Optimization of the conditions for hot-air treatment of postharvest Red Fuji apples using response surface method

The effect of hot-air treatment on quality of apples (cv: Red Fuji) was evaluated by response surface method(RSM) with different temperature-time combinations. Red Fuji apples were treated under different time-temperature combinations, and then were stored at (0±0.5)℃ for four months. After that, the apples were placed on simulated shelf at 20℃ for seven days, the changes of a^* value, firmness and SSC/TA of apples were measured. Three second order quadratic equations for hot-air treatment were established. The adequacy of the model equation for predicting the optimum response values was verified by the validated data. By analyzing the response surface graphs and corresponding contour graphs as well as solving the quadratic equations. The optimum hot-air treatment temperature is 36.3℃ and the processing time is 82.5 h.