A RESPONSE-SURFACE METHODOLOGY APPROACH TO THE OPTIMIZATION OF CONTROLLED LOW-TEMPERATURE VACUUM DEHYDRATION

A three-variable and three-level design, analyzed by response surface methodology, was used to determine optimum conditions for controlled low-temperature vacuum dehydration. A gelatin-microcrystalline cellulose model food system was used for this study. Effects of solid concentration (8-16%), drying temperature (-2 to 6-degrees-C), and sample thickness (0.6-1.8 cm) on various responses were studied. Optimization of the process was conducted using the combination of the effects of relative solubility of dried sample, bulk density, and drying rate. Controlled low-temperature vacuum dehydration operation was found to be mass-transfer dependent. Temperature was not a significant factor for drying rate but concentration and thickness were highly significant. Based on the results, relatively low temperatures, small sample thickness, and moderate solid concentrations are recommended conditions for this type of process.