Extraction of stevioside using aqueous two-phase systems formed by choline chloride and K3PO4

Limitations and disadvantages of artificial sweeteners in the food and beverage products act as an incentive for paying attention to the extraction and purification of natural sweeteners. Aqueous two-phase systems (ATPSs) are believed to be a desirable method for the extraction and separation of biomolecules. In recent years, researchers have focused on the use of innocuous, benign components having potential to form ATPSs. In this research, choline chloride, as a biocompatible and nutritious constituent, has been utilized to establish an ATPS performing the extraction of stevioside. To assess the efficiency of the ATPS composed of choline chloride and potassium phosphate, the partitioning of stevioside was explored. The effects of such parameters as the weight percents of choline chloride and potassium phosphate on the partitioning of stevioside were studied. All experiments were conducted at four temperatures of 298 K, 303 K, 308 K, and 313 K. Also, the effect of pH on the partitioning of stevioside was investigated. Different regression models were adopted to correlate the empirical results of the stevioside partition coefficient, and through statistical analyses the most reliable regression model was chosen.