Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 24, 2009
Publication Date: April 9, 2009
Citation: Sun, T., Simon, P.W., Tanumihardjo, S.A. 2009. Antioxidants and Antioxidant Capacity of Biofortified Carrots (Daucus Carota, L.) of Various Colors. Journal of Agricultural and Food Chemistry. 57(10):4142-4147.
Interpretive Summary: Antioxidants are naturally-occurring chemicals in many foods, especially fruits and vegetables. Foods rich in antioxidants help protect from disease attack and they slow the aging process. Natural pigments in foods have a particularly high antioxidant capacity. In this research we evaluated carrots rich in purple anthocyanin pigments, orange, yellow, and red carotenoid pigments, both classes of pigments, and neither one. We found that purple anthocyanin pigments and to a lesser extent, carotenoids, have a high antioxidant capacity. This research is of interests to nutritionists, food scientists and biochemists interested in nutritional qualities of foods; to carrot researchers and growers interested in ways to improve carrots, and carrot products; and to consumers interested in a healthy diet.
Antioxidants and antioxidant capacity of seven colored carrots were determined. Five anthocyanins, chlorogenic acid, caffeic acid, and four carotenoids, were quantified by HPLC. Total phenolic content was determined by the Folin-Ciocalteau method. Antioxidant capacities of the hydrophilic and hydrophobic fractions were determined by the 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2'-diphenyl-1-picrylhydrazyl (DPPH) methods. The relative antioxidant capacity index was determined. Anthocyanins were the major antioxidants in purple-white and purple-orange carrots and chlorogenic acid was a major antioxidant in all carrots. Carotenoids did not contribute to total antioxidant capacity, but correlated with antioxidant capacity of hydrophobic extracts. Both the DPPH and ABTS assays showed that the hydrophilic extract had higher antioxidant capacity (99.9% of total antioxidant capacity) than the hydrophobic extract. Purple-white had the highest antioxidant capacity, followed by purple-orange, and the other carrots did not differ. This information is useful for consumers and may help horticulturists develop carrots with higher antioxidant capacity.