CHANGES IN THERMAL PROPERTIES AND COLOUR ATTRIBUTES OF POTATO (CHANDRAMUKHI VARIETY) DURING FOAM MAT AND THIN LAYER DRYING

Abstract

Thermal properties of potato of Chandramukhi variety, including density, specific heat, thermal conductivity and thermal diffusivity during foam mat and thin layer drying were determined. The thin layer drying was conducted at three different temperatures i.e. 50oC, 55oC, 60oC. The foam mat drying was also conducted at three different temperatures (50, 55, 60oC) with three different concentrations of foaming agent (1%, 2%, and 3%). Glycerol monostearate (GMS) was used as a foaming agent. The specific heat, thermal conductivity and thermal diffusivity decreases as temperature increases from 50oC to 60oC in both of the drying. The foaming agent has a significant effect on drying rate and thermo-physical properties at p<0.05 level. Temperature and foaming both have a significant effect on color of dried powder at p<0.05 level. These thermal characteristics can be practically applied in modeling thermal behavior of potato mash during thermal processing operations.