Phosphatidylcholine, Defatted beef matrix, Lipid oxidation, Flavoromics, Thermal oxidation model reconstruction, Nutrition. Foods and food supply, TX341-641, Food processing and manufacture, TP368-456

Thermal oxidation of phospholipids and triglycerides is a major source of beef aroma compounds. In this study, phosphatidylcholine (PC) and triglyceride (TG) were isolated and purified from beef and added to defatted beef and raw beef. The composition of aroma compounds generated by thermal oxidation in three model systems were compared by flavoromics. The main aroma compounds produced by the thermal oxidation of PC were decanal, (E)-2-nonenal, (E)-2-undecenal, and (E,E)-2,4-decadienal, while the main aroma compounds produced by the thermal oxidation of TG were nonanal, (E)-2-undecenal, and decanal. Nonanal remains the main aroma compound produced by PC and TG in defatted beef. Octanal and nonanal were the major aroma compounds generated by thermal oxidation of raw beef samples spiked with PC and TG. Raw beef with added PC and TG had higher levels of sulfides and heterocycles after thermal oxidation compared to defatted beef with added lipids. The comparison of the aroma profiles in three thermo-oxidative models indicated that PC contributed more than TG to the key odor-active compounds in cooked beef. Additionally, the thermo-oxidative degradation of PC facilitated the formation of Maillard reaction products. However, the beef matrix may inhibit the formation of decanal and (E,E)-2,4-decadienal.