Clarification of red beet stalks extract by microfiltration combined with ultrafiltration

•The clarification of beet stalks extract was done by membrane separation processes.•The microfiltration and ultrafiltration were able to reduce the peroxidase activity.•The membrane processes provide a more intense luminous and red color to the extract.

Red beet stalks constitute an agro-industrial residue with potential to be utilized as betalains source. However, in order to maintain the stability of these natural pigments, it is necessary to minimize the factors that favor their degradation. The main aim of this study is the clarification of the juice extracted from beet stalks, which are rich in betalains, using microfiltration process combined with ultrafiltration. Despite the permeate flux reduction during the processes, the occurrence of fouling and betalain degradation in the permeate stream, these separation processes have been demonstrated to be efficient in clarifying the extracts. Comparing the initial extract (microfiltration feed) with the final permeate (ultrafiltration permeate), it was possible to achieve a 99.5% reduction in peroxidase activity, more than 99.9% reduction in turbidity and the color too appeared to be more intense, luminous and reddish.