Research on corn starch and black bean protein isolate interactions during gelatinization and their effects on physicochemical properties of the blends

The interaction between starch and protein during food processing is crucial for controlling food quality. This study aims to understand the interactions between corn starch and black bean protein isolate (BBPI) at various gelatinization phases and their effects on the physicochemical properties of the blends. BBPI reduced the rheological properties of the corn starch/BBPI mixed system during gelatinization, increasing light transmittance and gelatinization temperature, while decreasing total viscosity and enthalpy change. The changes in starch and protein microstructure during gelatinization indicated that BBPI adhered to the starch particle surface or partially penetrated the swollen starch particles. Fourier transform infrared spectroscopy (FT-IR) revealed that BBPI decreased the number of hydrogen bonds within starch, with no newly formed functional groups in the mixed system. Furthermore, BBPI reduced the composite relative crystallinity (RC). The effect of protein addition on water migration in the mixed system demonstrates that protein and starch compete for water during gelatinization, preventing water molecules from diffusing into starch particles.