soybean protein isolated modification methods

1 Heat treatment method
Sorgentini such as the 5%, 8%, 11%, 13% and 15% soy protein isolate at 80 ℃ or 100 ℃ for 30min, then cooled overnight at 4 ℃, when the concentration is greater than or equal to 8%, the formation of gel , at the same temperature, the higher the concentration, the more insoluble fractions; the same concentration of protein solution, 100 ℃ treatment the insoluble fraction to more than 80 ℃. Measured by DSC, 80 ℃ treatment, partially denatured proteins, and 100 ℃ processing, all the protein denaturation. After heat treatment, the soluble protein fraction and insoluble fraction of the surface hydrophilic (S0) changes, the concentration is low, due to thermal denaturation and exposure of internal hydrophilic, S0 increases. In the non-thermal denatured protein, the soluble components and non-soluble components, water binding capacity (WIC) the same, thermal denaturation, the soluble components of the WIC and non-soluble components have increased, especially in the highest concentration of 8%. After heat treatment, improved emulsifying properties of proteins South.

2 acid treatment
Wagner et al with acid isolated soy protein and soy globulin (Glycinin). Only from the long storage of extracted soybean meal protein by acid treatment, will reduce the solubility, pH changes in solubility and water binding capacity (WIC) has little effect, while the foaming and foam stability are very to improve. Acid processing, pH, denatured 11S globulin has a strong role.

3 enzyme treatment
Wu and papain hydrolyzed soy protein isolate and hydrolysates using ultrafiltration. 11S than 7S globulin protein subunits strictly based on the papain-sensitive. Papain soy protein isolate significantly increased the surface water absorption, solubility and emulsifying properties.

QI and other studies of trypsin for the hydrolysis of soy protein isolate. Trypsin include trypsin and chymotrypsin, hydrolysis of the two alkaline 11S glycinin subunits. Soy protein hydrolysis by trypsin, surface water absorption (S0) significantly increased, little change in solubility, emulsion of protein and oil content increased, emulsifying capacity increased, but the emulsion stability decreased.