Drying Kinetics and Quality Properties of Mellaki (Pyrus Communis L.) Pear Slices Dried in a Novel Vacuum-Combined Infrared Oven

Abstract

In a specially designed infrared oven equipped with a two-way infrared heating and vacuum pump systems, the effects of drying parameters (100-300 W infrared powers and 100-250 mmHg vacuum pressures) on drying kinetics and quality properties of pear slices were comprehensively studied. The samples dried at 300 W had high HMF values (12.73-95.68 mg/kg d.m). The highest sensory scores were observed in pear slices dried at 300 W and 250 mmHg. Six different mathematic models were taken into account to analyze the drying characteristics of pear slices, with the Wang and Singh model (R-2 = 0.9996, chi(2) = 0.0004, and RSME = 0.0062) presenting the best prediction of the drying behavior. The effective moisture diffusivity values were 1.1829-4.6684 x 10(-8). The activation energies for 100 and 250 mmHg vacuum applications were 44.21 and 43.89 kJ/mol, respectively. It was concluded that a vacuum-combined infrared dryer (300 W, 250 mmHg) could be a fast and economic method for drying pear slices. Novelty impact statement A combination of 300 W infrared power and 250 mmHg vacuum pressure was the fastest combination for the drying of pear slices and gave the highest score in sensory evaluation. The Wang & Singh model exhibited the best results in fitting the experimental data. As a result, the vacuum-combined infrared technology was improved the drying efficiency and quality of dried pear.