2.3. Preparation of oleoresin
Ginger powder (20 g), both control and enzyme-treated, were taken individually in different glass columns with a height to diameter ratio of about 5:1 and extracted with two solvents viz., ethanol and acetone. Solvent (30 ml) was first added to wet the bed, followed by another batch of solvent (30 ml). After 30 min, extract (20 ml) was collected and fresh solvent (20 ml) was added. The extraction was repeated at an interval of 30 min and a total of 8 extracts were collected. Totally, 160 ml of solvent was used for the extraction of oleoresin from powdered ginger samples. The extracts were pooled and transferred to a dried and pre-weighed round-bottomed flask and the solvent was evaporated using a rotary flash evaporator. After complete removal of solvent, the flask was weighed. Resin yield was expressed on weight of ginger on dry weight basis.