低温等离子体活化水对蓝莓表面微生物抑制作用及其贮藏品质的影响

Inhibitory Effect of Low Temperature Plasma-Activated Water on the Surface Microorganisms and the Quality Attributes of Blueberry

为探究低温等离子体活化水(plasma-activated water,PAW)对蓝莓表面微生物的抑制作用和蓝莓品质的影响。该研究采用不同反应时间生成的PAW(等离子体与去离子水反应20、40、60 min生成的PAW分别记作PAW20、PAW40、PAW60)浸泡蓝莓果实,并研究PAW处理前后的蓝莓果实中细菌、常见的真菌数量、果皮的色泽、花青素含量、抗坏血酸含量、β-胡萝卜素含量和自由基清除能力以及蓝莓在4、25°C条件下,贮藏期间的腐烂率和硬度的变化情况。结果表明,蓝莓经PAW60处理后,与对照组(蓝莓用去离子水处理)相比,细菌菌落总数下降1.09 lg(CFU/g),蓝莓果实表面的酵母、链格孢菌与灰霉菌数量分别下降1.47、1.43与2.02 lg(CFU/g),PAW处理显著降低了蓝莓的腐烂率(P<0.05)并且能够减缓蓝莓果实的软化;色差值ΔE在PAW20和PAW40组均小于1.5,而PAW60组为1.7左右;蓝莓的β-胡萝卜素含量显著下降(P<0.05);抗坏血酸含量在PAW20和PAW40组中增加(P<0.05),在PAW60组降低(P<0.05);PAW40和PAW60组蓝莓花青素含量和抗氧化能力均显著提高(P<0.05)。总之,PAW处理可以有效抑制蓝莓表面微生物的生长,降低蓝莓贮藏期间腐烂率,延长了蓝莓的储藏时间,提高蓝莓贮藏期间的品质。该研究为PAW技术在蓝莓保鲜与加工领域的应用提供了参考。

This study aimed to investigate the inhibitory effect of low temperature plasma-activated water(PAW)on the surface microorganisms and the quality attributes of blueberry.In this study,the blueberry fruits were treated by submerging them in the PAW generated at different plasma-activated time(Deionized water was activated by plasma treatment for 20,40 and 60 min.Accordingly,the samples after treatment were named as PAW20,PAW40,and PAW60).The effects of PAW on microbial loads and quality attributes of the treated blueberries such as surface color of peels,anthocyanin contents,ascorbic acid content,carotenoid contents and radical scavenging capacity,and the changes in firmness and decay incidence during the storage at 4 and 25°C were studied.The results showed that compared with controls(blueberries were treated with deionized water),after PAW60 treatment,the total number of bacteria decreased by 1.09 lg(CFU/g),the number of Saccharomyces cerevisiae,Alternariaalternate and Botrytis cinerea decreased by 1.47,1.43 and 2.02 lg(CFU/g),respectively.PAW treatment significantly reduced the decay incidence of blueberries(P<0.05)and maintained the firmness of blueberries during the storage.TheΔE values determined in this study were less than 1.5 in PAW20 and PAW40 groups,however,it was approximately 1.7 in PAW60 group.Theβ-carotene content of blueberries significantly decreased after PAW treatment(P<0.05).The ascorbic acid content of blueberries increased after PAW20 and PAW40 groups,but it decreased after PAW60 treatment(P<0.05).The anthocyanin content and free radical scavenging ability of blueberries significantly increased after PAW40 and PAW60 treatment(P<0.05).In conclusion,PAW treatment could effectively inhibit the growth of microorganisms on the surface of blueberries,reduce the decay incidence of blueberries,and improve the quality of blueberries during the storage.This study would provide a reference source for the application of PAW technology in blueberry preservation.