The present study aimed to dry orange slices at 50, 60, and 70°C using vacuum microwave dryer (VMD), vacuum infrared dryer (VID), and tray dryer (TD) and to compare the effects of different drying techniques on drying kinetics and product qualities. For this purpose, drying kinetics, total phenolic content, vitamin C, pH, total titratable acidity, bulk density, and color values of dried orange slices were evaluated. The VMD significantly increased the drying rates and the effective moisture diffusivities of orange slices compared with the VID and the TD. The drying times of orange slices for the VMD, the VID, and the TD at 70°C were detected as 69, 92, and 180 min, respectively. The experimental data were fitted to six thin‐layer drying models with R² range between .929 and 1.000. The results showed that the VMD had the smallest change in total phenolic content, vitamin C, pH, total titratable acidity, bulk density, and color values (L*, a*, b*, ΔE, ΔC, and Hue°) of dried orange slices, whereas the TD had the highest changing.

中文翻译：

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热风，真空红外和真空微波干燥机对橙片干燥动力学和品质特性的影响

本研究旨在使用真空微波干燥机（VMD），真空红外干燥机（VID）和托盘干燥机（TD）在50、60和70°C下干燥橙片，并比较不同干燥技术对干燥动力学的影响和产品质量。为此，对干燥的橙片的干燥动力学，总酚含量，维生素C，pH，总可滴定酸度，堆积密度和色值进行了评估。与VID和TD相比，VMD显着提高了橙片的干燥速率和有效水分扩散率。检测到的VMD，VID和TD的橙片在70°C的干燥时间分别为69、92和180分钟。将实验数据拟合到具有R ^2的六个薄层干燥模型范围介于.929和1.000之间。结果表明，该VMD曾在总酚含量，维生素C，pH值，总可滴定酸度，堆积密度最小化，和颜色值（大号*，一个*，b *，Δ ê，Δ Ç和色相度）干燥的橙片，而TD的变化最大。