Properties of model systems of sunflower oil and green coffee extract after heat treatment and storage

- Green coffee extract limited oxidation of sunflower oil during storage and heating.
- Coffee polyphenols increased scavenging activity of unheated and heated sunflower oil.
- Low correlation between PUFA content and PV during sunflower oil heating was observed.

Model systems of sunflower oil and green coffee extract (GCE) were examined. GCE was added to the oil at 3 g/100 g. Complex systems of the oil with saccharose, starch and egg white protein were studied. Samples were heated at 110 °C or 180 °C for 60 min and stored for 3 months. The research was aimed at determining the effects of high concentrations of green coffee antioxidants on the oxidative status of fatty acids and antioxidant activity of the systems depending on their composition. The fatty acid profile using the GC-FID method and peroxide value of sunflower oil as well as potentiometric determination of redox potential and the DPPH radical scavenging ability of model systems were analyzed. The obtained results showed a limiting of oxidation of sunflower oil heated with 3 g/100 g of GCE alone and in more complex systems. The average inhibition degree was 65% when compared to analogical non-enriched systems. The research also concluded that, despite prolonged heating and storage, these systems exhibited a significantly higher (P < 0.05) antioxidant activity in a test with DPPH when compared to those without GCE.