Functional properties and in vitro trypsin digestibility of red kidney bean (Phaseolus vulgaris L.) protein isolate: Effect of high-pressure treatment

Shou-Wei Yin; Chuan-He Tang; Qi-Biao Wen; Xiao-Quan Yang; Lin Li

doi:10.1016/j.foodchem.2008.02.090

Functional properties and in vitro trypsin digestibility of red kidney bean (Phaseolus vulgaris L.) protein isolate: Effect of high-pressure treatment

Food Chem. 2008 Oct 15;110(4):938-45. doi: 10.1016/j.foodchem.2008.02.090. Epub 2008 Mar 18.

Authors

Shou-Wei Yin¹, Chuan-He Tang², Qi-Biao Wen¹, Xiao-Quan Yang¹, Lin Li¹

Affiliations

¹ Department of Food Science and Technology, South China University of Technology, Guangzhou 510640, People's Republic of China.
² Department of Food Science and Technology, South China University of Technology, Guangzhou 510640, People's Republic of China. Electronic address: chtang@scut.edu.cn.

PMID: 26047283
DOI: 10.1016/j.foodchem.2008.02.090

Abstract

The effects of high-pressure (HP) treatment at 200-600MPa, prior to freeze-drying, on some functional properties and in vitro trypsin digestibility of vicilin-rich red kidney bean (Phaseolus vulgaris L.) protein isolate (KPI) were investigated. Surface hydrophobicity and free sulfhydryl (SH) and disulfide bond (SS) contents were also evaluated. HP treatment resulted in gradual unfolding of protein structure, as evidenced by gradual increases in fluorescence strength and SS formation from SH groups, and decrease in denaturation enthalpy change. The protein solubility of KPI was significantly improved at pressures of 400MPa or higher, possibly due to formation of soluble aggregate from insoluble precipitate. HP treatment at 200 and 400MPa significantly increased emulsifying activity index (EAI) and emulsion stability index (ESI); however, EAI was significantly decreased at 600MPa (relative to untreated KPI). The thermal stability of the vicilin component was not affected by HP treatment. Additionally, in vitro trypsin digestibility of KPI was decreased only at a pressure above 200MPa and for long incubation time (e.g., 120min). The data suggest that some physiochemical and functional properties of vicilin-rich kidney proteins can be improved by means of high-pressure treatment.

Keywords: Emulsifying property; Functional property; High pressure; In vitro digestibility; Protein isolate; Red kidney bean (Phaseolus vulgaris L.).