Mechanical behavior and structural observation of soy protein and soy-soluble polysaccharide mixtures

In this study, soy protein (SPI: E, SE, SEH) and soy-soluble polysaccharide (SSPS) mixtures were used to investigate the mutual effects of varying the mixing ratio of soy proteins with different particle sizes based on their mechanical behavior. The mean particle size (MVD) of SPI was E > SE > SEH, and the span was E < SE < SEH. SSPS dissolved in water. Differential scanning calorimetry (DSC) measurements showed no endothermic or exothermic peaks in the measured temperature range for both SPI and SSPS. When SPI was used alone, protein aggregates formed a gel with virtually no gaps as observed in structural analysis. When mixed with SSPS, gaps were observed in the structural analysis, accompanied by reduced gel strength and decreased elastic component, suggesting that SSPS inhibits SPI gel formation. This tendency was more pronounced with SPI(E), indicating the influence of particle size. These results were considered useful for adjusting the physical properties when mixing SPI and SSPS in food products.