基于特征脂肪酸的食用油中棉籽油掺假鉴别技术

Adulteration detection of edible oil with cottonseed oil based on characteristic fatty acid

目的开发检测棉籽油特征标志物锦葵酸和苹婆酸的气相色谱-质谱法,实现食用油中棉籽油掺假确证性鉴别。方法利用碱式甲酯化方法对油脂样品进行酯化,正己烷提取脂肪酸甲酯,加入无水硫酸钠过滤,选择性离子扫描模式采集数据,外标法定量,以特征标志物判定食用油中是否掺假棉籽油。结果建立的食用油中锦葵酸和苹婆酸高灵敏检测技术能准确鉴定食用油中5%棉籽油掺假。与基于脂肪酸组成结合偏最小二乘法-判别分析仅能鉴别大豆油中10%以上的棉籽油掺假相比,本研究建立的基于标志物方法鉴别灵敏度更高。结论本研究建立了食用油中苹婆酸和锦葵酸高灵敏检测技术,为鉴别食用油中棉籽油掺假提供了关键检测技术支撑。

Objective To develop a method for the determination of characteristic markers of cottonseed oil including malvalic acid and sterculic acid by gas chromatography mass spectrometry to identify the edible oil adulterated with cottonseed oil.Methods The oil samples were processed using a basic methyl esterification method,fatty acid methyl esters were extracted by n-hexane,solid precipitates were filtered off after adding anhydrous sodium sulfate,data acquisition was performed using selective ion scanning mode,and quantification was performed by external standard method to determine whether cottonseed oil was adulterated by the content of characteristic markers.Results The highly sensitive detection technique for mallow acid and malic acid in edible oil established in this paper could achieve accurate verification of 5%cottonseed oil in adulterated edible oil.Compared with the fatty acid composition-based method combined with partial least squares-discriminant analysis,which could only identify more than 10%of cottonseed oil adulteration in soybean oil,the marker-based method developed in this study was more sensitive.Conclusion This study has developed a highly sensitive detection technique for malvalic acid and sterculic acid in edible oil,which provides a key technical support to realize the adulteration of cottonseed oil in other edible oils.