SPRAY-DRIED SOY PROTEIN ISOLATE SOLUBILITY, GELLING CHARACTERISTICS, AND EXTRACTABLE PROTEIN AS AFFECTED BY ANTIOXIDANTS

With the addition of antioxidants, spray-dried soy protein isolates (SPI) exhibited increased solubilities by 8% over the control in 0.1M NaCl. Increased solubilities corresponded to a 15% and 8% reduction in protein oxidation as determined by protein carbonyl contents. The greatest differences in solubility between a spray-dried SPI with antioxidant (66% protein solubility) and the control (54% protein solubility), as well as the minimum protein solubility, occurred in 0.2M NaCl. Following the initial solubilization step in SPI processing, amount of extracted proteins was increased by 4.5% over the control with addition of antioxidants. Gel fracturability, hardness and adhesiveness for heat set gels of 12% SPI processed with added antioxidants were increased by 26.3%, 23.5% and 24.6%, respectively.