State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China.
Western Regional Research Center, ARS, U.S, Department of Agriculture, Albany, CA 94710, United States.
Food Chem. 2022 Sep 30;389:132999. doi: 10.1016/j.foodchem.2022.132999. Epub 2022 Apr 18.
Heat shock and hygroscopicity are two main factors that resulted in low viability of probiotics in spray-dried microcapsules during storage. Hydrophobic polyester shellac was combined with whey protein isolate (WPI) to solve this problem. The results suggested that although the survival rate after drying decreased from 20.63% to 0.01% with increased shellac to WPI ratio, the 1:1 shellac-WPI provided the best protection among all samples during storage. The consistence between moisture-adsorption-isotherm and bacterial inactivation constants confirmed the moisture barrier effect of shellac under moderate humidity. Single-droplet drying and differential scanning calorimeter revealed that shellac addition reduced the drying rate and glass transition temperature of microcapsules, which in turn decreased the membrane integrity and growth capability of the probiotics after drying. This study revealed the dual effect of hydrophobic material on instant and long-term survival of spray-dried probiotic microcapsules, which provided new sight to the design of composite wall materials.
热冲击和吸湿性是导致喷雾干燥微胶囊中益生菌在储存过程中存活率低的两个主要因素。疏水性聚酯紫胶与乳清蛋白分离物（WPI）结合以解决此问题。结果表明，尽管随着紫胶与 WPI 比例的增加，干燥后的存活率从 20.63%降至 0.01%，但在所有样品中，1:1 的紫胶-WPI 在储存过程中提供了最佳的保护。吸湿等温线和细菌失活动力学常数之间的一致性证实了紫胶在中等湿度下的防潮屏障作用。单液滴干燥和差示扫描量热法表明，紫胶的添加降低了微胶囊的干燥速率和玻璃化转变温度，从而降低了干燥后益生菌的膜完整性和生长能力。本研究揭示了疏水性材料对喷雾干燥益生菌微胶囊即时和长期生存能力的双重影响，为复合壁材的设计提供了新的思路。
