Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/28/2011
Publication Date: N/A
Technical Abstract: As a preliminary step to understand and characterize which metabolites are responsible for the bitter off-favor of Huanglongbing infected fruit, the thresholds of limonin, nomilin, and their combination in a sugar and acid matrix, as well as in healthy ‘Valencia’ orange juice were determined by taste panels. Food grade limonin and nomilin were added alone or in combination to a simple (sucrose and citric acid) or complex (sucrose, glucose, fructose, citric and malic acid) matrix, or were added directly into orange juice. Thresholds were determined by 18 to 23 trained panelists using a three-alternative forced choice method (ASTM: E-679). In the simple matrix, the threshold of limonin was lower than nomilin. The synergetic effect of limonin and nomilin was significant in decreasing their individual thresholds. Interestingly, the thresholds of limonin and nomilin were lower in orange juice compared to the thresholds measured in the complex matrix. The threshold concentrations of limonin and nomilin when added to healthy ‘Valencia’ orange juice were higher than the concentrations of those compounds measured in juice made with symptomatic HLB fruit, which was perceived bitter by a taste panel. Possibly, the lower sugar and higher acid content of HLB fruit decreased the threshold of those bitter compounds.