Submitted to: Food Research International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/18/2004
Publication Date: 1/19/2005
Citation: Tadmor, Y., King, S., Levi, A., Davis, A.R., Meir, A., Wasserman, B., Hirschberg, J., Lewinsohn, E. 2005. Comparative fruit coloration in watermelon and tomato. Food Research International. 38:837-843.
Interpretive Summary: Watermelon is a principle vegetable crop grown in 44 states in the U.S. In recent years, there is an increased demand for watermelon, and a great interest in watermelon nutritional value. Recently, researchers reported that watermelon contains high levels of naturally occurring pigments called carotenoids. They are known to be a main dietary source of vitamin A in humans, and are associated with reduced risk of several chronic health disorders including some forms of cancer, heart disease and eye degeneration. There is insufficient information about carotenoid levels in watermelon. This study examines the levels of different carotenoids in watermelon and compares them with those found in the tomato, a fruit which is considered to have health promoting activity. This study showed that, like the tomato, watermelon contains high levels of the carotenoids 'lycopene' and 'beta-carotene', and low levels of the carotenoids 'phytoene', 'phytofluene', zeta-carotene', and 'pro-lycopene'. The results in this study are useful for further improvement of carotenoid content in watermelon varieties.
Technical Abstract: The characteristic red pigmentation of watermelon and tomato fruits is determined by accumulation of the carotenoid pigment lycopene and this phenotype is polyphyletic. Since several carotenoids are known to have health promoting activity, and watermelon can be a significant source of lycopene and other carotenoids, it is important to understand the genetic basis of watermelon fruit-specific carotenoid biosynthesis. Unlike tomato, very little is known about the regulation of carotenoid biosynthesis during fruit development in watermelon, a non-climacteric fruit. We have HPLC analyzed the carotenoids of red, yellow and orange watermelons and compared their carotenoid patterns with those of known fruit colour mutants of tomato. Interestingly, we could detect tomato mutant equivalents to most watermelon fruit colour phenotypes, including r, og, B and t.