Application of solar drying on the apple peels using an indirect hybrid solar-electrical forced convection dryer

Abstract

Apple peels are available worldwide as organic waste from the food processing industries which have many functional groups that can be exploited for industrial such as food supplements. The valorization and conservation of this organic waste with good quality at a low cost still remains a big problem in the agro-food industry. Hence, a forced convection solar drying is deemed as an environmentally friendly solution. This paper tackles the drying kinetics of the apple peels at four temperatures 50, 60, 70, and 80 °C, with two mass air flow rate 150 and 300 m3 h−1. The results are represented in a drying characteristic curve. The impact of aerothermal parameters on the drying behavior, the color, the dimension, and the bioactive profile of this co-product is also studied. An energetic study demonstrates that the total energy consumed during the drying experiments reaches the minimum at a higher temperature and a lower airflow while the energy efficiency gets a maximum value at a higher temperature and airflow.