低场核磁共振结合主成分分析法在食用油脂品质分析中的应用

The Quality Assessment of Edible Oils and Fats by LF-NMR Coupled with PCA

应用主成分分析法(PCA)对多种不同品质油脂样品的LF-NMR弛豫特性数据(T21、T22、T23、S21、S22、S23)进行了分析。研究表明,应用PCA可明显区分正常大豆油和棉籽油,但棕榈油和猪油样品分布范围有一定的重合;无论是轻度煎炸还是深度煎炸,不同种类的煎炸油脂在PCA得分图中能够明显分区;随煎炸时间的延长,油样在PCA得分图上的分布逐渐向左上方移动,四种油脂能够明显分为两类:棕榈油和猪油,大豆油和棉籽油;食用猪油与掺伪猪油样品在PCA得分图上能够明显区分,掺伪比例愈高,二者的区分效果愈好,试验验证正确。说明基于油脂的LF-NMR弛豫特性,结合主成分分析可实现对食用油脂种类、煎炸油程度及掺伪猪油的品质区分。

Principal component analysis（PCA） was used to analyze the low field nuclear magnetic resonance（LF-NMR） relaxation characteristics（T21,T22,T23,S21,S22,S23） of a variety of different oil samples.The results indicated that application of PCA to the LF-NMR data allowed a good differentiation between edible soybean oil and cottonseed oil;while palm oil and lard could not be obviously distinguished.Different kinds of fried oil samples could be properly differentiated,regardless of the frying degree.As the frying process prolonged,the distribution of the fried oil samples moved to upper right based on the principal component scores.And the fried oil samples could be obviously divided into two groups：palm oil and lard,soybean oil and cottonseed oil.In addition,it was easy to distinguish adulterated lard from edible lard according to their corresponding principal component scores.With adulteration ratio of fried lard increased,higher distinguish ability was found and experimentally verified correctly.Therefore,LF-NMR combined with PCA is feasible to analyze the variety of edible oil,the degree of fried oil,and the quality of adulterated lard.