Clarification and concentration of red cabbage anthocyanins using integrated membrane process

The objective of this study was to develop a membrane process, involving ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO), for clarification and concentration of the red cabbage anthocyanins extract. The trans-membrane pressure (TMP) and axial feed flow rate (Qf) was evaluated according to the total recycle mode (TRM). The integrated membrane process was studied according to the batch mode (TBM). The total anthocyanins content (TAcy) , pH value, total soluble solid (TSS) and color characteristics (CIE L* a* b*) were measured. The ceramic UF membrane showed better results than the polyether sulfone membrane in clarification. the optimal conditions were TMP=0.3 MPa and Qf =40 L/min using ceramic UF membrane module. NF membrane showed higher efficiency than RO membrane in concentration, the optimal conditions were TMP=1.0 MPa, Qf =25 L/min with NF membrane, and TMP=1.5 MPa, Qf =10 L/min with RO membrane. Both UF+NF and UF+RO membrane-based processes could be utilized to clarify and concentrate the anthocyanins extract. The research can provide a reference for non-thermal industrial production of clarified and concentrated natural bioactive compounds.