Study on The Effect of Traditional Cooking of Leafy Vegetables on the Content of Vitamin C, Essential Minerals and Antioxidant Activity
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Date
2016-06
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Addis Ababa University
Abstract
Leafy vegetables are the fresh and edible portions of herbaceous plants which are important in nutrition, especially as a favorable influence on the functions of the physiology of human. This study was carried out to assess the content of vitamin c, mineral composition and total antioxidant activity of fresh and traditionally cooked LV which are commonly used as food in Ethiopia. Four leafy vegetables were subjected to nutrient analysis. The Vitamin C contents of raw LV ranged from 80.7mg/100g (Ye,abesha gomen) – 18.41mg/100g(Swiss chard) and the vitamin C content of traditionally cooked LV ranged from 24.616mg/100g-0.597mg/100g. Ye,abesha gomen(B.carinata) had a significantly (P ≤ 0.05) higher vitamin C content than all the tested samples and Swiss chard had the lowest vitamin C content. In raw LV the micronutrients including Fe and Zn were found to be in the range, 9.17-3.9(Fe) and 0.34-0.24(Zn) ppm respectively. The results of macronutrients obtained in raw LV having values of Ca (1.91-1.80.3ppm) and Mg (2.45-1.99 ppm). The results indicate that all these vegetables Ye,abesha gomen, Yeguragae gomen, Cabbage and Swiss chard have the potential to provide essential nutrients to the human beings. Traditional cooking of LV caused significant (P ≤ 0.05) reductions in the Ca, Zn, Fe and Mg contents and caused significant (P ≤ 0.05) losses of Vitamin C. The result of the study revealed that longer time of cooking (higher than 10 min) caused negative impact by reducing nutritive value. The registered losses at 10 min were as follow: ash (88.38– 82.0 %), minerals: Ca (1.88-1.66), Mg (2.32-1.84), Fe (8.87-3.76) and Zn (0.33-0.22) and vitamin C (24.616–1.44). Furthermore at 30 min, the residual contents of minerals were: calcium (1.83 – 1.49 ppm), magnesium (2.16 – 1.69 ppm), iron (8.36 – 3.09ppm) and zinc (0.29 – 0.19 ppm). Traditional cooking of LV for 30min significantly affect the total antioxidant activities (61.07±0.88-4.33±0.21) and vitamin C ( 16.03 ± 0.23-0.597±0.04 ) .All these results suggest that the recommended time of traditional cooking must be less than 10 min for the studied LV in order to contribute efficiently to the nutritional requirement and to the food security of Ethiopian population. Key words: Leafy vegetables; vitamins, mineral;, DPPH; traditional cooking
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Leafy vegetables; vitamins, mineral;, DPPH; traditional cooking