低剂量电子束辐照对香菇采后抗氧化能力的影响

Effect of Postharvest Low Dose Electron Beam Irradiation on the Antioxidant Capacity of Lentinula edodes

摘要:

新鲜香菇采后易腐烂，为提高其采后贮藏品质，本研究采用1.0、2.0和3.0 kGy的电子束辐照剂量对鲜香菇进行辐照处理，贮藏于4±1 ℃、湿度为80%±5%的环境，以色泽、总酚含量、丙二醛含量、DPPH自由基清除能力和相关抗氧化酶（SOD、CAT）活性为评价指标，研究低剂量电子束辐照处理对鲜香菇抗氧化能力的影响。结果表明：在贮藏过程中相比其他剂量，2.0 kGy辐照剂量能延缓香菇褐变，保持总酚含量处在较高水平，能够减少丙二醛含量的积累，贮藏末期其含量仅为0.54 nmol/g。2.0 kGy辐照剂量能较好的清除DPPH自由基以及保持SOD、CAT较高活性水平，SOD和CAT活性仅降低3.78%、27.90%，与其它组相比有显著差异。由上可知，2.0 kGy电子束辐照处理能够使香菇采后保持较高的抗氧化活性水平，从而延迟香菇自身的衰老氧化反应，延长了贮藏保鲜期。

Abstract:

Fresh Lentinula edodes are susceptible to decay after harvest. In order to improve its post-harvest storage quality, fresh Lentinula edodes were subjected to electron-beam irradiation at doses of 1.0, 2.0 and 3.0 kGy in this study, before a storage at 4±1 ℃ and 80%±5% relative humidity. Then, the effect of low dose electron beam irradiation on the antioxidant capacity of fresh Lentinula edodes was examined based on the evaluation indices such as color, total phenol content, malondialdehyde content, DPPH radical scavenging ability, and activities of antioxidant enzymes (SOD and CAT). The results showed that compared with other doses, the treatment at 2.0 kGy could delay the browning of Lentinus edodes, maintain the total phenol content at a relatively high level, and reduce the accumulation of malondialdehyde (only 0.54 nmol/g at the end of storage). The irradiation dose of 2.0 kGy exhibited significant differences as compared to other groups: scavenged significantly more DPPH free radicals, and maintained higher activities of SOD and CAT (which decreased only by 3.78% and 27.90%, respectively). The above results indicated that electron beam irradiation at 2.0 kGy can enable fresh Lentinus edodes to maintain high post-harvest antioxidant activity thereby delaying the oxidation reaction in Lentinula edodes and prolonging its postharvest shelf life.