FAT OXIDATION, PROTEIN DEGRADATION AND COLOUR OF RAINBOW TROUT (ONCORHYNCHUS MYKISS) MEAT DURING 3 MONTHS OF FREEZER STORAGE

Abstract

The aim of the work was to analyze the effect of storage in freezing conditions (-18 ° C) during 3 months of storage on the formation of malondialdehyde MDA, TVB-N (total volatile basic nitrogen), and colour. Rainbow trout up to 500 g (RT) aged 1-1.5 years (n=15) and trout (RT1) up to 3.5 kg aged 2-2.5 years (n=15) were included in the experiment. The stated weight of the fish is already after processing. After slaughtering the fish, samples were taken from each fish for analysis of meat colour in the CIE colour space with a KONICA MINOLTA 2600D (L*, a*, b*) on the 1st day after slaughter and after the 1st, 2nd, 3rd month of storage. The content of TVB-N and MDA was measured parallel. For both weight categories of trout, after three months of freezing, we observed significant (RT1- P≤0.05; RT- P≤0.05) increase in TVB-N compared to the first day of measurement. Malondialdehyde content after three months of freezing was significantly (P≤0.05) higher than at the first measurement in both weight categories of rainbow trout. In the RT experimental group, trout meat after three months of freezing was significantly (P≤0.05) lighter (L*) and less yellow (b*). The meat of the RT1 group after 3 months of freezing storage was significantly (P≤0.05) darker , less red and less yellow.