Extraction, conformation characteristics and functional properties of soybean lipophilic proteins

Elucidation of soybean lipophilic protein (SLP) structural characteristics and functional properties would enhance its application. This study aimed to optimize the extraction and investigate the structural properties of SLP extracted from soybean meal with high oil concentration. Additionally, soybean lipophilic protein was compared to extracted SPI, 11S and 7S to promote its potential utilization. The results revealed that, under the optimal conditions defined using the response surface methodology, the yield of soybean lipophilic protein was (11.8%). Meanwhile, compared with other soybean proteins, SLP showed the highest phospholipids concentration (12.1%). Moreover, structural analyses showed that SLP had higher α-helix and β-sheet contents, a more compact tertiary conformation, and better thermal stability than SPI, 11S, and 7S. Soybean lipophilic protein also showed a high fat-holding capacity, good foaming, and emulsifying properties but low protein solubility and viscosity. The results suggested that soybean lipophilic protein can be used in various food and nutraceutical formulations. • The extraction of soy lipophilic protein was optimized using response surface methodology. • The maximum yield was 11.8% at 47 °C, pH of 8.5 and Tris-HCl of 0.05 M for 62 min. • Solubility, emulsifying properties and foaming properties of SLP were determined. • Conformation characteristics of soy lipophilic protein was compared to SPI, 11S and 7S.