Novel techniques for evaluating freshness quality attributes of fish: A review of recent developments

Fishery plays an important role in providing abundant nutrition for consumers as well as in international trade and foreign exchange earner. Due to the abundant endogenous enzymes and psychrophilic bacteria in fish bodies and the fragile organization of fish, fish and fish products are easily perishable and are affected by pre-harvest and postmortem factors, thus decreasing their value. It is thus significant to evaluate fish freshness in an effective and timely manner. In the current review, the principles and applications of novel techniques including enzyme biosensor, electrochemical biosensor, electronic nose, colorimetric sensor, electronic tongue, computer vision techniques, Vis/NIR spectroscopy, HSI spectroscopy and fluorescence spectroscopy as reliable and rapid evaluation tools complementing traditional time-consuming, expensive and cumbersome techniques are highlighted and the advantages and disadvantages of these methods are discussed. Moreover, challenges and future research trends are also proposed. Although recent development of novel technologies has demonstrated their superiority for time-saving, rapid, economic, and even nondestructive and on-line detection of fish freshness, some challenges still remain in optimizing and simplifying bionics techniques, developing algorithms and chemometrics in spectroscopic technologies and improving selectivity and sensitivity in biosensor methods. Further studies are still needed to facilitate the applications of these new evaluation technologies in the fish industry.