Prospect of fluorescence fingerprints for the noninvasive sensing of seafood freshness: a review

Seafood is one of the most traded food commodities in the world. Traditionally, frozen seafood is evaluated using destructive chemical methods, which are complicated and time-consuming. Therefore, this study proposed a noninvasive method for evaluation of frozen seafood, focusing on fluorescence fingerprints (FFs). FFs, also known as an excitation–emission matrix (EEM), refer to an arranged fluorescence spectrum of emission stimulated by different excitation wavelengths. As FFs is a set of fluorescence spectra acquired at consecutive excitation wavelengths, it produces a three-dimensional diagram that is composite fluorescence of every fluorophore, similar to a fingerprint. Compared with conventional fluorescence spectroscopy, the FFs technique can measure complex samples that contain many fluorophores, because it includes emission spectra excited at many different excitation wavelengths. In this review, the applications of FFs technology for nondestructive prediction of seafood quality are summarized. Postmortem metabolism and seafood freshness indices are discussed comprehensively. We have also introduced multidimensional fluorescence imaging, a combination of FFs and imaging techniques for visualizing seafood product quality. Finally, the advantages of the FFs technique for nondestructive evaluation of seafood quality, even at the frozen state, over traditional methods and previous fluorescent spectroscopic techniques are enumerated.