Breksa Andrew P, Ibarra Phil
Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 800 Buchanan Street, Albany, California 94710, USA.
J Agric Food Chem. 2007 Jun 27;55(13):5013-7. doi: 10.1021/jf063731c. Epub 2007 Jun 2.
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 a fruit extract with 4-(dimethylamino)benzaldehyde (DMAB) in the presence of perchloric and acetic acids. Absorbance maxima for the limonin and limonin glucoside derivatives were found to be 470 and 503 nm, respectively. The influence of DMAB concentration, reaction time, and solvent composition on color development and sensitivity were investigated and optimal assay conditions established. With a microplate format under these conditions, the limits of detection and quantification were determined to be 0.25 and 0.50 microg/mL for limonin and 0.50 and 1.0 microg/mL for limonin glucoside.
本文提出了一种以柠檬苦素和柠檬苦素葡萄糖苷当量来估算柑橘样品中总柠檬苦素苷元及葡萄糖苷浓度的方法。该方法包括提取，然后进行比色定量。比色定量基于在高氯酸和乙酸存在下，柠檬苦素、柠檬苦素葡萄糖苷或水果提取物与4-(二甲基氨基)苯甲醛(DMAB)反应生成红色至橙色衍生物。发现柠檬苦素和柠檬苦素葡萄糖苷衍生物的最大吸收波长分别为470和503nm。研究了DMAB浓度、反应时间和溶剂组成对显色和灵敏度的影响，并确定了最佳测定条件。在这些条件下采用微孔板形式，测定柠檬苦素的检测限和定量限分别为0.25和0.50μg/mL，柠檬苦素葡萄糖苷的检测限和定量限分别为0.50和1.0μg/mL。
