Effect of vacuum, microwave, and convective drying on selected parsley quality

Abstract

This study was conducted to evaluate the quality of and structural changes in parsley (Petroselinum crispum Mill.) during vacuum, microwave, and convective (hot air) drying. The selected quality attributes of the dehydrated parsley samples were investigated on the basis of ascorbic acid and chlorophyll retention, as well as color change and overall appearance. Ascorbic acid is an important indicator of quality, and its selection was due to its heat-labile nature. Ascorbic acid deterioration depends on air temperature, microwave power, and drying time. The lowest ascorbic acid value was found after convective drying, followed by vacuum drying and microwave drying. With convective drying, the appearance values of the dried parsley decreased when the drying period was extended. However, with microwave drying, appearance values were not drastically changed. The color values obtained from leaves supported the chlorophyll findings. At the end of the study, microwave drying at 750-850 W ensured the shortest drying time and the best overall quality of parsley; thus, it was chosen as the most appropriate technique for parsley drying.