不同宰杀方式对草鱼肉呈味水溶性成分的影响

Effect of Different Slaughter Methods on Water-Soluble Flavor Components in Grass Carp Meat

以不同宰杀方式草鱼的背部肉为对象,采用高效液相色谱法和氨基酸自动分析法研究不同宰杀方式(自然、急杀、去鳃)对草鱼背部肉核苷酸类化合物和游离氨基酸含量的变化,并测定背部肉p H值、糖原和乳酸的含量。结果表明:自然、急杀、去鳃3种宰杀方式的草鱼背肉苦味氨基酸含量占总游离氨基酸含量分别为78.95%、68.60%、69.44%,部肉的鲜度K值分别为20.28%、15.49%、12.13%,自然死亡组腺嘌呤核苷三磷酸含量最低,肌苷酸含量最低,鲜度最差。草鱼背肉中p H值的变化与乳酸含量的变化呈负相关,乳酸含量的变化与糖原含量的变化呈负相关,自然死亡的草鱼肉乳酸含量最高,pH值最低。不同宰杀方式对草鱼背肉呈味水溶性成分影响较大,自然死亡的草鱼肉滋味最差,急杀致死和去鳃致死组滋味差别不明显。因此,在加工过程中,要避免鱼血渗入肌肉,造成鱼肉土腥味产生。

The contents of nucleotide compounds and free amino acids in the dorsal meat of grass carp slaughtered by different methods, that is, natural death, emergency slaughter and gill removal, were determined and compared by high performance liquid chromatography（HPLC） and amino acid auto-analyzer. Besides, p H and the contents of glycogen and lactic acid in fish dorsal meat were also determined. The results showed that the percentage of bitter amino acids accounting for the total amount of free amino acids in the dorsal meat of grass carp subjected to the above three slaughter methods were 78.95%, 68.60% and 69.44%, respectively, and K values as a freshness index for fish meat were 20.28%, 15.49% and 12.13%, respectively. Dorsal meat samples from naturally dead grass carp exhibited the lowest contents of ATP and IMP and worst freshness. The changes in p H and lactic acid content were negatively correlated with each other along with the changes in lactic acid and glycogen contents in the dorsal meat of grass carp, regardless of the slaughter methods used. The dorsal meat of naturally dead fish had the highest lactic acid content and lowest p H value. Different slaughter methods had a large effect on water-soluble flavor components in grass carp meat. The taste of naturally dead grass fish was the worst and the taste difference between two other slaughter groups was not obvious. Thus, during slaughter and processing of fish the blood should be prevented from infiltrating into the muscle in order to avoid the generation of off-flavor.