스타터 첨가에 의한 가자미 식해 발효과정 중의 미생물 군집 변화

Abstract

The object of this study is to analyze the microbiological, physicochemical, and microbial community changes during fermentation process by adding lactic acid bacteria starter into the production process of Gajami Sik-hae, a traditional Korean fermented seafood product. Leuconostoc mesenteroides strains were isolated from Sik-hae products based on acid tolerance (pH 3, pH 4 and pH 5) and salt tolerance (1%, 3% and 5% NaCl) tests. Among them, L. mesenteroides strain C6 exhibiting the highest acid and salt tolerances was selected as the starter strain. Gajami Sik-hae was then prepared with the addition of L. mesenteroides C6 starter, and the changes of microorganisms, physicochemical characteristic, and microbial community were analyzed at 20℃ for 15 days with a 3-day cycle. Microbial experiments analyzed the viable cell count and number of lactic acid bacteria, and physicochemical experiments analyzed salinity, pH, acidity, and volatile basic nitrogen (VBN), and sensory evaluation was performed for appearance, fishy smell, fishy taste, salty taste, sour taste, sweet taste, texture and preference. DNA from the Gajami Sik-hae samples was extracted, and microbiome changes were confirmed through Next Generation Sequencing (NGS) analysis. As a result of the experiment, the C6 isolated strain showed a relatively high survival rate under acid- and salt-resistant conditions, confirming the possibility as a starter for fermented foods. The sensory evaluation results revealed that the 3rd day of fermentation is the best fermented periods to produce Gajami Sik-hae with addition of the C6 starter. In the 3rd day of fermentation, the number of lactic acid bacteria was found to be about 9.33 log CFU/g. In addition, the NGS analysis revealed that the genus Leuconostoc dominates from the initial of fermentation to the 15th day in Gajami Sik-hae with addition of L. mesenteroides C6 starter. The ratio of bacterial population of the genus Lactobacillus was lower in the Gajami Sik-hae with addition of the C6 starter than that of without the addition of C6 starter.