Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/12/2005
Publication Date: 9/14/2005
Citation: Fan, X., Sokorai, K.J. 2005. Ionizing irradiation increases antioxidant capacity and phenolic content of fresh-cut vegetables. IFT/EFFoST Nonthermal Processing Division Workshop, September 15-16, 2005, ERRC, Wyndmoor, PA. Abstract #3, p. 80.
Technical Abstract: Ionizing radiation inactivates foodborne pathogens, improves hygiene quality and extends shelf-life of many fresh fruits and vegetables. Fresh fruits and vegetables are rich in antioxidants which exhibit properties that prevent cancer and reduce mortality due to cancer and heart diseases. The impact of ionizing radiation on the antioxidant capacity of fresh fruits and vegetables is unclear. Therefore, this study was conducted to investigate irradiation-induced changes in antioxidant capacity of three common salad green vegetables. Midrib and non-midrib leaf tissues of Romaine and Iceberg lettuce and endive were irradiated with gamma rays at 0, 0.5, 1, and 2 kGy, and then stored at 7-8 C for 8 days. Antioxidant capacity and phenolic content of tissues as well as tissue browning were analyzed at 1, 4 and 8 days of storage. In general, irradiation increased phenolic content and antioxidant capacity of both tissue types of all three vegetables at day 4 and day 8. The rates of the increase were higher in midrib tissues than in non-midrib tissue, and increased with storage time and radiation doses. Irradiation at 0.5 kGy or above, however, increased tissue browning of Iceberg lettuce. Currently, a maximum dose of 1 kGy has been approved by the U.S. authority for use of ionizing radiation on fresh fruits and vegetables. At 1 kGy, antioxidant capacity was increased by at least 14% in lettuce and endive after 8 days of post-irradiation storage. Our results suggest that irradiation increased nutritional quality of vegetables in addition to the well- known benefit of improving microbial food safety.