稳定同位素比技术用于橄榄油的掺假鉴定

Olive Oil Adulteration Identification Using Stable Isotope Ratio Technique

市场上橄榄油掺假现象屡禁不止,传统鉴定方法存在局限性。本研究利用元素分析仪-稳定同位素比质谱仪(elemental analyzer-isotope ratio mass spectrometer,EA-IRMS)对市场上常见的7种植物油进行氢、碳稳定同位素比值检验,并对测量结果进行显著性差异分析,同时分析橄榄油中氢、碳稳定同位素比值的相关性。结果表明:橄榄油中δD范围为-146.78‰~-125.30‰,δ^(13)C范围为-29.72‰~-28.59‰,与其他品类植物油中氢稳定同位素比值差异显著(P<0.05),与除葵花籽油、野山茶油外的植物油中碳稳定同位素比值差异显著(P<0.05);且橄榄油中氢、碳稳定同位素比值具有较强的相关性(Pearson’s r=0.904)。计算模拟豆油、玉米油对橄榄油掺假的情况,结果表明,氢、碳稳定同位素比结合分析最低能检测出玉米油掺假10%、豆油掺假30%以上的情况。该研究可为橄榄油的掺假鉴定提供方法参考。

Olive oil adulteration issue on the market emerges in an endless stream.Stable isotope ratio technique can be effectively used for the adulteration identification of olive oil.In this research,isotope ratio differences between olive oil and other vegetable edible oils were investigated.Seven common vegetable edible oils were collected from markets.Stable hydrogen and carbon isotope ratios of selected edible oils were measured by elemental analyzer-isotope ratio mass spectrometer(EA-IRMS).The correlation between the hydrogen and carbon stable isotope ratios in olive oil was also analyzed.The results showed that the olive oil’sδD ranges from-146.78‰to-125.30‰,and the olive oil’sδ^(13)C ranges from-29.72‰to-28.59‰,which are both significantly different from the stable hydrogen and carbon isotope ratios of other vegetable oils(P<0.05).The stable hydrogen isotope ratio of olive oil has a strong correlation with its stable carbon isotope ratio(Pearson’s r=0.904).Simulation and calculation of olive oil adulteration showed that 10%adulteration by corn oil and 30%adulteration by soybean oil are the limit of determination by the combination of hydrogen and carbon stable isotope ratio analysis.