宰杀方式对冷冻斑点叉尾鮰品质的影响

Effect of Slaughter Methods on Quality of Frozen Channel Catfish Fillets

研究不同宰杀方式对冷冻斑点叉尾鮰鱼片品质的影响,寻求合适的宰杀方式以提高冷冻鮰鱼片的品质。采用四种不同宰杀方式:CO2窒息、电击、敲头及冰水中放血,宰杀后将鱼肉置于-18℃冰箱中保藏。考察各组样品的p H、色差、血红蛋白含量、解冻汁液流失、TVB-N及菌落总数。鱼肉p H值在宰后45 h内呈现先减小后增大的趋势,放血组的p H值变化最小,其次为敲头组,CO2窒息组变化最大。冰水中放血组鱼片白度和绿值与其他组有显著差异(P<0.05),血液残留少(P<0.05)。储藏60 d期间,CO2窒息组的解冻汁液流失率最大为5.53%(P<0.05),敲头组最小为3.25%(P<0.05)。冰水中放血组的鱼肉TVB-N值最小(P<0.05),其他三组之间没有显著差异(P>0.05)。菌落总数在储藏期间呈现下降趋势,冰水中放血组的菌落总数最小,其次为敲头组、窒息组和电击组。可知敲头和冰水中放血的致死方式能得到较好的鮰鱼片品质。

To improve the quality of frozen fish fillet, different slaughter methods were evaluated to determine their effect on the quality of frozen channel catfish. Fresh channel catfish were slaughtered by four methods(carbon dioxide stunning, electrical stunning, percussive stunning, and bleeding in ice slurry) and fillets were stored in a refrigerator at-18 ℃. The p H value, color, hemoglobin content, drip loss, total volatile base nitrogen(TVB-N), and bacterial counts in each group were evaluated. Muscle p H values showed an upward trend after an initial decline at 45-h post-mortem; the change in p H value for bleeding-in-ice-slurry group was the smallest, followed by percussive-stunning group; whereas the largest p H change was found in CO2-stunning group. The a* and L* values for the bleeding-in-ice-slurry group were significantly different from those for other groups(p < 0.05), whereas less blood was retained in the bleeding-in-ice-slurry group(p < 0.05). During the 60-day storage period, highest drip loss(5.53%) was observed for the CO2-stunning group(p < 0.05), while the lowest(3.25%) was found for the percussive-stunning group. The lowest TVB-N value was found for the bleeding-in-ice-slurry group(p < 0.05), with no significant differences among other three groups(p < 0.05). The bacterial count exhibited a declining trend during storage and the lowest count was found for the bleeding-in-ice-slurry group, followed by percussive-stunning, CO2-stunning, and electric-stunning groups. Thus, fish slaughter by bleeding in ice slurry and percussive stunning produce good-quality fillets of frozen channel catfish.