The characteristics of soybean protein isolate obtained by synergistic modification of high hydrostatic pressure and phospholipids as a promising replacement of milk in ice cream

Abstract

In this study, soybean protein isolate (SPI) was modified by high hydrostatic pressure (HHP) treatment and compounded phospholipids, and used to replace milk to produce a low-fat vegetable ice cream. We compared changes in the structure and functional properties of HHP- or phospholipid-modified SPI (HSPI, SPI-PLW), phospholipid-modified HSPI (HSPI-PLW), HHP-modified SPI-PLW (H(SPI-PLW)), and SPI, and their secondary structure, ζ point, average particle size, and scanning electron microscopy (SEM) images were recorded. The results showed that the secondary structure of the protein was significantly changed following HHP treatment. The addition of phospholipids increased the surface charge of SPI-PLW, HSPI-PLW, and H(SPI-PLW), and the average particle size increased regardless of the modification method. HSPI-PLW presented the best functional characteristics. Compared with SPI, the nitrogen soluble index was increased by 163.40%, emulsifying activity and emulsion stability were increased by 74.98 and 25.30%, respectively, and foaming and bubble stability were increased by 233.33 and 95.02%, respectively. In addition, the expansion and melting rates of both H (SPI-PLW) and HSPI-PLW ice creams were significantly improved. Sensory evaluation revealed good acceptability, and the overall quality was close to that of milk ice cream.