Abstract The internal cortex of potato (two varieties: Dali and Agria) 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 storage (SM i.e. elastic) and loss (LM i.e. inelastic) moduli were obtained. DETA, based on alternated current of frequency 20 kHz, continually determined both components of impedance. The PEF (pulse electric field) was applied prior to the DMA/DETA test; the experiments were arranged into four sets: b (no PEF), c (one 10 ms long pulse of alternated field 500 V/cm), d (two same pulses with a 0.1 s interval between them), e (the same pulses with a 1 s interval). The impedance was recalculated giving parameters of a single model represented by parallel connection of a resistor Re and a capacitor with capacitance ωC. The temperature range was divided into three stages: A (30–60 °C), B (60–80 °C), and C (80–90 °C). For set b and stage A parameter Re decreased, whereas capacitance was nearly constant. Both parameters were constant in stage C. In part B, between 70 and 80 °C, Re sharply decreased and the capacitance showed a sharp peak, both indicating either collapse of the cellular membranes or starch gelatinization. Application of PEF led to reduction of the peak but the process was more effective when application of PEF was repeated (sets d and e) and mainly if longer time interval between the pulses was used (e). PEF causes disintegration of cellular membranes and water release from vacuoles so that free vacuole's water makes possible that starch gelatinization appears at lower temperatures. The role of PEF as a disintegration source was tested and it was found that its efficiency is strongly enlarged when it is combined with heating.

中文翻译：

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烹饪过程中脉冲电刺激马铃薯的变化：DMA 和 DETA 分析

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 之间的温度扫描中测试了马铃薯（两个品种：Dali 和 Agria）的内皮层。获得了储存（SM 即弹性）和损失（LM 即非弹性）模量的温度图。DETA 基于频率为 20 kHz 的交流电，连续确定阻抗的两个分量。在 DMA/DETA 测试之前应用 PEF（脉冲电场）；实验分为四组：b（无 PEF）、c（一个 10 ms 长的交变场 500 V/cm 脉冲）、d（两个相同的脉冲，它们之间的间隔为 0.1 s）、e（相同的脉冲与1 秒间隔）。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。温度范围分为三个阶段：A (30–60 °C)、B (60–80 °C) 和 C (80–90 °C)。对于 b 组和 A 级参数 Re 减小，而电容几乎不变。两个参数在阶段 C 中都是恒定的。在 B 部分，在 70 到 80°C 之间，Re 急剧下降，电容显示出一个尖峰，这两者都表明细胞膜塌陷或淀粉糊化。应用 PEF 导致峰值降低，但当重复应用 PEF（组 d 和 e）时，该过程更有效，主要是如果使用较长的脉冲之间的时间间隔（e）。PEF 导致细胞膜崩解和液泡中的水释放，因此游离液泡中的水使淀粉在较低温度下出现糊化成为可能。测试了PEF作为崩解源的作用，发现当它与加热结合时，其效率大大提高。