高浓度二氧化碳气调包装通过调节酚代谢抑制鲜切莲藕的酶促褐变

High Concentration CO2 Modified-atmosphere Packaging Inhibits Enzymatic Browning of Fresh-cut Lotus Root Slices by Regulating Phenolic Metabolism

摘要:

鲜切莲藕褐变的主要原因是酶促褐变，高浓度CO2气调包装（Modified-atmosphere packaging，MAP）可以有效延缓鲜切果蔬褐变，而苯丙氨酸解氨酶（L-phenylalanine ammonia-lyase，PAL）、多酚氧化酶（Polyphenol oxidase，PPO）和过氧化物酶（Peroxidase，POD）的编码基因是引起果蔬褐变的主要基因。然而，高浓度CO2 MAP对鲜切莲藕片PAL、PPO、POD酶及其编码基因表达的影响却鲜有报道。本文分析了100% CO2MAP对鲜切莲藕贮藏过程中褐变度、总酚含量、PAL、PPO和POD酶活性及其编码基因表达的影响。结果表明：100% CO2 MAP对延缓鲜切莲藕褐变有较好效果，且100% CO2 MAP贮藏期间鲜切莲藕PAL、PPO和POD酶活性随褐变程度的增加而同步变化。此外，NnPAL1，NnPPOA和NnPOD2 / 3的表达变化与PAL，PPO和POD酶活性的变化及褐变相一致，说明高浓度CO2 MAP可能通过下调NnPAL1，NnPPOA和NnPOD2 / 3的表达来延缓鲜切莲藕褐变。

Abstract:

The main causes of quality loss in fresh-cut lotus root is enzymatic browning, high concentrations of CO2 MAP (Modified-atmosphere packaging) have been successfully developed to delay the browning of fresh-cut fruits and vegetables, and PAL(L-phenylalanine ammonia-lyase), PPO(Polyphenol oxidase)and POD(Peroxidase)genes were reported as being involved in lotus root browning. However, the effect of high concentration CO2 MAP on PAL, PPO and POD enzymes and genes expression of fresh-cut lotus root slice has been rarely reported. This paper analyzed the effect of 100% CO2MAP on browning, the phenolic content, PPO, PAL and POD enzyme activity and genes expression during fresh-cut lotus root slices storage. The results showed that 100% CO2 MAP was effective in delaying browning of fresh-cut lotus root slices. The change of PAL, PPO and POD enzymatic activity occurred in parallel with the increases in browning degree during storage with 100% CO2 MAP. Furthermore, the change in expression of NnPAL1, NnPPOA and NnPOD2/3 occurred in parallel with the changes in PAL, PPO and POD enzyme activities and browning, which suggested that high concentration CO2 MAP might delay fresh-cut lotus root slices browning by downregulating the expression of NnPAL1, NnPPOA and NnPOD2/3.