Effects of different stunning methods on the flesh quality of grass carp (Ctenopharyngodon idellus) fillets stored at 4°C

•Investigation of the effect of stunning methods on flesh quality of fillets.•Ice slurry stunning slowed ATP depletion and lactate formation of fillets.•Ice slurry stunning improved flesh quality and shelf life of grass carp fillets.•Stunning of grass carp in ice slurry is better than percussion and freezing. The effects of stunning methods (percussion (T1), stunning at −22°C in a freezer (T2), and immersion in ice slurry (T3)) on the flesh quality of grass carp fillets were evaluated in terms of K-value, total volatile base nitrogen (TVB-N), electrical conductivity (EC), total viable counts (TVC), biogenic amines, and sensory scores during storage. Moreover, fillets were analyzed periodically for pH, hardness, acid phosphatase activity, and the content of glycogen, adenosine triphosphate (ATP), and lactate. Significantly slower ATP depletion, slower reduction in pH, slower lactate formation, and higher initial glycogen level were observed in T3 compared to T1 and T2 (P