Extraction of stevia glycosides with CO2 + water, CO2 + ethanol, and CO2 + water + ethanol

Abstract

Stevia leaves are an important source of natural sugar substitute. There are some restrictions on the use of stevia extract because of its distinctive aftertaste. Some authors attribute this to soluble material other than the stevia glycosides, even though it is well known that stevia glycosides have to some extent a bitter taste. Therefore, the purpose of this work was to develop a process to obtain stevia extract of a better quality. The proposed process includes two steps: i) Pretreatment of the leaves by SCFE; ii) Extraction of the stevia glycosides by SCFE using CO2 as solvent and water and/or ethanol as cosolvent. The mean total yield for SCFE pretreatment was 3.0%. The yields for SCFE with cosolvent of stevia glycosides were below 0.50%, except at 120 bar, 16°C, and 9.5% (molar) of water. Under this condition, total yield was 3.4%. The quality of the glycosidic fraction with respect to its capacity as sweetener was better for the SCFE extract as compared to extract obtained by the conventional process. The overall extraction curves were well described by the Lack extended model

New seminal variety of Stevia rebaudiana: Obtaining fractions with high antioxidant potential of leaves

“…Stevia UEM-13 therefore presented a ratio RebA/Stev much higher (2.27) than the wild varieties that have inferiors values to 1 (Kovylyaeva et al 2007, Gardana et al 2010, Gupta et al 2013, Madan et al 2010. The new cultivar has significant levels of bioactive compounds when compared with other wild varieties (Gawel-Beben et al 2015, Pasquel et al 2000, Wölwer-Rieck 2012.…”

New proposal for production of bioactive compounds by supercritical technology integrated to a sugarcane biorefinery

“…A home-made unit, described by Pasquel et al (2000) was used for the experiments that use CO2 and ethanol mixtures, while another recently constructed unit was used in the experiments that only ethanol is used. This latter unit consists of a HPLC pump (Thermoseparation Products, Model ConstaMetric 3200 P/F, Fremoni, USA), a 6.57 cm 3 extraction cell (Thar Designs, Pittsburg, USA) containing a sintered metal filter at the bottom and upper parts, an electrical heating jacket and a back pressure regulator (BPR) valve (Model n°26-1761-24-161, Tesco, Elk River, USA).…”

Measurement of Natural and Artifical Radionuclides of <i>Stevia Rebaudiana</i> Bertoni Extract

“…The chlorophyll of the leaf has been removed by means of nhexane (Pasquel et al 2000). Then the leaves were dried again.…”