Exopolysaccharide 생성 유산균을 이용한 감초 추출물 첨가 Yoghurt의 품질특성 및 Helicobacter pylori KCCM 40449 억제활성

정승원¹, 김철우², 이수한³^,^*

Quality Characteristics and Inhibition Activity against Helicobacter pylori KCCM 40449 of Liquorice Yogurts Manufactured by Exopolysaccharide Producing Lactic Acid Bacteria

Seung-Won Jung¹, Cheol Woo Kim², Su Han Lee³^,^*

¹동국대학교 식품생명공학과

²한국식품공업협회

³을지대학교 식품산업외식학과

¹Department of Food Science & Biotechnology, Dongguk University

²Korea Advanced Food Research Institute

³Department of Food Technology and Services, Eulji University

^*Corresponding author: Su Han Lee, Department of Food Technology and Services, Eulji University, 212, Yanggi-dong, Sujeong-gu, Seongnam, Gyeonggi-do, 461-713, Korea, Tel: +82-31-740-7196; Fax: +82-31-710-7349, E-mail: shlee@eulji.ac.kr

ⓒ Copyright 2011 Korean Society for Food Engineering. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received: Oct 12, 2011; Revised: Nov 01, 2011; Accepted: Nov 01, 2011

Published Online: Nov 30, 2011

Abatract

This study was carried out to fortify the antimicrobial activity of yoghurt by adding liquorice extract to it. The liquorice extracts (1 mg/mL) showed relatively high antibacterial activity against H. pylori KCCM 40449 (p < 0.05). The solvent liquorice extracts of minimal inhibitory concentrations (MIC) against H. pylori KCCM 40449 were 25-100 μg/mL. Lactobacillus amylovorus DU-21 with high EPS production ability were inoculated to milk after the addition of different amounts of liquorice extracts (0.0%, 0.05%, 0.1% and 0.2%). The physico-chemical characteristics of yoghurts added with liquorice extracts were examined. The initial pH, titratable acidity, viscosity and viable cell counts of the yoghurt added liquorice extracts were 3.41-3.51, 1.021-1.091%, 1,686-1,930 cp and 9.41-9.38 Log CFU/mL, respectively. The viscosity and syneresis of yoghurt were better than that of the control. Antimicrobial activity against H. pylori KCCM 40449 increased with increasing addition of liquorice extract. However, the sensory score of yoghurt added with different amounts of liquorice extracts was lower than that of the control (p < 0.05). As a result of the sensory evaluations, the flavor, taste, texture, color and overall acceptability of the yoghurt with 0.05% liquorice extract were found to be much better than those of the other groups (p < 0.05). Overall, the optimal amount of liquorice extract added in the manufacture of yoghurt was 0.05% of the total weight. Further studies on increment of antimicrobial activity and palatability of liquorice extract added yoghurt are necessary.

Keywords: yoghurt; liquorice extracts; Helicobacter pylori; lactic acid bacteria; syneresis