快速鉴别掺伪橄榄油的拉曼光谱-聚类分析方法

Raman spectrum-cluster analysis for rapid discerning of adulterated olive oil

以不同产地、不同品牌的多批次橄榄油、大豆油、玉米油、菜籽油、葵花籽油、棕榈油、棉籽油及精炼地沟油为样品,探索建立快速鉴别掺伪橄榄油的拉曼光谱-聚类分析方法。在780、532 nm激光光源普通光栅、532 nm激光光源扩展光栅条件下,研究了橄榄油、低价食用植物油与精炼地沟油的拉曼光谱形态;并采用聚类分析法鉴别掺伪橄榄油。结果表明:在532 nm激光光源下,橄榄油与低价食用植物油及精炼地沟油扩展及其一阶导数拉曼光谱的信息量极为丰富,而且各类样品间的光谱形态差异显著。基于全波段光谱信息和形态建立的聚类分析模型既可准确鉴定橄榄油,还可准确鉴定各种类型的掺伪橄榄油。对30份不同橄榄油、105份不同低价食用植物油和38份不同精炼地沟油的判别正确率均为100%,对180份5%及以上的掺假橄榄油的判别正确率达94%以上,对75份5%及以上的掺杂橄榄油的判别正确率为100%,对72份5%及以上的掺杂植物油的判别正确率达88%以上。样品测量时无需制备样品及消耗化学试剂,测量和分析1份样品仅耗时5min左右,可实现对掺伪橄榄油的快速、无损和准确鉴别。

Raman spectrum- cluster analysis method was developed for rapid discerning of adulterated olive oil using multiple batches of olive oil,soybean oil,corn oil,rapeseed oil,palm oil,cottonseed oil and refined swill- cooked dirty oil with various origins and brands as samples. Raman spectrum patterns of olive oil,low- price edible vegetable oil and refined swill- cooked dirty oil were studied under the conditions of 780 nm and 532 nm laser sources with common gratings and 532 nm laser source with extended grating. Then the adulterated olive oil was discerned by cluster analysis method. The results indicated that the extended and first- order derivative Raman spectra showed abundant information and significantly different spectrum patterns among olive oil,low- price edible vegetable oil and refined swill- cooked dirty oil in 532 nm laser source. The cluster analysis model established on full- range spectrum information could discern olive oil as well as kinds of adulterated olive oils. The discriminant rates were 100% for30 olive oils,105 low- price edible vegetable oils,38 refined swill- cooked dirty oils and 75 olive oils mixed with at least 5% refined swill- cooked dirty oil. Besides,the discriminant rates were above 94%and 88% respectively for 180 olive oils mixed with at least 5% low- price edible vegetable oil and 72 vegetable oils mixed with at least 5% refined swill- cooked dirty oil. The measurement process required no sample preparation or chemical reagent consumption,and the time cost was 5 min for each sample,therefore the discerning of adulterated olive oil was rapid,non- destructive and accurate.