Culture characteristics of Leuconostoc mesenteroides WiKim32 in kimchi cabbage juice without supplements and sterilization

비살균 무첨가 배추즙에서 Leuconostoc mesenteroides WiKim32의 배양 특성

Abstract

This study was performed to develop an economical culture method of lactic acid bacteria (LAB) for kimchi fermentation. Leuconostoc mesenteroides WiKim32 was grown to $1{\times}10^9CFU/mL$ and maintained at 8.88 log CFU/mL for four days by culturing in kimchi cabbage juice (KCJ) without supplements and sterilization. Leuconostoc mesenteroides WiKim32 was cultured in 100 mL of KCJ by inoculating with 0.1% starter culture and adding 100 mL of KCJ everyday by adjusting pH to 5.5 using 1 M NaOH at $20^{\circ}C$ for four days. KCJ was prepared by extraction of kimchi cabbage leaves after washing them with citric acid and ethanol. Adjusting pH over 6.0 was favorable for the growth of LAB in the initial stage, but LAB growth was retarded in the later stage. In contrast, adjusting pH below 5.0 was not beneficial for the growth of LAB; therefore, pH was adjusted to 5.5.

배추 겉잎을 착즙하여 얻은 비가열 배추즙에 영양소를 첨가하지 않고 유산균을 접종하여 균수를 1 mL 당 10억 마리 이상으로 증식시키고 8.88 log CFU/mL 이상으로 4일간 유지하였다. 이때 배양조건은 배추즙 100 mL에 Leuconostoc mesenteroides WiKim32를 0.1% 접종하고 비살균 무첨가 배추즙을 매일 100 mL씩 첨가하고 1 M NaOH로 pH를 5.5로 조정하였으며 $20^{\circ}C$에서 4일간 정치 배양하였다. 배추즙은 배춧잎을 구연산과 에탄올로 세척하여 착즙하였고, pH를 6.0 이상으로 조정하면 초기 생육은 빠르나 후기에는 유산균의 생육이 억제되었고, 5.0 이하로 조정하면 조정 효과가 미약했으므로 5.5로 조정하였다. 이번 연구는 김치공장에서 종균을 경제성 있게 생산하는 방법으로 비살균 무첨가 배추즙에 유산균을 고농도로 배양할 수 있음을 보여주었다.

Table 1. Composition of kimchi cabbage and kimchi cabbage juice of outer leaves

Table 2. Influence of pH on the growth of lactic acid bacteria in kimchi cabbage juice at 5°C without supplements and sterilization (Unit: log CFU/mL)

Table 3. Influence of initial pH and yeast extracts supplement on the growth of lactic acid bacteria in kimchi cabbage juice at 5°C without sterilization (Unit: log CFU/mL)

Table 4. Effects of adjusting pH on the growth of lactic acid bacteria in kimchi cabbage juice at 5°C without sterilization (Unit: log CFU/mL)

Table 5. Effects of adding kimchi cabbage juice on the growth of lactic acid bacteria in 100 mL kimchi cabbage juice at 25°C without supplements and sterilization (Unit: log CFU/mL)

Table 6. Effects of starter inoculation, adjusting pH and adding kimchi cabbage juice on the growth of lactic acid bacteria in kimchi cabbage juice at 20°C without supplements and sterilization (Unit: log CFU/mL)