Toh Mingzhan, Liu Shao Quan
Food Science and Technology Programme, Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore.
National University of Singapore (Suzhou) Research Institute, No. 377 Linquan Street, Suzhou Industrial Park, Suzhou, 215123, Jiangsu, China.
AMB Express. 2017 Dec;7(1):156. doi: 10.1186/s13568-017-0456-4. Epub 2017 Jul 24.
This study evaluated the influence of three inactivated yeast derivatives (IYDs) used in wine production, namely OptiRed, OptiWhite and Noblesse, on the viability of the probiotic strain Lactobacillus rhamnosus HN001 in an acidic environment. Addition of the IYDs at 3 g/L significantly enhanced the survival of the probiotic bacteria by 2.75-4.05 log cycles after 10-h exposure in a pH 3.0 buffer. Acid stress assay with IYD components obtained after centrifugation and filtration revealed that water-soluble compounds were responsible for improving the acid tolerance of L. rhamnosus HN001 for all three preparations. Differences in protective effect amongst the IYDs on L. rhamnosus HN001 were observed when permeates and retentates of the water-soluble extracts, obtained through ultrafiltration with a 2 kDa membrane, were assayed against the lactic acid bacterium. Chemical analysis of the water-soluble components suggests that low molecular weight polysaccharides, specific free amino acids and/or antioxidants in the 2 kDa permeates could have contributed to the enhanced survival of L. rhamnosus HN001 during acid stress. The contrast amongst the 2 kDa retentates' viability enhancing property may have been attributed to the differences in size and structure of the higher molecular weight carbohydrates and proteins, as the survival of the probiotic did not relate to the concentration of these compounds. These results suggests that oenological IYDs could potentially be applied to probiotic foods for enhancing the acid tolerance of the beneficial microorganisms, and consequently prolonging the shelf life of these products.
本研究评估了葡萄酒生产中使用的三种灭活酵母衍生物（IYDs），即OptiRed、OptiWhite和Noblesse，对益生菌鼠李糖乳杆菌HN001在酸性环境中活力的影响。在pH 3.0缓冲液中暴露10小时后，添加3 g/L的IYDs可使益生菌的存活率显著提高2.75 - 4.05个对数周期。对离心和过滤后获得的IYD成分进行酸胁迫试验表明，所有三种制剂中，水溶性化合物是提高鼠李糖乳杆菌HN001耐酸性的原因。当用2 kDa膜超滤获得的水溶性提取物的渗透物和截留物针对乳酸菌进行检测时，观察到IYDs对鼠李糖乳杆菌HN001的保护作用存在差异。对水溶性成分的化学分析表明，2 kDa渗透物中的低分子量多糖、特定游离氨基酸和/或抗氧化剂可能有助于鼠李糖乳杆菌HN001在酸胁迫下提高存活率。2 kDa截留物提高活力特性的差异可能归因于较高分子量碳水化合物和蛋白质的大小和结构差异，因为益生菌的存活率与这些化合物的浓度无关。这些结果表明，酿酒用IYDs可能潜在地应用于益生菌食品，以提高有益微生物的耐酸性，从而延长这些产品的保质期。
