Factors impacting acrylamide formation in table olives with particular focus on polyphenols

Abstract

The food-borne toxicant acrylamide occurs in table olives, but the formation mechanism is not fully understood. This study investigated different factors influencing acrylamide formation in green and naturally black table olives. Experiments with isotopically substituted asparagine and 3-aminopropionamide revealed that acrylamide formation through asparagine is possible with formation rates between 0.19 and 1.3 mol%. However, the calculation with these rates showed that this pathway is not the predominant one in olives. In addition to asparagine, a peptide led to acrylamide formation in model systems. In mixtures of olive extract with hydroxytyrosol, acrylamide contents rose by a factor of 2 for the green and 1.6 for the naturally black table olive during 14 days of standing. Furthermore, various experiments indicated that the oxidation of polyphenols enhances acrylamide formation in olives and that reactions already start under mild conditions. Hydroxytyrosol appears to play an important role in this, as it increases acrylamide formation in green and natural black table olive extracts by up to 35% compared to other polyphenols after heating at 120 °C.