Associations Among Fatty Food Sensations, Diet, and Expectorated Emulsions

Saliva influences chemical and textural sensations, yet details on sources of individual variability for these phenomena are still lacking. In this project, we investigated fatty sensations, dietary habits, and saliva’s emulsifying properties. Through a remote tasting and spitting protocol, participants were asked to rate sensory properties of fatty candies with varying concentrations of added linoleic acid (LA) as well as discriminate among fatty candies with/without LA and high/low fat ranch dressings. Additionally, participants swished and expectorated an oil/water mixture, and the expectorated emulsion was visually analyzed. Dietary habits were also assessed by 3-day dietary recalls.

Linear mixed model was used to analyze sensory response, diet, and spit data. Sensory ratings of fatty candies indicate differences based on successful completion of either discrimination tasks. People who passed either discrimination tests (N=26 passed LA; N=22 passed high/low fat tests) rated higher “Fattiness” for the highest LA concentration. In contrast, people who failed the tests (N=36 failed LA; N=40 failed high/low fat tests) rated higher “Bitterness” with the highest LA concentration. Importantly, only 7 individuals overlapped in these two groups who passed the discrimination tasks. Lower total fat intake and larger expectorated fat layer were associated with higher “Bitterness,” particularly among those who passed the LA discrimination test and those who failed the high/low fat test. Moreover, lower protein and greater carbohydrate intake seemed to associate with the greater formation and stability of oral emulsions, particularly in individuals who failed the high/low fat discrimination task. Other factors such as total fat intake, medication usage, and BMI were mixed. In conclusion, sensory experience of fatty candies may vary based on the ability of an individual to sense the LA or fat content, and saliva’s ability to emulsify fat into water may vary with diet.