Abstract

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 (aw), pH, acidity, non-enzymatic browning, surface colour, vitamin content (C and E), mineral content, and antioxidant capacity. The drying kinetics of A. vera gel 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 °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 °C). However, minor alterations in the physicochemical and nutritional properties of A. vera gel were produced at drying temperatures of 60-70 °C, resulting in the production of a high quality gel. © 2008 Elsevier Ltd. All rights reserved.