Low-temperature Vacuum Drying of Natural Gardenia Yellow Pigment

摘要

Gardenia yellow pigment solutions were dried in a vacuum dryer. Effects of operational parameters such as temperature, solution layer thicknesses and the level of vacuum on the drying kinetics were investigated. It was found that the heating temperature had the most significant effect on drying kinetics. Three non-linear regressions, i.e., 3rd degree polynomial model, Henderson and Pabis model and two-term model were presented to fit the experimental data. Simulation results showed the 3rd degree polynomial model gave the best prediction. According to Fick’s law, the effective diffusion coefficients for Gardenia yellow pigment solutions (20% w.b.) were computed. They were in the range: 8.449×10-9 m2/s at 35℃ to 1.093×10-8 m2/s at 55℃.