Detection of Qinghai-Tibet Plateau flaxseed oil adulteration based on fatty acid profiles and chemometrics

Flaxseed oil is an important ingredient in functional foods, as it is rich in polyunsaturated fatty acids, phenolic compounds (lignans, ferulic and p-coumaric acid), and mucilage. Therefore, economically motivated flaxseed oil adulteration is a common occurrence. Developing effective approaches to detecting such adulteration is essential to preserve flaxseed oil quality and safety. Herein, similarity evaluation (SE), discriminant analysis (DA), principal component analysis (PCA), and heat map approaches were employed to differentiate between samples of flaxseed oil that had been adulterated with a range of concentrations of rapeseed, corn, peanut, safflower, soybean, or sesame oil (10–50%) based on their fatty acid composition. The standard fatty acid fingerprint of pure flaxseed oil was analyzed with 100% accuracy when the adulterant concentration was greater than 10%. DA approach was able to identify specific vegetable oil types in flaxseed oil samples that had been adulterated with less than 20% rapeseed, corn, peanut, sunflower, soybean, or sesame oil. Heat map indicated that linolenic acid was the reliable marker of flaxseed oil adulteration and PCA analyses was more effective in identifying adulteration concentration for all models other than rapeseed oil and corn oil. Overall, the stepwise hierarchical approach developed and outlined in the present study represents a valuable approach to asses flaxseed oil adulteration.