Heat treatment in the presence of arginine increases the emulsifying properties of soy proteins

Hiroshi Kano; Kentaro Shiraki

doi:10.1016/j.fochx.2023.100567

Heat treatment in the presence of arginine increases the emulsifying properties of soy proteins

Food Chem X. 2023 Jan 7:17:100567. doi: 10.1016/j.fochx.2023.100567. eCollection 2023 Mar 30.

Authors

Hiroshi Kano¹, Kentaro Shiraki²

Affiliations

¹ Research Institute for Creating the Future, Fuji Oil Holdings INC, 1 Sumiyoshi-cho, Izumisano-shi, Osaka 598-8540, Japan.
² Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan.

Abstract

This study aimed to improve the emulsifying properties of commercial soy protein isolates (CSPIs). CSPIs were thermally denatured without additives (CSPI_H) and with arginine (CSPI_A), urea (CSPI_U), and guanidine hydrochloride (CSPI_G), which improve protein solubility to prevent aggregation. These additives were removed by dialysis, and the samples were lyophilized. CSPI_A resulted in high emulsifying properties. FT-IR analysis showed that the β-sheet content in CSPI_A was reduced compared to that of untreated CSPI (CSPI_F). Fluorescence analysis showed that the tryptophan-derived emission peak of CSPI_A shifted between CSPI_F and CSPI_H which was exposed to hydrophobic amino acid chains with aggregation. As a result, the structure of CSPI_A became moderately unfolded and exposed the hydrophobic amino acid chains without aggregation. The CSPI_A solution had a more reduced oil-water interface tension than other CSPIs. These results support that CSPI_A attaches efficiently to the oil-water interface and produces small, less flocculated emulsions.

Keywords: Aggregation; Arginine; Commercial soy protein isolate; Emulsifying properties; Flocculation.