Study on banana slice drying process by combining hot air and microwave

Taking a combination drying method of hot-air and microwave(AD+MD), and through L16(45) orthogonal experiments, effects on drying rate by hot air temperature, air velocity, water content of conversion point and power of microwave during the combinated drying process of banana slices were explored and optimum conditions were carried out in this paper. Meanwhile, taking L value of color, content of VC, texture, rehydration ratio and sensory quality of products as index, products from combination drying were compared with single hot-air drying and vacuum freeze-drying ones. Results showed that hot air - microwave drying method has faster drying speed and lower energy consumption, and products quality produced by this method approximated single vacuum freeze-drying ones, the best parameters are that making the conversion moisture content of material 55% under condition of hot air temperature 65 ℃, hot-air velocity 2.4 m/s by hot-air drying method firstly, then getting to the finished products with microwave power 200 W by microwave drying method.