Identification of the Bitter Principle of Cocoa

Abstract

Abstract The following diketopiperazines have been identified in roasted cocoa: Cyclo(‐Pro‐Leu‐), Cyclo(‐Val‐Phe‐), Cyclo(‐Pro‐Phe‐), Cyclo(‐Pro‐Gly‐), Cyclo(‐Ala‐Val‐), Cyclo(‐Ala‐Gly‐), Cyclo(‐Ala‐Phe‐), Cyclo(‐Phe‐Gly‐), Cyclo(‐Pro‐Asn‐), Cyclo(‐Asn‐Phe‐). The typical bitterness of cocoa is due to an interaction of the purine theobromine ( 2 ) and diketopiperazines, which are formed during the roasting of the coca beans.