Clarification and concentration of yerba mate extract by membrane technology to increase shelf life

Abstract

Our study is the first to describe clarification as an alternative method to increase the physical and chemical stabilities of the yerba mate extract. Here, the aqueous extract was clarified by sequential treatment with three membranes, microfiltration (0.1μm), ultrafiltration 1 (30kDa–80kDa), and ultrafiltration 2 (4kDa). The clarified extract was then tested for stability and concentrated using a reverse osmosis membrane. The turbidity of the clarified membrane extracts was less than 36 NTU and there was no significant difference in the phenolic compound content between the crude and clarified extracts. Ultrafiltration membrane 1 (vinylidene polychloride) performed the best, and produced extracts with the lowest loss in phenolic compounds (18%) and turbidity (99.9%), while maintaining a stable permeate flux. The reverse osmosis membrane concentrated the polyphenols and the extract solids three times, and this study was the first to report the concentration of yerba mate extracts by reverse osmosis. The clarified yerba mate extract maintained its phenolic compound stability and decreased turbidity over 30 days of storage. Taken together our results suggest that membrane clarification may be used to increase the shelf life of yerba-mate extracts.