Novel thiazoles and 3-thiazolines in cooked beef aroma

Over 50 alkylthiazoles and alkyl-3-thiazolines are reported for the first time in the headspace volatiles from pressure-cooked beef steaks. The substituents in the 4- and 5-positions were methyl or ethyl, while the 2-position contained isopropyl, isobutyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, or n-nonyl groups. The meat was obtained from cattle that had been fed diets containing linseed or fish oil supplements. Volatiles from all samples contained the thiazoles and S-thiazolines. However, the concentrations of 2-n-alkyl-3-thiazolines were much higher in the steaks from the cattle fed with fish oil supplements than in the control samples. These 3-thiazolines may form from the interaction of intermediates of the Maillard reaction with aldehydes derived from lipid degradation. The cooked meat from the animals that had been fed fish oil had considerably higher concentrations of saturated and unsaturated aldehydes than meat from the control.