Physiological and analytical studies on flavor perception dynamics as induced by the eating and swallowing process (original) (raw)
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Chemical Senses, 2001
The process of eating and drinking was observed in vivo by application of videofluoroscopy, a dynamic X-ray technique, as well as real-time magnetic resonance imaging. The study was aimed at elucidating the timing and performance of the physiological organs involved in mastication and swallowing, mainly the tongue, the pharynx and the soft palate (velum palatinum). It was shown for the first time that effective physiological barriers do exist during food consumption that are capable of retaining volatiles such as helium within the oral cavity. These barriers allow the access of odorants to the nasal cavity only at certain times during the eating process. Their effectiveness is related to the texture of the food as well as the amount of food material present in the oral cavity and, thereby, directly influences retronasal aroma perception.
Food Flavors and Chemistry
Taste is an essential component of flavour. Although taste carries fewer distinctive qualities than odour, it provides an essential base on which aroma builds to generate the widely varying flavour of our foods and beverages. The present review covers a wide range of perceptual/psychophysical topics on taste. The first section reviews the taste research questions of early last century; the second section addresses the psychophysical taste research topics of the last few decades; and in the third section, the question is raised whether the old research topics of 80-100 years ago, which have largely not been answered, are worth reconsidering and pursuing.
Taste is an essential component of flavour. Although taste carries fewer distinctive qualities than odour, it provides an essential base on which aroma builds to generate the widely varying flavour of our foods and beverages. The present review covers a wide range of perceptual/psychophysical topics on taste. The first section reviews the taste research questions of early last century; the second section addresses the psychophysical taste research topics of the last few decades; and in the third section, the question is raised whether the old research topics of 80–100 years ago, which have largely not been answered, are worth reconsidering and pursuing.
Use of an Immediate Swallow Protocol to Assess Taste and Aroma Integration in fMRI Studies
Chemosensory Perception, 2011
Perception of flavor is a complex process involving the integration of taste and aroma. Few functional magnetic resonance imaging (fMRI) studies have assessed the crossmodal interactions which result in flavor perception, and all previous studies have used a retro-nasal aroma delivery with a delayed swallow, which delays retro-nasal aroma release, and thus, alters taste and aroma integration. In this paper, we assess crossmodal interactions in flavor processing using an immediate swallow fMRI paradigm in 13 healthy volunteers. We compare unimodal taste (sucrose) and unimodal retro-nasal aroma stimuli, with a congruent taste and aroma combination (flavor), to assess crossmodal flavor interactions using an immediate swallow paradigm. Subtraction and conjunction analysis methods are described, and the use of a control stimulus is addressed. Subtraction analysis was found to reveal areas of anterior insula, frontal operculum, anterior cingulate, and orbitofrontal cortex, whilst the conjunction analysis revealed additional active areas in oral somatosensory areas (SI), rolandic operculum and posterior cingulate, supporting the hypothesis that taste, olfactory, and tactile sensations are integrated to produce a flavor percept.
Intranasal Concentrations of Orally Administered Flavors
Chemical Senses, 2005
The odorants emanating from the oral cavity during eating and drinking reach the olfactory mucosa via the pharynx (retronasal olfaction). It is unclear which variables influence the perception of intraorally applied substances. The aim of the present study was to determine the temporal profiles of volatile odor concentrations at different locations in the nasal cavity during consumption of liquid and solid custard samples using proton transfer reaction mass spectrometry. Intranasal odor concentrations were measured at least twice in nine subjects (six female, three male) at four nasal positions during the consumption of liquid and solid custards. The low-viscosity custard was swallowed earlier than the more solid one. The compounds were found to reach the nose in different concentrations. Largest maximal amplitudes were measured in the nasopharynx, whereas lowest concentrations were found in the region of the olfactory cleft. In addition, different odorants reached the different regions in the nasal cavity in varying concentrations, indicated by a significant interaction between factors ''position'' and ''compound.'' Furthermore, the compounds were found to reach the positions within the nasal cavity with different latencies. These results indicate that different volatile flavor compounds exhibit different temporal and spatial profiles in terms of their intranasal distribution. . (2000) Peripheral odor coding in the rat and frog: quality and intensity specification.
Flavour Perception: Aroma, Taste and Texture Interactions
Flavour perception is determinant for the acceptability of food products by consumers. Aroma and taste play an important role in flavour perception and it is well known that the chemical composition of the matrix and consequently its structure influences release and perception of flavour. However, from simultaneous measurements of human perception and physical concentration in vivo, texture – aroma and texture – taste interactions are not always explained by physico-chemical mechanisms. Moreover aroma – taste interactions have been the subject of many studies already reviewed and are mainly explained by cognitive interactions even if in some case physico-chemical mechanisms may occur. Finally, few studies mentioned the impact of aroma and taste on texture perception. The aim of this review is to focus on the impact of aroma, taste and texture interactions on flavour perception. For each type of binary interactions (texture – aroma, aroma – texture, texture – taste, taste – texture, taste – aroma and aroma – taste) we will present a short state of the art and the mechanisms that could be involved in the interactions: physico-chemical and cognitive mechanisms. The mechanisms of aroma – taste and taste – aroma interactions are known to mainly depend on learning association. However, the mechanisms involved in texture – flavour and flavour – texture interactions are more complex and need further developments to understand the part explained by flavour partition in the product, flavour release in the mouth after food breakdown and cognitive interactions.
