| Abstract
| - A method for estimating the total limonoid aglycone and glucoside concentrations in Citrus samplesin terms of limonin and limonin glucoside equivalents is presented. The method consists of extractionfollowed by colorimetric quantification. The colorimetric quantification was based on the formationof red to orange colored derivatives resulting from the treatment of limonin, limonin glucoside, or afruit extract with 4-(dimethylamino)benzaldehyde (DMAB) in the presence of perchloric and aceticacids. Absorbance maxima for the limonin and limonin glucoside derivatives were found to be 470and 503 nm, respectively. The influence of DMAB concentration, reaction time, and solvent composition on color development and sensitivity were investigated and optimal assay conditionsestablished. With a microplate format under these conditions, the limits of detection and quantification were determined to be 0.25 and 0.50 μg/mL for limonin and 0.50 and 1.0 μg/mL for limoninglucoside. Keywords: Limonoids; citrus; solid-phase extraction; juice analysis
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