Improvement of Fish Sauce Quality by Strain CMC5‐3‐1: A Novel Species of Staphylococcus sp. |
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| Authors: | Natteewan Udomsil Sureelak Rodtong Somboon Tanasupawat Jirawat Yongsawatdigul |
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| Affiliation: | 1. Food Protein Research Unit, School of Food Technology, Inst. of Agricultural Technology, Suranaree Univ. of Technology, Nakhon Ratchasima, Thailand;2. School of Microbiology, Inst. of Science, Suranaree Univ. of Technology, Nakhon Ratchasima, Thailand;3. Dept. of Microbiology, Faculty of Pharmaceutical Sciences, Chulalongkorn Univ, Bangkok, Thailand |
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| Abstract: | Staphylococcus sp. CMC5‐3‐1 and CMS5‐7‐5 isolated from fermented fish sauce at 3 to 7 mo, respectively, showed different characteristics on protein hydrolysis and volatile formation. These Gram‐positive cocci were able to grow in up to 15% NaCl with the optimum at 0.5% to 5% NaCl in tryptic soy broth. Based on ribosomal 16S rRNA gene sequences, Staphylococcus sp. CMC5‐3‐1 and CMS5‐7‐5 showed 99.0% similarity to that of Staphylococcus piscifermentans JCM 6057T, but DNA–DNA relatedness was <30%, indicating that they were likely to be new species. DNA relatedness between these 2 strains was only 65%, suggesting that they also belonged to different species. The α‐amino group content of 6‐month‐old fish sauce inoculated with Staphylococcus sp. CMC5‐3‐1 was 740.5 mM, which was higher than that inoculated by the strain CMS5‐7‐5 (662.14 mM, P < 0.05). Histamine was not produced during fermentations with both strains. Fish sauce inoculated with Staphylococcus sp. CMC5‐3‐1 showed the highest content of total glutamic acid (P < 0.05). The major volatile compound detected in fish sauce inoculated with Staphylococcus sp. CMC5‐3‐1 was 2‐methypropanal, contributing to the desirable dark chocolate note. Staphylococcus sp. CMC5‐3‐1 could be applied as a starter culture to improve the umami and aroma of fish sauce. |
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| Keywords: | DNA– DNA hybridization fish sauce glutamic acid 16S rRNA gene Staphylococcus sp volatile compounds |
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