Functional Properties of Heat-induced Gel Prepared from Crude Fractions of Soybean 7S or 11S Proteins

Abstract

From defatted soybean meal, crude protein fractions were prepared by means of a conventional method to fractionate 7S and 11S proteins (7 SPRF, 11 SPRF), basing on the difference of precipitation behaviors with calcium salt between both. The functional properties of those protein fractions were then investigated. The results showed; 1) The optimum temperature to form heat-induced gel was around 70°C with fish jelly (surimi), around 80°C with 7 SPRF and more than 90°C with 11 SPRF. Comparing with 7 SPRF, 11 SPRF formed hard and tough gel, specially having higher tensile strain. 2) Functional properties of surimi were quite different between commercial products prepared during winter and summer. Addition of 11 SPRF to surimi prepared during summer could improve its properties. 3) Comparing with 7 SPRF, 11 SPRF showed higher water capacity, keeping gel-forming properties. 4) Comparing with 11 SPRF, 7 SPRF showed slightly higher emulsifying capacity.