Effect of Digestive Enzyme Treatment on Antioxidant Properties of Germinated Green Gram Fortified with Minerals

The antioxidant activity (AA) of green gram germinated in mineralfortified water (with iron at 100 or 200 mg/100 mL or zinc at 50 or 100 mg/100 mL), cooked under pressure (PC), or microwaved and subjected to digestive enzyme treatment was determined by using three assay methods. Total AA showed that dehulled grains (DG) had higher AA than whole grains (WG). Cooking reduced the AA in both methods compared with raw grains with a lower percent retention of AA, although significant variations were not found between methods. The percent retention of AA in postdigestion samples was 22.68-51.39 (DG) and 15.67-44.0 (WG). Free radical scavenging activity indicated a different pattern, in which WG exhibited higher AA than DG and, among cooking methods, PC grains had higher activity. A reducing-power assay showed similar results: DG had lower and PC samples had higher AA. Postdigestion AA of WG was higher for cooked than raw samples, although DG showed the opposite trend. In all cases, samples fortified with iron showed less AA because of prooxidant action of iron. In all assays, postdigestion samples had less activity than predigested extracts. In conclusion, germinated grains showed high AA, influenced by the presence of minerals, dehulling process, and cooking.