乙醇熏蒸处理对鲜切西兰花活性成分和抗氧化活性的影响

Effect of Pretreatment with Ethanol on Bioactive Compounds and Antioxidant Activity in Fresh-Cut Broccoli Florets

研究乙醇熏蒸处理对鲜切西兰花总酚、总黄酮、总硫代葡萄糖苷和萝卜硫素等活性成分含量及抗氧化活性的影响。先将花球在20℃条件下分别用体积分数为2%、5%、10%、20%乙醇溶液熏蒸处理6 h,再切割成小花并在10℃条件下贮藏。结果表明,10%乙醇溶液熏蒸处理可以显著延长鲜切西兰花的货架期、提高总酚和总黄酮含量、延缓总硫代葡萄糖苷和萝卜硫素含量下降,并可有效保持较高的DPPH(1,1-diphenyl-2-picrylhydrazyl)自由基清除能力和还原力,提高其清除超氧阴离子自由基和羟自由基能力,从而延缓西兰花采后衰老、保持较高的抗氧化活性。同时发现,总酚、总黄酮和萝卜硫素含量与DPPH自由基清除能力存在极显著的正相关性。这些结果表明乙醇熏蒸处理在鲜切西兰花保鲜中具有较好的应用前景。

The effect of ethanol vapor treatment on bioactive compounds, such as total phenols, flavonoids, total glucosinolates and sulforaphane, and antioxidant activity of fresh-cut broccoli florets was investigated. The broccoli heads were pretreated with 2%, 5%, 10% or 20% ethanol vapor at 20 ℃ for 6 h, then cut into small florets and stored at 10 ℃for 10 days. The results showed that pretreatment with 10% ethanol significantly prolonged the shelf life of fresh-cut broccoli, increased the contents of total phenols and flavonoids, delayed the decrease in the contents of total glucosinolates and sulforaphane. This treatment also effectively maintained higher DPPH(1,1-diphenyl-2-picrylhydrazyl) free radical scavenging activity and reducing power, improved superoxide anion and hydroxyl free radical scavenging ability, thereby delaying postharvest senescence and maintaining higher antioxidant activity of fresh-cut broccoli florets. Meanwhile, it was found that there was a significant positive relationship between the contents of total phenols, flavonoids, glucosinolates and DPPH free radical scavenging activity. These results demonstrate that ethanol treatment may be a promising method to extend the shelflife and maintain the nutritional quality of fresh-cut broccoli.