1-MCP对不同成熟度猕猴桃电特性的影响

以适期采收(成熟度Ⅰ,可溶性固形物6.2%)和晚采收(成熟度Ⅱ,可溶性固形物8.8%)的‘海沃德’猕猴桃为试材,研究0.5μL/L 1-MCP处理对在室温(20℃)贮藏条件下果实电特性的影响。结果表明,在1MHz频率下,成熟度Ⅰ的果实复阻抗明显高于成熟度Ⅱ的果实,而且从贮藏7d开始,两成熟度果实复阻抗(Z)值差异达显著水平(P<0.05)。在10kHz频率下,成熟度Ⅰ果实并联等效电容(Cp)值明显高于成熟度Ⅱ的果实,而且从贮藏7d开始,两成熟度果实Cp值差异达显著水平(P<0.05)。在0.1kHz和1MHz电激励频率条件下,随着贮藏时间的延长,1-MCP有抑制果实复阻抗下降的趋势;在10kHz频率条件下,1-MCP处理果Cp值明显高于对照果;但并联等效电感(Lp)和阻抗相角(θ)对成熟度和1-MCP处理的响应不灵敏,不能作为区分成熟度或1-MCP处理的敏感电参数。

Influence of 1-MCP on Dielectric Properties of Kiwifruit at Different Maturities

In this study,Hayward,kiwifruit at the appropriate harvest(maturity I,with a TSS of 6.2%) and late harvest(maturityⅡ,with a TSS of 8.8%) was used to investigate the effect of 0.5μL/L 1-methylcyclopropene(1-MCP) on postharvest electric properties of fruits at room temperature(20 ℃).Kiwifruits at maturity I revealed a remarkable increased in impedance(Z) at the frequency of 1 MHz when compared with those at maturity Ⅱ and a significant difference in Z value began appearing on storage day 7(P <0.05).The same results were observed for capacitance in the parallel equivalent circuit mode(Cp) at 10 kHz.1-MCP inhibited the decrease of Z value in kiwifruit with prolonged storage period at 0.1 kHz or 1 MHz.1-MCP-treated kiwifruit presented a significantly higher Cp at 10 MHz than the control.However,inductance in parallel equivalent circuit mode(Lp) and impedance phase angle(θ) had insensitive response to fruit maturity and 1-MCP,and consequently was not a measure of maturity and 1 MHz treatment or not.