In-mouth flavour release from milk proteins

The in-mouth release of flavour (2-nonanone) from whey protein isolate (WPI) and sodium caseinate in aqueous solutions, and the influence of the thickener, sodium carboxymethylcellulose (CMC), on the release of 2-nonanone were investigated using proton-transfer-reaction mass spectrometry. During consumption, a significant release of 2-nonanone from WPI (2%) was observed. After swallowing the samples, a substantial amount of flavour was detected in the breath, suggesting that some sample solution remained in the mouth and throat, resulting in a further release of flavour from proteins. In the presence of CMC, a significant release of 2-nonanone from not only WPI but also sodium caseinate was observed, which may be attributable to the increase in viscosity of the solutions. It is likely that a thicker coating of the mouth and throat with the higher viscosity sample after swallowing results in additional release of protein-bound flavour.