Characteristic of the interaction mechanism between soy protein isolate and functional polysaccharide with different charge characteristics and exploration of the foaming properties

The commercial production process will partially damage the foaming properties of soy protein isolate (SPI). Adding functional polysaccharides have a positive effect on the foaming properties of SPI, but the effects are affected by several factors. For this reason, three kinds of polysaccharides with different charges, including chitosan (CS, a cationic polysaccharide), guar gum (GUG, a neutral polysaccharide) and gellan gum (GEG, an anionic polysaccharide), were complexed with SPI at different mass ratios to discuss their interaction mechanism, and the foaming properties of these complexes were preliminarily explored. After complexation, the structure of SPI was further folded and interacted with three polysaccharides mainly through non-covalent bonding. Specifically, SPI and CS interacted through weak electrostatic interaction, volume exclusion effect and hydrogen bonding at a high CS concentration. SPI and GEG interacted through strong electrostatic interaction and hydrogen bonding. However, SPI and GUG interacted only through hydrogen bonding. In addition to SPI/CS10, the foamability of SPI/polysaccharide complexes was significantly lower than single SPI. By contrast, the foam stability of all the complexes was much higher than single SPI, and increased with the increase of the polysaccharide concentration, among which the SPI/GEG complexes showed the highest foam stability. These findings provided the interaction mechanism between SPI and polysaccharides with different charges, and the complexes with outstanding foam stability can be used for improving the stability and texture of aerated foods.