Separation and Concentration of Anthocyanins from Jamun: An Integrated Process

Abstract

Aqueous two-phase extraction (ATPE) was employed to separate sugars from the extract of jamun anthocyanins. Polyethylene glycol (PEG) 6000/magnesium sulfate (16.0/10.9%, w/w) was found to be the most suitable system for effective differential partitioning of anthocyanins and sugars during ATPE. Tie line length of 34.26% and volume ratio of 0.76 resulted in maximum partitioning of anthocyanins to the PEG-rich (top) phase (yield ∼100.0%) and sugars to the salt-rich (bottom) phase (yield—72.9%). Multistage ATPE resulted in an increase in removal of sugars (by about 96.1%) with 91.9% yield of anthocyanins in the PEG-rich (top) phase. The phase forming polymer (PEG 6000) was successfully separated from anthocyanins employing organic-aqueous extraction. Integration of ATPE with membrane processes such as osmotic membrane distillation (OMD) and forward osmosis (FO) resulted in an increase in concentration of anthocyanins from 430.1 mg/L (7.8° Brix) to 790.3 mg/L (21° Brix) and 2890.3 mg/L (40° Brix), respectively. Evaluation of colorant properties confirmed that the anthocyanins extracted and concentrated employing ATPE followed by membrane processes (FO and OMD) are stable.