Abstract :
Stevia is a natural sweetener obtained from the leaves of Stevia rebaudiana (Bertoni),belonging to the Asteraceae family. The objective of the present study was to develop a rapid and effective methodology for the extraction of stevioside and rebaudioside A from Stevia leaves and to compare the yields with different extraction techniques. Modified method of extraction was done with water finally the glycosides were precipitated by methanol-water solvent (0.25:1.0 v/v). The solvent from the extract was removed by lyophilization. Extracted product was analyzed by HPLC-PDA followed by mass-spectrometric (MS) detections. The decolorized extract was separated on an NH2 column using PDA detection with excitation at 210 nm. The mobile phase consisted of acetonitrile/water (80:20 v/v) with a flow rate of 1 ml/min. Evaluative criteria for stevioside and rebaudioside yield in this new method was high. An improved analytical method was developed which may be applied to quality control of stevioside content in dried leaves of Stevia before processing.
Keyword :
Stevia rebaudiana, Asteraceae, Lyophilization, HPLC-PDA, Stevioside, Rebaudioside a