基于7种脂肪酸含量测定和化学计量学的沙棘籽油质量评价研究

Study on quality evaluation of seabuckthorn(Hippophae rhamnoides L.) seed oil based on determination of 7 kinds of fatty acids content and chemometrics

目的建立气相色谱法同时测定沙棘籽油中7种脂肪酸的含量,并结合化学计量学进行质量评价。方法样品经甲酯化后,采用DB-23色谱柱(60 m×0.25 mm,0.25μm)测定脂肪酸含量。通过聚类分析(cluster analysis,CA)、主成分分析(principal component analysis,PCA)和正交偏最小二乘判别分析(orthogonalpartial least squares discriminant analysis,OPLS-DA)对19批沙棘籽油进行质量评价。结果 7种脂肪酸甲酯在各自浓度范围内线性关系良好,r≥0.9999,棕榈酸(palmitic acid)、棕榈油酸(palmitoleic acid)、硬脂酸(stearic acid)、油酸(oleic acid)、亚油酸(linoleic acid,LA)、γ-亚麻酸(γ-linolenic acid,γ-LA)和α-亚麻酸(α-linolenic acid,α-LA)平均加样回收率为91.9%~97.4%。通过聚类分析将样品聚为4类,根据主成分分析的样品综合得分进行排名。同时结合正交偏最小二乘判别分析,最终筛选得到油酸、亚油酸和α-亚麻酸是引起沙棘籽油质量差异的标志物,与主成分分析结果基本一致。结论通过脂肪酸含量测定并结合化学计量法,可以对沙棘籽油的质量进行评价,为质量控制提供参考依据。

Objective To establish a method for simultaneous determination of 7 kinds of fatty acids in seabuckthorn seed oil by gas chromatography,and evaluate its quality with chemometrics analysis.Methods The fatty acids content of the samples were determined by DB-23 column(60 m×0.25 mm,0.25 μm) after methyl esterification.The quality of 19 batches of seabuckthorn seed oil was evaluated by cluster analysis(CA),principal component analysis(PCA) and orthogonal partial least squares discriminant analysis(OPLS-DA).Results The linear relationships of the 7 kinds of fatty acid methyl esters were good within the respective concentration ranges,r≥0.9999,and the average recoveries of palmitic acid,palmitoleic acid,stearic acid,oleic acid,linoleic acid(LA),γ-linolenic acid(γ-LA) and α-linolenic acid(α-LA) were 91.9%-97.4%.The results of CA showed that the samples could be clustered into 4 categories,the results of PCA showed comprehensive score and the order,and the results of OPLS-DA showed oleic acid,linoleic acid and α-linolenic acid were screened to be the markers that caused the differences in the quality of seabuckthorn seed oil,and they were consistent with PCA.Conclusion The determination of the content of fatty acids components and combined with stoichiometry can evaluate the quality of seabuckthorn seed oil,and provide a reference basis for the quality control.