Submitted to: North Carolina Vegetable Growers Association Yearbook
Publication Type: Proceedings
Publication Acceptance Date: November 18, 2012
Publication Date: November 27, 2012
Citation: Farnham, M.W. 2012. What makes those collard, turnip and mustard greens so good for you? North Carolina Vegetable Growers Association 2012 Yearbook. p. 53. Technical Abstract: Collard, turnip, and mustard greens are economically important leafy-green vegetables grown throughout the United States that are especially important in the South. These cruciferous vegetables are known to be rich sources of numerous vitamins and other important nutritional components, but formal reports describing leaf concentrations of such components in field-grown plants are lacking. With this in mind, we conducted field and laboratory studies to determine the general makeup of important vitamins and other nutritional components including vitamin C, vitamin K, folic acid, proVitamin A, and lutein, in field harvested leaves. We also ran tests to discern the relative effects played by the vegetable variety and the leaf age when sampling plants. On a 100 g fresh weight basis, dry weight (14.7 g versus 13.2 g), total vitamin C (132.7 mg versus 109.1 mg), folate (183 'g versus 112 'g) and lutein (9790 'g versus 8950 'g) concentrations were significantly higher in younger versus older leaves. Vitamin K (435 'g versus 459 'g) and proVitamin A (11,130 'g versus 11,619 'g) were equally concentrated in younger and older leaves. All vitamins were found to be highly concentrated in leaves of all nineteen leafy-green crucifer varieties with particular varieties within each crop group having exceptionally high concentrations. Thus, the results indicate that collard, turnip, and mustard greens are exceptionally rich sources of all the vitamins assayed. This research provides a more accurate estimation than previously available of the amount of particular vitamins that consumers may derive in their diet when eating these nutritious vegetables. Results also reveal potential differences that might be exploited in genetic improvement through plant selection and breeding.