Effect of drying system, layer thickness and drying temperature on the drying parameters, product quality, energy consumption and cost of the marjoram leaves

El-Sayed G Khater; Adel H Bahnasawy; Mai H Abd El-All; Hassan M M Mustafa; Ahmed M Mousa

doi:10.1038/s41598-024-55007-7

Effect of drying system, layer thickness and drying temperature on the drying parameters, product quality, energy consumption and cost of the marjoram leaves

Sci Rep. 2024 Feb 26;14(1):4637. doi: 10.1038/s41598-024-55007-7.

Authors

El-Sayed G Khater¹, Adel H Bahnasawy², Mai H Abd El-All², Hassan M M Mustafa³, Ahmed M Mousa⁴

Affiliations

¹ Agricultural and Biosystems Engineering Department, Faculty of Agriculture, Benha University, Moshtohor, P.O. Box 13736, Toukh, Kalubia, Egypt. alsayed.khater@fagr.bu.edu.eg.
² Agricultural and Biosystems Engineering Department, Faculty of Agriculture, Benha University, Moshtohor, P.O. Box 13736, Toukh, Kalubia, Egypt.
³ Mechanical Engineering Department, Engineering and Renewable Energy Research Institute, National Research Centre, Giza, Egypt.
⁴ Agricultural Machinery and Power Engineering Department, Faculty of Agricultural Engineering, Al-Azhar University, Cairo, Egypt.

Abstract

The main aim of this work is to study the main factors affecting the quality of the dried product and the energy requirements through optimizing these factors. To achieve that different drying systems (solar, hybrid solar and oven dryings), layers thickness (1, 2 and 3 cm) and drying temperatures (50, 60 and 70 °C) were used. The obtained results indicated that, the accumulated weight loss of marjoram leaves ranged from 73.22 to 76.9%, for all treatments under study. The moisture content of marjoram leaves ranged from 273.39 to 333.17, 258.02 to 333.04 and 269.38 to 324.90% d.b. for hybrid solar, oven and solar drying systems, respectively. The highest value of the drying rate of marjoram leaves (223.73 g_water kg^-1 h^-1) was obtained when the marjoram dried by oven drying system at 70 °C at 1 cm layer thickness. The highest values of the basil and marjoram oil content (2.91%) was obtained when the marjoram dried under sun drying system. The energy consumption for drying marjoram decreases with increasing drying temperature and layer thickness for hybrid solar and oven drying systems. The cost of dried marjoram dried under hybrid solar drying system was lower than those of oven drying system, the highest cost (13.48 LE kg^-1) was obtained at a temperature of 50 °C and a layer thickness of 1 cm.

Keywords: Cost; Drying rate; Energy; Essential oil content; Marjoram; Solar drying.