The influence of ante-mortem hypoxia on the physicochemical stability of myofibrillar proteins in the muscle tissue of white shrimp (Litopenaeus vannamei) exposed to multiple freeze–thaw cycles

The influence of ante-mortem hypoxia on physicochemical stability of white shrimp ( Litopenaeus vannamei ) muscle exposed to multiple freeze–thaw (F/T) cycles was evaluated. Results showed 5.7 and 10.8% decrements in water-holding capacity and myofibrillar protein solubility, respectively, for stressed shrimp during the first F/T cycle compared to control. Significant differences ( P ≤ 0.05) on myosin T max were found comparing stressed and control fresh shrimp with a 1.4 °C increased on stressed fresh shrimp; however, no differences were found on Δ H values. With regard to stressed fresh shrimp actin, T max increased ( P ≤ 0.05) 0.8 °C, while Δ H decreased ( P ≤ 0.05) by 0.12 J g −1 , respectively. Regardless of the results found in fresh shrimp, no differences were found for myosin T max and Δ H between stressed and control during the F/T cycles. SDS-PAGE showed no relevant changes induced by autolysis during the experiment. Histological analysis showed an increase of 257% in blank area of stressed fresh shrimp when comparing to control. Results showed the influence of ante-mortem hypoxia on the stability of fresh shrimp myofibrillar proteins, affecting its physicochemical properties. In contrast, for shrimp exposed to F/T cycles, the hypoxia effect was not relevant .