Release and perception of aroma compounds during consumption

Key words: MS-Nose, in vivo aroma release, aroma perception, mouth model, artificial throat, liquid protocol, sweeteners, reversible protein-aroma interactions, emulsions, oil content, droplet size distribution, gel hardness, texture, cross-modal interactions.This thesis evaluated and validated the MS-Nose as a tool to measure aroma release during food consumption. Subsequently, the MS-Nose was used to enhance understanding of the interaction between release and perception of aroma during consumption. Cross-modal interactions, intra and interpersonal variation, and the development of a more relevant in vitro testing device (the artificial throat) were investigated.For aroma release measurements of liquids, a strict protocol was developed to reduce intra and interpersonal variation in mouth movements, breathing, and swallowing. With the use of this protocol it was shown that appropriate concentrations of both sweeteners and protein did not affect in vivo aroma release, despite their well-established effect on aroma release in static headspace and mouth model studies. Also for emulsions, the effect of oil content was smaller under in vivo conditions than under static headspace and mouth model conditions. These discrepancies indicate the necessity to perform in vivo aroma release measurements, rather than static headspace and mouth model studies to investigate the effect of food parameters on the release of aroma compounds during consumption.An artificial throat simulating the consumption of liquid foods was developed and validated as an alternative for conventional model systems, which generally focus on simulating aroma release during oral processing. The results obtained with the artificial throat correlated linearly with in vivo aroma release measurements. The aroma release and perception of a range of gels with different gel hardnesses were evaluated and a cross-modal interaction was demonstrated: An increase in gel hardness decreased the perceived aroma intensity, while the in vivo aroma release was unaffected.These findings have increased the understanding of aroma release and perception and will open the way to new approaches to modulate perceived aroma intensity.