The Coagulating Effects of Cations and Anions on Soy Protein

Abstract

7S and 11S soy proteins were mixed with various salts to investigate the coagulating effects of cations and anions of the coagulants. When coagulants were added to mixture of 7S and 11S proteins (ratio of 7S:11S from 0:10 to 10:0) in such a way that the resultant mixture contained protein content of 4.0% (w/v) and coagulants at 0.008M, different states of curds were formed. Depending on the coagulants, the mixture would remain as liquid, form uniform curds or precipitate. Coagulants which result in the formation of precipitates in most protein ratios are defined as those with the strongest coagulating power. Based on the different states of curds, the coagulating powers of various salts were in the order of CaCl₂ > MgCl₂ > CaSO₄ > MgSO₄. Similar order was found by turbidity measurements. Coagulants with strong coagulating power were able to form uniform curds of firmer texture, having lower pH and higher L* values compared those with weaker coagulating power.