EFFECTS OF NONENZYMATIC BROWNING REACTIONS ON LIPID OXIDATION IN EMULSIFIED MODEL SYSTEMS

The effect of non-enzymatic browning (NEB) reactions (Maillard reactio n, caramelization) on lipid oxidation was studied in emulsified model systems in order to confirm the antioxidative activity of Maillard Rea ction Products (MRPs) and to verify the eventual antioxidant propertie s of the caramelization products (CPs). The model system (E) was broke n up into its components in order to form four other systems and to st udy the different chemical reactions: A) soybean oil (control); B) sys tem A with water and xanthan; C) system B with glucose; D) system B wi th lysine. The complete model system (E) was made up of oil, water, gl ucose, Lysine and xanthan. All model systems were treated at 90 degree s C for 120 hours and samples were taken at regular intervals. Peroxid e value, paraanisidine number and volatile hydrocarbons were used as l ipid oxidation indices; colour and carbon dioxide present in the head space vapour of equilibrated samples were used as indices of NEB react ions. In our experimental conditions lipid oxidation was clearly slowe d down by MRPs but not by CPs. However, lysine seemed to have a prooxi dant effect, if judged by pentane formation.