傅里叶变换近红外光谱结合RVM与新聚类算法鉴别灵芝孢子油多样掺假类别

食品掺假种类众多,手段隐蔽,成为食品安全检测一个重要难题。为摆脱传统模型识别食品中是否存在新掺假类别的局限性,实验以纯净的灵芝孢子油和掺杂不同比例花生油、玉米油、薏仁油、地沟油的五种类别为研究对象,采用傅里叶变换近红外光谱(Fourier transform near infrared spectroscopy,FT-NIR)收集12 400~4 000cm~(-1)范围内的近红外光谱。假设掺杂地沟油为新掺假类别,利用前四种类别的校正集样本构建相关向量机(RVM)多分类器,分别对建模的预测集样本和掺杂地沟油样本进行判别,并借助新聚类算法对判别为纯净的灵芝孢子油的样本做进一步分析验证。研究表明,RVM分类器对于建模的预测集样本判别准确率高达93.75%,说明模型有较强的判别能力,但由于模型局限性,掺杂地沟油样品被误判为纯净的灵芝孢子油;在新聚类算法的决策图上,纯净灵芝孢子油校正集和预测集混合样本的聚类中心数为1,而纯净灵芝孢子油校正集和掺杂了地沟油混合样本聚类中心数为2,直观验证判别结果的准确性。结果表明利用FT-NIR技术结合RVM分类器与新聚类算法对于灵芝孢子油掺假能够有效识别,并且能够定性识别新型掺假类型,为解决食品掺假多样化问题提供一种新思路。

Study on Diversified Adulteration of Ganoderma Lucidum Spore Oil by RVM and New Clustering Algorithms

In recent years,food adulteration of various ki nds has become a severe problem in food safety detection.In order to get rid of the limitations of traditional qualitative identification of new food adulterat ion,Fourier transform near-infrared spectroscopy (FT-NIR) was used to collect the spectrum ranging from 12 400 to 4 000 cm-1.The pure ganoderma lucid um spore oil adulterated with peanut oil,corn oil,coix seed oil,and hogwash o il were investigated in this study,where the ganoderma lucidum spore oil adulte rated with hogwash oil was taken as the new category of food adulteration.Then,Multiple Relevance Vector Machine (RVM) classifiers were constructed with calib ration samples of the first 4 categories.The prediction samples and ganoderma l ucidum spore oil adulterated with hogwash oil were discriminated by the 4 kinds of classifier.In addition,the discriminated results were further verified with new clustering algorithm.Results showed that the discriminant accuracy of the first four categories was close to 93.75％ with RVM classifier,but the ganoderm a lucidum spore oil adulterated with hogwash oil was mistaken for pure ganoderma lucidum spore oil because of the limitations of model.So a new clustering algo rithm based on local density and distance decision graph was applied to verify t hat.It was found that the cluster centers were 1 when the samples only containe d pure ganoderma lucidum spore oil,however,the cluster centers were 2 when the samples mixed with pure ganoderma lucidum spore and adulterated with hogwash oi l.The results demonstrated the FT-NIR in combination with RVM classifier and n ew clustering algorithm could be used for the identification of the adulterant i n the pure ganoderma lucidum spore oil and qualitatively identify new category o f food adulteration,providing a new method to solve the problem of food diversi fied adulteration.