Differentiation of Plant Oils Using Chemical Markers

Presentation title: Differentiation of Plant Oils Using Chemical Markers

Abstract: Plant oils are vital food ingredients in human food and nutrition, providing essential fatty acids and vitamins. However, issues such as adulteration including fraudulent blending of cheaper oils with more expensive ones have been reported, posing challenges for authenticity and safety. These adulterations are difficult to detect, and while routine analytical techniques, such as fatty acid composition analysis, offer valuable insights into quality, they may not be sufficient to prevent food fraud.

Minor chemical components, such as sterols, vary significantly based on the plant oil source and can serve as reliable chemical markers for differentiation. By comparing the presence and relative ratios of sterols, an orthogonal method for identifying plant oils can be developed. Recognizing the importance of this approach, the Food Chemicals Codex (FCC) aims to modernize its sterol analysis methodology.

In this study, we analyzed the sterol profiles of eight plant oils—camellia seed oil, sesame oil, sunflower oil, soybean oil, rice bran oil, corn oil, peanut oil, and rapeseed oil—and identified seventeen distinct sterols. The new method employs advanced solid-phase extraction, replacing the outdated and labor-intensive thin-layer chromatography (TLC) technique. Sterol separation was achieved using a 60-m × 0.250-mm (i.d.) fused-silica column with a 0.10-μm film of 5% phenyl–95% methylpolysiloxane coating. Hydrogen, utilized as the carrier gas, demonstrated improved separation performance compared to helium, with a split ratio of 1:20.

This innovative method not only enhances the identification and authentication of plant oils but also establishes sterols as robust chemical markers to combat plant oil adulteration and ensure plant oil quality and integrity.