which is very beneficial to food processing.
Among soybean protein, the foaming property of isolated protein is the best. Using the foaming property of soybean protein can endow food with loose structure and good taste.
When the meat is chopped, the mixture of protein isolate and egg protein is coated on the fiber surface to form a film, which is easy to dry, can prevent the loss of odor, is conducive to the rehydration process, and provides a reasonable structure for the rehydrated products.
Health products, health nutrition, infant food, solid drinks, dairy products, convenience food, puffed food, condiments, middle-aged and elderly food, baked goods, snack food, cold food and cold drink, etc.