Associations among fatty food sensations and saliva's emulsifying properties

Individuals vary in saliva composition, which could in turn influence variability of oral sensations. This study was designed to investigate associations among saliva's ability to emulsify an oil/water mixture, fatty sensations, and diet. Participants (N = 62) gave sensory ratings for a white chocolate substitute with 0, 0.1, and 1% added linoleic acid. Discrimination sorting tasks were performed using the chocolate substitute with/without linoleic acid and with high/low-fat salad dressing. Participants swished and expectorated an oil/water mixture, and the size of the emulsified layer of this spat-out sample was measured. This novel technique was used to estimate the emulsifying ability of saliva, as oral swishing caused the fat to disperse into the water, stabilized by saliva. Estimated macronutrient intake was assessed by 3-day dietary recalls. Results indicate that people who correctly sorted the chocolate substitute with/without linoleic acid had saliva that better emulsified the oil/water mixture and rated the 1% linoleic acid sample as fattier. Those who incorrectly sorted the chocolate samples rated the 1% linoleic acid sample as more bitter. The same pattern for fattiness and bitterness of 1% linoleic acid samples was observed for those who correctly/incorrectly sorted the high/low-fat salad dressings. Regarding dietary data, the only observed relationship was higher dietary protein intake associated with less saliva emulsion stability over time. Overall, the results indicate relationships among how saliva influences dispersions of fat and fatty sensations, but the role of diet should be reexamined with larger and more tightly controlled groups.