冷冻牡蛎贮存过程中脂溶性有毒物质的变化研究

Research on Fat-Soluble Toxicant in Stored Frozen Oyster

牡蛎是我国出口量较大的水产品之一，由于产品本身的特殊性，在生长过程中易产生腹泻性贝毒（DSP）。本实验中原料牡蛎DSP生物法检测结果为阴性，冷冻贮存4个月后检测结果即为阳性。本研究以分析这一变化原因为目的，采用LC-MS法对DSP生物检测的阳性样品进行确认，结果表明，生物法DSP检测的结果为假阳性，造成生物法DSP检测中小白鼠死亡的是牡蛎在贮藏过程中产生的脂溶性有毒物质。进一步分析确定该有毒物质为牡蛎脂肪水解物——游离脂肪酸。同时本研究对牡蛎在不同贮存温度和贮存时间下产生的游离脂肪酸含量进行了测定，在-10℃贮存温度下，贮存0，2，4，6，8，10个月，游离脂肪酸的变化范围为5．2-788．6mg／kg；在-10℃，-18℃，-25℃贮存温度下，贮存4个月，游离脂肪酸的变化范围为92．5-389mg／kg。

The oyster is one of the main exports of aquatic products in our country. Due to the specificity of this product, diarrhetic shellfish poisoning（DSP） is easy to produce in the growth process. In this ex- periment, the DSP biological test results are negative in raw oysters, but positive when they were in frozen storage for four months. The purpose of our research was to analysze this change. The LC-MS method was used for the biological detection of DSP-positive samples. It confirmed that DSP biological detection results were false-positive, and what led to the death of mice in the biological detection of DSP was the fat-soluble toxic substances produced in the oysters in the frozen storage. Further analysis indicated that the toxic substances were the hydrolysates of oyster fat-free fatty acids（FFA）. At the same time, FFA of oyster were determined at different storage temperatures and storage times. FFA changed in the range of 5.2-788. 6 mg/kg when stored 0, 2, 4, 6, 8 and 10 months at -10 ℃, and in the range of 389 -92. 5 mg/kg when stored for 4 months at -10 ℃, -18 ℃ and -25 ℃. Key words,