Evaluation of Peptide Contribution to the Intense Umami Taste of Japanese Soy Sauces

Authors

  • Hanifah Nuryani Lioe,

    1. Author Lioe is with Dept. of Food Science and Technology, Faculty of Agricultural Technology, Bogor Agricultural Univ., Kampus IPB Darmaga, Bogor 16680, Indonesia. Authors Takara and Yasuda are with Dept. of Bioscience and Biotechnology, Faculty of Agriculture, Univ. of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan. Direct inquiries to author Yasuda (E-mail: yasuda@agr.u-ryukyu.ac.jp).
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  • Kensaku Takara,

    1. Author Lioe is with Dept. of Food Science and Technology, Faculty of Agricultural Technology, Bogor Agricultural Univ., Kampus IPB Darmaga, Bogor 16680, Indonesia. Authors Takara and Yasuda are with Dept. of Bioscience and Biotechnology, Faculty of Agriculture, Univ. of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan. Direct inquiries to author Yasuda (E-mail: yasuda@agr.u-ryukyu.ac.jp).
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  • Masaaki Yasuda

    1. Author Lioe is with Dept. of Food Science and Technology, Faculty of Agricultural Technology, Bogor Agricultural Univ., Kampus IPB Darmaga, Bogor 16680, Indonesia. Authors Takara and Yasuda are with Dept. of Bioscience and Biotechnology, Faculty of Agriculture, Univ. of the Ryukyus, 1 Senbaru, Nishihara-cho, Okinawa 903-0213, Japan. Direct inquiries to author Yasuda (E-mail: yasuda@agr.u-ryukyu.ac.jp).
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  • The authors thank the sensory panel members of the Dept. of Bioscience and Biotechnology, Univ. of the Ryukyus, Okinawa, Japan, for their sensory assessments. We also thank Koji Wada of Univ. of the Ryukyus and Takayoshi Aoki of Kagoshima Univ., Kagoshima, Japan, for their advice.

Abstract

ABSTRACT: Koikuchi and tamari shoyu are 2 types of traditional Japanese soy sauce whose low-molecular-weight fractions (less than 500 Da) are known to have the most intense umami taste. Given that peptides were also abundant in some umami fractions of both shoyu, further investigation was conducted to evaluate the precise contribution of peptides to the soy sauce tastes. To locate and isolate peptide fractions, separation procedures using Sephadex G-25 SF, Sephadex G-10, and reversed-phase high-performance liquid chromatography (RP-HPLC) linked to sensory evaluation (by taste dilution analysis), as well as amino acid analysis were performed. Peptides having glutamyl residue were present in most peptide fractions. However, they all revealed negligible contributions to the intense umami taste of the soy sauces. On the other hand, free Glu, in the presence of sodium salt, as well as free Asp and several sweet-taste eliciting free amino acids were considered to be the main contributors to the umami taste of the soy sauces. This study of Japanese soy sauces gives a clear explanation of the frequently questioned peptide contribution to the taste of savory food product.

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