Title : Using the ellagic acid-borax fluorescence interaction with cyclodextrin in a food samples nanosensor
Abstract:
The food industry needs cheap, fast and sensitive methods to increase the number of analyzes that are routinely made; for which reason, new methods are constantly being sought. This work describes a novel fluorecence nanosensor based on cyclodextrin (CDs) to determine ellagic acid (EA, a potential bioactive compound with biological benefits) tested in a blueberry extract. The encapsulation of EA in the presence of borax was studied using a novel UV/mathematical method. Firstly, the complexation of EA-borax was tested to determine a concentration where EA was totally complexed. Moreover, the stoichiometry of the EA-borax complex showed a 1:2 (one EA per borax) complex, with a KF1 = 2548 +/- 127 M-1 and a KF2 = 302 +/- 15 M-1. Furthermore, when one borax is only presented, no fluorescence was shown. Different CDs (α-, β-, γ-, 2-Hydroxypropyl-βCD [CIDs 44134771] and Methyl-βCD [CID 10171019]) were used to obtain a 1:1:1 CD-EAborax (one borax is released to enter a CD) complex and γ-CD provided the best complexation constant (KF3 = 364 +/- 18 M-1). Furthermore, when the accuracy and sensitivity of the nanosensor were tested using a crude blueberry extract, the CD/ borax mixture provided an 18 times stronger signal than the crude extract alone and 7 times stronger than the obtained by borax alone without any signal interferences. These results can be used to create novel methods to measure EA in different food samples, and, moreover, increases of knowledge of the EA-borax interaction
