Abstract
Gastric acid resistance of aerobic Lactobacilli and anaerobic Bifidohacteria in commercial 19 drink and 18 liquid yogurts in Korea was investigated after exposure to simulated gastric fluid (pH 1.5). The initial survival of Lactobacilli in commercial drink and liquid yogurts was $10^8~10^{10}$ cfulml and $10^6~10^{10}$cfdml, respectively. On the other hand, the initial survival of Bifidobacteria in commercial drink yogurts was ($10^6~10^{10}$cfulml. The survival of Lactobacilli and Bifidobacteria in some commercial drink and liquid yogurts drastically changed depending on the type of commercial products when exposed to simulated gastric fluid for 120 min (<$10^3~10^6$ cfulml). Their survival decreased as a function of time in the simulated gastric fluid. In the case of drink yogurt containing Bifidobacteria-loaded capsu1es;the survival of Bifidobactena in only Mi after excluding capsules was similar to other commercial drink yogurts after exposure to gastric fluid for 30-120 min (ca. TEX>$10^5$ cfulml). However, the survival of Bifidobacteria in capsules was greatly enhanced due to their stability in low pH condition (>$10^8$ cfulml). The drink yogut containing Bifidobacteria-loaded capsules showed about 10-737 times higher survival in the gastric fluid for 120 min when compared to other commercial drink yogurts. It was evident that the gastric acid resistance of Bifidobacteria could be increased when encapsulated.
국내 시판 19종의 드링크 및 18종의 액상 요구르트 제품에 함유된 2종의 유산균인 Lactobacilli 및 Bifidobacteria의 내산성을 인공위액(pH 1.5) 조건에서 비교 고찰되었다. 드링크 및 액상 요구르트 제품중 초기 Lactobacilli의 생존율은 각각 $10^8~10^{10}$ cfu/ml 및 $10^6~10^{10}$cfu/ml 범위 내에 있었다. 한편 드링크 요구르트 중 초기 Bifidobacteria의 생존율 $10^8~10^{10}$cfu/ml 이었다. 요구르트 제품중 Lactobacilli 및 Bifidobacteria의 생존율은 인공위액에 노출 시간이 증가함에 따라 점차 감소하는 경향을 나타내었으며 120분 노출시에 제품들간에 큰 차이를 나타내었다. (<$10^3~10^6$cfu/ml),캡슐을 함유한 요구르트 제품의 경우, 캡슐을 제외한 Mix는 인공위액에 30분에서 120분 노출시에 약$10^5$cfu/ml이상의 생존율을 나타내었으며 타사 제품과 유사한 거동을 보였다. 그러나 Bifidobacteria를 함유한 캡슐요구르트 제품의 경우 인공위액에 약 120문 노출시켰으때 타사 제품보다 생존율이 약10~737배 이상 증가하였다. 즉 Bifidobacteria의 내산성은 코팅물질을 사용한 캡슐로 봉입하였을 때 증가됨을 알 수 있었다.