真空冷冻干燥橄榄假丝酵母的制备及其对苹果青霉病的防治

Formulation Optimization of a Cryoprotectant for Freeze-Dried Candida oleophila and Its Application to Control Blue Mold in Apple

选用真空冷冻干燥技术,糖醇类试剂包括海藻糖、蔗糖、乳糖、山梨糖醇,抗氧化类试剂谷氨酸钠,以及赋形剂包括脱脂奶粉和β-环糊精三大类试剂作为保护剂,通过保护剂的单因素筛选试验、正交试验得到真空冷冻干燥橄榄假丝酵母的最优保护剂配方为海藻糖添加量15%、谷氨酸钠添加量2%和脱脂奶粉添加量10%,所得酵母存活率为69.7%。此外,通过比较冻干橄榄假丝酵母和新鲜橄榄假丝酵母对苹果果实青霉病的发病率和病斑直径的研究,并测定冻干橄榄假丝酵母和新鲜橄榄假丝酵母接种处理后酵母在苹果果实伤口处的生长动态,以期制备性能良好的生物防治试剂。

Candida oleophila is an efficient antagonist.Many studies have shown that it can control postharvest diseases in various fruits.However,because of difficulties in its transportation and storage,C.oleophila is difficult to apply commercially.Freeze-drying is widely used to preserve microorganisms.Thus,in the present research,the selection and optimization of cryoprotectant components(sugars and sugar alcohols including trehalose,sucrose,lactose and sorbitol;the antioxidant sodium glutamate;excipients including skim milk andβ-cyclodextrin)as well as their levels for vacuum freeze-drying of C.oleophila were optimized using one-factor-at-a-time and orthogonal array design methods.The optimal formulation was composed of 15%trehalose,2%sodium glutamate,and 10%skim milk powder.A survival rate of 69.7%was obtained using this formulation.The effects of fresh and freeze-dried C.oleophila on the incidence of blue mold and lesion diameter in apple were compared,and the growth dynamics of the yeast inoculated in apple wounds.Through this study,we hope to obtain a good biocontrol agent against blue mold in apple.