一株桃褐腐病生防酵母菌活性冻干粉的制备及保鲜应用

Preparation and Preservation Application of a Yeast Active Freeze-dried Powder for Biocontrol of Peach Brown Rot

为研究出一种能有效防治水蜜桃采后褐腐病的生防制剂,以一株间型假丝酵母菌Y-17为研究对象,通过单因素实验和响应面中心组合设计对间型假丝酵母菌Y-17冷冻干燥保护剂的配方进行筛选和优化,考察了所制备的活性冻干粉的生防效力和存放效力,并研究了其对水蜜桃的蜜桃采后贮藏的保鲜效果。结果表明,山梨醇5.43 g/100 mL、海藻糖12.45 g/100 mL、谷氨酸钠13.56 g/100 mL时,组合保护效果最好,酵母菌存活率可达84.21%±0.87%,且冻干后的菌粉仍具有较高的生防效力,-20℃贮藏180 d酵母存活率为34.66%。保鲜应用实验表明,酵母菌Y-17活性冻干粉能够有效抑制水蜜桃腐烂,25℃贮藏至第9 d时,腐烂指数仅为6.28%。酵母冻干粉还能减少桃果实贮藏期间水分流失,减缓果实软化速度,25℃贮藏7 d后,桃果实可溶性固形物含量、维生素C含量、可滴定酸含量分别为10.67%、2.15 mg/100 g、0.17%,均高于对照组,且能有效维持果皮细胞膜完整性,对水蜜桃采后的贮藏保鲜具有积极作用。

In order to study a biocontrol agent which can effectively control honey peach brown rot after harvest,a strain of Candida intermedia Y-17 was used as the object.The cryoprotectant formulation was selected and optimized by single factor test and response surface center composite design.The biocontrol effect and storage effect of the active lyophilized powder were investigated,and its fresh-keeping effects on honey peach after harvest were also studied.It was found that the combination of 5.43 g/100 mL sorbitol,12.45 g/100 mL trehalose and 13.56 g/100 mL sodium glutamate had the best protective effect,and the survival rate of yeast could reach 84.21%±0.87%.The freeze-dried powder still had high biocontrol effect,and the yeast survival rate was 34.66%after 180 days of storage at-20℃.Fresh-keeping experiment showed that,yeast Y-17 active lyophilized powder could effectively inhibit the rot incidence of peach during storage,and the decay index was only 6.28%when stored at 25℃until the 9th day.In addition,the yeast freeze-dried powder could also reduce the loss of water and slow down the softening rate of peach during storage.After 7 days storage at 25℃,the content of soluble solids,vitamin C and titratable acid in peach were 10.67%,2.15 mg/100 g and 0.17%,respectively,which were higher than those in the control group.Freeze-dried powder could also effectively maintain the integrity of peel cell membrane and played a positive role in maintaining the quality of peach after harvest.