US Patent 7838044 Extraction, separation and modification of sweet glycosides from the

The invention disclosed relates to a method for the extraction of sweet glycosides from the Stevia rebaudiana Bertoni plant and recovery of individual rebaudioside A and stevioside. The extraction is developed in the presence of pectinase, and the extract is purified using cyclodextrin and bentonite. High purity rebaudioside A is obtained by crystallization and recrystallization from ethanol. High purity stevioside is prepared from the filtrate by purification with cyclodextrin, bentonit, and ion exchange resins. The enzymatic modification of the rebaudioside A, stevioside and the purified extract is carried out using the transferring enzymes derived from Thermoactinomyces vulgaris and Bacillus halophilus.