Effects of heat treatment and glucono-δ-lactone-induced acidification on characteristics of soy protein isolate

The storage modulus (G′) and gel hardness of non-heated and heat-treated SPI at neutral pH and those of subsequently formed GDL-induced gels were measured. The values obtained for acid-induced gels formed by heat-treated SPI were significantly increased compared to those formed by non-heated SPI. The physicochemical properties of non-heated SPI and heat-treated SPI at pH 6.9 (denaturation degree, dispersibility, water-holding capacity, sulfhydryl groups and surface hydrophobicity) were measured to correlate their effects to gel strength and gel hardness, sulfhydryl groups and water-holding capacity of GDL-induced gels.