Effects of swallowing and spitting on flavor intensity
Journal of Sensory Studies, 2017
Does spitting provide the same flavor experience as swallowing? The objective of this research was to compare swallowing and spitting as procedures for evaluating flavor intensity. Participants evaluated taste or flavor intensity by both swallowing and expectorating water solutions, puddings, and cookies with added tastes and odors; each taste/odor was evaluated at several different concentrations. Flavor intensity was perceived to be more intense for caffeine solutions, ethyl butyrate solutions, and almond extract-flavored puddings when panelists swallowed than when they expectorated. Such differences were not observed for sucrose solutions, citric acid solutions, and most monosodium glutamate solutions. Swallowing versus expectorating had no effect on the flavor intensity of cookies flavored with orange extract. Our observations that swallowing/ expectorating does not impact all attributes equally, suggests that spitting will change both the intensity profiles and the character of a food compared with normally swallowing. Practical applications Spitting is a common practice in trained panel evaluations of food, wine judging, and other situations where people wish to minimize the amount of food they ingest. Spitting, however, changes the perceived intensities of some flavors, but not others, thus potentially altering the sensory character of the food.
Odor/taste integration and the perception of flavor
Experimental Brain Research, 2005
Perceptions of the flavors of foods or beverages reflect information derived from multiple sensory afferents, including gustatory, olfactory, and somatosensory fibers. Although flavor perception therefore arises from the central integration of multiple sensory inputs, it is possible to distinguish the different modalities contributing to flavor, especially when attention is drawn to particular sensory characteristics. Nevertheless, our experiences of the flavor of a food or beverage are also simultaneously of an overall unitary perception. Research aimed at understanding the mechanisms behind this integrated flavor perception is, for the most part, relatively recent. However, psychophysical, neuroimaging and neurophysiological studies on cross-modal sensory interactions involved in flavor perception have started to provide an understanding of the integrated activity of sensory systems that generate such unitary perceptions, and hence the mechanisms by which these signals are functionally united when anatomically separated . Here we review this recent research on odor/taste integration, and propose a model of flavor processing that depends on prior experience with the particular combination of sensory inputs, temporal and spatial concurrence, and attentional allocation. We propose that flavor perception depends upon neural processes occurring in chemosensory regions of the brain, including the anterior insula, frontal operculum, orbitofrontal cortex and anterior cingulate cortex, as well as upon the interaction of this chemosensory flavor network with other heteromodal regions including the posterior parietal cortex and possibly the ventral lateral prefrontal cortex.
Food Chemistry, 2008
An analytical concept is developed for the on-line investigation of the temporal and spatial dynamics in ortho-and retronasal odor perception. It aims at the elucidation of the relationship between the molecular level and perception during and after administration of a chemical stimulus. One basic principle is to apply precisely defined odorous stimuli, and to measure their temporal characteristics using an on-line analytical technique, proton-transfer reaction mass spectrometry (PTR-MS). In parallel, the subjects' response to the stimulus can be investigated with electrophysiological and psychophysical techniques. This approach can be modified to elucidate the processes involved in the perception of food and drinks. Panellists may take an active role as they modulate chemosensations with certain patterns of mastication/swallowing. Using videofluoroscopy or real-time magnetic resonance imaging these mechanical oropharyngeal processes may be visualized.
Journal of Agricultural and Food Chemistry, 2003
The goal of this study was to better understand the correspondence between sensory perception and in-nose compound concentration. Five aroma compounds at three different concentrations increasing by factors of 4 were added to four matrixes (water, skim milk, 2.7% fat milk, and 3.8% fat milk). These were evaluated by nosespace analysis with detection by proton transfer reaction mass spectrometry (PTR-MS), using five panelists. These same panelists evaluated the perceived intensity of each compound in the matrixes at the three concentrations. PTR-MS quantification found that the percent released from an aqueous solution swallowed immediately was between 0.1 and 0.6%, depending on the compound. The nosespace and sensory results showed the expected effect of fat on release, where lipophilic compounds showed reductions in release as fat content increases. The effect is less than that observed in headspace studies. A general correlation between nosespace concentration and sensory intensity ratings was found. However, examples of perceptual masking were found where higher fat milks showed reductions in aroma compound intensity ratings, even if the nosespace concentrations were the same.