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Accelerated solvent extraction (ase) of total phenols from stevia rebaudiana bertoni leaves

Stevia rebaudiana Bertoni leaves are used as natural low-calorie sweeteners where a mixture of eight sweet diterpene glycosides and dulcoside were present. Stevioside and rebaudioside are the major steviol glycosides found in stevia leaves with an averages ranging from 4-20 % in the dry matter of the plant leaves. The presence of important biologically secondary plant products in stevia leaf also contributes to its medicinal value, since they exhibit various physiological activity. A number of studies revealed that steviosides from stevia leaves could provide therapeutic benefits such as antioxidant, antimicrobial and antinflammatory activities. Additionally, Stevia rebaudiana is considered as natural source of antioxidants due to considerable phenolic content. Objectives in the study were to evaluate the total phenols content (TPC) from the leaves of Stevia rebaudiana Bertoni using accelerated solvent extraction (Dionex ASE® 350, USA). Different extraction conditions (temperature, extraction time, and cycle number) under constant pressure (10.2 MPa) were investigated. Extraction conditions: temperature (100-160 ºC), extraction time (5 and 10 min), and cycle number (one, two and three) were optimized by multifactor ANOVA. Obtained results indicated that higher extraction temperature as well as longer extraction time retrieved higher TPC. Also, increased number of cycles during extraction provided more of the TPC for both extraction times.

Stevia rebaudiana Bertoni leaves; water extract; total phenols content; accelerated solvent extraction (ASE)

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