Casein makes up the majority of the proteins in cheese and quark. Although casein itself does not taste bitter, its digestion in the stomach also produces bitter-tasting protein fragments (peptides). This has been proven for the first time in a study led by the Leibniz Institute for Food Systems Biology at the Technical University of Munich (LSB). The study also suggests that the bitter peptides are able to stimulate acid secretion from gastric cells via their cellular bitter receptors. A mechanism that, according to the research team, could contribute to the long-known satiating effect of milk protein.