ARS | Publication request: OPTIMIZING THE USE OF HYDROLYTIC ENZYMES TO FACILITATE PEELING OF CITRUS FRUIT

Submitted to: Proceedings of Florida State Horticultural Society
Publication Type: Proceedings
Publication Acceptance Date: December 20, 2005
Publication Date: February 1, 2006
Citation: Ismail, M.A., Chen, H., Baldwin, E.A., Plotto, A. 2005. Optimizing the use of hydrolytic enzymes to facilitate peeling of citrus fruit. Proceedings of Florida State Horticultural Society. 118:400-402.

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 treatment of citrus fruits with different food-grade commercial enzymes, accompanied by hot water dips for the most efficient peeling of both oranges and grapefruit. It was found that grapefruit require less enzyme and that hot water incubation was helpful.

Technical Abstract: Seven commercially produced enzyme preparations were tested for their effectiveness in facilitating the peeling of Florida oranges and grapefruit. An automated citrus peeling machine, developed by the Florida Department of Citrus, was used to objectively assess peeling efficiency. Four enzyme preparations were very effective, achieving nearly 100% peel removal. Fruit were infused with 0.25% or 0.50% enzyme solution and incubated in water heated to 43 °C or 49 °C for 30 minutes. Incubation in 43 °C was more effective than 49 °C water. Incubation in water was also more effective in facilitating peel removal than incubation in heated air, especially for ‘Valencia’ oranges. Air incubation produced firmer fruit compared to water incubation. A treatment protocol was developed to achieve maximum peeling efficiency, product safety and quality.