Effect of Vacuum, Microwave, and Convective Drying on Selected Parsley Quality

The impact of ultrasound and steam blanching pre-treatments on the drying kinetics, energy consumption and selected properties of parsley leaves

“…It can be concluded that prolonged drying time impair the chlorophyll molecules, whereas higher microwave power (300 W) allowed to preserve 24% more pigments in the same air temperature. The protective effect of higher microwave power in some ranges and thus lower drying time was also noted by Akbudak and Akbudak [1] and Sledz et al [31] for parsley. Generally, at the higher air temperature chlorophylls were more resistant but only at 100 W. The protective effect of shortening of the drying time was camouflaged at higher doses of energy (higher both microwave power and air temperature), as it was proved formerly [31].…”

Influence of Drying Processes and Pretreatments on Nutritional and Bioactive Characteristics of Dried Vegetables: A Review

“…When vacuum, microwave and convective drying were evaluated for parsley, higher total chlorophyll values were attained at 75°C and 20 mmHg by vacuum drying, at 750 W by microwave drying and at 125°C by convective drying, with retention values of 87, 83 and 70 %, respectively [4]. The authors concluded that although all samples loose some of their total chlorophyll content, higher chlorophyll retentions in the dried product were attained with shorter drying times.…”

“…The chlorophyll content was assessed after solar drying of mustard, mint, spinach [41], air drying of coriander leaves [3], microwave vacuum and air drying of parsley [4], solar and air drying of savoy beet and amaranth [65], solar, air and freeze drying of savoy beet [63] and vacuum freeze, vacuum microwave, air, air spouted bed and microwave spouted bed drying of lettuce [24].…”

“…Vitamin C content was evaluated in several dried vegetables, such as parsley [4], worowo [20], kale [43], mushrooms [28], asparagus [67], savoy beet [63] and amaranth [65], carrots [49], tete, soko and igbagba [68]. Comparing air drying, microwave and vacuum drying of parsley, higher retention percentages of ascorbic acid were observed in vacuum drying (losses of 13-44 %), followed by microwave (losses of 28-46 %) and convective drying (losses of 38-68 %), probably due to longer drying period and lower values of temperature and water content [4]. [49] and [28] reported vitamin C losses of 21 and 46 % using microwave drying, whereas convective drying originated losses of 61 and 67 %, respectively.…”

Color and Microstructure Properties of Tomatoes Dried by Microwave, Convective, and Microwave-Convective Methods

“…The most popular and efficient way to preserve food by reducing its moisture content is convective drying. [7] However, there are many problems associated with this drying method, such as the relatively long drying time, the high temperatures used, and the high velocities of the drying airflow. [8] Microwave drying is an alternative method that has various advantages, including energy savings and precise process control.…”