Modeling of the panning process in the production of hazelnut dragees

To predict the crystallization and layering of sucrose syrup on the central core (hazelnut) during the hard panning process, the growth rate of dragees was evaluated. Three sugar solutions were prepared with concentrations of 80, 85, and 87 (w/w%). Sucrose solutions were poured into a rotating pan at 100 ° C and an external flame was used to maintain the temperature of the panning process at 70±2 °C. By blowing air at 30±1°C, the internal humidity of the pan was removed. The growth rate of dragees in different soluble solids was determined experimentally. The crystal growth rate through crystallization kinetics based on saturation state, temperature, and solution concentration 125±0.03, 122±0.02, 127±0.02 µm/min predicted. The modeling results were consistent with the theoretical and experimental results. Physical and chemical properties of dragees including aw, weight, and moisture content, the thickness of coating layer, total sugar and invert sugar, growth rate, mutual diffusion coefficient, CMF, and glass transition temperature of dragee and solution, were studied. The amount of aw in all dragees was less than 0.56. By increasing the Brix of the solution, a decrease in the percentage of total sugar from 89.42 to 85.71% and an increase in invert sugar from 0.08 to 0.15% in the coating layer of dragees obtained. A decreasing trend was observed in the mutual diffusion coefficient from 2.11×10-9 to 1.94×10-9 m2/s with increasing sucrose concentration. Increasing the initial concentration of syrup did not show a significant effect on crystal growth rate. With the reduction of total sugar based on sucrose in dragees, the CMF factor decreased from 25.1 to 20.3. The glass transition temperature of dragee was 31.27°C, and the sucrose-water solution used in this study predicted 51°C. The predicted data were consistent with the experimental ones. Changes on those properties in process conditions have been discussed.