김치로부터 분리한 유산균의 콜레스테롤 저하 효과

Abstract

Probiotics potential properties of lactic acid bacteria isolated from kimchi. The isolated four strains were identified by examing their morphological and metabolic properties and 16S rRNA gene sequences. They were identified as Lactobacillus plantarum EM, Lactobacillus plantarum HD1, Lactobacillus plantarum NO1, and Leuconostoc kimchii GJ2. Growth of the isolated strains was measured at 30℃ and 37℃ for 48 h. The probiotic potential properties of lactic acid bacteria investigated include antibiotic resistance, acid and bile tolerance, enzymatic activities and cholesterol assimilation ability. Antibiotic susceptibility tests indicated that four isolates were sensitive to ampicillin, vancomycin, gentamycin, kanamycin, streptomycin, erythromycin, clindamycin, tetracycline and chloramphenichol, which were included in the European Food Safety Authority. To obtain antibiotic susceptibilities of lactic acid bacteria, minimum inhibitory concentration (MIC) of 8 antibiotics for 4 LAB isolates from Kimchi were determined. Four strains were highly resistant to acid, simulated gastric juice, and bile salt. The enzyme profiling is an important factor for selection of strains. When examined by API-ZYM kit, β-glucuronidase was not produced by Lb. plantarum EM, HD1, Leu. kimchii GJ2. The ability of cholesterol-binding appeared to be growth and strain specific. The isolated LAB strains were able to assimilate cholesterol at varying levels ranging from 76.2 to 96.4% at 30℃ and from 72.4 to 95.1% at 37℃ in MRS medium supplemented with oxgall. Additionally, the isolated LAB showed the cholesterol assimilation capability from 50.3 to 98.4% at 30℃ and from 23.8 to 97.9% at 37℃ in MRS medium supplemented with taurodeoxycholic acid. The four strains showed still high cholesterol assimilation ability with dead cell stage. cholesterol assimilation ability with the growing cell and dead cell were confirmed by scanning electron microscopy observation. SEM showed that cholesterol was adhered to the cellular surface of the lactic acid bacteria cells. In conclusion, these results suggest that the Lactobacillus plantarum EM potentially probiotic functional strain.