Second-degree polynomial regression of total volatile bases (TVB-N) of tilapia fillets following treatments T1 (control sample), T2 (modified-atmosphere packaging – 40/60 co2/N2), T3 (gamma radiation – 1.5 kGy), T4 (modified-atmosphere packaging and gamma radiation, using the same conditions as treatments 2 and 3), samples from the fishery cooperative; and T5 (control sample), T6 (modified-atmosphere packaging – 40/60 co2/N2), T7 (gamma radiation – 1.5 kGy) and T8 (modified-atmosphere packaging and gamma radiation, using the same conditions as treatments 6 and 7), samples from the pilot plant.