From formation to solutions: Off-flavors and innovative removal strategies for farmed freshwater fish

Framed freshwater fish, integral to "blue food," address global protein demands for population growth. Rising concerns about inherent off-flavors limit consumer and industry acceptance. Thus, it's vital to identify off-flavor formation in farmed freshwater fish and develop innovative removal strategies. This review highlights off-flavor formation in framed freshwater fish and innovative removal strategies, exploring mechanisms in aquaculture and post-harvest stages. Six strategies—ozone treatment, cold plasma, molecular sieves, edible coatings/films, photocatalysis, and probiotics—were summarized for their removal principles and applicability. Obstacles and potential research trajectories of these strategies were also discussed. Farmed freshwater fish exhibit eight distinct off-flavors: fishy, grassy, earthy, mushroom, muddy, metallic, camphor, and musty. Post-harvest unpleasant odors, such as trimethylamine, amines, and aldehydes, result from three major factors: protein degradation, microbial action, and lipid oxidation. Six innovative strategies aim to alleviate these off-flavors post-harvest and during aquaculture. Ozone treatment, cold plasma, molecular sieves, and edible films/coatings target post-harvest off-flavors, while photocatalysis and probiotics address aquaculture-stage off-flavors. Future research should optimize these strategies for efficient off-flavor removal, considering safety and environmental impact. Comprehensive studies are needed to evaluate the long-term effects on fish quality and shelf life.