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ORIGINAL RESEARCH article

Front. Microbiol.
Sec. Food Microbiology
Volume 15 - 2024 | doi: 10.3389/fmicb.2024.1392774

In vitro digestive properties and the bioactive effect of walnut green husk on human gut microbiota

Provisionally accepted
Xiaolan Zhao Xiaolan Zhao 1,2*Jiabao Ying Jiabao Ying 2*Zhuochen Wang Zhuochen Wang 3*Yulu Wang Yulu Wang 2Zhen Li Zhen Li 2Tianyi Gu Tianyi Gu 2*Shujun Liu Shujun Liu 2Yulong Li Yulong Li 2*Bing Liu Bing Liu 1*Fengjiao Xin Fengjiao Xin 2,4*Boting Wen Boting Wen 4,5*
  • 1 State Key Laboratory of Food Nutrition and Safety, College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, Tianjin, China
  • 2 Laboratory of Biomanufacturing and Food Engineering, Institute of Food Science and Technology (CAAS), Beijing, Beijing, China
  • 3 Institute of Agro-products Processing, Anhui Academy of Agricultural Sciences (CAAS), Anhui, China
  • 4 Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
  • 5 Laboratory of Biomanufacturing and Food Engineering, Institute of Food Science and Technology,100193, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China

The final, formatted version of the article will be published soon.

    Walnut green husk (WGH) is a waste byproduct from walnut industry. However, it is not wellknown about its bioactive effect on human gut health. This study conducted in vitro digestion and fermentation experiments to study the bioactive effect of WGH. Microbial fermentation was the primary mechanism to efficiently release phenolics and flavonoids, resulting in more excellent antioxidant capacities (ABTS, DPPH, and FRAP assays), which reached a highest value with 14.82 ± 0.01 mg VcE/g DW, 3.47 ± 0.01 mmol TE/g DW and 0.96 ± 0.07 mmol FeSO4• 7H2O/g DW respectively. The surface microstructure of WGH became loose and fragmented after microbial fermentation. The analytical results of gut microbiota demonstrated that WGH could significantly increase the relative abundance of Proteobacteria in phylum level and Phascolarctobacterium in genus level while certain pro-inflammatory bacteria (such as Clostridium_sensu_stricto_1, Dorea, Alistipes and Bilophila) was inhibited. Additionally, 1373 differential metabolites were identified and enriched in 283 KEGG pathways. Of which some metabolites were significantly up-regulated including ferulic acid, chlorogenic acid, umbelliferone, scopolin, muricholic acid and so forth. These results indicated that WGH could have antioxidant and anti-inflammatory activities in the human gut, which could improve the economical value of WGH in the food industry.

    Keywords: Walnut Green Husk, in vitro digestion, In vitro fermentation, Gut Microbiota, Metabolism

    Received: 28 Feb 2024; Accepted: 31 Jul 2024.

    Copyright: © 2024 Zhao, Ying, Wang, Wang, Li, Gu, Liu, Li, Liu, Xin and Wen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence:
    Xiaolan Zhao, State Key Laboratory of Food Nutrition and Safety, College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, Tianjin, China
    Jiabao Ying, Laboratory of Biomanufacturing and Food Engineering, Institute of Food Science and Technology (CAAS), Beijing, 100193, Beijing, China
    Zhuochen Wang, Institute of Agro-products Processing, Anhui Academy of Agricultural Sciences (CAAS), Anhui, China
    Tianyi Gu, Laboratory of Biomanufacturing and Food Engineering, Institute of Food Science and Technology (CAAS), Beijing, 100193, Beijing, China
    Yulong Li, Laboratory of Biomanufacturing and Food Engineering, Institute of Food Science and Technology (CAAS), Beijing, 100193, Beijing, China
    Bing Liu, State Key Laboratory of Food Nutrition and Safety, College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, Tianjin, China
    Fengjiao Xin, Laboratory of Biomanufacturing and Food Engineering, Institute of Food Science and Technology (CAAS), Beijing, 100193, Beijing, China
    Boting Wen, Laboratory of Biomanufacturing and Food Engineering, Institute of Food Science and Technology,100193, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.