Volatile compounds produced from peanut oil heated with different amounts of cysteine

Volatile compounds produced in the headspace of peanut oil heated with cysteine (0.5-10.0 g) at 200 degree C for 5 h were collected by a simultaneous purging and solvent extraction apparatus. Volatiles in the extracts were analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). Ninety-eight compounds were positively identified among over 150 gas chromatographic peaks. The majority of these were sulfur-containing compounds such as thiophenes, thiazoles, thiazolines, thiazolidines, and cyclic polysulfides. The two most abundant sulfur-containing compounds were 2-methylthiazolidine and 2-methyl-2-thiazoline. Decarboxylation of cysteine at high temperatures and subsequent reaction with aldehydes was proposed as a formation mechanism of both 2-alkylthiazolidines and 2-alkyl-2-thiazolines.