College of Biomass Science and Engineering, Sichuan University, Chengdu, 610065, China.
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China.
Food Microbiol. 2023 Jun;112:104239. doi: 10.1016/j.fm.2023.104239. Epub 2023 Feb 17.
Physical injury carried by dried process was an inevitable and hostile problem which could seriously affect the quality and viability of microbial agents. In this study, heat preadaptation was successfully applied as a pretreatment to fight against the physical stresses encountered during freeze-dried and spray-dried process and develop a high activity Tetragenococcus halophilus powder. The results indicated T. halophilus cells maintained a higher viability in dried powder when cells were treated with heat preadaptation before dried process. Flow cytometry analysis illustrated that heat preadaptation contributed to maintain a high membrane integrity during dried process. Besides, glass transition temperatures of dried powder increased when cells were preheated, which further verified that higher stability was obtained in group preadaptation during shelf life. Additionally, dried powder prepared by heat shock presented a better fermentation performance, suggesting heat preadaptation may be a promising strategy to prepare bacterial powder by freeze drying or spray drying.
物理损伤是干燥过程中不可避免且具有敌意的问题，会严重影响微生物制剂的质量和活力。在本研究中，热驯化成功地作为一种预处理方法，用于对抗冷冻干燥和喷雾干燥过程中遇到的物理压力，从而开发出高活性的四链球菌粉末。结果表明，在干燥过程之前对细胞进行热驯化处理，可使四链球菌细胞在干燥粉末中保持更高的活力。流式细胞术分析表明，热驯化有助于在干燥过程中保持较高的细胞膜完整性。此外，当细胞预热时，干燥粉末的玻璃化转变温度升高，这进一步证明在货架期内，预驯化组获得了更高的稳定性。此外，热休克制备的干燥粉末表现出更好的发酵性能，这表明热驯化可能是通过冷冻干燥或喷雾干燥制备细菌粉末的一种有前途的策略。
