Abstract The tissue of carrot (variety Jereda) was tested using dynamic mechanical analysis (DMA) combined with dielectric thermal analysis (DETA), in air of 90% humidity in temperature scans between 30 and 90 °C. Temperature plots of loss tangent were determined. In DETA, based on alternated current of frequency 20 kHz, both components of impedance were continually determined. Pulsed electric field (PEF) was applied prior to the DMA and DETA tests. Four sets of experiments were performed, without PEF (b), with a single 10 ms long pulse given an alternated field of 500 V/cm (c), with two similar pulses at 0.1 s interval (d) and with two similar pulse at 1 s interval (e). The impedance was recalculated giving parameters of a single model represented by parallel connection of a resistor Re and a capacitor with capacitance ωC. Three stages of the range of temperature, namely subcritical (30–70 °C), critical (70–80 °C), and supercritical (80–90 °C) were considered. For set b, in subcritical stage, the parameter, Re decreased whereas capacitance was nearly constant. Both of these parameters decreased slightly in the supercritical stage but whereas Re is in supercritical stage much lower than in the subcritical stage, the capacitance is in supercritical stage rather higher than it is in subcritical stage. In critical stage, Re sharply decreased and the capacitance showed a sharp peak, both indicating collapse of the cellular membranes. Application of PEF led to little reduction of the capacitance peak and the reduction was more effective after the repeated pulse application (that is in sets d and e). These results at carrot were compared with the previous research at potato and it was shown that PEF effects in critical and supercritical stages significantly differ in the both plant tissues.

中文翻译：

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加热前施加脉冲电场对胡萝卜的影响

摘要 使用动态力学分析 (DMA) 结合介电热分析 (DETA)，在 90% 湿度的空气中，在 30 至 90 °C 之间的温度扫描中对胡萝卜（品种 Jereda）的组织进行了测试。确定了损耗角正切的温度图。在 DETA 中，基于频率为 20 kHz 的交流电，阻抗的两个分量都被连续确定。在 DMA 和 DETA 测试之前施加脉冲电场 (PEF)。在没有 PEF (b) 的情况下进行了四组实验，在给定 500 V/cm (c) 的交替场的情况下使用单个 10 ms 长脉冲，在 0.1 s 间隔 (d) 处使用两个相似的脉冲，在1 s 间隔 (e)。阻抗被重新计算，给出由电阻器 Re 和电容为 ωC 的电容器的并联连接表示的单个模型的参数。考虑了温度范围的三个阶段，即亚临界 (30–70 °C)、临界 (70–80 °C) 和超临界 (80–90 °C)。对于 b 组，在亚临界阶段，参数 Re 减小，而电容几乎恒定。这两个参数在超临界阶段都略有下降，而 Re 处于超临界阶段远低于亚临界阶段，而电容处于超临界阶段而不是高于亚临界阶段。在关键阶段，Re 急剧下降，电容出现尖峰，均表明细胞膜塌陷。PEF 的应用导致电容峰值几乎没有降低，并且在重复脉冲应用（即在组 d 和 e 中）后降低更有效。