Impact Of Long-Term Storage On The Instrumental Textural Properties Of Frozen Common Carp (Cyprinus Carpio,L.) Flesh

The aim of the work was to measure and confirm changes in the qualitative properties of frozen carp flesh (Cyprinus carpio L.) during 84 days of storage at -20°C, using instrumental texture profile analysis focused on hardness, cohesiveness, and springiness. Hardness in fresh fish was 2.908 N, in fish stored 28 days 1.238 N, after 56 days 0.505 N, and after 84 days 0.491 N. Cohesiveness (dimensionless unit) in fresh fish was 0.838, after 28 days 0.740, after 56 days 0.720, and after 84 days 0.712. Springiness (dimensionless unit) in fresh fish was 0.682, after 28 days 0.625, after 56 days 0.577, and at 84 days of storage 0.534. The texture profile analysis effect was determined by several regression and linear models. It is possible to calculate a certain time period in which changes develop up to the level of 50% of deterioration—in hardness 17.5 days and in cohesiveness 12.9 days, as this was proven to a defined significance level (P > 0.01). Only changes in springiness showed a linear regression in the level of 0.002 (rounded) for each day. Studies showed that the intensity of the most important changes in instrumental textural properties occurred during the initial 56 days after freezing and after up to 84 days of storage the changes continued at a lesser rate.