自发气调包装结合1-MCP处理下杏鲍菇乙烯代谢和褐变进程的变化

Changes in Ethylene Metabolism and Browning Processes of Postharvest Pleurotus eryngii under Modified Atmosphere Packaging Combined with 1-MCP Treatment

摘要:

为明确自发气调包装结合1-甲基环丙烯（1-methylcyclopropene，1-MCP）处理对杏鲍菇采后衰老的影响，在低温货架条件（12~15 ℃）下，以打孔的19 μm聚乙烯保鲜袋（Modified Atmosphere, MA）为对照组，并用MA和MA结合1-MCP保鲜卡对杏鲍菇进行处理，研究其采后乙烯代谢和褐变进程的变化。结果表明：MA处理可有效抑制杏鲍菇的呼吸速率，但对控制其乙烯释放效果不佳，当结合1-MCP处理时，有效抑制了其组织乙烯合成关键酶（ACC Synthase, ACS）和（ACC Oxidase, ACO）活性，由此乙烯生成速率低于对照组9.75%~51.61%。此外，MA可显著延缓杏鲍菇的采后褐变和腐烂，当MA与1-MCP联合处理时，可通过提高其组织的过氧化物酶（Peroxidase，POD）、过氧化氢酶（Catalase, CAT）和超氧化物歧化酶（Superoxide Dismutase, SOD）活性，抑制其相对电导率上升和（Malondialdehyde, MDA）积累；同时保持其货架后期较高的总酚含量，和更低的（Polyphenol Oxidase, PPO）和（Phenylalanine Ammonia-lyase, PAL）活性，最终进一步减缓其采后酶促褐变进程，在16~20 d时对照组褐变度高于MA组3.93~4.29倍、高于MA联合1-MCP组8.85~9.42倍。综上，MA联合1-MCP复合处理可在单独MA的基础上进一步减缓杏鲍菇的采后衰老，延长低温货架期约7 d，为食用菌采后保鲜提供了理论及技术支持。

Abstract:

To examine the effects of modified atmosphere (MA) packaging combined with 1-methylcyclopropene (1-MCP) treatment on postharvest senescence of Pleurotus eryngii, experiments were conducted under low-temperature storage conditions (12~15 ℃). Samples were packaged in a 19-μm polyethylene bag (MA) or in a card containing the anti-staling agent 1-MCP (MA+1-MCP), at temperatures ranging 12~15 ℃. The control group was P. eryngii packaged in a 19-μm polyethylene bag with eight holes. Ethylene metabolism and browning processes of P. eryngii after harvest were investigated. MA packaging significantly inhibited the respiration rate of P. eryngii but performed poorly in controlling the ethylene production rate. Notably, the activities of 1-aminocyclopropane-1-carboxylate (ACC) synthase and ACC oxidase, the key enzymes involved in ethylene synthesis, were effectively inhibited by MA packaging combined with 1-MCP. Therefore, the ethylene production rate of P. eryngii in the MA+1-MCP group was lower than that of the control group by 9.75%~51.61%. In addition, MA packaging significantly delayed postharvest browning and decay of P. eryngii. Combining MA packaging with 1-MCP enhanced the activities of peroxidase, catalase, and superoxide dismutase and inhibited increases in relative conductivity and accumulation of malondialdehyde in P. eryngii. In addition, the combined treatment led to a higher total phenolic content in P. eryngii at the end of shelf life, and lower polyphenol oxidase and phenylalanine ammonia-lyase activities. As a result, the postharvest enzymatic browning process of P. eryngii was further slowed down by the combined treatment. At 16~20 days, the degrees of browning of the control group were 3.93~4.29 and 8.85~9.42 times those of the MA and MA+1-MCP groups, respectively. In conclusion, the MA+1-MCP composite treatment slowed the postharvest senescence of P. eryngii compared with the performance of MA packaging alone, thereby extending the shelf life at low temperatures for about 7 days. The findings provide theoretical and technical support for the postharvest preservation of edible mushrooms.