Sweeteners from Pre-Treated Stevia Leaves: Evaluation of The Effect of Extraction Cycles by Semi-Continuous Percolation

Abstract

Stevia rebaudiana could be used to makes to produce nutraceuticals and functional foods instead of sucrose and artificial sweeteners. Due to the nutritional and technological advantages of sucrose, innovative approaches for extracting sweeteners from Stevia leaves have been developed and optimized over the years. The purpose of this study was to evaluate the effect of extractingsteviol glycosides from leaves of a new variety of Stevia rebaudiana that had been pre-treated with ethanol. The extractions were carried out in a semi-contiunous mode in a percolator, evaluating the effects of the proportion of solvent to sample (ratio 1/10 and 1/40) and temperature (30 °C and 100 °C) for leaves pre-treated with ethanol. The Tukey Test (p<0.05) was utilized to identify sweeteners through gas chromatography.The highest temperature and proportion of solvent to sample were the best conditions to get an extract rich in sweeteners (13.93 g/100g of dry extract). Under these conditions, the application of two cycles proved to be sufficient to achieve a satisfactory recovery of glycosides in the extract (~93%), while allowing for a lower solvent consumption. Temperature reduction (30°C) decreases glycoside recovery (15.71%) and mass yield (11.14%) in the first extraction cycle. However, temperature ceased was no longer a significant factor (p<0.05) when the solvent volume was reduced to a 1/10 ratio. It is thought that particles with a smaller diameter could be used to gethigher levels of sweeteners, in future.