Carotenoids in Watermelon and Mango

Carotenoids, which impart yellow, orange, and/or red colors to many fruits, have antioxidant health properties. A series of experiments were undertaken to establish horticultural relationships to carotenoids in watermelon and mango in cooperation with U.S. commodity boards. Watermelon was assayed to determine effects of germplasm, storage temperature, and fresh cut on lycopene and beta carotene content. Seedless watermelons were generally highest in lycopene and storage at 21°C increased both lycopene and beta carotene contents. Fresh cut watermelon lost about 6% of carotenoids, probably through oxidation of cut surfaces. Mangos of the five major varieties imported over a 12 month period into the U.S. from Peru, Mexico, Brazil, and Ecuador were ripened at 20-25°C and assayed for beta carotene and vitamin C content. Beta carotene content (mg/kg fwt) averaged 5.0, 7.0, 10.4, 16.8, and 26.1 for 'Tommy Atkins', 'Haden', 'Keitt', 'Kent', and 'Ataulfo', respectively. Total vitamin C (mg/100 g fwt) was 19.2 ('Tommy Atkins') to 126.4 ('Ataulfo'). Results of our experiments show that U.S. watermelons are a rich source of lycopene while mangos imported into the U.S. offer consumers a new natural source of beta carotene and vitamin C. INTRODUCTION Carotenoids comprise the colorful pigments of many fruits. Some of these, such as beta carotene, alpha carotene, and beta cryptoxanthin, are precursors of vitamin A. Vitamin A is needed for eyesight and nerve health. Lycopene, which imparts a red color in tomatoes, red grapefruit, guava, and watermelon, is not a vitamin A precursor but has received much scientific interest due to its strong antioxidant properties (Collins et at., 2006). A series of experiments were conducted from 1999 to 2006 on watermelon to determine the relative amounts of lycopene and beta carotene among types (seeded, seedless), cultivars, ripeness stages, and changes with storage of whole or fresh cut watermelons. Mango fruit are a recent introduction to the U.S. marketplace. Unlike many U.S. commodities, there is little consumer knowledge about the nutrient content of the fruit. Five mango varieties make up the majority of available fruit in supermarkets and almost all mangos are imported to the U.S. from Mexico, South America, and the Caribbean Basin. A comparison of beta carotene and vitamin C, the major nutrients found in mango, was conducted over a year to determine relative amounts among varieties and fruit