ABSTRACT

Non leafy vegetables occupy an important place among food crops as they provide adequate amounts of vitamins and minerals for humans. It is well known that cooking alters the nutritional value of fresh vegetables. Several studies have focused on how cooking changes the nutritional components and phytochemical content of vegetables, few have investigated the true retention of vitamins following exposure to different cooking methods. The study aims to determine the effect of different cooking methods on the content of vitamins and true retention in selected non leafy vegetables by Processing and preparing vegetables through different cooking method such as boiling, steaming, blanching and microwaving, determine effects of the different cooking methods on the vitamin content of the vegetable and evaluating the true retention of the nutrients on the vegetables using the retention ratio. This study adopted an experimental study design to determine the vitamin and mineral content of non-leafy vegetable. One way analysis of variance (ANOVA) was carried out using the IBM Statistical Product of Service Solution (SPSS) version 22.0 to compare between the mean values while treatment means was separated using Duncan multiple range test at 95 % confidence level (P<0.05). Among the raw sample, Sample RA4 (Raw okra) has the highest concentration of Vitamin C at 32.47 mg/g, while RA6 (Raw sweet potato) has the lowest at 13.61 mg/g. Among the raw samples, Sample RA6 has the highest concentration of Calcium at 108.55 mg/g, while RA4 has the lowest at 73.77 mg/g. When compared with the raw samples, the result shows that B101, blanched carrot sample contain almost the same amount of beta-carotene as the raw sample of carrot, the nutrient retention of the steamed samples. There is low retention of vitamin B1 and magnesium in steamed carrots whereas it has a higher retention of vitamin A, vitamin C and calcium. The nutrient retention of the microwaved samples. The microwaved carrot and okra showed a higher retention of Vitamin B, vitamin C, and vitamin A but there was a lowered retention of the minerals, calcium and magnesium. This study should be recommended to processing industries and factories on the proper cooking method for different vegetables and also be recommended to household on the adequate and cooking method to be used for different vegetables.