冷冻干燥影响乳酸菌发酵活力机制的研究进展

Research Progress on the Mechanism of Freeze-drying Affecting the Fermentation Activity of Lactic Acid Bacteria

乳酸菌是食品中常用的发酵菌株或益生菌,常以冻干粉的形式应用于工业生产。冻干过程中的脱水及低温等条件对乳酸菌形成胁迫,造成菌株活力下降甚至死亡。冻干粉中菌株活菌数或发酵活力是乳酸菌冻干粉的重要指标。目前大部分研究集中在解析菌株抗冻干机制以及提高菌体冻干存活率等技术,本文围绕乳酸菌发酵活力指标,综述了冷冻干燥过程中影响发酵活力的因素,阐述了细胞膜流动性、通透性和细胞膜损伤异质性等对乳酸菌发酵活力的作用及机制,为进一步阐明冷冻干燥影响乳酸菌发酵活力的途径,开发提高乳酸菌冻干粉发酵活力的技术提供依据。

Lactic acid bacteria(LAB) are commonly used as fermentation strains or probiotics in food. The main application form of LAB in the industry is freeze-dried powder. During freeze-drying, formation of ice crystals and dehydration could damage LAB cells, resulting in decreased metabolic activity or even cell death. The viable count or fermentation activity are important quality indices of the freeze-dried powder for lactic acid bacteria. At present, viability derived freeze-drying stress response mechanisms and survival improvement technology are gained widespread attention. In this study, the factors affecting fermentation activity in freeze-drying process are reviewed. And the effects and mechanisms of cell membrane fluidity, permeability, and heterogeneity of cell membrane damage on the fermentation activity during the freeze-drying were expounded. The study provides a basis for the further clarifying mechanism of freeze-drying affecting the fermentation activity of LAB. It also promotes the development of freeze-drying technique for LAB.