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Near-infrared spectroscopic characterization of steviol glycosides extracted from Stevia rebaudiana Bertoni using high-power ultrasound and gas-phase plasma

The purpose of this study was to examine the possibility of extraction of steviol glycosides from dried leaves of Stevia rebaudiana by application of high-intensity ultrasound and gas atmospheric plasma, in which water is used as a solvent. In contrast to Soxhlet extraction (by water), an increase in the yield of average value of steviol glycosides was achieved by ultrasound (59 %) and gas plasma (43 %). Highest effect was at treatment for 30 min, the amplitude of 90 μm, and a temperature of 45 °C. After gas plasma treatments, the average yield of steviol glycosides (101.34 g·kg⁻¹) was slightly lower than that after the application of ultrasound. This study also established a near-infrared spectroscopy (NIR) model for direct and rapid analysis of the expected content of steviosides. NIR spectroscopy showed the capacity that, combined with multivariate analysis tools (principal component analysis, partial least squares regression), was successful in grouping data.

steviol glycosides ; near-infrared spectroscopy ; gas-phase plasma ; high-intensity ultrasound ; principal component analysis ; partial least squares regression

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