Antimicrobial Efficacy of Fermented Dark Vinegar from Unpolished Rice

Abstract

식초는 세계적으로 사용되는 조미료로 밀, 과일, 곡물 등을 원료로하여 다양한 방법으로 제조된다. 지금까지 식초에 대한 대부분의 연구들은 항산화활성에 한정된 연구였다. 본 연구에서는 현미를 이용하여 만든 현미 발효 식초의 이화학적 특성과 항균활성에 대해 시험하였으며, 현미발효식초의 항균활성은 paper disc-agar diffusion 방법을 이용하여 조사하였 때, 병원성 박테리아와 효모에 대해 강한 항균활성을 나타내었다. 특히 Staphylococcus aureus, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella typhimurium, Yersinia enterocolitica, and Lodderomyces elongisporus의 균주에 대해서는 상용되는 항생제인 카베니실린과 테트라사이클린보다 더 높은 항균활성을 보였다. 항산화활성은 2,2-diphenyl-1-picrylhydrazyl (DPPH) 라디칼 소거능을 이용하여 측정하였고, 대표되는 항산화제인 아스코르빅 산과 비슷한 활성을 나타내었다. 현미발효흑초의 발효중에 나타나는 균주를 동정하기 위해 TSB 고체배지와 YPD 고체배지에 현미발효흑초를 도포하였을 때, 분리된 콜로니를 16S rDNA sequence 분석을 통하여, FDVS-1, 2, 3 세가지 균주를 분리하였으며, phylogenic tree 분석법을 이용하여 조사하였을 때, 각각 Acetobacter papayae, Acetobacter pasteuranus, Acetobacter peroxidans와 유사하였다. 【Vinegar is a widely used acidic seasoning and can be manufactured using various methods and bases, including cereals, wheat, and fruits. Most studies on vinegar have been conducted to evaluate its antioxidant activity. In the present study, fermented dark vinegar (FDV) produced from unpolished rice was examined for its antimicrobial activity, biochemical content, including the amounts of sugar, total soluble sugar, organic acid, and free amino acids, and pH and physiological activity. The antimicrobial efficiency of FDV was assessed using the paper disc-agar diffusion method. FDV exhibited strong antimicrobial activity against the pathogenic bacteria and yeast strains that were tested. In fact, the activity of FDV was shown to be higher than that of the commercial antibiotics carbenicillin (50 µg/ml) and tetracycline (50 µg/ml) against Staphylococcus aureus, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella typhimurium, Yersinia enterocolitica, and Lodderomyces elongisporus. The antioxidant activity of FDV and ascorbic acid was evaluated. Using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method, we found that FDV has the highest activity of the antioxidants. After spreading FDV onto tryptic soy broth and yeast extract-peptone-dextrose agar media, the microbial strains were isolated and characterized through physiological and biochemical analysis. Based on 16S ribosomal DNA sequence analysis, the isolated microorganisms exhibited a close similarity to Acetobacter papayae, Acetobacter pasteurianus, and Acetobacter peroxidans.】