Carotenoid content and characteristic profile of Zimbabwean Brassica oleracea green vegetables (645.3)

Abstract

Green vegetables of the brassica oleracea family are an important part of Zimbabwean diet, consumed daily as casseroles together with the maize based staple food. These green vegetables are rich in carotenoids such as lutein and β‐carotene which are important for macula health and as precursors of vitamin A. In this study five different brassica oleracea vegetable commonly grown and consumed in Zimbabwe where identified as chou mollier, covo, rugare, viscose and drum head cabbage. The green leafy vegetables were cut into pieces and ground into a puree; the carotenoids were extracted with methanol and tetrahydrofuran (THF). The carotenoid contents and profile were compared to kale grown and consumed in the US. Statistical Analysis was conducted with SAS (SAS Inc., NC) using descriptive statistics and ANOVA. All brassica oleracea vegetables analyzed contained lutein, trans β‐carotene and 9 cis β‐carotene with the contents being significantly different among the 6 varieties. Kale grown in the USA had the highest content of lutein (12.5 ±1.3) and β‐carotene (8.5 ±0.8) mg/100g fresh weight respectively. Among the Zimbabwean green vegetables covo variety had the highest contents of lutein (10.4±0.5) and β‐carotene (7.8±0.4) mg/100g fresh weight. rugare (5.2 ±0.3) and cabbage (6.0 ±0.2) mg/100g fresh weight had the lowest trans β‐carotene content. Zimbabwe green vegetable had a 13 cis β‐carotene isomer as opposed to the US kale. Zimbabwe Viscose variety also had phytene and phytophlene carotenoid compounds. The Zimbabwean brassica oleracia vegetable are a very good source of provitamin A carotenoids and lutein. The provitamin A carotenoids content is sufficient enough to justify the promotion of these vegetables as part of a diet to combat vitamin A deficiency which is a public health problem in Zimbabwe. Funding support from International Atomic Agency and USDA Financial support USDA contract #58‐1950‐0‐014Grant Funding Source: Supported by USDA #58‐1950‐0‐014: IAEA