Antioxidant activity in commonly grown and consumed vegetables: a screening survey

A diet rich in fruits and vegetables is associated with a reduced risk of developing cardiovascular diseases and certain types of cancer. This positive effect is related to bioactive phytochemicals found in plants. The vegetables were grown in the field or in greenhouses at the Norwegian University of Life Sciences (59 degrees 40'N) during the years 2000-2002. The vegetables were harvested at commercial maturity and analysed for dry matter and antioxidant activity assessed by the FRAP (Ferric Reducing Ability of Plasma) assay. There was a large variation in antioxidant activity both between and within different species. The highest antioxidant activity was observed in kale, red cultivars of cabbage and table beet. The lowest antioxidant activity was observed in lettuce, cucumber, carrots and tomato. The vegetables possessing a red colour showed higher antioxidant activity with the exception of carrots and tomatoes.