3.7. Extraction of alcohol from grape wine and natural colorant extract
In order to extract the alcohol from the real systems, alcohol
was removed from the grape wine (14.5% alcohol) and anthocyanin
extract (15% alcohol) by employing liquid emulsion membranes
composed of hexane as membrane phase for repeated extraction.
The extraction was performed using optimum conditions for maximum
alcohol extraction such as surfactant concentration 2%,
membrane phase (hexane) concentration 98%, ratio of emulsion
to feed 1:1, ratio of volume of inner aqueous to membrane phase
3:1, stirring time 20 min, stirring speed 200 rpm. Multistage
extraction involved reusing the treated feed each time with fresh
emulsion. Multistage extraction involving liquid emulsion membrane
was found to remove 92.9% alcohol from grape wine in 4-
stages (Fig. 8).
During extraction of anthocyanin from red cabbage, banana
bract and betalins (Betacyanin and Betaxanthin) from beet root,
all the extracts contained alcohol of the order 15% and color concentrations
as mentioned:anthocyanin, 102.5 mg/l in red cabbage,
84.32 mg/l in banana bract solution and 41.43 mg/l betacyanin and
29 mg/l betaxanthin in beetroot. Fig. 9a indicates that more than
90% alcohol was removed after four stages of liquid membrane
extraction, which also resulted in a corresponding loss of anthocyanin
and betalins, shown in Fig. 9b.