宰前二氧化碳麻醉对罗非鱼肉品质影响的研究

Effect of Pre-slaughter Carbon Dioxide Anesthesia on Flesh Quality of Tilapia

研究了宰前二氧化碳麻醉对罗非鱼肉肉品质的影响。本研究以敲头作为对照组,比较二氧化碳麻醉放血宰后于1±1℃下贮藏,测定7 d各组僵直度、pH值、质量耗损率、挥发盐基氮、感官评价、质构硬度和剪切力等指标。结果表明:宰前二氧化碳麻醉能延迟进入僵直期的时间,且有较高的初始pH和较低的最终pH。随贮藏时间的延长,两组的质量耗损率呈显著上升趋势,在宰后3 d内两组间无显著性差异,却在宰后4到7 d内,二氧化碳麻醉组要明显低于对照组。除宰后0 d和4到5 d外,二氧化碳麻醉组的TVB-N均明显低于敲头对照组。另外,两组间的质构恶化和感官评价在宰后无显著差异,但两组的剪切力和硬度以及感官评价在宰后第7 d要明显劣于0 d。结合各项指标,宰前二氧化碳麻醉比敲头致晕更适合于罗非鱼鱼片的生产加工。

The aim of this study was to evaluate the effects of pre-slaughter carbon dioxide （CO2） anesthesia （directly percussive blow to the head as control group） on the flesh quality of Tilapia. Then the processed Tilapia were vacuum-packed in low-density polyethylene （LDPE） bags and stored at 1±1℃. Rigor mortis, muscle pH, weight loss, total volatile base nitrogen （TVB-N）, sensory evaluation, texture hardness and shear force were measured over a 7 d time span. Results showed that carbon dioxide narcosis prolonged the pre-rigor period of the fillet; pH of muscle was higher initially while decreased in the end. Weight loss of both methods had no significant difference after 3 d post-mortem.But from 4th day to 7th day, weight loss of CO2 anesthesia group was significantly lower than the control group. Except for post-mortem of the 0 d, 4th day and 5th day, TVB-N value of CO2 anesthesia group was obviously lower than the control group. No evident difference in the texture deterioration and sensory qualities were found between the two group, but hardness, shear force and sensory quality of the sample at 7th day were dramatically lower than that at 0 day. The pre-slanghter method of CO2 anesthesia, combined with all quality indicators, was more suitable to process tilapia flesh than percussive stunning.