Broccoli is a member of the brassica family. It is usually green in colour and has flowery heads on a thick stalk. Its name comes from the Italian word 'brocco', meaning arm or branch. Broccoli is available year round. When selecting broccoli look for fresh, bright-green heads which have compact clusters of tightly closed florets. Stalks and stem leaves should be tender yet firm. Frozen broccoli is a also a great option as it is pre-cut and can be stored for longer.
Nutrition information
Broccoli contains the antioxidant vitamins beta-carotene, vitamin C, vitamin E and folate. It also contains fibre, iron and potassium. Broccoli is a source of glucosinolates, compounds which when eaten may have benefits for health.
What are glucosinolates?
Glucosinolates are primarily found in brassica vegetables (e.g. broccoli cabbage, cauliflower and brussels sprouts). Glucosinolates are responsible for the characteristic bitter flavours of these vegetables. More than 90 different glucosinolates are known. Studies have shown positive health effects for the intake of brassica vegetables in terms of decreased risk for cancers of the lung, stomach, colon and rectum (1). A type of glucosinolate known as isothiocyanates have been shown to have the most potential in reducing risk of developing tumours.
Cooking effects
Preparation, cooking and digestion of vegetables causes the breakdown of glucosinolates. The amount of glucosinolates in broccoli and other vegetables varies greatly depending on the degree of processing (chopping, cooking or heat treatment) and storage conditions. Cooking reduces glucosinolate levels by 30-60%(2). Like most vegetables, it is best to cook broccoli in minimal amounts of water (e.g. steam) to maximise nutrient retention.
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1. Verkerk, R. (2001) J Science of Food and Agriculture, 81, 953.
2. Mithen, R. et al. (2000) J Science of Food and Agriculture, 80, 967-84.
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