THE EVOLUTION OF SOME BIOCHEMICAL INDICES DURING CHILLING OF FOUR FRESHWATER FISH SPECIES

Abstract

The  purpose  of  this  paper  was  to  study the  evolution  of  some  biochemical  parameters  in freshwater fish, subjected to chilling for 72 hours in fresh and after smoking. The biological material was  represented  by  four  species  of  fish  (catfish,  trout,  carp  and  grayling)  from  which  there  were prepared  fresh  and  hot  smoked  (60  minutes  at  +70°C) samples,  then  chilled  at  +5°C for  72  hours. After 12, 48 and 72 hours of refrigeration the following aspects were determined:  Acidity Index (AI) and  Peroxide  Index  (PI)  of  the  fat,  and  Amine  Nitrogen  (AN).  Both  after  12  and  after  72  hours  of chilling, the largest percentage increases of biochemical indices, as  compared to controls (fresh and smoked  samples  before  refrigeration),  were  recorded  in  unsmoked  samples.  During  the  72  hours  of refrigeration, in all analyzed cases, the AN has recorded the highest growth, followed, in order, by AI and PI. The evolution of PI values during chilling of the four freshwater fish species, have shown the freshness  maintenance  of  fat  just  in  catfish  and  carp,  both  in  fresh  samples  and  in  smoked  ones. Regarding AN of the four analyzed fish species, the values obtained have indicated a relative freshness of meat after 72 hours (catfish and carp) or even after 48 hours of refrigeration (trout and grayling).