热水处理减轻黄瓜果实低温冷害的贮前延迟条件优化

Optimization of Pre-Storage Delay Conditions After Hot Water Treatment to Alleviate Chilling Injury of Cucumber During Low Temperature Storage

【目的】旨在利用电导法结合二次回归正交旋转组合设计对热水处理减轻黄瓜(Cucumis sativus L.)果实低温冷害的水浴和空气放置的贮前延迟条件进行优化对比分析。【方法】以’申青’黄瓜为材料,果实经40℃热水处理20 min后在不同水浴和空气延迟条件下放置,并于(4±1)℃,相对湿度(80±5)%的冷库中低温胁迫6 d。以电解质外渗率为冷害表征指标,在单因素试验的基础上,通过进行二次回归正交旋转试验以及响应面分析法来确定热水处理减轻黄瓜果实低温贮藏冷害的最佳贮前延迟条件。【结果】优化得出的最佳水浴延迟条件(20.8℃,54.07 min)和最佳空气延迟条件(16.92℃,1.98 h)均可显著降低电解质外渗率,并且建立的回归模型均极显著,无失拟因素存在。在此条件下,黄瓜果实的电解质外渗率实测值分别为12.01%(水浴)和10.14%(空气),与理论值相对误差仅为0.75%和0.84%,较未延迟组降低了6.63%和8.5%,与未热处理组相比则降低了16.72%和18.59%,说明该模型准确可靠。【结论】经响应面优化得出的水浴和空气延迟条件对果实细胞膜透性均有不同程度的影响,并且空气延迟条件比水浴延迟条件更能有效降低果实细胞膜透性和保持果实细胞膜完整性,更有利于维持原有热激作用,并减轻黄瓜果实冷害症状,提高其贮藏品质。研究可为采后果蔬贮藏保鲜提供一定的理论依据和技术参考,并具有可观的应用前景。

[Objective]The aim of this study was to optimize and compare the pre-storage delay conditions of water bath and air to reduce chilling injury of cucumber(Cucumis sativus L.)fruits by using the electric conductivity method combined with quadratic regression orthogonal rotation design.[Method]Taking“Shenqing”cucumber as the materials,the fruits were placed under different water and air delay conditions after being treated with 40℃hot water for 20 min,and then under low temperature stress in cold storage with(4±1)℃and RH(80±5)%for 6 d.The electrolyte leakage rate was used as characterization index of chilling injury.Based on the single factor experiment,the optimal pre-storage delay conditions for reducing chilling injury of cucumber fruits by hot water treatment were determined by quadratic regression orthogonal rotation test and response surface analysis.[Result]The results showed that the optimal water bath delay conditions(20.8℃,54.07 min)and air delay conditions(16.92℃,1.98 h)could both significantly reduce the electrolyte leakage rate,the established regression models were both extremely significant,and there were no misfitting factor.Under these conditions,the measured values of the electrolyte leakage rate were 12.01%(water bath)and 10.14%(air)with the relative error of 0.75%and 0.84%respectively,which were 6.63%and 8.5%lower than those in the group without delay.Compared with the untreated group,the electrolyte leakage rate decreased by 16.72%and 18.59%,which showed that the models were accurate and reliable.[Conclusion]The optimized water bath and air delay conditions obtained by response surface both had affected the fruit cell membrane permeability to some extent.Besides,compared with water bath delay condition,air delay condition could more effectively reduce fruit cell membrane permeability and maintain fruit cell membrane integrity,which was more beneficial to maintain the original heat shock,alleviate the symptoms of chilling injury and improve the storage quality of cucumber fruits.By providing a theoretical basis and technical reference for storage and preservation of postharvest fruits and vegetables,this study has considerable application prospects.