【摘要】 本研究以大红火龙果为试验材料，经不同浓度的褪黑素MT（0.2、0.4、0.8 mmol/L）处理，在温度（7±1）℃、相对湿度75%～85%的条件下贮藏，明确MT对其保鲜效果的影响。结果表明：0.2、0.8 mmol/L MT处理有效降低了火龙果果实腐烂率（DI）,MT处理能有效降低呼吸速率（RR），抑制相对电导率（RC）的增加。0.2 mmol/L MT可有效延缓抗坏血酸（AsA）含量下降，抑制丙二醛（MDA）含量的增加及过氧化氢（H₂O₂）、超氧阴离子（O₂^-）的生成，提高抗氧化酶（SOD、CAT、APX）活力，有效促进活性氧（ROS）代谢，清除自由基，提高果实抗氧化能力。同时，0.2 mmol/L MT可有效维持抗病相关酶（PAL、POD、PPO）活力，从而诱导提高火龙果果实抗病能力。此外，0.2 mmol/L MT能增加可溶性糖（SS）、类黄酮（flavonoids）含量，但CK和MT处理果实的失重率（WLR）无显著差异。相关性分析表明，19个指标间存在显著相关性且火龙果果实腐烂率与ROS代谢紊乱、膜质过氧化密切相关。主成分分析表明，0.2 mmol/L MT处理的火龙果各贮藏时期得分均高于CK，且其累计综合评分最高，表明其综合保鲜效果最好。综上，0.2mmol/LMT处理主要通过维持ROS代谢平衡及提高火龙果果实抗病性来延缓衰老并维持其品质。本研究为MT处理技术在火龙果低温贮藏保鲜中的深入研究及应用推广奠定基础。更多还原

【Abstract】 In this study, Dahong pitaya fruit were treated with different concentrations of MT（0.2, 0.4, 0.8 mmol/L） and stored at（7±1） ℃ and 75%-85% RH to clarify the effect of MT on its preservation. The results showed that 0.2 and 0.8 mmol/L MT could decrease the rot rate（DI） of pitaya fruit, while MT could decrease the respiratory rate（RR） and inhibit the increase of relative conductivity（RC）. 0.2 mmol/L MT could effectively delay the decrease of the content of ascorbic acid（AsA）, inhibit the increase of the content of malondialdehyde（MDA） and the formation of hydrogen peroxide（H₂O₂） and superoxide anion（O₂^-）, and increase the activity of antioxidant enzymes（SOD, CAT, APX）, effectively promote reactive oxygen species（ROS） metabolism, scavenging free radicals, improve fruit antioxidant capacity. At the same time, 0.2 mmol/L MT could effectively maintain the activity of disease-resistance-related enzymes（ PAL, POD and PPO）, and induce and improve the disease resistance of pitaya fruit. In addition, 0.2 mmol/L MT could increase the contents of soluble sugar（SS） and flavonoids, but there was no significant difference in weight loss rate（WLR） between CK and MT. The correlation analysis showed that there were significant correlations among the 19 indexes, and the rotting rate of pitaya fruit was closely related to ROS metabolism disorder and membrane peroxidation. The results of principal component analysis showed that the score of 0.2 mmol/L MT was higher than that of CK at all storage periods,and the cumulative comprehensive score of 0.2 mmol/L MT was the highest, indicating that the effect of 0.2 mmol/L MT was the best. In conclusion, 0.2 mmol/L MT could delay senescence and maintain quality of pitaya fruit by maintaining ROS metabolism balance and improving disease resistance. This study would lay a foundation for the further research and application of MT technology in hylocereus longus storage at low temperature.更多还原