Flavor analysis of Hamlin and Valencia juice from greening (Huanglongbing) trees in 2009

Authors: Dea, Sharon; Plotto, Anne; VALIM, F - University Of Florida; ROUSEFF, RUSSELL - University Of Florida; Baldwin, Elizabeth - Liz; McCollum, Thomas; IREY, MIKE - Us Sugar Corporation

Submitted to: Subtropical Technology Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 10/18/2009
Publication Date: 10/22/2009
Citation: Dea, S., Plotto, A., Valim, F., Rouseff, R., Baldwin, E., Mccollum, T., Irey, M. 2009. Flavor analysis of 'Hamlin' and 'Valencia' juice from greening (Huanglongbing) trees in 2009. Subtropical Technology Conference Proceedings. 60:33-36.

Interpretive Summary:

Technical Abstract: Difference-from-control tests were run for “healthy” juice obtained from fruit harvested from 15 control non-Huanglongbing (HLB) symptomatic trees versus HLB juice from asymptomatic fruit harvested from 15 HLB-symptomatic trees within the same grove (~450 fruit for healthy and HLB). A trained panel was also used to evaluate the flavor of the above juice plus juice from symptomatic fruit (small, green, lopsided) harvested from HLB-symptomatic trees (a few trees, ~200 fruit). Fruit were juiced using a JBT 391 extractor and pasteurized under simulated commercial conditions (Microthermics HTST Model 25, 90 ºC/10 s). For Hamlin samples, harvested in February, the Brix ranged from 10.33 to 11.16, acid from 0.54% to 0.58 %, ratio from 19.1 to 21.1 and oil from 0.014% to 0.019 %. For the April Valencia samples, the Brix ranged from 11.9 to 12.5 , acid from 0.65% to 1.18 % (symptomatic HLB juice being highest), ratio from 10.1 to 18.6 and oil from 0.020% to 0.037 % (symptomatic fruit juice had the highest oil content). For the June Valencia samples, the Brix ranged from 10.6 to 12.2, acid from 0.50% to 0.58 %, ratio from 20.8 to 21.2 and oil from 0.014% to 0.028 % (highest for symptomatic fruit). For the Hamlin samples, there were no major differences in Brix, acid, ratio and oil content, but for Valencia fruit from the first harvest (April), the juice from symptomatic HLB fruit was high in acid and oil content compared to the controls, and the asymptomatic HLB fruit juice was in between symptomatic and control values. For the second Valencia harvest, the main difference was that the oil content was higher in asymptomatic and symptomatic fruit juice, possibly due the action of the extractor on fruit of smaller size. Juice samples were frozen for other chemical analyses (individual sugars and acids, vitamin C, limonin, nomilin and other secondary metabolites as well as aroma volatiles) for later analysis by HPLC and GC, and samples for gas chromatography-olfactometry (GC-O) work were prepared. Some of this data will be also be presented.