褪黑素处理对枸杞果实采后生理及贮藏品质的影响

Effects of melatonin treatment on postharvest physiology and storage quality of goji berry

为探究外源褪黑素处理对枸杞鲜果采后生理及贮藏品质的影响,该实验以"宁杞5号"鲜果为材料,分别用0(对照)、25、50和75μmol/L的褪黑素溶液浸泡处理,分析果实低温贮藏期间呼吸强度、乙烯释放速率、超氧阴离子和过氧化氢含量、色泽、硬度、固酸比、总酚含量、类黄酮及类胡萝卜素含量等生理与品质指标的变化,并采用主成分分析法对贮藏果实品质变化规律进行综合评价。结果表明,褪黑素处理降低了呼吸强度和乙烯释放速率,延缓了色泽、硬度、固酸比等品质指标的下降。此外,褪黑素处理还能清除果实内活性氧,促进总酚和类黄酮等物质的积累,并减缓类胡萝卜素的分解。由此可见,外源褪黑素处理可抑制贮藏期间枸杞果实的衰老过程,保持果实贮藏品质,其中以50μmol/L褪黑素处理枸杞鲜果的保鲜效果最佳。

To explore the effect of exogenous melatonin(MT) treatment on the postharvest physiology and quality of fresh goji berry stored at low temperature, ‘Ningqi-5’ goji fruit were soaked with MT at 0(control check, CK), 25, 50 and 75 μmol/L, respectively. Subsequently, the changes of physiological and quality indicators including respiration rate, ethylene release rate, the content of superoxide anion and hydrogen peroxide, color, hardness, the ratio of solid and acid, total phenols, flavonoids and the content of carotenoids during fruit storage at low temperature were analyzed in the present study. Moreover, the method of principal component analysis(PCA) was also used to comprehensively evaluate the changes in storage quality. The results showed that MT treatment reduced the respiratory intensity and the rate of ethylene release. Meanwhile, the decline of quality indicators containing color, hardness and the ratio of solid and acid were delayed in MT treated fruit. Furthermore, MT can also remove reactive oxygen species and promote the accumulation of total phenols and flavonoids in the goji fruit. In addition, the decomposition of carotenoids was slowed down in the fruit treated by MT. These results suggested that exogenous MT treatment could significantly(P<0.05) inhibit the senescence and maintain the storage quality of goji berry during storage at low temperature. Among which, MT at 50 μmol/L had the best preservation effect on the fresh goji berry.