Influence of saline environment and depuration time on quality and proximate composition of Nile tilapia fillet (Oreochromis niloticus)

Abstract

This study investigated the depuration time of tilapia in saline and freshwater environments and its influence on animal performance and meat quality. Depuration until the seventh day resulted in significant reductions in average weight, condition factor, viscerosomatic index, hepatosomatic index and fillet yield in both environments. Regarding proximate composition, the saline environment promoted the maintenance of crude protein, moisture and ash percentages. Depuration in the freshwater environment resulted in reduced percentages of crude protein, ash and energy and increased humidity. Total lipids were reduced in both environments, but with a significantly lower in saline. Maximum rigor index occurred in up to three and nine hours for fish depurated in freshwater and saline environments, respectively. During the post-rigor period, the rigor index experienced a sharp drop in the freshwater environment, while in the saline environment it remained similar to that of the pre-depuration group. Depuration in a saline environment for up to seven days was efficient at maintaining of proximate composition and rigor mortis, however, depuration until the fifth day is indicated to maintain performance indices.

Keywords:
starvation; rigor mortis; pre-slaughter; salinity; proximate composition