Effect of early detection Huanglongbing on juice flavor and chemistry

Authors: Plotto, Anne; Baldwin, Elizabeth - Liz; McCollum, Thomas; Narciso, Jan; IREY, MIKE - UNITED STATES SUGAR CORP

Submitted to: Proceedings of Florida State Horticultural Society
Publication Type: Proceedings
Publication Acceptance Date: 11/19/2008
Publication Date: 4/1/2009
Citation: Plotto, A., Baldwin, E.A., Mccollum, T.G., Narciso, J.A., Irey, M. 2008. Effect of early detection Huanglongbing on juice flavor and chemistry. Proceedings of Florida State Horticultural Society. 121:265-269.

Interpretive Summary: Huanglongbing (HLB) is an emerging disease that is affecting Florida citrus industry. Anecdotal reports mention that trees affected with the disease produce fruit that impart off-flavor to the juice made of that fruit. In this experiment, juice made with fruit from trees affected with HLB at an early stage were tested against juice made with fruit from healthy trees. Panelists could perceive a difference between the two juices most of the time. Juice from HLB-affected trees tended to be sweeter than the control.

Technical Abstract: When Huanglongbing (HLB) was first discovered in Florida, trees with early symptoms of disease were harvested to determine whether there was any flavor difference between juice made from infected trees but with asymptomatic fruit, and fruit harvested from healthy trees. It is of interest to the processing industry to determine what affect fruit from trees of various stages of infection would have on processed orange juice quality. Valencia oranges were harvested in 2006 from HLB-positive trees in the early stages of disease development (HLB fruit), and compared to fruit from healthy trees. A consumer panel did not perceive differences for juice taste or smell between healthy and HLB fruit in a triangle test. An experienced panel, however, did perceive that juice from HLB fruit was sweeter than juice from non-HLB fruit. Further tests were performed by using the "difference-from-control" test with filtered or unfiltered juice, to determine the effect of pulp on difference perception. When juice was filtered, panelists could perceive a difference by smell and by taste; when juice was served unfiltered they could only perceive a difference by taste. One of the descriptors that came up frequently for the HLB filtered juice for taste difference was again "sweeter". Chemical analyses showed that the juice from HLB fruit was higher in Brix/acid ratio than from juice from non-HLB fruit which is in agreement with the "sweeter" perception. No consistent differences in aroma volatiles between juice of HLB and non-HLB fruit were observed.