采前喷施拮抗酵母菌对草莓采后贮藏性能的影响

Effect of preharvest spraying antagonistic yeast on the postharvest storability of strawberry

[目的]研究采前喷施拮抗酵母菌以提高草莓贮藏性能,减少采后损失。[方法]采用葡萄有孢汉逊酵母（Hanseniaspora uvarum）和季也蒙毕赤酵母（Pichia guilliermondii）对草莓采摘前3 d进行喷施处理,测定不同浓度酵母菌菌悬液对草莓常温贮藏[25℃、相对湿度（RH）90%~95%]病害的抑制效果以及最佳浓度酵母菌悬液对果实冷藏[（2±1）℃、RH 90%~95%]性能的影响。[结果]常温贮藏结果显示：采前喷施拮抗酵母菌显著降低果实腐烂指数（P〈0.05）,提高商品率,能较好地保持果实外观品质。1×10^6CFU·m L^-1复合酵母菌和1×108CFU·m L^-1单一酵母菌组果实商品率较高,可作为最佳冷藏试验浓度。冷藏试验结果表明：采前喷施拮抗菌能抑制果实硬度和维生素C含量的下降,减轻果实的腐烂,且腐烂指数显著低于对照组（P〈0.05）,其中复合菌处理组商品率高达85%,显著高于单一处理组（P〈0.05）。但采前喷施拮抗菌对草莓色泽、可溶性固形物（TSS）和p H值没有显著影响。处理组的超氧化物歧化酶（SOD）、过氧化物酶（POD）、多酚氧化酶（PPO）、过氧化氢酶（CAT）和β-1,3-葡聚糖酶（GLU）活性均高于对照组,丙二醛（MDA）含量低于对照组,且低浓度复合菌处理组果实冷藏效果好于高浓度单一酵母菌处理组。[结论]采用低浓度1×106CFU·m L^-1的复合菌菌悬液采前喷施,较其他处理能更有效提高草莓果实抗性,延长贮藏寿命,因此可以作为一种提高草莓采后贮藏性能的生物防治方法。

[Objectives]Applying antagonistic yeasts to strawberries in the field to enhance their storability and reduce postharvest losses was studied. [Methods]Strawberry fruits were treated with single and composite antagonistic yeast,Hanseniaspora uvarum suspension and Pichia guilliermondii suspension before 3 days of harvest,then the efficacy of different yeast treatments on postharvest diseases of strawberries at 25 ℃ with relative humidity（ RH） 90%- 95% and storability was investigated. The yeast treatments with better antagonistic activity were selected to apply to strawberry during storage[at（ 2±1） ℃ with RH 90%-95%]and to examine their efficacy on the postharvest diseases and storability of strawberries. [Results]The results showed antagonistic yeast treatments before the strawberries were harvested could significantly reduce their decay index,as a result,improve their commodity rate（ P 0. 05） at25 ℃ with RH 90%-95%. The treatments of 1×10^6CFU·m L^-1complex yeast and 1× 108CFU·m L^-1single yeast showed a better antagonistic activity compared with other treatments and thus were used for strawberries[at（ 2±1） ℃ with RH 90%-95%]. The cold storage experiment suggested that antagonist yeast treatments could maintain fruits＇ appearance quality,firmness and vitamin C content. During storage,the decayrate of treatment groups was significantly lower（ P0.05） than that of the control. Commodity rate of the fruits treated with the composite H. uvarum and P. guilliermondii was up to 85%,while that of the control was only 25%. There＇s no difference in total soluble solids（ TSS）,p H between treatments and the control. The activity of enzymes including superoxide dismutase（ SOD）,peroxidase（ POD）,polyphenol oxidase（ PPO）,catalase（ CAT）,and β-1,3-glucanase（ GLU） of treatment groups were much higher than that of the control. The accumulation of malondialdehyde（ MDA） of treatment groups was less than that of the control. Among the treatment groups,the one treated with composite suspension had higher enzyme activities and less MDA than those treated with single suspension. [Conclusions]These results suggest preharvest application of antagonist yeasts and their compound is a useful biological method to control postharvest diseases and enhance storage properties of strawberry fruits.