PEF作用下亚致死损伤酿酒酵母修复条件的初步研究

Recovery of sublethally injured Saccharomyces cerevisiae cells after pulsed electric fields treatment

为进一步探究高压脉冲电场（PEF）对酿酒酵母的灭菌机理,初步研究了PEF处理下亚致死损伤酿酒酵母（Saccharomyces cerevisiae）的修复条件。采用酵母浸出粉、蛋白胨和葡萄糖缓冲溶液作为模拟酿酒酵母的培养修复环境,通过选择性培养基与非选择性培养基对PEF（20k V/cm,400μs,15℃）处理前后亚致死酵母细胞进行菌落计数,结果显示PEF作用下亚致死酿酒酵母于三种模拟体系下可在30~70min内完成修复,在酵母浸出粉复杂模拟体系中修复速度最快。通过在p H7.2的磷酸盐缓冲液（PBS）模拟体系和实际食品体系（鲜草莓汁）添加K＋、Ca2＋和Mg2＋离子,结果表明在模拟和实际体系中添加金属阳离子对均会产生不同的修复效果。

To explore the inactivation mechanism of S.cerevisiae caused by pulsed electric field（ PEF）, the influence of the recovery liquid medium on the repair of S.cerevisiae sublethally injured cells after PEF was revealed.The yeast extract, peptone and glucose buffer solution was adopted as the sublethally injured cells culture environment.Sublethal S.cerevisiae cells under certain conditions（20kV/cm,400μs, 15℃（3）were detected by using a selective medium plating technique.The results showed that self repair of S.cerevisiae sublethally injured cells could be recoved in 30-70rain in liquid medium（yeast extract, peptone and glucose buffer solution）, injured cells had their maximum repair capacity when suspended in yeast extract.Metal ions（ K ＋ .Ca2＋ .Mg2＋ ）were added to the phosphate buffer （PBS）and fresh strawberry juice, S.cerevisiae sublethally injured cells in these systems presented self-repair.