Optimization of mechanical convective drying parameters for fermented uf-18 cacao beans using response surface methodology

Abstract

Mechanical drying is considered an efficient drying technique; however, continuous mechanical drying may compromise flavor and textural properties. This study aimed to create optimized drying parameters of fermented UF-18 cacao beans using a laboratory scale mechanical dryer and Response Surface Methodology (RSM). A central composite design consisting of 20 experiments was conducted within temperature ranges of 29.77 to 80.22 °C, air velocity of 0.5 to 1.5 m/s, and relative humidity of 10 to 20%. Drying time and bean quality were evaluated as response variables. The drying time was a linear function (Adjusted R² = 0.9854, Predicted R² = 0.9783), with temperature as the most significant factor (p < 0.05). Drying at 80.22 °C achieved the shortest drying time of 12 h but resulted in poor quality (score 5). The optimum conditions were at 57.85 °C, air velocity of 0.5 m/s and relative humidity of 10% under intermittent drying with predicted drying time of 34 h and bean quality score of 8.83 with desirability of 0.95.