|Ibarra Jr, Felipe|
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 3, 2007
Publication Date: June 2, 2007
Citation: Breksa III, A.P., Ibarra Jr, F.G. 2007. Colorimetric Method for the Estimation of Total Limonoid Aglycones and Glucoside Contents in Citrus Juices. Journal of Agricultural and Food Chemistry. (Article) 55(13):5013-5017. Interpretive Summary: Limonoids are highly oxygenated triterpenoid compounds that are found in all citrus tissues as limonoid A-ring lactones, glucosides or aglycones. These compounds are important to consumer acceptance and may potentially contribute to human health and nutrition. Lacking among the methods to quantitate these compounds is a simple, rapid and inexpensive method to estimate limonoid aglycone and glucoside concentrations in fruit samples. We report the development of such a method.
Technical Abstract: A method for estimating the total limonoid aglycone and glucoside concentrations in Citrus samples in terms of limonin and limonin glucoside equivalents is presented. The method consists of extraction followed by colorimetric quantification. The colorimetric quantification was based on the formation of red to orange colored derivatives resulting from the treatment of limonin, limonin glucoside or an extract with 4-(dimethylamino)benzaldehyde (DMBA) in the presence of perchloric and acetic acids. Absorbance maximums for the limonin and limonin glucoside derivatives were found to be 470 and 503 nm respectively. The influence of DMBA concentration, reaction time and solvent composition on color development and sensitivity were investigated and optimal assay conditions established. Utilizing a micro-plate format under these conditions, the limits of detection and quantification were determined to be 0.25 and 0.50 ug/mL for limonin and 0.50 and 1.0 ug/mL for limonin glucoside.