[Occurrence of bitter taste after roasting of proteins (author's transl)]

Proteins of animal and plant origin (e.g. casein, zein, soyprotein, gliadin), heated to 260 degrees C for 10 min, yield aqueous extracts of strong bitter taste. The thresholds (0.0005-0.008%) are in the range of the value for chininhydrochloride (0.001%) and are much lower than thresholds for enzymatic protein hydrolyzates. Polysaccharides, heated under identical conditions (e.g. cellulose, starch, agar, carrageene), don't yield bitter products. It is assumed, that proteins are important precursors for bitter compounds on roasting.