Abstract This study evaluated the effects of ultrafiltration (UF) and diafiltration (DF) on the chemical composition and selective fractionation of red beetroot juice. UF was performed using membranes with molecular weight cut-offs of 2 and 5 kDa to assess permeate flux, solute retention, and fouling behavior, with the 2 kDa membrane exhibiting higher rejection of phenolic compounds and betalains. DF was subsequently applied to the UF retentate obtained with the 2 kDa membrane to enhance the removal of low-molecular-weight sugars. The highest recovery values were observed at a diafiltration volume of 6, reaching 68.87% and 73.4% for phenolics and betalains, respectively. Under these conditions, 17.62% of the total soluble solids and 17.86% of the sugar content were retained in the retentate. Collectively, the integrated UF-DF process enabled the production of a concentrate enriched in phenolic compounds and betalains, while generating a permeate fraction enriched in sugars.
Aslı Arslan Kulcan (Fri,) studied this question.