44C-16 |
Lycopene stability in stored and cut watermelon |
J. K. COLLINS, USDA-ARS-SCARL, Hwy 3 west, Lane, OK 74555 and P. Perkins-Veazie. Lycopene is a carotenoid pigment with strong antioxidant properties. Lycopene is found naturally only in plants and algae. Lycopene is easily oxidized by light while heating stabilizes lycopene. Watermelon provides a high amount of lycopene per serving (12-15 mg) but is consumed almost exclusively as a fresh product. Fruit are usually picked slightly under maximum ripeness but often are held at the retail level for several weeks. The stability of lycopene following storage of whole melons, or cutting watermelon for prepackaged consumption, is not known. The objective was to determine total lycopene content and carotenoid profiles of whole watermelon stored for two weeks or cut watermelon stored for 2 or 7 days. ‘Summer Flavor 800 (seeded) and ‘Summer Sweet 5244 (seedless) uncut watermelons were stored at 13 and 5 oC for 2 weeks. Additional melons of these varieties were aseptically cut into 5 cm3cubes, placed in storage containers, and held 2 or 7 days at 2 and 5 oC. Total lycopene content was analzyed spectrophotometrically at 503 nm by extracting tissue with a 2:1:1 mixture of hexane:acetone:ethanol and 0.05% BHT. Carotenoid profiles were determined using HPLC techniques and a Varian Microsorb MVC-18 250 x 4.6 mm (5 µm) column. Stored uncut melons lost 6-10% in lycopene content (80 to 74 µg/g) compared to freshly harvested fruit. Losses were similar between seeded and seedless varieties and between storage temperatures. The lycopene content of cut watermelons was reduced 6 to 15% after storage, but did not differ between storage temperatures or days of storage. Carotenoid profiles from cut and uncut melons will be discussed. These results indicate that total lycopene content is relatively stable in watermelon in both cut and uncut fruit.
Session 44C, Fruit & Vegetable Products: Chemistry
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