title: Method of determining the optimal dilution ratio for fluorescence fingerprint of food constituents.
abstract: Quantitative determination by fluorescence spectroscopy is possible because of the linear relationship between the intensity of emitted fluorescence and the fluorophore concentration. However, concentration quenching may cause the relationship to become nonlinear, and thus, the optimal dilution ratio has to be determined. In the case of fluorescence fingerprint (FF) measurement, fluorescence is measured under multiple wavelength conditions and a method of determining the optimal dilution ratio for multivariate data such as FFs has not been reported. In this study, the FFs of mixed solutions of tryptophan and epicatechin of different concentrations and composition ratios were measured. Principal component analysis was applied, and the resulting loading plots were found to contain useful information about each constituent. The optimal concentration ranges could be determined by identifying the linear region of the PC score plotted against total concentration.
authors.affiliation: a Food Engineering Division, National Food Research Institute , National Agriculture and Food Research Organization , Tsukuba , Japan.
authors.forename: Vipavee
authors.initials: V
authors.lastname: Trivittayasil
authors.forename: Mizuki
authors.initials: M
authors.lastname: Tsuta
authors.forename: Mito
authors.initials: M
authors.lastname: Kokawa
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Yoshimura
authors.forename: Junichi
authors.initials: J
authors.lastname: Sugiyama
authors.forename: Kaori
authors.initials: K
authors.lastname: Fujita
authors.forename: Mario
authors.initials: M
authors.lastname: Shibata
mesh_terms: D002392:Catechin / Q000737:chemistry*; D005453:Fluorescence; D005504:Food Analysis; D015999:Multivariate Analysis; D025341:Principal Component Analysis; D012996:Solutions; D013050:Spectrometry, Fluorescence / Q000592:standards / Q000706:statistics & numerical data*; D014364:Tryptophan / Q000737:chemistry*
chemical_list: D012996:Solutions; D014364:Tryptophan; D002392:Catechin
keywords: concentration; excitation–emission matrix; multivariate analysis; principal component analysis