Novel Amadori and Heyns compounds derived from short peptides found in dried cocoa beans

Chemical transformations of Amadori compounds are responsible for the formation of aroma volatiles at the end of the Maillard reaction cascade, which in turn contributes to unique organoleptic characteristics of chocolate. A large amount of short peptides reported in fermented cocoa suggests the existence of a much larger variety of these flavor precursors than previously suspected. An HPLC-MS-MS study was performed on dried Malaysian cocoa beans to identify novel Amadori and Heyns compounds. In total, 34 species were found, including 26 previously unknown derived from di- and tripeptides. We illustrate how the structures were elucidated via tandem MS experiments, as well as present a comparative study on their relative quantities in samples coming from 11 countries of origin. There were significant differences between them, and discrimination was possible by principal component analysis based on Amadori content alone. However, the PCA separation could be a result of various post-harvest practices exerted among said countries.