Investigating the Effects of a Novel Combined Infrared-Vacuum Dryer on the Drying Kinetics and Quality Parameters of Apple Chips

In this study, the kinetic and quality parameters of apple chips dried by a novel dryer equipped with two-way infrared heating (۱۸۰, ۲۷۵, and ۳۲۵ W) and vacuum pump systems (۱۰۰ and ۴۰۰ mmHg) were investigated. The final drying time of the sample was reduced with the increasing infrared power. However, it significantly decreased with the increasing vacuum pressure at only ۱۸۰ W. While the rehydration ratio and sugar content decreased at higher infrared power, the degree of browning and ۵-hydroxymethylfurfural increased. Apple chips had high HMF contents (۲۰۵.۳۹-۳۵۱.۳۰ mg/kg DM). After sensory evaluation, the highest color, crispness, chewiness, taste, and general acceptance values were determined in the apple chips dried at ۲۷۵ W and ۴۰۰ mmHg. The results showed that Midilli’s model was the best option to describe the experimental drying data. The effective moisture diffusivity increased with increasing power and ranged from ۱.۴۴۹۹ to ۲.۹۳۶۲ × ۱۰−۸ m۲/s. The activation energies of drying kinetics for ۱۰۰ and ۴۰۰ mmHg were ۴۰.۵۵۰۷ and ۳۶.۵۱۳۴ kJ/mol, respectively. Results showed that the higher energy efficiency and product quality for apple chips could be obtained with a specially designed infrared vacuum combined dryer (۲۷۵ W and ۴۰۰ mmHg).

کلیدواژه ها:

Apple chips ، Infrared-vacuum drying ، Mathematical modeling ، physicochemical properties ، Sensory evaluation