真空包装结合低温贮藏对鲜切芋头的保鲜效果

Preservative Effects of Vacuum Packaging Combined with Cold Storage on Fresh-cut Taro

鲜切芋头即使贮藏在低温条件下,切面也会出现变黄变褐的症状,导致商品性降低。为明确真空包装结合低温贮藏对鲜切芋头的保鲜效果,研究了低温贮藏条件下真空包装处理对鲜切芋头褐变和微生物总数的影响。结果表明:在低温贮藏条件下真空包装(VP)处理抑制了切面L的下降,抑制a、b、色差(△E)和褐变指数(BI)的增加,表明VP处理能显著抑制鲜切芋头褐变。VP处理有效控制微生物的生长和繁殖,在12 d时细菌总数降低了94.31%,酵母总数降低了65.02%,表明VP结合低温贮藏对鲜切芋头具有很好的保鲜效果。VP处理降低了鲜切芋头PAL和PPO活性,降低了总酚、总黄酮和总可溶性醌含量,表明VP通过减少酚类物质的合成和氧化抑制鲜切芋头褐变。VP处理抑制CAT活性的下降,提高贮藏前期的POD活性,降低LOX活性、H2O2和MDA含量,表明VP处理通过保持鲜切芋头的抗氧化活性,延缓低温贮藏期间的品质劣变。本研究证实真空包装结合低温贮藏是一种保鲜效果好、简单易用的物理保鲜技术,为真空包装在鲜切芋头保鲜中的应用奠定了基础。

The cut surface of fresh-cut taro tends to yellowing and browning even stored at low temperatures,leading to a decrease in commercial values.In this study,to confirm the preservative effects of vacuum packaging(VP)combined with cold storage on fresh-cut taro,the effects of VP treatment on the browning and total microbial counts in fresh-cut taro during cold storage were studied.The results showed that VP treatment delayed the decrease of L values and the increase of a,b,color differences(△E),and browning index(BI)values,indicating that VP treatment significantly prevented the browning of fresh-cut taro during cold storage.Furthermore,VP treatment effectively restrained the growth and reproduction of microbials,reducing the total number of bacteria by 94.31%and the total number of yeast by 65.02%at 12 d,suggesting that VP combined with cold storage had a good preservative effect on fresh-cut taro.VP treatment led to decreased PAL and PPO activities,as well as reduced levels of total phenolics,total flavonoids,and total soluble quinones,suggesting that VP treatment hindered the browning by reducing the biosynthesis and oxidation of phenolic compounds of fresh-cut taro.Moreover,VP treatment restrained the decline in CAT activity,increased POD activity at early storage,and reduced LOX activity,H2O2 contents and MDA contents,suggesting that VP treatment alleviated cutting-induced oxidative damages by maintaining the antioxidant activity of fresh-cut taro,thus restraining the quality deterioration during cold storage.This study demonstrates that VP treatment combined with cold storage is a physical preservative technology with good preservation effects,simple and easy to use,laying a foundation for the application of VP method in the preservation of fresh-cut taro.