Volume 45, Issue 12 e13983
ORIGINAL ARTICLE

Branched-chain amino acid synthesis and glucosinolate–myrosinase system during takuan-zuke processing of radish root

Wataru Kobayashi

Wataru Kobayashi

Department of Health and Nutrition, Takasaki University of Health and Welfare, Takasaki-shi, Japan

Contribution: Conceptualization, Data curation, Formal analysis, Validation, Visualization, Writing - original draft

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Taito Kobayashi

Taito Kobayashi

Faculty of Agriculture, Takasaki University of Health and Welfare, Takasaki-shi, Japan

Contribution: Data curation

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Asaka Takahashi

Asaka Takahashi

Faculty of Nutritional Science, Tohto University, Fukaya-shi, Japan

Contribution: Conceptualization

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Kei Kumakura

Kei Kumakura

Faculty of Agriculture, Takasaki University of Health and Welfare, Takasaki-shi, Japan

Contribution: Data curation, Methodology

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Sonoko Ayabe

Sonoko Ayabe

Department of Health and Nutrition, Takasaki University of Health and Welfare, Takasaki-shi, Japan

Contribution: Writing - review & editing

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Hiroki Matsuoka

Corresponding Author

Hiroki Matsuoka

Faculty of Agriculture, Takasaki University of Health and Welfare, Takasaki-shi, Japan

Correspondence

Hiroki Matsuoka, Faculty of Agriculture, Takasaki University of Health and Welfare, 37-1 Nakaorui-machi, Takasaki-shi, Gunma 370-0033, Japan.

Email: [email protected]

Contribution: Conceptualization, Methodology, Project administration, Supervision, Writing - review & editing

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First published: 03 November 2021
Citations: 4

Abstract

The traditional Japanese fermented pickle, takuan-zuke, is produced via dehydration and salt-aging of the Japanese winter radish root (Raphanus sativus L.). It has been reported that γ-aminobutyric acid (GABA; antihypertensive factor) accumulates during this production. Herein, the results of the comprehensive study (metabolites, enzyme activity, and gene expression levels were investigated) on the mechanism of branched-chain amino acid (BCAA) synthesis and glucosinolate (GLS)–myrosinase system of daikon dehydration have been reported. BCAAs, GLS, and their precursors were temporarily upregulated, and the genes linked to BCAA, GLS, and isothiocyanate synthesis (BCAT4, MAM3, IPMDH1, RMB1, RMB2, and GRS1) were upregulated during daikon dehydration. BCAAs and GLS accumulated in daikon during dehydration owing to the upregulation of genes, encoding these synthases as a stress response. These results suggest that the biological response of daikon adds characteristic flavor and health functionality to takuan-zuke and helps optimize the processing parameters to produce pickles with improved health benefits.

Practical applications

Takuan-zuke is a popular pickle in Japan, which is produced from a Japanese winter radish root (Raphanus sativus L.), commonly referred to as daikon in Japan. Takuan-zuke is produced by dehydrating daikon either by the process of salt-pressing (shio-oshi) or sun-drying (hoshi). The processes influence the variations in the nutritional value of the final product. The results reveal that both the daikon dehydration processes can be followed to generate increased amounts of health-promoting components (e.g., branched-chain amino acid and glucosinolate) in takuan-zuke.

CONFLICTS OF INTEREST

The author declares that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.

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