Investigation of 60Co gamma irradiation on dehydration kinetics: A case study of apple slices

Abstract

ABSTRACTLittle research has been done on the effects of irradiation on dehydration kinetics of dried fruit in recent decades. Hot air drying is a convenience method frequently used for dehydration and moisture removal in products, such as fruits and vegetables. However, there are some disadvantages to using hot air dryers that often lead to the production of dried products with inferior quality due to its low drying efficiency. The present research aims to investigate the hot air dryer performance and presents a new strategy to improve dried bio‐products quality using gamma irradiation as a drying pretreatment. The effects of irradiation dosage (control, 0.5, 2, and 5 kGy) and air temperature (50, 65, and 80°C) on the dehydration rate, moisture ratio, activation energy, and diffusion coefficient of dried apple slices were investigated. The results showed that different dose 0.5, 2, and 5 kg decreased moisture content average 35, 21, and 11%, respectively. Also, by decreasing dehydration temperature, moisture content decreased to 42, 31, and 25%, respectively. The effective diffusivity values at different temperatures increased by increasing the irradiation dosage (control, 0.5, 2, and 5 kg increased to 12, 17, 29, and 43% respectively), and vice versa for the activation energy.Practical ApplicationsIrradiation is one of the few food technologies that can maintain food quality and address food safety and security problems without significantly affecting a food's sensory or nutritional attributes. The destructive effect of 60Co γ‐ray irradiation on interior tissue of some fruit and vegetables may change product structure to some extent. These kinds of structural changes can affect the drying kinetics, dehydration rate, moisture ratio, activation energy, and diffusion coefficient. Therefore, the investigation of hot‐air drying kinetics of apple slices pretreated by 60Co γ‐ray was required to improve the product quality. Additionally, it can cause a reduction in drying quality and improve the product characteristics during the drying process.