Optimization of Process Parameters for Aqueous Extraction of Stevioside from Leaves of Stevia rebaudiana Bertoni

Stevioside, a diterpene glycoside extracted from the leaves of Stevia rebaudiana Bertoni, is a natural non-caloric sweetener. Different process parameters such as leaf to water ratio (1: 5 to 1: 25), heating time (20 to 120 min) and temperature (30 to 90°C) were optimized for hot water extraction of stevioside from Stevia rebaudiana leaves using response surface methodology (RSM). The combined effects of these independent variables on extracted stevioside content, colour, sugar content, total soluble solids and pH of extract were studied. Based on RSM analysis, temperature of 76°C, extraction time of 60.6 minutes and leaf to water ratio 1: 14 gave the best results which were in close agreement with the prediction model.