Drying characteristics of infrared radiation combining hot air for apple slices

Effect of infrared radition distance and hot air temperature on drying characteristics of apple slices were studied in this paper,and the drying time,color,hardness,crispness and redehydration ratio were analyzed.The results showed that hot air temperature had a significant influence on drying characteristics and drying products quality.The whole drying process present a falling rate period.The effective moisture diffusion coefficient of apple slices was range from 2.92 × 10^-8 to 8.85 × 10^-8m²/ s accroding to Fick's Second Law,and it was increased with hot air temperature increasing.The activation energy was 75.67 k J / mol accrodring to Arrenius equation.Drying time of apple slices was greatly shortened( 162 min) with the best color( L*75.01,a*8.92,b*32.97) and texture( hardness 1063.66 g,crispness 0.531 s) when infrared radiation distence was 50 mm,infrared power was 1500 W,hot air temperature was 80 ℃ and air velocity was 0.8 m / s. Infrared radiation combined hot air drying can inhibit enzyme activition,increase drying rate effectively and improve product quality.