Effects of walnut seed coat polyphenols on walnut protein hydrolysates: Structural alterations, hydrolysis efficiency, and acetylcholinesterase inhibitory capacity

Guowan Su; Jieqiong Chen; Lin Huang; Mouming Zhao; Qingrong Huang; Jianan Zhang; Xi Zeng; Yehui Zhang; Liuxin Deng; Tiantian Zhao

doi:10.1016/j.foodchem.2023.137905

Effects of walnut seed coat polyphenols on walnut protein hydrolysates: Structural alterations, hydrolysis efficiency, and acetylcholinesterase inhibitory capacity

Food Chem. 2024 Mar 30;437(Pt 1):137905. doi: 10.1016/j.foodchem.2023.137905. Epub 2023 Oct 30.

Authors

Guowan Su¹, Jieqiong Chen², Lin Huang¹, Mouming Zhao³, Qingrong Huang⁴, Jianan Zhang¹, Xi Zeng⁵, Yehui Zhang⁶, Liuxin Deng¹, Tiantian Zhao⁷

Affiliations

¹ School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China.
² School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China; Sericulture & Agri-food Research Institute Guangdong Academy of Agricultural Sciences, Key Laboratory of Functional Foods, Ministry of Agriculture and Rural Affairs, Guangdong Key Laboratory of Agricultural Products Processing, Guangzhou 510610, China.
³ School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China; Chaozhou Branch of Chemistry and Chemical Engineering Guangdong Laboratory, China.
⁴ Department of Food Science, Rutgers University, New Brunswick, NJ 08901, United States.
⁵ Guangzhou Institute for Food Control, Guangzhou 511400, China.
⁶ Sericulture & Agri-food Research Institute Guangdong Academy of Agricultural Sciences, Key Laboratory of Functional Foods, Ministry of Agriculture and Rural Affairs, Guangdong Key Laboratory of Agricultural Products Processing, Guangzhou 510610, China.
⁷ Sericulture & Agri-food Research Institute Guangdong Academy of Agricultural Sciences, Key Laboratory of Functional Foods, Ministry of Agriculture and Rural Affairs, Guangdong Key Laboratory of Agricultural Products Processing, Guangzhou 510610, China; Department of Food Science, Rutgers University, New Brunswick, NJ 08901, United States; Chaozhou Branch of Chemistry and Chemical Engineering Guangdong Laboratory, China. Electronic address: fettzhao1989@163.com.

PMID: 37922803
DOI: 10.1016/j.foodchem.2023.137905

Abstract

The walnut meal is rich in nutrients such as protein from the kernel and polyphenolic compounds from the seed coat. However, the influences of seed coat polyphenols on walnut protein (WP) hydrolysis remained unclear. In this study, our findings indicated that polyphenols induced alterations in the secondary structure and amino acid composition of WP. These changes resulted in both a hindrance of hydrolysis and an enhancement of acetylcholinesterase (AChE) inhibition. Furthermore, four peptides of 119 identified peptides (LR, SF, FQ, and FR) were synthesized based on higher predicted bioactivity and Vinascores in silico. Among them, FQ showed interaction with amino acid residues in AChE through the formation of four π-π stacking bonds and two hydrogen bonds, resulting in the highest AChE inhibitory capacity. The combination index showed that chlorogenic acid derived from the seed coat and FQ at the molar ratio of 1:4 exhibited synergistic effects of AChE inhibition.

Keywords: AChE inhibition; Hydrolysis efficiency; Seed coat polyphenols; Structural alterations; Synergistic effects; Walnut hydrolysates.

MeSH terms

Acetylcholinesterase / metabolism
Amino Acids / analysis
Hydrolysis
Juglans* / chemistry
Peptides / chemistry
Polyphenols / analysis
Polyphenols / pharmacology
Protein Hydrolysates / chemistry
Seeds / chemistry

Substances

Polyphenols
Acetylcholinesterase
Protein Hydrolysates
Peptides
Amino Acids