36E-21 |
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F. NUNEZ, Dept. of Food Science & Human Nutrition, University of Florida, 359 FSHN Bldg Newell Drive, Gainesville, FL 32611-0370 and S. T. Talcott, Dept. of Food Science & Human Nutrition, Univ. of Florida, 459-C FSHN Bldg., PO Box 110370, Gainesville, FL 32611-0370. Guava (Psidium guajava ) is an exotic tropical fruit considered an excellent source of nutrients, antioxidant phytochemicals, and especially ascorbic acid. Many tropical fruits have chemical or thermal quarantine requirements imposed on fresh commodities importation into the United States, but currently no regime has been established for guava in part due to its short shelf life and high incidence for fruit fly infestation. Furthermore, limited data exists on phytochemical composition and resultant changes during postharvest handling. These studies evaluated the effects of varying times of hot water (HW) immersion as a potential thermal quarantine treatment on phytochemical and antioxidant capacity of guava. Fruit (n=200) from a single harvest were manually segregated into three groups according to their ripeness level: Stage I (light green skin, firm), Stage II (20-50% yellow, firm), and Stage III (>75% yellow, soft). Guava from each stage were randomly selected and subjected to four HW immersion times (0 (control), 15, 30, and 60 min at 46°C) and held at 15°C until fully ripe, with Stage III fruit held two days after treatment. Chemical analyses included ascorbic acid, lycopene, yellow carotenoids, antioxidant capacity, total soluble phenolics, soluble solids, and pH. Ascorbic acid (867 mg/kg), yellow carotenoids (3.25 mg/kg), soluble solids (6.80 °Brix), and pH (4.10) were unaffected by the ripening stage in the control fruit while antioxidant capacity, soluble phenolics, and lycopene content decreased as ripening stage increased. Overall, HW treatment times insignificantly affected levels of AOX, soluble phenolics, lycopene, AA, soluble solids, pH, and yellow carotenoids when applied at each ripening stage. Results of this study demonstrated that HW quarantine treatments could be successfully applied to fresh guava without affecting its quality, phytochemical content and antioxidant capacity.
Session 36E, Fruit & Vegetable Products: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |