Effects of Chilling and Partial Freezing on Rigor Mortis Changes of Bighead Carp (Aristichthys nobilis) Fillets: Cathepsin Activity, Protein Degradation and Microstructure of Myofibrils

Abstract

To investigate the effects of chilling and partial freezing on rigor mortis changes in bighead carp (Aristichthys nobilis), pH, cathepsin B, cathepsin B+L activities, SDS-PAGE of sarcoplasmic and myofibrillar proteins, texture, and changes in microstructure of fillets at 4 °C and -3 °C were determined at 0, 2, 4, 8, 12, 24, 48, and 72 h after slaughter. The results indicated that pH of fillets (6.50 to 6.80) was appropriate for cathepsin function during the rigor mortis. For fillets that were chilled and partially frozen, the cathepsin activity in lysosome increased consistently during the first 12 h, followed by a decrease from the 12 to 24 h, which paralleled an increase in activity in heavy mitochondria, myofibrils and sarcoplasm. There was no significant difference in cathepsin activity in lysosomes between fillets at 4 °C and -3 °C (P > 0.05). Partially frozen fillets had greater cathepsin activity in heavy mitochondria than chilled samples from the 48 to 72 h. In addition, partially frozen fillets showed higher cathepsin activity in sarcoplasm and lower cathepsin activity in myofibrils compared with chilled fillets. Correspondingly, we observed degradation of α-actinin (105 kDa) by cathepsin L in chilled fillets and degradation of creatine kinase (41 kDa) by cathepsin B in partially frozen fillets during the rigor mortis. The decline of hardness for both fillets might be attributed to the accumulation of cathepsin in myofibrils from the 8 to 24 h. The lower cathepsin activity in myofibrils for fillets that were partially frozen might induce a more intact cytoskeletal structure than fillets that were chilled.

Oxidative stress involved in textural changes of sea cucumber Stichopus japonicus body wall during low-temperature treatment

“…In the present study, the textural analysis results could be explained by the dissolution of collagen, because the change in the content of soluble collagen coincides with the decline of hardness and chewiness. Similarly, Lu et al [22] reported the hardness and springiness of bighead carp fillets at 4°C increased until 8 h, followed by a slow decrease to the end of storage.…”

The impact of desmin on texture and water‐holding capacity of ice‐stored grass carp (Ctenopharyngodon idella) fillet

“…, the reduction in the fillet firmness mainly occurred during the first 3 days of storage and the value decreased to 76%, respect to the initial value. The marked decrease in firmness was in agreement with the results reported in previous study (Liu et al ., ) and might be probably related to the loss of water from the muscle (Wojtysiak & Połtowicz, ) or the reduction in integrity of the muscle cell (Lu et al ., ). Additionally, the activity of endogenous proteases and the rate and extent of energy metabolism as well as the low ultimate pH further affected the texture of fillet (Duun & Rustad, ).…”

Effect of Proteolysis on the Meat Quality of a Brand Fish, Red Sea Bream <i>Pagrus major</i>

“…1). Previous studies showed the marked decrease in the firmness and texture of fish fillets during storage (Liu et al, 2013;Zang et al, 2017), which might be related to a reduction in the integrity of muscle cells (Lu et al, 2015). Moreover, it was reported that the extent and rate of energy metabolism, protein degradation, and the activity of endogenous proteases affected the texture of fish fillets (Duun and Rustad, 2008;Zang et al, 2017).…”