title: The γ-aminobutyric acid-producing ability under low pH conditions of lactic acid bacteria isolated from traditional fermented foods of Ishikawa Prefecture, Japan, with a strong ability to produce ACE-inhibitory peptides.
abstract: Many traditional fermented products are onsumed in Ishikawa Prefecture, Japan, such askaburazushi,narezushi,konkazuke, andishiru.Various kinds of lactic acid bacteria (LAB) are associated with their fermentation, however, characterization of LAB has not yet been elucidated in detail. In this study, we evaluated 53 isolates of LAB from various traditional fermented foods by taxonomic classification at the species level by analyzing the 16S ribosomal RNA gene (rDNA) sequences and carbohydrate assimilation abilities. We screened isolates that exhibited high angiotensin-converting enzyme (ACE) inhibitory activities in skim milk or soy protein media and produced high γ-aminobutyric acid (GABA) concentrations in culture supernatants when grown in de Man Rogosa Sharpe broth in the presence of 1% (w/v) glutamic acid. The results revealed that 10 isolates, i.e.,Lactobacillus buchneri(2 isolates),Lactobacillus brevis(6 isolates), andWeissella hellenica(2 isolates) had a high GABA-producing ability of >500 mg/100 ml after 72 h of incubation at 35 °C. The ACE inhibitory activity of the whey cultured with milk protein by using L.brevis(3 isolates),L. buchneri(2 isolates), andW. hellenica(2 isolates) was stronger than that of all whey cultured with soy protein media, and these IC50were < 1 mg protein/ml. Three of 10 isolates had high GABA-producing activities at pH 3, suggesting that they could be powerful candidates for use in the fermentation of food materials having low pH.
authors.affiliation: Department of Food Science, Ishikawa Prefectural University, Nonoichi, Ishikawa 921-8836, Japan; Department of Civil & Environmental Engineering, Old Domination University, Norfolk, VA 2352, USA.
authors.forename: Florin
authors.initials: F
authors.lastname: Barla
authors.affiliation: Department of Food Science, Ishikawa Prefectural University, Nonoichi, Ishikawa 921-8836, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Koyanagi
authors.affiliation: Department of Food Science, Ishikawa Prefectural University, Nonoichi, Ishikawa 921-8836, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Tokuda
authors.affiliation: Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Nonoichi, Ishikawa 921-8836, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Matsui
authors.affiliation: Graduate School of Biostudies, Kyoto University, Kyoto, Kyoto 606-8511, Japan.
authors.forename: Takane
authors.initials: T
authors.lastname: Katayama
authors.affiliation: Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Nonoichi, Ishikawa 921-8836, Japan.
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Kumagai
authors.affiliation: Department of Chemistry/Food, Industrial Research Institute of Ishikawa, Kanazawa, Ishikawa 920-8203, Japan.
authors.forename: Toshihide
authors.initials: T
authors.lastname: Michihata
authors.affiliation: Department of Chemistry/Food, Industrial Research Institute of Ishikawa, Kanazawa, Ishikawa 920-8203, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Sasaki
authors.affiliation: Department of Chemistry/Food, Industrial Research Institute of Ishikawa, Kanazawa, Ishikawa 920-8203, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tsuji
authors.affiliation: Department of Food Science, Ishikawa Prefectural University, Nonoichi, Ishikawa 921-8836, Japan.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Enomoto
keywords: ACE inhibitory activity; Fermented food; Lactic acid bacteria; γ-Aminobutyric acid