化学计量法结合气相色谱鉴别米糠油掺伪菜籽油

摘要

To establish a rapid qualitative and quantitative detection method of rice bran oil( RBO) adul-terated by rapeseed oil, pure RBO and adulterated RBO with different proportions of rapeseed oil were detected by capillary gas chromatography. Using contents of C14∶0, C16∶0, C16∶1, C17∶0, C18∶0, C18∶1,C18∶2,C18∶3,C20∶0,C20∶1 and C22∶1 as variables,qualitative detection was made by cluster analysis and discriminant analysis and quantitative detection was made by the linear method and chroma-tographic fingerprint similarity method. The results showed that cluster analysis and discriminant analysis were able to make correct identification when RBO was mixed with more than 2% rapeseed oil. Linear model of characteristic fatty acid ( Y ) and adulteration amount ( X ) of rapeseed oil was established as follows:YC22∶1 =0. 158 2X+0. 350 7(R2 =0. 991 0) and the limit of detection was 2%. The vectorial angle method ( VAM) was brought forward to calculate similarity of chromatographic fingerprint between adulterated RBO and pure RBO,and the fitting model of similarity ( Y) and adulteration amount ( X) was Y= -23. 62X3 -8. 380 6X2 -6. 138 3X+100. 12(R2 =0. 999 4).%为研究米糠油掺伪菜籽油的快速定性定量检测方法，采用毛细管气相色谱法测定掺伪不同比例菜籽油的米糠油脂肪酸含量，将 C14∶0、C16∶0、C16∶1、C17∶0、C18∶0、C18∶1、C18∶2、C18∶3、C20∶0、C20∶1、C22∶1含量作为变量，通过聚类分析和判别分析对掺伪油样进行定性分析，采用一元线性法与指纹图谱相似度法对掺伪油样进行定量分析。结果表明：米糠油掺伪菜籽油2%以上，聚类分析和判别分析均能正确进行辨别；特征脂肪酸一元线性模型为 YC22∶1=0.1582X +0.3507(R2=0.9910)，检出限为2%；利用向量夹角余弦法计算纯米糠油与掺伪米糠油的相似度，建立的掺伪量与相似度的线性模型为Y=-23.62X3-8.3806X2-6.1383X+100.12(R2=0.9994)。