二氧化硫对采后葡萄果皮酚类物质合成及其抗氧化能力的调控作用

Regulatory Effect of Sulfur Dioxide on the Synthesis of Phenolic Substances and Antioxidant Capacity of Postharvest Grape Peel

摘要:

为探究二氧化硫（Sulfur Dioxide，SO2）对葡萄果皮酚类物质合成及其抗氧化能力的影响，该试验以木纳格葡萄为试材，采用500 μL/L SO2熏蒸处理2 h，以空气熏蒸为对照，放置于（0±1）℃贮藏44 d。定期测定各酚类物质含量变化，采用高效液相色谱法测定黄烷醇单体含量。结果表明：贮藏结束时，SO2处理组总酚、总黄烷醇、总黄酮、总花青素、(+)-儿茶素、(-)-表儿茶素、(-)-表没食子儿茶素和(-)-表儿茶素没食子酸酯含量分别是CK组的0.74、1.26、1.33、1.33、1.47、1.79、1.59和1.49倍；1,1-二苯基-2-三硝基苯肼（DPPH）、2,2'-联氮-二（3-乙基-苯并噻唑-6-磺酸）二铵盐（ABTS）自由基清除活性以及铁离子还原能力（FRAP）分别比CK组高13.76%、20.44%和4.98%。SO2处理在一定程度上诱导了苯丙氨酸解氨酶基因（L-Phenylalanine Ammonia-Lyase，PAL）、肉桂酸-4-羟基化酶基因（Cinnamate 4-Hydroxylase，C4H）、4-香豆酸-辅酶连接酶基因（4-Coumarate:CoA Ligase，4CL）、查尔酮合酶基因（ChalconeSynthase，CHS）、查尔酮异构酶基因（Chalcone Isomerase，CHI）、二氢黄酮醇-4-还原酶基因（Dihydroflavonol 4-Reductase，DFR）、无色花色素还原酶基因（Leucoanthocyantin Reductase，LAR）和花青素还原酶基因（Anthocyanidin Reductase，ANR）的表达。可见SO2处理可上调相关酚类合成基因的表达量，延缓酚类化合物含量的下降，并提高葡萄果皮的抗氧化活性。该试验为研究SO2对葡萄采后酚类物质合成的调控提供了理论依据。

Abstract:

In order to explore the effect of sulfur dioxide (SO2) on the synthesis of phenolic compounds and antioxidant capacity of grape peel, this research used Munage grape as the test material, which was fumigated with 500 μL/L SO2 for 2 h then stored at (0±1) ℃ for 44 d. The grape subjected to air fumigation was used as the control. The changes in the contents of phenolic substances were determined regularly, and the content of flavanol monomers was determined by HPLC. The results show that at the end of storage, the contents of total phenols, total flavanols, total flavones, total anthocyanins, (+)-catechin, (-)-epicatechin, (-)-epicatechin and (-)-epicatechin gallate in the SO2-treated group were 0.74, 1.26, 1.33, 1.33, 1.47, 1.79, 1.59 and 1.49 times those of the CK group, respectively. The DPPH radical scavenging activity, ABTS+ radical scavenging activity and FRAP were higher than the CK group by 13.76%, 20.44% and 4.98% respectively. The SO2 treatment induced to certain extents the expression of L-phenylalanine ammonia-lyase (PAL), Cinnamate 4-hydroxylase (C4H), 4-coumarate: CoA ligase (4CL), Chalconesynthase (CHS), Chalcone isomerase (CHI), Dihydroflavonol 4-reductase (DFR), Leucoanthocyantin reductase (LAR), Anthocyanidin reductase (ANR) genes. It was found that the SO2 treatment couldup-regulate the expression of phenolic synthesis-related genes, delay the decline in the contents of phenolic compounds, and improve the antioxidant activity of grape peel. This study provided a theoretical basis for studying the regulatory effect of SO2 on the synthesis of phenolic substances in postharvest grape.