不同贮藏温度对西州密25号哈密瓜果实软化的影响

Effects of Different Temperatures on the Fruit Softening of Xizhoumi No.25 Hami Melon during Storage

【目的】分析不同贮藏温度对西州密25号哈密瓜果肉细胞壁降解酶的影响,研究温度调控西州密25号哈密瓜采后软化作用机制,为哈密瓜采后贮藏保鲜提供参考。【方法】以成熟期西州密25号哈密瓜为试材,采后分别置于不同温度(0、5、10和15℃)环境下贮藏,每隔5 d测定果实硬度、呼吸强度,果肉β-半乳糖苷酶(β-Gal)、多聚半乳糖醛酸酶(PG)、果胶酶(PE)、纤维素酶(Cx)等细胞壁降解酶活性指标,分析不同贮藏温度对果实软化的影响。【结果】不同贮藏温度对西州密25号哈密瓜果实硬度、呼吸强度及细胞壁降解酶活性影响具有显著性差异。温度越低,果肉硬度下降越慢,果实呼吸强度峰值越低,果肉细胞壁降解酶活性越低。温度低于5℃时,果肉出现明显冷害症状。【结论】5℃适合西州密25号哈密瓜果实贮藏。西州密25号哈密瓜果实硬度与呼吸强度呈负相关关系,与β-Gal、PG、PE和Cx活性呈极显著负相关关系。

【Objective】To study the effect of different storage temperatures on cell wall degradation enzymes in pulp of Xizhoumi No.25 Hami melon and explore the mechanism of temperature regulation on postharvest softening of the melon in the hope of providing theoretical reference for postharvest storage and preservation of Hami melon.【Method】The mature Xizhoumi No.25 Hami melon was taken as test material and stored in different temperatures(0℃,5℃,10℃,15℃),the fruit hardness and respiratory intensity were measured every 5 days.The effects of different storage temperatures on fruit softening were analyzed by analyzing the activity indexes of cell wall degradation enzymes such asβ-galact osidase(β-Gal),polygalacturonase(PG),pectinase(PE)and cellulose(Cx).【Result】The effects of different storage temperatures on fruit hardness,respiration intensity and cell wall degradation enzyme activity of Xizhoumi No.25 Hami melon were significantly different.The lower the temperature was,the slower the pulp hardness decreased,the lower the peak value of fruit respiration intensity,and the lower the activity of pulp cell wall degradation enzyme.When the temperature was lower than 5℃,the pulp showed obvious symptoms of cold injury.【Conclusion】All things considered,5℃is the best for Xizhoumi No.25 Hami melon storage.The results of correlation analysis showed that the fruit hardness of Xizhoumi No.25 is negatively correlated with respiratory strength,and significantly negatively correlated withβ-Gal,PG,PE and Cx activities.