低场核磁共振结合化学计量学方法快速检测掺假核桃油

以掺假核桃油样品为低场核磁共振检测对象,利用主成分分析法(PCA)和偏最小二乘回归法(PLSR)分析处理Carr-Purcell-Meiboom-Gill(CPMG)序列的核磁共振弛豫数据,旨在探求一种能快速检测核桃油品质的新方法。对几种常见掺假形式(掺入大豆油、玉米油、葵花油)的核桃油样品和纯核桃油样品进行检测和评价。实验结果表明:纯核桃油和掺入不同种类食用油的掺假核桃油在主成分得分图上可以得到很好的区分,且掺假样品随掺假比例在图中呈规律性分布;采用PLSR法对CPMG数据和实际掺假率进行回归,可实现对核桃油掺假水平的准确定量测定。方法快速、无损、准确,在食用油制品的品质控制及评价方面具有很大的应用潜力。

Rapid Detection of Adulterated Walnut Oil by Low Field-Nuclear Magnetic Resonance Combined with Chemometric Method

In order to search for a new method for the quick detection of walnut oil quality,the adulterated walnut oil samples were tested by low field-nuclear magnetic resonance(LF-NMR),and the relaxation data of CPMG sequence were analyzed and processed by chemometric methods including principal component analysis(PCA) and partial least squares regression(PLSR).The adulterated walnut oil samples with soybean oil,corn oil or sunflower oil and pure walnut oil were used for the LF-NMR detection and evaluation.The experimental results showed that PCA can distinguish pure walnut oil and different kinds of adulterated walnut oil.Moreover,the adulterated walnut oil samples display regular distribution with different adulterated ratios.The CPMG data and actual adulteration value were adopted for the quantitative analysis of walnut oil adulteration level by PLSR.Therefore,the combination of LF-NMR technology and chemometrics could provide a fast,non-destruction and accurate method for the detection of walnut oil adulteration,and show a great application potential in control and evaluation of edible oil products quality.