Influence of temperature on the drying kinetics, physicochemical properties, and antioxidant capacity of Aloe Vera (Aloe Barbadensis Miller) gel

The effect of air temperature on the physicochemical and nutritional properties and antioxidant capacity of Aloe vera (Aloe barbadensis Miller) gel was investigated. The following parameters were analysed: proximal composition, water activity (a(w)), pH, acidity, non-enzymatic browning, surface colour. vitamin content (C and E), mineral content, and antioxidant capacity. The drying kinetics of A. vera get was modelled using the Wang-Singh equation, which provided a good fit for the experimental data. Analysis of variance revealed that the drying temperature exerted a clear influence on most of the quality parameters. A drying temperature of 80 and 90 degrees C resulted in significant variation in and/or loss of the physicochemical and nutritional properties of the gel; in addition, the antioxidant capacity of the gel was decreased at these temperatures. These effects were also observed as a result of a lengthy drying period (i.e., 810 min at 50 degrees C). However, minor alterations in the physicochemical and nutritional properties of A. veto gel were produced at drying temperatures of 60-70 degrees C, resulting in the production of a high quality gel. (C) 2008 Elsevier Ltd. All rights reserved.