Tempos de descanso pós-transporte sobre a qualidade da carne da patinga (Piaracuts mesopotamicus ♀ x Piaractus brachypomus ♂)

Abstract

Pre-slaughter transport is a stressful practice for fish, making it necessary for animals to remain at rest in the processing unit to return to their homeostasis. This procedure is important to minimize the impacts that pre-slaughter stress causes on the quality of fish meat. Thus, in order to evaluate the effect of different post-transport rest times on blood glucose and meat quality characteristics in the pre and post rigor mortis of the patinga, an experiment was carried out in a 4x2 factorial scheme, with four transport recovery times (0, 2, 4 and 6 hours) and two processing phases (pre- and post-rigor mortis), in addition to a control treatment (fish removed from the pond and immediately euthanized). After harvesting, the live fish were transported by road in a specific box for one hour, then distributed in water tanks to remain at different resting times (0, 2, 4 and 6 hours). At each time, blood was collected for glucose analysis from 15 fish, with subsequent euthanasia by spinal cord section. 10 fish were processed during pre-rigor mortis and, 24 hours later, another 5 fish were processed (post-rigor mortis phase). In 24 hours after slaughter and in 45 days of storage under freezing, the fillets were analyzed for pH, color, shear force, water holding capacity (WHC) and water loss by cooking (WLC). A decrease in blood glucose was observed as the resting times increased, and after 6 hours, glucose levels returned to baseline. In the fillets, after 24 hours, the interaction between resting time and rigor mortis state had a significant effect on color and texture, where fish processed in the pre-rigor after 6 hours showed fillets with greater luminosity, less red intensity and greater strength of shear. Fish fillets processed after 4 hours in a state of pre-rigor mortis showed a higher intensity of red, while in post-rigor they showed a higher intensity of yellow. Evaluating only the resting time, after 6 hours the fish presented fillets with lower WLC and higher WHC. Evaluating the state of rigor mortis in isolation, fillets processed during post-rigor showed lower pH, lower WLC, lower luminosity, lower yellow intensity and higher WHC. After 45 days of storage, the interaction between the post-transport rest time and the rigor mortis state provided a higher pH in post-rigor fillets with 0 hours of rest, greater luminosity and lower WHC in a post-rigor state with 6 hours. of rest, greater intensity of red in the pre-rigor with 2 hours of rest and greater shear force in fillets with 4 h of recovery, in the post-rigor. Evaluating the resting time alone, pH and yellow intensity were higher in fillets with 4 hours of. The WHC was lower for 6 hours of rest and the intensity of red was greater for the treatment of 4 hours of rest. For the rigormortis state alone, it was observed that the fillets underwent lower WLC and higher WHC when processed in the post-rigor state. It is concluded that the post-transport rest for 6 hours is effective for recovering from transport stress, positively impacting the quality of the patinga fillets. In addition, it is recommended to process the fish in the post-rigor mortis period, as the fillets present greater firmness, less cooking losses, greater water retention capacity and lighter color.