In situ analysis of the effect of saliva and eating behaviour on oral salt release

The release and migration of flavour compounds during food oral processing is a process of mass transfer and is governed by its principles. It is therefore anticipated that the rate of flavour release and the dynamic intensity of flavour perception are closely linked to the properties of saliva and eating behaviour of consumer individuals. To prove this hypothesis, model food gels containing different amounts of salt (NaCl) were investigated for in situ salt release and perceived intensity of saltness among ten healthy subjects. A mathematical model was developed based on mass transfer principles to analyze salt release. It was found that oral mass transfer coefficient (k) correlates negatively with salivary viscosity and positively with salivary flow rate (p < 0.05); moderate tongue agitation reduces stagnant layer thickness to enhance k; food components (e.g., xanthan gum, catechin) alter k via modifying saliva viscosity or stagnant layer thickness. The model successfully predicts salt release, linking individual variability in oral physiology/eating behaviour to saltiness perception. Results confirmed our initial hypothesis and provided new insights on the governing physics of flavour perception.