Fractionation of Stevia rebaudiana aqueous extracts via two-step ultrafiltration process: towards rebaudioside a extraction

The consumption of sugar-based foods has generated significant attention when dealing with influence towards chronic diseases, such as obesity diabetes mellitus, cancer, lipid metabolism disorders, among others. The food industry has currently found a profitable market in using reduced-calorie artificial sweeteners to elaborate dietary products. However, many studies have addressed the possibility of harmful effects of the prolonged consumption of artificial sweeteners on human health, e.g. cancer and diabetes. For this reason, industries have been focused on the use of natural sweeteners, such as steviol glycosides (SGs), which have become important into food industry. Herein, we propose an integrated membrane system, implementing two different ultrafiltration membranes (100 and 1 kDa), to separate rebaudioside A (reb A) from aqueous extracts of Stevia rebaudiana. By using this approach, we found out that the UF100 membrane served mostly to remove total solids (∼42%) and carbohydrates (∼41%) from the crude extract, while tight UF1 membrane was able to retain the phenolic compounds (∼98%). Moreover, the integrated membrane system allowed the recovery of reb A (up to 38 mg). Our results demonstrate that such a membrane-based process is a viable alternative for the fractionation and extraction of SGs from Stevia rebaudiana, but also some other high-added valued molecules (such as carbohydrates and polyphenols) can be concurrently recovered.