Submitted to: Proceedings of Florida State Horticultural Society
Publication Type: Proceedings
Publication Acceptance Date: 12/20/2005
Publication Date: 2/1/2006
Citation: Ismail, M.A., Chen, H., Baldwin, E.A., Plotto, A. 2005. Changes in enzyme-assisted peeling efficiency and quality of fresh ‘Valencia’ orange and of stored ‘Valencia’ orange and ‘Ruby Red’ grapefruit. Proceedings of Florida State Horticultural Society. 118:403-405. Interpretive Summary: Peeling of citrus fruit using food-grade enzymes creates a healthy ready-to-eat product that is ideal for school lunch programs, airline cuisine, or a healthy snack. Optimizing the enzyme peeling process is important for a consistent high quality product. This study analyzed the peelability of oranges and grapefruit over the harvest season and after storage. Also analyzed were the effects of storage on flavor of the peeled citrus segments.
Technical Abstract: ‘Valencia’ oranges were harvested at three-week intervals, beginning on February 11 and ending on June 17, 2002. Fruit were peeled after infusion with 0.25% to 0.50% Peelzyme using an automated citrus peeling machine developed by the Florida Department of Citrus. Greater than 50% peeling efficiency was achieved in fruit harvested in March and May, compared to 11% in February, 30% in April and 45% in June. Flesh firmness remained high throughout the harvest season but declined slightly during storage at 2.8 °C for 14 days. A slight increase in total soluble solids was measured accompanied by a steady decline in percent citric acid equivalents, resulting in a sharp increase in the °Brix to acid ratio in April, May and June. Organoleptic evaluation of sectioned fruit was conducted after 1, 7, and 14-day storage at 2.8 °C using approximately 20 trained taste panelists. Storage time had little effect on flavor scores of sections prepared from fruit harvested in February, March and April, but declined in May and June. ‘Valencia’ orange and ‘Ruby Red’ grapefruit, stored up to twelve weeks, were effectively peeled, however peeling efficiency declined after 15 weeks or storage.