title: Functional properties and in vitro trypsin digestibility of red kidney bean (Phaseolus vulgaris L.) protein isolate: Effect of high-pressure treatment.
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.
authors.affiliation: Department of Food Science and Technology, South China University of Technology, Guangzhou 510640, People's Republic of China.
authors.forename: Shou-Wei
authors.initials: SW
authors.lastname: Yin
authors.affiliation: Department of Food Science and Technology, South China University of Technology, Guangzhou 510640, People's Republic of China. Electronic address: chtang@scut.edu.cn.
authors.forename: Chuan-He
authors.initials: CH
authors.lastname: Tang
authors.affiliation: Department of Food Science and Technology, South China University of Technology, Guangzhou 510640, People's Republic of China.
authors.forename: Qi-Biao
authors.initials: QB
authors.lastname: Wen
authors.affiliation: Department of Food Science and Technology, South China University of Technology, Guangzhou 510640, People's Republic of China.
authors.forename: Xiao-Quan
authors.initials: XQ
authors.lastname: Yang
authors.affiliation: Department of Food Science and Technology, South China University of Technology, Guangzhou 510640, People's Republic of China.
authors.forename: Lin
authors.initials: L
authors.lastname: Li
keywords: Emulsifying property; Functional property; High pressure; In vitro digestibility; Protein isolate; Red kidney bean (Phaseolus vulgaris L.)