Integrated membrane process for the concentration of anthocyanin

Abstract

Many natural colorants, which have been extracted from plant/vegetable sources, have more than 90% water in addition to the low tinctorial strength. Membrane technologies offer the potential of pigment concentration. In view of this, an attempt has been made to concentrate anthocyanin, a natural red colorant from red radish using integrated membrane process, which involves ultrafiltration (UF), reverse osmosis (RO) and osmotic membrane distillation (OMD). The effect of anthocyanin concentration on water flux in each process was studied. Comparison of UF, RO and OMD was made when they are operated individually and in combination with each other. It was observed that, the integrated membrane processes have the advantages of achieving higher concentration of anthocyanin compared to that of the individual membrane processes. Final concentration of 26 °B (from 1 °B) was achieved; which resulted an increase in the concentration of anthocyanin from 40 mg/100 ml to 980 mg/100 ml.