Studies on non-volatile amines as potential indexes for freshness of marine invertebrates

研究了非挥发性胺的浓度与普通鱿鱼、扇贝和对虾的分解过程的关系。采用带荧光检测器的梯度洗脱高效液相色谱仪分离腐胺（Put）、革胺（Agm）、尸胺、酪胺和色胺。Agm作为普通鱿鱼新鲜度的潜在指标似乎最有用。新鲜肌肉中检测到少量Agm，随着存放时间的延长，Agm浓度逐渐增加，在初期分解阶段超过30 mg/100g，在后期分解阶段达到40 mg/100g。Put没有在可接受的阶段产生，并且在初始分解阶段检测到少量（小于1 mg/100g）。因此，Put作为初始分解阶段的一个指标是有用的。在扇贝中，初始分解阶段的Put含量为0.5 ~ 0.7 mg/100g，深度分解阶段的Put含量超过2.1 mg/100g。Put似乎可以作为扇贝内收肌新鲜度的潜在指标。在对虾中，Put也适合作为分解的指标。新鲜肌肉中不存在Put，在初始分解阶段检测到少量（小于1 mg/100g），随着分解的进行显著增加。在初始分解阶段，VBN和K值分别为30 mg/100g和30%。研究了加氯霉素和不加氯霉素的鱿鱼和扇贝肉中非挥发性胺含量和总细菌活菌数的变化。结果表明，非挥发性胺不是由肌肉脱羧酶产生的，而是由细菌脱羧酶产生的。当活菌数在鱿鱼和扇贝中分别达到10^3/g和10^3/g至10^4/g时，观察到非挥发性胺的形成。

The concentrations of non-volatile amines were investigated in relation to decomposition processes of common squid, scallop and prawn. Putrescine (Put), agmatine (Agm), cadaverine, tyramine and tryptamine were well separated from each other by gradient elution high performance liquid chromatograph with a fluorescence detector. Agm appeared to be most useful as a potential index for freshness of common squid. Agm was detected in small amounts in the fresh muscle and the concentration increased with storage time, exceeding 30 mg/100g at the stage of initial decomposition and reached the level of 40 mg/100g at the stage of advanced decomposition. Put was not produced at the acceptable stage and detected in small amounts (less than 1 mg/100g) at the stage of initial decomposition. Therefore, Put was useful as an indicator for the stage of initial decomposition. In scallop Put was detected at the level of 0.5 to 0.7 mg/100g at the stage of initial decomposition and exceeded 2.1 mg/100g at the stage of advanced decomposition. Put appeared to be useful as a potential indicator for freshness of scallop adductor muscle. In prawn Put was also suitable as an index for decomposition. Put was not present in the fresh muscle, detected in small amounts (less than 1 mg/100g) at the stage of initial decomposition and increased remarkably as decomposition progressed. VBN and K value showed 30 mg/100g and 30 %, respectively, at the stage of initial decomposition. The changes in non-volatile amines contents and viable counts of total bacteria were examined in the meats of squid and scallop with and without chloramphenicol. It was elucidated that non-volatile amines were not produced from amino acids by decarboxylases of muscle but by those of bacteria. When viable counts reached the level of 10^3/g in squid and 10^3/g to 10^4/g in scallop, the formation of non-volatile amines was observed.