Impacts of carnosine on the formation of perfume compounds by ascorbic acid-methionine model reaction

By the solid phase micro-extraction - gas chromatography - mass spectrometry (SPME-GC-MS) technology, this article identifies products from the model reaction between ascorbic acid and methionine (ASA-Met), and studies the impacts of carnosine on the formation of perfume compounds from the model reaction. 16 perfume compounds have been identified, including furan, pyrazine, thiophene, pyrrole, compounds containing benzene rings and sulfur compounds, of which sufur compounds, such as alicyclic sulfides, thioether and pyrazine, are the main flavor components. For carnosine being added to the model system, one the one hand, the yields of some sulfur compounds will be significantly reduced, or even disappear; on the other hand, it promotes the production of several nitrogen compounds such as methyl pyrazine, ethyl pyrazine and 2,6-dimethyl pyrazine, and other alkyl pyrazine. This indicates that carnosine inhibits the thermal degradation of Met in the model reaction, and also implies that as the nitrogen source during the thermal degradation of carnosine NH3 may be generated. After a competing reaction occurs between NH3 and the degradation products of H2S and ASA, nitrogen compounds are formed, such as alkyl pyrazine, so as to cause the lower production of sulfur compounds.