Thermal degradation of cystine in aqueous solutions was studied by using a closed model system. The degradations were carried out at pH's of 5.5 and 2.3 and at 160 °C, representing roasting temperature. Forty-two volatile compounds were identified at pH 5.5 and twenty-three at pH 2.3. Three novel sulfides were found in the pH 5.5 volatile mixture: ethyl 1-(ethylthio)ethyl disulfide and the corresponding tri-and tetrasulfides. Only the disulfide was found at pH 2.3. The organoleptic character of the disulfide was sulfury, roasted, and oniony. A mechanism for the formation of these sulfides is proposed. Fifty-five percent of the volatile yield at pH 2.3 were 1,2,4-trithiolanes. Mechanisms for the formation of secondary products are discussed.
All Science Journal Classification (ASJC) codes
- Agricultural and Biological Sciences(all)