Complexation of thermally-denatured soybean protein isolate with anthocyanins and its effect on the protein structure and in vitro digestibility

Yan Zhang; Si Chen; Baokun Qi; Xiaonan Sui; Lianzhou Jiang

doi:10.1016/j.foodres.2018.01.040

Complexation of thermally-denatured soybean protein isolate with anthocyanins and its effect on the protein structure and in vitro digestibility

Food Res Int. 2018 Apr:106:619-625. doi: 10.1016/j.foodres.2018.01.040. Epub 2018 Feb 8.

Authors

Yan Zhang¹, Si Chen¹, Baokun Qi², Xiaonan Sui³, Lianzhou Jiang⁴

Affiliations

¹ College of Food Science, Northeast Agricultural University, Harbin 150030, China.
² College of Food Science, Northeast Agricultural University, Harbin 150030, China; National Research Center of Soybean Engineering and Technology, Harbin 150030, China.
³ College of Food Science, Northeast Agricultural University, Harbin 150030, China; National Research Center of Soybean Engineering and Technology, Harbin 150030, China. Electronic address: xiaonan.sui@neau.edu.cn.
⁴ College of Food Science, Northeast Agricultural University, Harbin 150030, China; National Research Center of Soybean Engineering and Technology, Harbin 150030, China. Electronic address: jlzname@163.com.

PMID: 29579967
DOI: 10.1016/j.foodres.2018.01.040

Abstract

The complexation of anthocyanin-rich black rice extracts (ARBRE) with soybean protein isolate (SPI) heated at 0, 70, 85, and 100 °C and its effect on protein digestibility were studied. The structural changes of SPI during its interaction with ARBRE in all the samples were studied by Fourier transform infrared, circular dichroism, and fluorescence spectroscopy. The secondary structure changes of SPI in all the samples after complexation with ARBRE showed a significant increase in α-helix and a significant decrease in β-sheet contents. Results also showed that ARBRE quenched the SPI fluorescence (in both unheated and heated samples) via static quenching with a single binding site. The digestibility of unheated and heated SPI was improved upon complexing with ARBRE. The formation of the SPI-ARBRE complexes is beneficial for the application of soy protein-based products in foods by increasing their protein digestibility and nutritional quality.

Keywords: Anthocyanin-rich black rice extracts; Protein digestibility; Protein secondary structure; Simulated in vitro digestion; Soybean protein isolate.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Anthocyanins / chemistry*
Binding Sites
Circular Dichroism
Digestion*
Food Handling / methods*
Gastric Juice / chemistry
Hot Temperature*
Intestinal Secretions / chemistry
Nutritive Value
Protein Binding
Protein Conformation, alpha-Helical
Protein Conformation, beta-Strand
Protein Denaturation
Soybean Proteins / chemistry*
Spectrometry, Fluorescence
Spectroscopy, Fourier Transform Infrared

Substances

Anthocyanins
Soybean Proteins