Combined effect of air temperature and velocity on drying of Thai rice cracker

Abstract

Fried glutinous rice cracker or “Khaotan” is a traditional snack of local Thai communities. Drying is one of the important steps in production of rice cracker. Hot air drying is an alternative method to direct solar drying used to reduce moisture of the rice cracker during rainy season. In this work, effect of air temperature (40, 50, and 60°C) and velocity (0.5, 1, and 1.5 m/s) in a hot air dryer was investigated. Full factorial and central composite designs of experiments were adopted. The results indicated that air temperature and velocity affected the drying time. The relationship was in second order polynomial with high correlation coefficient R² of 0.8719. Moderately good agreement in predicting drying time between experiments and the regression model was reported.