VITAMIN AND PROVITAMIN PROFILES OF SELECTED VEGETABLES AS AFFECTED BY DIFFERENT DRYING METHODS

Abstract

The vitamin profiles of selected common vegetables as affected by three different drying methods were investigated. Seven vegetables were each subjected to three drying methods: air drying, oven drying and freeze drying. The experiment was a 3x7 factorial arrangement in a completely randomized design. Dried leaves were thereafter milled and analyzed for selected phytochemical contents (total carotenoids, pyridoxine, riboflavin, ascorbic acid, tocopherol and ergocalciferol). Air dried sample had significantly higher (P<0.05) total carotenoids (1177.49 μg/100g), pyridoxine (0.588 mg/100g), riboflavin (0.455 mg/100g), ascorbic acid (39.114 mg/100g), ergocalciferol (46.554 μg/100g) and tocopherol (57.522 μg/100g) compared with other drying methods. Air dried moringa had significantly higher (P<0.05) total carotenoids (1079.482 μg/100g), riboflavin (0.412 mg/100g), ergocalciferol (46.397 μg/100g) and tocopherol (58.445 μg/100g) while air dried gourd melon had the higher (P<0.05) pyridoxine (0.732 mg/100g). Interaction of drying methods on leaf types was significantly higher (P<0.05) for air dried samples compared to other drying methods. In conclusion, vitamin and provitamin profiles were most preserved by air drying method.