title: Effect of liberibacter infection (huanglongbing disease) of citrus on orange fruit physiology and fruit/fruit juice quality: chemical and physical analyses.
abstract: More than 90% of oranges in Florida are processed, and since Huanglongbing (HLB) disease has been rumored to affect fruit flavor, chemical and physical analyses were conducted on fruit and juice from healthy (Las -) and diseased (Las +) trees on three juice processing varieties over two seasons, and in some cases several harvests. Fruit, both asymptomatic and symptomatic for the disease, were used, and fresh squeezed and processed/pasteurized juices were evaluated. Fruit and juice characteristics measured included color, size, solids, acids, sugars, aroma volatiles, ascorbic acid, secondary metabolites, pectin, pectin-demethylating enzymes, and juice cloud. Results showed that asymptomatic fruit from symptomatic trees were similar to healthy fruit for many of the quality factors measured, but that juice from asymptomatic and especially symptomatic fruits were often higher in the bitter compounds limonin and nomilin. However, values were generally below reported taste threshold levels, and only symptomatic fruit seemed likely to cause flavor problems. There was variation due to harvest date, which was often greater than that due to disease. It is likely that the detrimental flavor attributes of symptomatic fruit (which often drop off the tree) will be largely diluted in commercial juice blends that include juice from fruit of several varieties, locations, and seasons.
authors.affiliation: United States Department of Agriculture, USDA-ARS Citrus & Subtropical Products Laboratory, South Atlantic Area, Agricultural Research Service, Winter Haven, Florida 33881, USA. Liz.Baldwin@ars.usda.gov
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Baldwin
authors.forename: Anne
authors.initials: A
authors.lastname: Plotto
authors.forename: John
authors.initials: J
authors.lastname: Manthey
authors.forename: Greg
authors.initials: G
authors.lastname: McCollum
authors.forename: Jinhe
authors.initials: J
authors.lastname: Bai
authors.forename: Mike
authors.initials: M
authors.lastname: Irey
authors.forename: Randall
authors.initials: R
authors.lastname: Cameron
authors.forename: Gary
authors.initials: G
authors.lastname: Luzio
mesh_terms: D001628:Beverages / Q000032:analysis*; D032084:Citrus sinensis / Q000737:chemistry* / Q000502:physiology; D005431:Florida; D005638:Fruit / Q000737:chemistry / Q000502:physiology; D010935:Plant Diseases / Q000382:microbiology*; D012230:Rhizobiaceae / Q000502:physiology*; D012621:Seasons