Effect of constant and fluctuating temperatures during frozen storage on quality of marinated fillets from Atlantic and Baltic herrings (Clupea harengus)

The production of cold fish marinades is characterized by high seasonality, and therefore producers have problems with providing the sufficient supply of marinades. Besides, after the spawning season, herrings do not ripen properly. Therefore, in the present study, marinated Atlantic and Baltic herring fillets were frozen and stored for 2 days up to 5 months using constant and fluctuating temperatures (recrystallization). The freezing-thawing of marinades improves the hardness, color, and overall sensory evaluation of meat. Temperature fluctuations increase the disintegration of the muscle tissue structure and lysosomal membranes, enhancing the activity of aspartyl endopeptidase responsible for improving the texture of meat and increasing the concentration of protein-hydrolyzing products. The highest thaw drip loss and lipid oxidation were observed after 3 months of frozen storage with temperature fluctuation. Frozen storage had a different effect on fatty and thin herrings. Frozen-thawed marinades stored for up to 5 months were of good microbiology quality. Study results show that the freezing of the semi-marinades may be one of the methods for quality improvement and for extending marinades shelf-life before the seasonally increased demand on the market.