Aroma Release During Eating

FIGURE 3.12 Raw data obtained on aroma release during the chewing of amint gum. (From Taylor, A.J., R.S.T. Linforth, I. Back, M. Marin, M.J. Davidson, Fmntiers of Flavour Science, RE. Schieberle, K.H. Engel, Eds., Deutsche Forschung. Lebensmit., Garching, 2000, p. 255. With permission.) 

Despite the research area being relatively new, considerable work has been published using this type of methodology [83,84]. Researchers have fonnd that aroma release is influenced by the chemical interactions that occnr within a food (thereby altering vapor pressnre) and the physical properties of the food. Unfortunately, the interactions that occnr are difficult to quantify and mathematically model [83]. Also, the latest resnlts reinforce that sensory perception is mnlti modal — we must not only consider the aroma portion of a food but the taste, texture, and visual stimuli [1]. Thus, it appears that understanding aroma release from a food is not the final answer in understanding hnman perception, but we must also understand the cognitive and interactive aspects of these senses. 

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The release of aroma compounds in the mouth during eating is primarily determined kinetically, rather than thermodynamically, because of the processes occurring when food is consumed. The model-mouth system was developed to study in vitro-like aroma release and considers the bolus volume, volume of the mouth, temperature, salivation, and mastication (van Ruth et al., 1994). Volatile compounds in the effluent of the model mouth are collected on porous polymers, such as Tenax TA. Alternatively, the effluent can be measured on-line by direct mass spectrometry techniques. The model mouth can be used to study the effects of food composition and structure on aroma release, as well as the influence of oral parameters related to eating behavior. 

In recent years, several methods have become available to measure aroma release in real time in the nosespace of test persons during eating [17-19]. In the present study, we used the MS-Nose , developed by Taylor and coworkers [18,19]. The system allows sensitive and fast monitoring of the in vivo aroma release. 

Determination of the Kgg values for each compound with increasing saliva-to-emulsion ratios at equilibrium highlighted the affinity of each compound for the matrix as a function of the hydrophobicity of each compound. By using both the model mouth and the RAS to mimic conditions observed during eating, the effect of saliva on the release of aroma compounds from an emulsion at nonequilibrium conditions was determined by quantification of the amount of each compound released from emulsions with varying... 

The characterisation of a fruit type or variety will be reflected in the flavour profile of its volatile components. Analytical techniques can produce an accurate peak profile using gas chromatography, but in simpler terms the sensory receptors of most individuals can quickly differentiate between fruit varieties. We have four basic taste senses, sometimes described as sweet, sour, acid and bitter, and these are identified by taste receptors situated mainly on the tongue. The key component of flavour differentiation, so-called top-notes and the like, is detected not so much by taste as by aroma in the nasal cavity. Thus, during the process of eating and drinking, the release of aroma volatiles can be identified and an assessment of their value arrived at. 

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