Submitted to: International Food Technology
Publication Type: Abstract Only
Publication Acceptance Date: December 15, 2005
Publication Date: May 15, 2006
Citation: Collins, J.K., Perkins Veazie, P.M., Arjmandi, B., Claypool, P., Clevidence, B.A. 2006. Antioxidants status of humans after intervention with watermelon or tomato juice [abstract]. International Food Technology. p. 215.
Watermelon and tomato have similar carotenoid compositions but differ in phenolic composition. In plant extract studies, both foods exhibited antioxidant activity as measured by the trolox antioxidant capacity (TEAC) assay. Increased antioxidant capacity of plasma as measured by ferric reducing ability of plasma (FRAP) and malondialdehyde formation products (MDA) was found with processed tomato diet intervention. No studies have been conducted to measure the antioxidant capacity of plasma following watermelon intervention. In this study, antioxidant status of middle-aged adults was assessed using a subset of subjects from a larger study designed to assess the bioavailabilty of lycopene from watermelon and tomato juice. Ten healthy men and women (50+/- 11 years) in a diet controlled clinical trial were supplemented with watermelon juice (20mg lycopene, 24mg total carotenoids/day), tomato juice (18.4mg lycopene, 22mg total carotenoids/day), and a control for three weeks in a crossover design. Plasma collected weekly was analyzed for the antioxidant biomarkers of MDA, plasma glutathione peroxidase (GPX) and FRAP. Data were analyzed using Proc Mixed Procedure and associations between antioxidant measures were identified by Pearson's product moment correlation analysis. Neither treatment intervention changed ex vivo antioxidant biomarkers compared to baseline or control. The results of MDA assay were positively correlated to FRAP assay (p=0.001, 0.474 correlation coefficient) with a linear relationship (r**2 =0.2321), while GPX was not correlated with either assay. Including watermelon or tomato juice in the diet of subjects did not affect plasma antioxidant status. However, the MDA and FRAP data were correlated and these assays may provide dual measurements for determining the antioxidant status in humans.