유산균을 이용한 녹차 추출물의 발효전환

In order to improve the sensory preference and to mitigate the bitter taste of green tea extract products, 100 microorganisms isolated from Korean traditional fermented foods were used to ferment green tea extract and the analysis of catechins and sensory evaluation of the fermented green tea extract products were undertaken. When the isolates were cultured into 2, 4, 6, 8, and 10% green tea extract, the highest growth rates were observed when 2 and 4% of green tea extract were used as growth medium. When the contents of catechin components of non-fermented and fermented green tea extracts were analyzed by HPLC, there was a significant decrease in content of epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin (EC) (EGCG: 125.45→65.42 μg/mg, EGC: 85.96→38.03 μg/ mg, EC: 25.64→13.84 μg/mg), whereas there was a significant increase in content of gallocatechin gallate (GCG) and gallocatechin (GC) (GCG: 7.79→85.22 μg/mg, GC: 9.46→64.59 μg/mg). Eleven strains of lactic acid bacteria, which showed relatively small content of gallate-type catechins (EGCG, ECG, GCG, CG) in their fermented green tea extracts, were selected and used for sensory test. As a result of sensory evaluation, Lactobacillus plantarum 62901 and Leuconostoc pseudomesenterioides K200132 showed the best score in overall preference. Their fermented products also showed strong roasted flavor while decreased grass flavor and bitter taste were observed.