김치로부터 분리한 Weissella 속, Leuconostoc 속, Lactobacillus 속 특성 규명

Abstract

The four different commercial kimchi (midium enterprises kimchi) were used as samples, which were fermented at 6.5℃ for 7∼9 days. SJ was isolated from these kimchi. It was identified using morphological and nucleotide sequence determination of 16s rRNA gene. It was identified as Weissella koreensis SJ. General characteristics of Kimchi lactic acid bacteria (LAB), LAB 9 strains were seleted; Weissella koreensis SK, W. confusa GJ6, W. cibaria 31, Leuconostoc citreum GR1, Leu. kimchii 2 strains, Leu. mesenteroides 2 strains, Lactobacillus sakei 4 strains, Lb. plantarum 2 strains, Lb. curvatus BU1 strain were investigated. To investigate the antagonistic activity of kimchi lactic acid bacteria (LAB) against kimchi LAB, 29 LAB strains were selected; W. koreensis 5 strains, W. cibaria 2 strains, W. confusa 2 strains, Leu. citreum 4 strains, Leu.. kimchii 2 strains, Leu.. mesenteroides 4 strains, Lb. sakei 7 strains, Lb. plantarum 2 strains, Lb. curvatus 1 strain. Antagonistic activity of LAB were examined using paper disc method and direct method. W. koreensis did not inhibit the growth of most of Leuconostoc and Lactobacillus species, while W. confusa and W. cibaria weakly inhibited the growth of Leuconostoc and Lactobacillus species. Leuconostoc species inhibited only the growth of Lb. curvatus among Lacobacillus species. Most of Leuconostoc species did not inhibit the growth of W. koreensis. Lactobacillus species inhibited the growth of all Leuconostoc and Weissella species, and Lb. plantarum showed the strongest antagonistic activity against all tested LAB strains. The growth of the LAB were measured; W. confusa GJ6, W. cibaria 37 and Lb. sakei SC1, Lb. sakei YY1 rapidly reached stationary phase at 12 h. W. koreensis SK, Lb. plantarum HD1 reached stationary phase at 24 h. To investigate the growth of the kimchi refrigerator’s different temperature (-1∼-2℃, 6.5℃, 15℃) and the general refrigerator’s temperature (4℃), LAB 9 strains were selected. Growth of the selected LAB 9 strains were measured at –1∼-2℃ for 8 weeks; the selected LAB 9 strains was initial the viable cells about 5.0 log CFU/mL. W. koreensis SK rapidly reached 9.3∼9.4 log CFU/mL at 3 weeks. Also Leu. kimchii GJ2 and Leu. mesenteroides TA reached 6.8∼7.9 log CFU/mL, Lb. sakei SC1 and Lb. sakei YY1 steadily increased to 8.0∼8.4 log CFU/mL at 8 weeks. Interestingly, W. confusa GJ6 and W. cibaria 31 slowly decreased to 3.4∼3.9 log CFU/mL for 6 weeks but they increased to 5.3∼6.7 log CFU/mL at 8 weeks. Lb. plantarum HD1 slowly decreased to 4.4 log CFU/mL for 8 weeks. and Leu. citreum GR1 maintained for 3 weeks, after weakly decreased to 4.4 log CFU/mL at 8 weeks. Therefore, Lb. plantarum was restricted at psychrophilic temperature. Growth of the selected LAB 9 strains were measured at 15℃ for 7 days; the most of selected LAB reached stationary phase at 2∼3 days except Lb. plantarum HD1. Lb. plantarum HD1 slowly reached stationary phase at 5 days. The overall growth rates at 15℃ were similar the growth rate at 30℃. The effect of initial pH (pH 4, 5) of the growth medium on the growth was observed. Also, the effect of acids on the growth rate of LAB 9 strains were observed. Among these LAB 9 strains, Lactobacillus spp. exhibited a relatively high survival rate in MRS medium, which was adjusted to pH 4.0. It is important to understand at detail the properties and roles of Weissella sp. Leuconostoc sp. Lactobacillus sp. during kimchi fermentation if desirable properties of Lactic acid bacterium are fully utilized for the production of high quality kimchi with good taste and enhanced biofunctionalities. These results indicate that a more systematic kimchi production manual should be developed to industrialize and globalize kimchi.