采后失水处理对葡萄电学特性的影响

摘要

With the aim to investigate the effect of postharvest dehydration on dielectric properties of grape during cold storage, the dielectric parameters of the Red Globe grape were measured at 0. 1 kHz,l kHz, 10 kHz, 100 kHz and 1 MHz by using LCR electronic measure instrument, and the results were compared with those of un-dehydrated grape under the same condition. For the un-dehydrated and dehydrated grapes, both of them have the same trends at same storage day; the impedance, reactance, inductance and resistance were all gradually decreased while the susceptance increased with the increase of the frequency; and the loss tangent, dielectric constant and impendence phase angle firstly decreased with the frequency increasing from 0. 1 kHz to 100 kHz, and then increased at 1 MHz. Compared with the un-dehydrated grape, the dehydrated one has higher impedance, reactance, inductance, resistance and lower dielectric constant, impendence phase angle during 45 days storage. All the test results show that postharvest dehydration is a more effective way in keeping the quality of grape during cold storage.%为研究采后失水处理对葡萄贮藏过程中电学特性的影响,运用LCR电子测量仪测定了冷藏条件下红地球葡萄在0.1 kHz、1 kHz、10 kHz、100 kHz和1 MHz频率下的部分电学参数.结果表明,在同一贮藏时间,未失水处理和经失水处理的红地球葡萄复阻抗Z、电抗X、电感Lp和电阻Rp随着测试频率的增加逐渐减小,电纳B逐渐增加；损耗角正切值tanδ、相对介电常数ξ '和复阻抗相角θ在0.1～100 kHz频率范围内随着频率增加逐渐减小,到1 MHz时又有所增加.在0～45 d贮藏期内,随着果实的衰老,采后失水处理使葡萄保持了较高的Z、Lp、X和Rp以及较低的ξ’和θ,对保持果实品质更为有效.