Emerging Techniques for Differentiation of Fresh and Frozen–Thawed Seafoods: Highlighting the Potential of Spectroscopic Techniques

Abstract

Fish and other seafood products have a limited shelf life due to favorable conditions for microbial growth and enzymatic alterations. Various preservation and/or processing methods have been developed for shelf-life extension and for maintaining the quality of such highly perishable products. Freezing and frozen storage are among the most commonly applied techniques for this purpose. However, frozen–thawed fish or meat are less preferred by consumers; thus, labeling thawed products as fresh is considered a fraudulent practice. To detect this kind of fraud, several techniques and approaches (e.g., enzymatic, histological) have been commonly employed. While these methods have proven successful, they are not without limitations. In recent years, different emerging methods have been investigated to be used in place of other traditional detection methods of thawed products. In this context, spectroscopic techniques have received considerable attention due to their potential as being rapid and non-destructive analytical tools. This review paper aims to summarize studies that investigated the potential of emerging techniques, particularly those based on spectroscopy in combination with chemometric tools, to detect frozen–thawed muscle foods.

Light and Autofluorescence, Multitasking Features in Living Organisms

“…Besides the most common participation in signaling, the identification of these compounds has also driven to suggest an antibacterial role [212] (Figure 25). A separated but not least topic is the fluorescence of fish as seafood for human alimentary purposes for the development and application of spectroscopic techniques, including fluorescence and hyperspectral imaging, to monitor the freshness and check the fresh or frozen-thawed origin of food [213]. The main fluorophores described in this section are summarized in Table 7.…”

“…Bilirubin-fatty acid a fatty acid binding protein complex 450-500 nm 500-580 nm Advantage in communication and antioxidant protection in cryptic eels [207][208][209] Guanine crystals 450-600 nm 600-700 nm Visual contrast and signaling functions in cryptid fishes [210] A separated but not least topic is the fluorescence of fish as seafood for human alimentary purposes for the development and application of spectroscopic techniques, including fluorescence and hyperspectral imaging, to monitor the freshness and check the fresh or frozen-thawed origin of food [213]. The main fluorophores described in this section are summarized in Table 7.…”

Seasonal Evaluation of Freshness Profile of Commercially Important Fish Species

“…Some examples are infrared, fluorescence [ 6 ], nuclear magnetic resonance, and Raman spectroscopies, as well as some instrumental sensors, such as the electronic nose [ 7 ]. These techniques are fast, low cost, environmentally friendly, usually require little or no sample preparation, and allow one to avoid sample destruction [ 8 , 9 , 10 ]. Despite the mentioned advantages, the utilization of spectroscopic techniques in real-life applications is still limited.…”

Rapid Differentiation of Unfrozen and Frozen-Thawed Tuna with Non-Destructive Methods and Classification Models: Bioelectrical Impedance Analysis (BIA), Near-Infrared Spectroscopy (NIR) and Time Domain Reflectometry (TDR)

“…On the contrary, during the thawing process, the melting of the ice crystals occurs. This process causes physical and chemical changes in the frozen products, affecting their quality [ 42 ]. Generally, the freezing and thawing process contributes to a decrease in the water holding capacity (WHC) of muscles due to the denaturation of the muscle proteins.…”