Study of the concentration effect by rheological measurements for ultrasound and heat-treated native soy protein isolate
摘要
Ultrasound is a highly effective, environmentally friendly technique for inducing structural changes in soy protein isolates. When combined with simultaneous heating, this process can produce synergistic or additive effects. Previous studies on native soy protein isolates focused on foamability and viscoelasticity, correlating these properties with particle size distribution and surface charge at 2, 4, and 6% (w/w) protein concentrations. Building on this, the current work investigated the combined effect of ultrasound and temperature on these same concentrations. We found a clear correlation between protein concentration and the functional properties. The objective of this study was to determine the impact of a combined ultrasound and temperature treatment on the solubility, viscosity, surface hydrophobicity, and gelling properties of native soy protein isolates at these concentrations. Our findings indicate that the treatments promoted concentration-dependent changes in these functional parameters. Although solubility magnitude depends on the storage conditions of the flour, the effects of the treatments can be identified as an interaction between ultrasound and temperature for all concentrations. It was seen that ultrasound promoted an increase in solubility while temperature generated a reduction in solubility at the same time. Viscosity increased at high temperatures or in the combined treatment, most markedly at 2% due to the formation of soluble aggregates. In contrast, at 6% of protein concentration, gelling properties showed a stronger dependence on surface hydrophobicity and solubility. Thus, the combined technology, through a synergistic effect, depended on the protein concentration, a revelation that is highly important for various food processing applications.