Lipid deterioration during chilled storage of Atlantic Pomfret (Brama brama)

Abstract

Lipid damage produced during Atlantic pomfret (Brama brama) chilled storage (up to 19 d) was studied. The formation of various lipid parameters, such as free fatty acid and conjugated dienes (CD), peroxide value, thiobarbituric acid reactive substances and fluorescent compounds was measured in 2 different white muscle zones (dorsal and ventral). The results were compared with the formation of volatile amines (total volatile base-nitrogen, TVB-N, trimethylamine-nitrogen, TMA-N). A gradual lipid hydrolysis was observed in both zones during the entire experiment. CD and peroxides formation was prominent during the experiment, whereas peroxides showed the highest value at day 15 in both zones followed by a peroxide breakdown at day 19. Interaction of oxidized lipids with nucleophilic compounds present in the fish muscle led to a gradual development of fluorescent material during storage in both zones. The mean value of the lipid content tended to be higher in the ventral zone than in the dorsal one, although significant differences could not be detected (p >0.05). Concerning the lipid damage, very small differences (p <0.05) could be assessed between both zones. TVB-N content showed no variation till day 15. At day 19, a sharp increase was observed for both muscle zones. In the case of TMA, a gradual increase was observed in both muscles during the 19-day storage. Higher mean values of TVB-N and TMA-N indices were obtained for the ventral than for the dorsal zone. This might be due to the fact that the ventral zone is close to the viscera, where microorganisms are known to concentrate. Of all the different indices tested for quality assessment, TMA-N and the formation of fluorescent compounds were strongest related to the duration of storage (r2≥0.87). These might therefore be the most accurate parameters to follow quality loss of chilled Atlantic pomfret