title: Freshness estimation of intact frozen fish using fluorescence spectroscopy and chemometrics of excitation-emission matrix.
abstract: The current study attempted to provide a convenient, non-invasive and time-saving method to estimate the freshness of intact horse mackerel (Trachurus japonicus) fish in a frozen state using autofluorescence spectroscopy in tandem with multivariate analysis of fluorescence excitation-emission matrices (EEM). The extracted fluorescence data from different freshness conditions were pretreated, masked and reorganized to resolve fish fluorescence spectra from overlapping signals and scattering profiles for detecting and characterizing freshness changes. The real freshness values of the examined fish samples were then traditionally determined by the hard chemical analysis using the high performance liquid chromatography (HPLC) method and expressed as K-values. The fluorescence EEM data and the real freshness values were modeled using partial least square (PLS) regression and a novel algorithm was proposed to identify the ideal combinations of excitation and emission wavelengths being used as perfect predictors. The results revealed that freshness of frozen fish could be accurately predicted with R(2) of 0.89 and root mean square error estimated by cross validation (RMSECV) of 9.66%. This work substantially demonstrated that the autofluorescence spectroscopy associated with the proposed technical approaches has a high potential in non-destructive sensing of fish freshness in the frozen state.
authors.affiliation: Department of Computer Science and Engineering, Toyohashi University of Technology, Toyohashi, Aichi, Japan; Suez Canal University, Faculty of Agriculture, Agricultural Engineering Department, Ismailia, Egypt. Electronic address: g.elmasry@vpac.cs.tut.ac.jp.
authors.forename: Gamal
authors.initials: G
authors.lastname: ElMasry
authors.affiliation: Department of Computer Science and Engineering, Toyohashi University of Technology, Toyohashi, Aichi, Japan.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Nagai
authors.affiliation: Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Tokyo, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Moria
authors.affiliation: Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Tokyo, Japan.
authors.forename: Naho
authors.initials: N
authors.lastname: Nakazawa
authors.affiliation: Food Engineering Division, National Food Research Institute, National Agriculture and Food Research Organization, Tskuba, Japan.
authors.forename: Mizuki
authors.initials: M
authors.lastname: Tsuta
authors.affiliation: Food Engineering Division, National Food Research Institute, National Agriculture and Food Research Organization, Tskuba, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Sugiyama
authors.affiliation: Department of Food Science and Technology, Tokyo University of Marine Science and Technology, Tokyo, Japan.
authors.forename: Emiko
authors.initials: E
authors.lastname: Okazaki
authors.affiliation: Department of Computer Science and Engineering, Toyohashi University of Technology, Toyohashi, Aichi, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Nakauchi
mesh_terms: D000465:Algorithms; D000818:Animals; D063427:Food Quality; D005615:Freezing; D048088:Informatics / Q000379:methods*; D016018:Least-Squares Analysis; D015999:Multivariate Analysis; D010473:Perciformes; D013050:Spectrometry, Fluorescence; D013997:Time Factors
keywords: Excitation–emission matrix; Fish; Fluorescence spectroscopy; Freshness; Horse mackerel; K-value; Partial least square (PLS)