Olfaction-taste interactions

Delarue, J. and Sieffermann, J.-M. (2004b). Use of 2(-4-methoxyphenoxy)propanoic acid (Na-PMP) to investigate flavour interactions in real food products. I4th Intematiorud Symposium on Olfaction and Taste (ISOT/JASTS). Kyoto, Japan. 

As humans, we have developed five perceptive senses smell, taste, touch, sight, and hearing. Sensory response is a good example of adaptation at the molecular level and for this we shall examine the potential of the first two. Odor, like taste, is related to a direct contact of molecules with the olfactive (or gustative) epithelium. These membranes or surfaces contain chemo-receptors which upon excitation by a stimulant give characteristic organoleptic sensations. The specific interactions between small molecules and receptors involve an equilibrium between absorption and desorption and can be studied by chemists using models. 

Analogous events occur in the nose when many odorants interact with the epithelia therein. The odor component is conveyed via the odorant s interaction with molecular receptors on olfactory sensory neurons (first cranial nerve) in the olfactory epithelium [9] irritation is initiated by interactions with receptors or other mechanisms that stimulate the trigeminal (fifth cranial) nerve [10]. The term chemesthesis has been applied to distinguish this sensory experience from olfaction or, in the oral cavity, taste [11,12]. Importantly, chemesthesis is a bodywide experience. It is only on some portions of the head, e.g., eyes, nose, mouth, and some other facial areas, where information is conveyed by the trigeminal nerve (Fig. 1). 

Olfaction is very much present and influential in our everyday life and its day-to-day quality [1]. For instance, it has been shown by Delwiche [2] that taste and smell are rated as being the most important sensations in flavor. Thus, olfaction is the key to our relationship with food and in particular plays a major role in identifying it [3]. That is why significant changes in chemosensory perception have the capacity of interacting with aroma perception, diet selection, and to some extent nutritional status [4]. 

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