Extraction and Clarification of Steviol Glycosides (Sweetener) from Stevia Rebaudiana Bertoni

Abstract

In the present study, the separation and purification of Steviol glycosides from the leaves of S. rebaudiana was carried out using physical separation techniques such as extraction and clarification. The extraction of the Steviol glycosides from the leaves of S. rebaudiana was carried out using hot water. The effect of Steviol glycosides to water ratio on extraction efficiency was studied. Higher percentage of recovery was obtained at the Steviol glycosides to water ratio of 1:35. The clarification of extract is an important stage as it imparts better visual quality to the final product, and this was done using decolouring and flocculating agent such as calcium hydroxide combing with filter aid followed by carbonation using carbon dioxide gas. Stoke law for setting solids was employed to work out sedimentation parameters such as settling time and settling velocity to understand the stevia clarification process. Subsequent to extract clarification, a new method for HPLC analysis has been developed for the analysis of Steviol glycosides. It was observed that clarification of Steviol glycosides with a recovery of 76% Steviol glycosides of high purity and a reasonably significant percentage of rebaudioside A in the clarified extract.