Mohammed Abdalbasit A. Gasmalla^{1, 2}, Ruijin Yang^1,, Abubakr Musa¹, Xiao Hua¹, Wenbin Zhang¹

Stevia rebaudian Bertoni, belonging to the Compositae family, is a sweet herb contains diterpene glycosides, namely, stevioside, rebaudiosides A–F, steviolbioside, and dulcoside A, which are responsible for the typical sweet taste. Stevia (Stevia rebaudian Bertoni) leaves were analyzed for their physiochemical properties, chemical composition and microbiological contamination in addition to rebauidioside A productively. The carbohydrates content was 63.10%, while the moisture, fiber, protein, ash, fat and reducing sugar contents were 10.73%, 5.03%,13.68%,12.06%,6.13% and 4.50%, respectively. Anti-nutritional value (tannin) was 5.43 %. The total soluble substance was 17.03%. The Stevia leaves showed a good antimicrobial agent for all tested bacterial groups including Coliforms, Staphylococcus. Rebauidioside A was extracted and purified from the dried Stevia leaves by ultrasonic-assisted extraction method. The optimum extraction time was 6 min in which the maximum rebauidioside A content was obtained (32.79 g/100 g). Results show that particle size of sample treated for 6 min is bigger than those for 12, 18 and 24 min. Application of ultrasound-assisted extraction on the Stevia plant substantially affects the Color, and particle size of the stevia leaf extract and rebauidioside A yield.

color, particle size, Physico-chemical, microbial analysis, Extraction, stevia, Rebaudioside A