Improvement in texture and color of soy protein isolate gel containing capsorubin and carotenoid emulsions following microwave heating.

ABSTRACT

The effects of microwave heating on the properties and pigment release of soybean protein isolate (SPI) emulsion gel and hydrogel were investigated. The properties of the samples were analyzed by rheology and texture. The results showed that the hardness of the emulsion gel was lower than that of the hydrogel, but the cohesiveness was the opposite. The hydrogen bonding and electrostatic interaction between SPI and soybean soluble polysaccharide (SSPS) enhanced the thermal stability of the gel, and the enthalpy values were the lowest. In addition, a chroma meter was used to assess the slow-release effect of pigment, with results indicating that the emulsion gel was more red and yellow than the hydrogel; the values of a* and b* were reduced with the extension of heating time, indicating that the emulsion had a good protective effect on carotenoids and capsorubin, which was helpful to the application of the pigment in food.