A trained sensory panel assessed flavour and sweetness intensity in solutions containing varying concentrations of hydroxy propyl methylcellulose (HPMC), sugar and flavour volatile. The flavour and sweetness of the viscous solutions were rated using magnitude estimation with a controlled modulus. In addition, the concentration of volatile released on the breath was measured using MS Nose. For low concentrations of HPMC (<0.5 g/100 g), perceived flavour intensity remained the same; however, a steady decrease was noted at higher concentrations (>0.6 g/100 g). The change in perceived intensity occurred at the point of random coil overlap (c(*)) for this hydrocolloid. The perceived sweetness of the solution showed a similar pattern with increasing HPMC concentration, although the inflection at c(*) was not so obvious. Despite the change in perceived flavour intensity, the actual concentration of volatile measured on the breath was not affected by the change in HPMC concentration. Low-order polynomial models were produced to describe perceived flavour intensity and sweetness in viscous solutions containing HPMC and potential explanations for the changes in perception are discussed.

The perception of sweetness and flavour were studied in viscous solutions containing 50 g/l sucrose, 100 p.p.m. iso-amyl acetate and varying concentrations of three hydrocolloid thickeners (guar gum, lambda-carrageenan and hydroxypropylmethyl cellulose). Zero-shear viscosity of the samples ranged from 1 to 5000 mPas. Perception of both sweetness and aroma was suppressed at thickener concentrations above c* (coil overlap concentration, the point at which there is an abrupt increase in solution viscosity as thickener concentration is increased). Sensory data for the three hydrocolloids was only loosely correlated with their concentration relative to c* (c/c* ratio), particularly above c*. However, when perceptual data were plotted against the Kokini oral shear stress (tau), calculated from rheological measurements, data for the three hydrocolloids aligned to form a master-curve, enabling the prediction of flavour intensity in such systems. The fact that oral shear stress can be used to model sweetness and aroma perception supports the hypothesis that somatosensory tactile stimuli can interact with taste and aroma signals to modulate their perception.

The release of sucrose and menthone from chewing gum was measured in-mouth and in-nose, respectively, during eating. Swabs of saliva were taken from the tongue and analyzed using a rapid, direct liquid-mass spectrometry procedure. Menthone concentration in-nose was monitored on a breath-by-breath basis using direct gas phase atmospheric pressure chemical ionization-mass spectrometry. Simultaneously with the volatile release, trained panelists followed the change in mint flavor by time-intensity (TI) analysis. Two types of commercial chewing gum were analyzed. Both showed that the panelists perception of mint flavor followed sucrose release rather than menthone release. The temporal analysis of the chemical stimuli, with simultaneous TI analysis, provided unequivocal evidence of the perceptual interaction between nonvolatile and volatile flavor compounds from chewing gum.

Flavour results from the integration of aroma, taste and chemosensory information within the brain. Understanding interactions between the anatomically separate systems which relay this information is crucial to our appreciation of how different aspects of food contribute to flavour perception and the formulation of successful products. To examine these interactions, a beverage system was created containing elements capable of stimulating gustatory, olfactory and trigeminal systems. Using ingredients relevant to commercial beverages, water, aroma volatiles, tastants and carbonation, enabled examination of the effects of tastant-aroma-carbonation interactions on sensory perception. Samples, selected according to Doptimal designs, were evaluated by a trained panel. Predictive polynomial models were generated from mean panel data to explain variations in the attributes as a function of design factors. Increasing both sugars and acids resulted in increases in perceived flavour. Evidence of differential flavour enhancement profiles of two sugars at perceptually equi-sweet levels, glucose and fructose, supported previous findings in a non-carbonated system (Hewson et al., Food Qual Prefer 19:323-334, 2008). This difference was also evident in models generated for some mouthfeel attributes (tingling and irritant attributes). Carbonation increased sourness, in agreement with previous literature (McLellan et al., J Food Sci 49:1595-1597, 1984 Yau and McDaniel, J Food Sci 57:1412-1416, but also suppressed sweetness. Interestingly, evaluation of beverages revealed the perception of a bitter aftertaste, which was primarily driven by CO 2 level, enhanced by citric acid, and suppressed by increasing sugar concentration. This study provides a comprehensive assessment of the sensory profile of a model carbonated beverage. Analysis provided novel evidence of the influence of multimodal interactions from gustatory, olfactory and trigeminal origin on sensory perception and highlighted the differential effects of two monosaccharides on key sensory attributes.

Joanne (2014) Phenotypic variation in oronasal perception and the relative effects of PROP and Thermal Taster Status. Food Quality and Preference, 38. pp. 83-91. Abstract Individual variation in taste perception has long been investigated, particular in relation to PROP taster status (PTS). Recently, a new marker has been identified, Thermal Taster Status (TTS), whereby individuals are categorised as thermal tasters (TTs) or thermal non-tasters (TnTs) based on their ability to perceive taste solely from temperature stimulation. The aim of this study was to investigate the incidence of thermal tasters and relative effects of PTS and TTS on oronasal sensitivity across the whole perceptual range. Both detection thresholds (ASTM E679) and intensity measures at suprathreshold level (rated on gLMS) for stimuli from a range of modalities were determined from up to 124 subjects pre-screened for their PTS and TTS. No significant differences were found within either PTS or TTS groups at detection threshold level, with one exception; TTs has a lower threshold for sucrose (p<0.05). At supra-threshold level, PROP supertasters (pSTs) and medium tasters (pMTs) rated stimuli higher than non-tasters, and a consistent trend was observed that TTs rated stimuli higher than TnTs, although only ratings for temperature (warm and cold) reached significance. Global analyses applied across each modality, showed that in general TTs rated gustatory and trigeminal modalities significantly higher than TnTs, whilst this was not the case for olfactory stimuli, indicating that the mechanism for increased perception for TTs may be located in the oral cavity. PTS and TTS were shown to be independent phenotypes, but interestingly, ANOVA revealed significant interactions between TTS and PTS across the three modalities. Most notably, within pMTs, TTs rated stimuli intensity higher than TnTs, while the opposite trend was observed for pSTs. The intensity advantage gained by thermal tasters appears to be more apparent for pMTs than the already highly sensitive pSTs.