ARS | Publication request: Blueberry fruit response to postharvest application of ultraviolet radiation

Submitted to: Postharvest Biology and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 31, 2007
Publication Date: February 5, 2008
Citation: Perkins Veazie, P.M., Collins, J.K., Howard, L. 2008. Blueberry fruit response to postharvest application of ultraviolet radiation. Postharvest Biology and Technology. 47:280-285.

Interpretive Summary: Blueberry fruit contain many healthful compounds, some of which can be determined using total antioxidant tests. In addition, very few fungicides are permitted for use after fruit harvest to prevent postharvest decay. Ultraviolet light is used in food and health industries to sterilize surfaces and instruments, and has had some success in increasing shelf life of strawberries and tomatoes. Fruit of ‘Bluecrop’ and ‘Collins,’ two popular northern highbush blueberry varieties, were harvested and exposed to ultraviolet C radiation, applied at 0 to 4 kJ/m2 rates. Fruit were held for 7 days at 5 C then moved to 20 C for 2 days to simulate retail storage conditions. The incidence of ripe rot, a serious postharvest disease in blueberry, was reduced by 10 to 15%. Total antioxidants increased in response to storage and light treatment for ‘Bluecrop’ but had little effect for ‘Collins’. These results indicate that blueberry fruit can be treated with ultraviolet light without adverse effects, and ultraviolet light may help decrease postharvest ripe rot incidence

Technical Abstract: Blueberries (Vaccinium corymbosum, cvs. Collins, Bluecrop) were exposed to UV-C radiation treatments from 0 to 4 kJ/m2 prior to 7 days storage at 5 C plus 2 days at 20 C, 90% RH. Weight loss and firmness were not affected by light treatment. Decay incidence from ripe rot (Collectotrichum acutatum, syn. C. gloesporides Penz) on fruit was decreased by 10 % with 1 to 4 kJ/m**2 UVC light treatments. Antioxidants as measured by total anthocyanin, total phenolics, and FRAP were higher in Collins fruit given 0 or 1 kJ/m2 UVC compared to unstored fruit. In Bluecrop, antioxidant values increased with treatment intensity, with highest values seen in fruit given 4 kJ/m**2 UVC. ORAC values were not affected by radiation treatment or storage in either blueberry cultivar. These results indicate that postharvest application of UVC radiation can decrease decay caused by ripe rot in blueberries and may enhance antioxidant level.