Functional characteristics and structural properties of soybean protein isolate–maltose conjugates

Abstract Background and objectives Glycation is a natural and green modification method and can be used to improve the functional properties of proteins. In this study, the effects of reaction conditions on structural characteristics and functional properties of soy protein isolate (SPI) conjugated with maltose (M) were investigated. Findings When the mass ratio of protein and maltose was 1:2 and reaction temperature was 60°C, the degree of grafting of SPI‐M conjugates was highest and the degree of browning was moderate. The solubility of SPI‐M conjugates increased by 48.5%; after 60 hr of reaction, and the emulsification activity index and the emulsion stability index of SPI‐M conjugates increased by 79.4% and 102%, respectively. SDS‐PAGE and FT‐IR indicated that the introduction of maltose led to changes in the spatial structure of the SPI. The in vitro pancreatic digestibility of SPI‐M conjugates also was improved. Conclusion The solubility, emulsification, and the in vitro digestibility of SPI‐M conjugates were improved. The spatial structure of SPI was changed after glycation. Significance and novelty The results showed that glycation can improve the functional properties of SPI and provide a theoretical basis for the development of new soybean protein products.