註釋 Multiple factors influence the release of flavor molecules and perceived flavor intensity including the food matrix and temperature as well as physiological parameters such as salivary flow rate. Chewing-style (open versus closed mouth) and texture (hard versus soft), while understudied, is important for understanding how flavors are affected in order to improve food production. The objective of this study was to observe how open versus closed mouth chewing and hard versus soft textures affect the concentration of a volatile flavor compound reaching the olfactory epithelium. Presently, we used selected ion flow tube mass spectrometry to measure the concentration of ethyl butyrate (EB) captured from 15 subject's nasal-exhaled air when chewing model gels with an open- or closed-mouth chewing condition as well as a hard and soft model gel system. EB concentrations collected from each panelist under the four conditions were collated, averaged and compared. Texture measurements from the texture analyzer and the perceived texture sensory scales were also taken on the different gels. In our studies, peak EB concentration in exhaled air was impacted to a great extent by chewing condition, but not greatly by the texture. The different gels, while experiencing batch-to-batch variability, did still show that the hard gel was always significantly greater than the soft gel for the hardness, fracturability and springiness. Our results showed that the closed mouth chew enabled greater volatile release into the nasal sinus than the open mouth chewing condition. This finding was consistent across both hard and soft gel types, but was more notable in the hard gel. Whereas most subjects opened their nasopharyngeal closure during the closed-mouth chewing condition to allow EB into the olfactory sinus, this was not always the case during the open-mouth condition. Indeed, during the open-mouth condition, mostly noted evaluating hard gels, there was a much higher occurrence of panelists closing or alternating between a closed and open epipharynx thus preventing EB from gaining access to the nasal cavity and being exhaled. Further analysis comparing time intensity sensory plots for each condition showed that significant differences were not found among the parameters, most likely due to the difficulty of the task. Results show that chewing-style can impact the concentration of volatile flavor compounds reaching the nasal sinus and driving flavor perception. This could be due to minimal loss of volatiles when the mouth is closed rather than open. Another potential mechanism underpinning this finding is the likelihood of the epipharynx being open which our results showed to be more likely when subjects chew with their mouth closed. Also there were no significant differences found between the exhaled or perceived volatiles of ethyl butyrate between the two textures. A better understanding of what affects retronasal flavor concentration and perception can help optimize food production. 