腐败希瓦氏菌对凡纳滨对虾氨基酸及生物胺含量的影响

Effect of Shewanella putrefaciens on the Amino Acids Metabolism and Biogenic Amines Production in Litopenaeus vannamei

以凡纳滨对虾为研究对象,通过分析接种腐败希瓦氏菌的对虾在30℃和4℃贮藏条件下微生物生长情况、感官品质、氨基酸及生物胺含量的变化,比较不同温度下腐败希瓦氏菌生长代谢活性及凡纳滨对虾品质的变化。结果表明,与30℃条件相比,4℃条件下凡纳滨对虾的感官品质下降趋势较缓,且腐胺和尸胺含量都较低,腐败希瓦氏菌在低温下表现出较强的适应能力。在感官不可接受点时,4℃条件下接菌组样品中总氨基酸含量却较30℃条件下的低,分别为(168.25±1.86)mg/g和(174.16±0.89)mg/g,其中以总赖氨酸、总精氨酸和总酪氨酸下降幅度最为显著,同时游离氨基酸含量也明显较低。凡纳滨对虾贮藏期间,腐败希瓦氏菌在对数生长期时,对虾的总赖氨酸含量下降最快。低温虽然能够抑制腐败希瓦氏菌菌落数的增长和生物胺的累积,但是腐败希瓦氏菌在低温环境下生长代谢需要更多的氨基酸,以促进凡纳滨对虾蛋白质和氨基酸的降解,降低对虾的风味和营养品质。

The effect of Shewanella putrefaciens on degradation of amino acids and biogenic amines in Pacific white shrimp at 30 ℃ and 4 ℃ was studied by determining the bacterial counts, sensory scores, amino acids and biogenic amines. Compared with the shrimp at 30 ℃, the shrimp stored at 4 ℃ hada better sensory quality with low contents of putrescine and cadaverine. However, S. putrefaciens could survive and grow at low temperature. At the sensory rejection time, the total content of total amino acids in shrimps stored at 4 ℃ were even lower than shrimps stored at 30 ℃, c.a.（168.25±1.86） mg/g and（174.16±0.89） mg/g, respectively. Among them, total LYS, ARG and TYR of shrimp stored at4 ℃ were significantly lower than those stored at 30 ℃. The favor free amino acids of shrimpa also decreased drastically during storage at 4 ℃. The decreasing tendency of LYS indicated that LYS decreased drastically with the log phases of S.putrefaciens. Low temperature could inhibit growth of S. putrefaciens and accumulation of biogenic amines. However, it may still lead to the loss of flavor and nutrients by accelerating the degradation of protein and amino acids.