8. Post Mortem Changes in Snake Headed Fishes (Taki, Channa punctatus and Shol, Channa striatus) During Storage at Room Temperature (28 to 30 °C) and in Ice

Abstract

Studies were conducted on the post-mortem changes in freshwater snake headed fishes (Taki, Channa punctatus and Shol, Channa striatus) stored at room temperature (28 to 30°C) and in ice to examine the progress of rigor-mortis, changes in muscle pH and shelf life of the fishes by testing the organoleptic, biochemical and bacteriological parameters. Rigor started within 1h after death of fishes at both storage temperatures but it lasted long in ice stored fish Rigorindex reached to the maximum value of 82.14% and 85.13% within 8 h after death in Taki and Shol, respectively at room temperature while in ice stored condition values reached to the maximum of 89.09% within 9 h in Taki and 89.52% within 10hrs in Shol. With the lapse of storage time rigor-index increased gradually. The rigor relaxed up to 12.65% and 15.65% within 40 h of ice storage in Taki and Shol, respectively. The pH of fish muscles were 6.91 and 6.87 in Taki and Shol, respectively just after catch which decreased gradually with the progress of storage time at both storage temperatures. In another experiment, the quality changes in Taki and Shol, during 32 days of ice storage (in an insulated box) were evaluated. Score of organoleptic characteristics observation showed that, Taki and Shol were in acceptable conditions until 28 days in ice. The values for TVB-N, peroxide and NPN also showed that, the fishes remained acceptable state for the similar period. The myofibrillar protein solubility of muscle of the experimental fishes decreased from 86.32±0.012% and 88.24±0.006% to 32.48±0.012% and 33.69±0.006% within the same storage time. The initial bacterial loads were 7.50×103 and 6.20×103 CFU/g in Taki and Shol, respectively which increased to 9.23×108 and 8.9×108 CFU/g at the end of the 32 days of storage indicating that the fishes were organoleptically rejected after that period.