Roberts, D.D. and Acree, T.E.
Effect of Saliva, Temperature, Stirring, and Oil on Simulated Retronasal Aroma,
Retronasal aroma is often a different quality and intensity from orthonasal aroma, due to salivation, mastication, and a temperature change of the food. Using a large scale retronasal aroma simulator made from a Waring blender, the significance of these effects was determined with a sweetened and flavored acidic beverage. Synthetic saliva, buffered as in actual saliva, caused a differential change in the flavor volatilities, resulting in a different retronasal from orthonasal profile. While 1,8-cineole, a neutral compound, showed a decrease in volatility upon saliva addition, methyl anthranilate and 2-acetyl pyridine showed increases of up to 50 %. 2-Methoxy-3-methyl pyrazine and o-aminoacetophenone showed slight increases over 1,8-cineole. The temperature change from room temperature to 37 C and stirring at the shear rate which occurs in the mouth increased volatility of the flavors 100 and 15 % respectively.
In another study investigating oil versus water as the food bases, large decreases in volatility were observed with oil, especially with a-pinene, ethyl-2-methyl butyrate and 1,8-cineole. The more polar flavors, maltol and butyric acid did not show this effect.