Comparative Study between the Bioactive Compounds and Antioxidant Activity of Broccoli and Cauliflower and the Effect of Domestic Processing on Them

Abstract

This study was performed to determine and compare the contents of some bioactive compounds of broccoli (Brassica oleacea var italica) and cauliflower (Brassica oleracea var. botrytis ) as well as their antioxidant activities. Also, the effect of several domesting processing methods (blanching in hot water, steaming and microwave) on the studied bioactive contents was investigated. Data of study confirmed that fresh broccoli had higher amounts of β- carotene, vitamin A and vitamin C, total polyphenolic compounds, folic acid and glucosinolates than those of fresh cauliflower. Broccoli and cauliflower contained 4952.93, 1633.18µg/g, 8254.88, 2721.96IU/100g,869.34,575.84mg/100g, and1105.00,633.00mg/100g of β- carotene, vitamin A, ascorbic acid and total polyphenols on dry weight basis, respectively. Antioxidant activity of fresh broccoli (70.29%) was higher than that in fresh cauliflower (40.89%). More over fresh broccoli contained higher amount of glucosinolates, being 12.29 µM/g comparing with those of fresh cauliflower which were10.36 µM/g (on dry weight). Fresh broccoli contained higher amount of folic acid than that of the cauliflower. Folic acid content was 3033.75 µg/100g in fresh broccoli and it was 2168.52 µg/100g in fresh cauliflower ( on dry weight). Steaming method caused the lowest reduction in all studied bioactive components in both broccoli and cauliflower,meanwhile blanching in boiled water caused the higher reduction in them .The studies of chlorophyll and its derivatives content showed that fresh broccoli contained high amounts of total chlorophyll being 1102.4 mg/100g with 496.8 and 605.4 mg/100g (on dry weight basis) for chlorophyll a, b, respectively, a significant reduction in total chlorophyll and chlorophyll a and b was recorded as a result of processing. Steamed method led to the lowest reduction in them among the three processing methods, while chlorophyll was not detected in cauliflower samples.