Abstract

Probiotic application remains a challenge since decades, as microorganisms lose their viability and functionality during the manufacture and storage of freeze-dried powders. Appropriate cryoprotectants are important in achieving particular probiotic preparation. Recently, Enterococcus spp. such as Enterococcus faecalis and E. faecium have been used as probiotics for human or animal health promotion. We aimed to determine a suitable protectant to protect the viability and pathogen inhibition potential of E. faecalis probiotic strains during freeze-drying and subsequent storage. E. faecalis probiotic strains were lyophilized in the presence of glucose, fructose, sucrose, skim milk, and distilled water. The lyophilized vials were stored at 4 °C for up to 30 days. Then, the cells from these vials were evaluated for their probiotic functionality. Among several protectants, skim milk exhibited highly protective capability to protect E. faecalis cell viability during freeze-drying and 30-day storage, with survival rates of E. faecalis strains ranging from 95.96 ± 0.20% to 103.42 ± 1.96% and 95.68 ± 0.72% to 102.95 ± 2.12%, respectively. The presence of skim milk could also effectively enhance the antimicrobial activity of all freeze-dried E. faecalis strains against toxigenic Clostridium difficile strains and maintain their activity after 30-day storage. Furthermore, hemolytic analysis demonstrated the safety of these freeze-dried E. faecalis strains. Overall, the results indicate that skim milk could be used as a suitable cryoprotective substance for freeze-dried E. faecalis probiotics, with potential applications in functional food, medicine, and feed industries.

摘要

几十年来，益生菌的应用仍然是一个挑战，因为微生物在冻干粉末的制造和储存过程中失去了它们的活力和功能。适当的冷冻保护剂对于实现特定的益生菌制剂很重要。最近，肠球菌属。例如粪肠球菌和粪肠球菌已被用作促进人类或动物健康的益生菌。我们旨在确定一种合适的保护剂，以保护粪肠球菌益生菌菌株在冷冻干燥和随后的储存过程中的活力和病原体抑制潜力。粪肠球菌在葡萄糖、果糖、蔗糖、脱脂牛奶和蒸馏水存在下冻干益生菌菌株。冻干的小瓶在 4°C 下储存长达 30 天。然后，评估这些小瓶中的细胞的益生菌功能。在几种保护剂中，脱脂乳在冷冻干燥和30天储存期间表现出对粪肠球菌细胞活力的高度保护能力，粪肠球菌菌株的存活率范围为95.96±0.20%至103.42±1.96%和95.68±0.72 % 至 102.95 ± 2.12%，分别。脱脂奶的存在还可以有效增强所有冻干粪肠球菌菌株对产毒艰难梭菌的抗菌活性菌株并在储存 30 天后保持其活性。此外，溶血分析证明了这些冻干粪肠球菌菌株的安全性。总体而言，结果表明脱脂奶可作为一种合适的冷冻干燥粪肠球菌益生菌的冷冻保护物质，在功能性食品、医药和饲料行业具有潜在应用。