A new pre-slaughter stunning method promotes quality of tambaqui (Colossoma macropomum) fillets compared to conventional methods

The study aimed to evaluate the influence of pre-slaughter stunning methods on the quality of tambaqui (Colossoma macropomum) fillets, namely ice asphyxiation (AG); asphyxia in air (AA); electronarcosis (EE); and hypothermia followed by bleeding (HS). The quality was evaluated using the pH of the meat; the rigor mortis index; and meat texture, blood glucose and colorimetry. For each treatment, 12 animals were used, and six animals from each treatment were kept intact for pH and rigor mortis analysis during the times of 0, 1, 1.5, 2.5, 4.5, 6.5, 24, 36, 48, 72, 96, 120, 160 and 360 hours after slaughter. The pH values were kept in compliance with the legislation, below 7. As for the rigor mortis index, the group killed by electronarcosis took one hour longer to show full rigor. For texture attributes, no differences were found between treatments. Therefore, the tambaqui fillets submitted to EE and HS tended to lower red coloration. EE, in addition to draining more blood, promotes the integrity of the cut, providing more succulence and tenderness to the fillet.