DEVELOPMENT OF THE DRYING CHARACTERISTIC COEFFICIENTS OF DRIED MARIGOLD PETALS BY USING OF AN ELECTRICAL LABORATORY DRYING SYSTEM

Abstract

Marigold plant is considered one of the most important medicinal plants. It is used in pharmacological industrials, beauty tools and its pigment is utilized as a natural alternative of chemical pigment. So, the objectives of this paper are to determine the drying characteristic coefficients and investigate the chemical and sensory characteristics of dried marigold petals by utilizing electrical drying equipment at different drying air temperatures and airflow rates. In electrical laboratory drying system (ELDS), the experiments were conducted at two controlled factors to study the drying characteristics for marigold petals, airflow rate (Qe), cu-m/min. at three levels of (0.65, 0.81 and 1.05 cu-m/min.) and drying air temperature (T), °C at four levels of (43, 48, 53 and 63° C). At high drying air temperature levels of 63°C and air flow rates ranged at 0.65 -1.05 had the best average drying rates of (9.28-11.63% db/min) and the best constant drying rate of (18.61-21.35% db/min). The highest drying factors were in the range of (3.462-4.56 1/h). It had the low critical moisture content time of (20-40 min.). Also it had the best sensory characteristics for color, appearance and quality. It had the best carotene concentration (Con) value range of 310.35-312.29 mg/g with an excellent unchanging control treatment which had value of 332.39 mg/g. Drying air temperature (T), °C had a high significant increasing effect on all drying, sensory and chemical characteristics. Meanwhile, the air flow rate had no significant effect on the previous drying characteristics.