Effect of temperature of preheated soy protein isolate on the structure and properties of soy protein isolate...

In this paper, soy protein isolate (SPI) was preheated and combined with vitamin D₃ (VD₃ ) to study the protective effect of modified SPI on VD₃ . The structure and properties of the SPI with heat treatment-VD₃ (SPI(H)-VD₃ ) complex were determined. The secondary and tertiary structure of SPI(H)-VD₃ results showed that the content of α-helix decreased and the content of random coil increased, indicating that the rigid structure of the protein decreased, the flexibility increased, and the maximum fluorescence intensity wavelength was red shifted. When the heat treatment temperature was 85°C, the embedding rate of SPI(H)-VD₃ composite was the highest. As the heat treatment temperature increased, the internal hydrophobic groups of SPI were exposed, and the average particle size decreased significantly. The light stability results showed that the content of VD₃ in the SPI(H)-VD₃ composite at a heat treatment temperature of 85°C was significantly increased compared with the unheated SPI. PRACTICAL APPLICATIONS: This article mainly discusses the structure and properties of modified soy protein isolates bound to VD₃ by preheating soy protein isolates at different temperatures. It provides more possibilities for the application of VD₃ in food.