Wang Cuina, Wang Mu, Wang Hao, Sun Xiaomeng, Guo Mingruo, Hou Juncai
Key Laboratory of Dairy Science Northeast Agriculture University Harbin China.
Department of Food Science, College of Food Science and Engineering Jilin University Changchun China.
Food Sci Nutr. 2019 Jul 24;7(8):2708-2715. doi: 10.1002/fsn3.1130. eCollection 2019 Aug.
Probiotic cultures are commonly freeze-dried for storage and distribution. However, freeze-drying and subsequent storage are accompanied by a decline in cell viability. Whey protein (WP) or polymerized whey protein (PWP) was used to protect LA-5 against damage during freeze-drying process and the subsequent storage. The protection capacity and effects of polymerized whey protein protected freeze-dried LA-5 on physiochemical properties of cow and goat milk yoghurts were evaluated in comparison with maltodextrin (MD). The survival rate of LA-5 after freeze-drying decreased in the order of MD (80.91%) > PWP (69.86%) > WP (64.89%). The particles of WP- and PWP-based freeze-dried samples showed an average diameter of about 10 μm, which was significantly higher than that of MD-based particles (1.5 μm). Both whey protein preparations showed higher protecting effect than MD at high humidity condition during the 180-day storage. Addition of freeze-dried LA-5 with the presence of WP or PWP improved the protein content and decreased spontaneous whey separation and syneresis significantly for both yoghurts. PWP-protected LA-5 addition significantly improved the firmness and adhesiveness of the yoghurt. Freeze-dried LA-5 mixed with PWP had higher survivability in yoghurts compared with the culture alone at the end of storage. Data indicated that whey protein can be used to protect probiotics during freeze-drying and may also improve the physiochemical properties of the yoghurt.
益生菌培养物通常进行冷冻干燥以进行储存和分发。然而，冷冻干燥及随后的储存会伴随着细胞活力的下降。乳清蛋白（WP）或聚合乳清蛋白（PWP）被用于在冷冻干燥过程及随后的储存期间保护嗜酸乳杆菌LA-5免受损伤。与麦芽糊精（MD）相比，评估了聚合乳清蛋白保护的冷冻干燥LA-5对牛奶和羊奶酸奶理化性质的保护能力和效果。冷冻干燥后LA-5的存活率从高到低依次为MD（80.91%）>PWP（69.86%）>WP（64.89%）。基于WP和PWP的冷冻干燥样品颗粒的平均直径约为10μm，显著高于基于MD的颗粒（1.5μm）。在180天储存期间的高湿度条件下，两种乳清蛋白制剂均显示出比MD更高的保护效果。添加含有WP或PWP的冷冻干燥LA-5可提高两种酸奶的蛋白质含量，并显著减少自然乳清分离和脱水收缩。添加PWP保护的LA-5可显著提高酸奶的硬度和粘附性。在储存结束时，与单独的培养物相比，与PWP混合的冷冻干燥LA-5在酸奶中的存活率更高。数据表明，乳清蛋白可用于在冷冻干燥期间保护益生菌，并且还可能改善酸奶的理化性质。
