摘要
为明确真空冷冻干燥过程中长双歧杆菌长亚种细胞损伤的主要阶段和损伤原因。该研究测定了长双歧杆菌长亚种BB68S在真空冷冻干燥不同阶段,包括预冻阶段、升华干燥阶段和解吸干燥阶段菌体细胞的存活性、水分变化、细胞壁完整性和细胞膜通透性等特征。结果表明,预冻阶段自由水在低温下形成冰晶,挤压细胞,导致细胞壁肽聚糖结构受损,降低了细胞壁完整度,细胞存活性下降14.1%;升华干燥阶段水分大量散失,导致细胞膜磷脂双分子层脱水后结构改变,通透性增加,致使乳酸脱氢酶、β-半乳糖苷酶等胞内代谢关键酶渗漏到细胞外,细胞活性剧烈降低49.7%;解析干燥阶段水分和细胞存活性变化均较小。因此,BB68S冻干过程中菌体细胞损伤的主要阶段为预冻阶段和升华干燥阶段,主要是由于水分变化引起细胞壁和细胞膜结构损伤,降低了其功能性,最终导致细胞活性下降。该研究解析了长双歧杆菌长亚种在冻干过程中细胞损伤的机制,为控制真空冷冻干燥工艺提高菌株冻干存活性提供了理论依据。
This study aimed to clarify the primary stages and caused of cell damage in Bifidobacterium longum subsp.longum during vacuum freeze-drying.This study assessed the cell viability,water content,cell wall integrity,and cell membrane permeability of B.longum subsp.longum BB68S at various stages of the vacuum freeze-drying process,including the pre-freezing stage,sublimation drying stage,and desorption drying stage.Results revealed that,during the pre-freezing stage,the formation of ice crystals from free water at low temperatures caused cell extrusion.This process resulted in damage to the peptidoglycan structure of the cell wall,leading to reduced cell wall integrity and a 14.1%decrease in cell viability.In the sublimation drying stage,significant water loss induced structural changes in the phospholipid bilayer of the cell membrane following dehydration,resulting in increased permeability.This alteration led to the leakage of key intracellular metabolic enzymes such as lactate dehydrogenase andβ-galactosidase into the external environment,causing a drastic 49.7%decrease in cell activity.Water content and cell viability changes were minimal during the desorption drying stage.Therefore,the primary stages of cellular damage during B.longum subsp.longum BB68S lyophilization occurred during pre-freezing and sublimation drying stages due to moisture-related compromises on both cell wall and membrane structures,ultimately reducing functionality and leading to decreased cellular activity.This study analyzed mechanisms of B.longum subsp.longum cellular damage during freeze-drying processes and provided a theoretical basis for optimizing vacuum freeze-drying procedures to enhance strain survivability.
作者
冯海红
王然
葛绍阳
张永祥
赵亮
李晓霞
姚凯
桑跃
FENG Haihong;WANG Ran;GE Shaoyang;ZHANG Yongxiang;ZHAO Liang;LI Xiaoxia;YAO Kai;SANG Yue(Department of Nutrition and Health,China Agricultural University,Beijing 100193,China;Beijing Heyiyuan Biotechnology Company Limited,Beijing 100089,China;Inner Mongolia Langege Dairy Co.Ltd.,Ulanchap 012000,China)
出处
《食品与发酵工业》
北大核心
2025年第13期62-68,共7页
Food and Fermentation Industries
基金
内蒙古自治区“揭榜挂帅”项目(2022JBGS0002)
乌兰察布市科技计划项目(2023PT402)。
关键词
长双歧杆菌长亚种
真空冷冻干燥
细胞壁
细胞膜
关键代谢酶
Bifidobacterium longum subsp.longum
vacuum freeze-drying
cell wall
cell membrane
key metabolic enzymes
