Effect of drying procedures on nutritional composition, bioactive compounds and antioxidant activity of wheatgrass...

Fresh wheatgrass was dried using shade, oven and freeze drying methods. The ascorbic acid and β-carotene and content of oven dried wheatgrass was significantly lower (133.13 µg and 1.98 mg) in comparison to shade dried (193.62 µg and 2.30 mg) and freeze dried (230.35 µg and 3.18 mg) wheatgrass. A significantly lower iron and zinc was observed in freeze dried (13.19 and 6.55 mg) wheatgrass in comparison to shade dried (28.94 and 7.40 mg) and oven dried (19.65 and 8.35 mg) wheatgrass. The chlorophyll in freeze dried (3.61 g) wheatgrass was significantly higher than shade dried (2.35 g) and oven dried (2.14 g) wheatgrass. The tannin content in wheatgrass was significantly higher in oven dried wheatgrass (8.18 mg/100 g) as compared to shade dried (6.68 mg/100 g) and freeze dried (6.34 mg/100 g) wheatgrass. The antioxidant activity of shade, oven and freeze dried wheatgrass was 50.13, 48.94 and 53.78%, respectively. The study concluded that freeze drying had preserved maximum amounts of chlorophyll, flavonoids, saponins and antioxidant activity in wheatgrass.