The effects of different killing methods on flesh quality of some fish (Oncorhynchus mykiss, Walbaum 1792 ve Cyprinus carpio, Linnaeus 1758) which have economical importance

Two killing methods, instant and struggled, were applied to carp (Cyprinus carpio L.)and trout (Oncorhynchus mykiss W.) and they were stored at 100C during 60 hour.During this period physical, chemical and microbiological properties of carp and troutfleshs were investigated. The level of malondialdehyde (MDA), phsycophilic andmesophilic counts in flesh obtained from carp and trout which was applied stress weresignificantly higher than those of the flesh obtained from carp and trout which waskilled instantly (p<0.05) for the beginning of cold storage. So, the lipolitic andmicrobiological degradation rate was higher in the flesh struggled. In texture analysis,hardness values of fillets obtained from carp and trout which were killed with stressdecreased rapidly in comparison to the fillets obtained from carp and trout which waskilled instantly during storage period. The decreasing in the values for texture showed asoftening body in the flesh. The initial lactic acid concentrations were higher instruggled flesh than unstressed flesh (p<0.05). No significant differences in the level oftotal volatile basic nitrogen (TVB-N) and pH of carp and trout fleshes were observedbetween killing methods. The results indicated that the struggled killing methodnegatively influenced the physical, chemical and microbiological quality of the flesh.Key Word: carp, rainbow trout, killing methods, stress, lactic acid, bacterial count,cold storage, total volatile basic nitrogen (TVB-N), texture analysis, flesh quality,malondialdehyde (MDA), pH.