This study investigates the effect of pulsed electric fields (PEF) on the kinetics of vacuum drying (VD) of carrot and on the preservation of the quality of dried carrot tissue. The impacts of PEF-treatment and VD on β-carotene content and color of carrot samples were studied. PEF treatment was applied with intensity E = 0.6 kV/cm and total treatment time t_PEF = 0.1 s to reach a high level of carrot tissue electroporation. The VD was applied at the pressure p = 0.3 bar for different temperatures, T_d = 25, 50, 75, and 90 °C. The spectrophotometric method was used to determine the β-carotene content. The color was measured using the CIE L* a* b* method. Obtained results indicated that PEF treatment let to a noticeable decrease of drying time (by 33–55% at T_d = 25–90 °C). The activation energy was found to be 18.25 kJ/mol and 13.4 kJ/mol for untreated and PEF-pretreated samples, respectively. The reduction of drying time by PEF pretreatment was beneficial for the retention of β-carotene in dried samples. The application of PEF treatment resulted in smaller changes in color ∆E as compared with untreated samples; this tendency was observed for all studied temperatures.

中文翻译：

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脉冲电场对真空干燥及胡萝卜干品质特性的影响

这项研究调查了脉冲电场（PEF）对胡萝卜真空干燥（VD）的动力学以及对干燥胡萝卜组织质量的保存的影响。研究了PEF处理和VD对胡萝卜样品中β-胡萝卜素含量和颜色的影响。PEF处理的强度为E = 0.6 kV / cm，总处理时间t _PEF = 0.1 s，以达到较高的胡萝卜组织电穿孔水平。在不同温度，T _d = 25、50、75和90°C的压力p = 0.3 bar下施加VD 。用分光光度法测定β-胡萝卜素含量。使用CIE L * a * b *测量颜色方法。获得的结果表明，PEF处理使干燥时间显着减少（在T _d = 25-90°C时减少了33-55％）。发现未处理样品和PEF预处理样品的活化能分别为18.25 kJ / mol和13.4 kJ / mol。通过PEF预处理减少干燥时间有利于干燥样品中β-胡萝卜素的保留。与未处理的样品相比，PEF处理的结果是颜色ΔE的变化较小。在所有研究温度下都观察到了这种趋势。