Application of foam column as green technology for concentration of saponins from sisal (Agave sisalana) and Juá (Ziziphus joazeiro)

Saponins, molecules classified as triterpenic or steroidal glycosides, are metabolites distributed in all the plant kingdom that can be used for the production of foods, cosmetics, and pharmaceuticals, as well as in soil bioremediation. Saponins are normally extracted from natural resources with water, ethanol and/or methanol, and then concentrated by liquid-liquid partitioning with n-butanol. An alternative concentration method is with a foam column, by which the saponins can be concentrated via preferential adsorption at a gas-liquid interface. Therefore, the objective of this work was the use of a foam column for the concentration of saponins from juá and sisal, evaluating parameters such as: initial working volume in the column, saponin concentration in the extracts from juá and sisal, air flow rate, pH, Raschig rings loading and operation time. When a gradient air flow rate and 25 g of Raschig rings were used, 82.6% of the jua saponins loaded onto the system were recovered in a 3.46-fold concentrated solution after 9 h of operation. Regarding sisal saponins, a concentration factor of 1.98 was observed with 90.5% of saponin recovery during 4.5 h of operation