New strategies for mitigating undesirable odors connected to geosmin and 2-MIB in minced fish muscle: a model system approach

Freshwater fish species commonly suffer from muddy odor problems linked to geosmin and 2-methylisoborneol (2-MIB). This study examined whether the release of geosmin and 2-MIB from spiked fish muscle could be reduced by adding poly-/oligosaccharides (pectin, carrageenan, alginate, cyclodextrins (CD)) or organic acids (ascorbic acid, isoascorbic acid, citric acid, tannic acid), as well as 5 and 10% (dw/dw) of biomasses rich in some of these molecules (apple/lingonberry press-cakes (APC, LPC) and red seaweed (Palmaria palmata)). All pure molecules were added at 0.18, 0.35 and 0.70% (w/w) based on ADI levels set by EFSA. Results showed alginate, carrageenan, β- and γ-CD significantly decreased geosmin and 2-MIB release by up to 90%, while pectin did not. All organic acids reduced geosmin release, while isoascorbic and citric acid prevented release of geosmin and 2-MIB; effects accompanied by pH reductions. 2-MIB release was also significantly reduced by APC and LPC. Molecular docking confirmed the experimental data that carrageenan prevented release better than alginate; and that geosmin bound to polysaccharides better than 2-MIB. This study concludes organic acids, alginate, carrageenan and CDs can be used within safe limits to prevent geosmin and 2-MIB release in fish muscle. New routes to mitigate muddy off-odor in commuted freshwater fish products were revealed, some stimulating upcycling of plant side streams leaving the food chain despite nutritional and technological functions.