Influence of temperature on vacuum drying characteristics, functional properties and micro structure of Aloe vera (Aloe barbadensis Miller) gel

Abstract

Aloe vera possesses therapeutic, antioxidant and some other functional properties. These properties may be affected by processing operations. The present study investigated the influence of operating temperature on vacuum drying characteristics, functional properties and the inner solid structure of the fresh aloe vera gel. The gel was dried at a constant pressure of 720 mm Hg in the drying chamber at varying temperature of 30-60°C. The experimental data of moisture ratio of Aloe vera were used to fit different models and the effective moisture diffusion coefficients and activation energy were also calculated. The Page model was found to be the best fit to experimental data. The functional properties like water retention capacity, fat absorption capacity, and swelling of the dried product were studied and found to be decreased with increasing operating temperature. The damage to the inner solid structure was more pronounced at higher temperatures because of faster mass transfer through the pores of the solid. The best quality product was obtained when the temperature was maintained at 30°C.

Keywords

• therapeutic
• moisture ratio
• activation energy