Effects of oils on thermal gelation of soybean protein.

Abstract

The effects of adding oils to soybean protein were examined with respect to hardness of the formed gel. The gel hardness increased with a decrease in the chain length of the added fatty acid methyl esters or triglycerides. When the gels were observed under a scanning electron microscope, the addition of fatty acid methyl ester with a shorter chain length produced a good, hard gel, while the gel formed with fatty acid methyl ester of a longer chain length was easily broken. There were few differences in the hardness of gels formed after adding various unsaturated fatty acid methyl esters, triolein or edible oils, but these gels were firmer than those without oils. The behavior of the protein solution containing oils on thermo-denaturation was the same as that without oils. The amount of protein adsorbed on oil droplets increased with a decrease in the chain length of the fatty acid methyl ester. The hardness of the gel formed with oils may be strengthened by the protein-oil interaction after thermo-denaturation of protein.