Reducing calories, fat, saturated fat, and sodium in restaurant menu items: Effects on consumer acceptance.

OBJECTIVE: To assess consumer acceptance of reductions of calories, fat, saturated fat, and sodium to current restaurant recipes. METHODS: Twenty-four menu items, from six restaurant chains, were slightly modified and moderately modified by reducing targeted ingredients. Restaurant customers (n = 1,838) were recruited for a taste test and were blinded to the recipe version as well as the purpose of the study. Overall consumer acceptance was measured using a 9-point hedonic (like/dislike) scale, likelihood to purchase scale, Just-About-Right (JAR) 5-point scale, penalty analysis, and alienation analysis. RESULTS: Overall, modified recipes of 19 menu items were scored similar to (or better than) their respective current versions. Eleven menu items were found to be acceptable in the slightly modified recipe version, and eight menu items were found to be acceptable in the moderately modified recipe version. Acceptable ingredient modifications resulted in a reduction of up to 26% in calories and a reduction of up to 31% in sodium per serving. CONCLUSIONS: The majority of restaurant menu items with small reductions of calories, fat, saturated fat, and sodium were acceptable. Given the frequency of eating foods away from home, these reductions could be effective in creating dietary improvements for restaurant diners.

Mixed Messages: Ambiguous Penalty Information in Modified Restaurant Menu Items.

Restaurant menu items from six national or regional brands were modified to reduce fat, saturated fat, sodium and total calories. Twenty-four items were tested with a current recipe, and two modifications (small and moderate reductions) for 72 total products. Approximately 100 consumers tested each product for acceptability as well as for desired levels of tastes/flavor, amounts of key ingredients and texture/consistency using just-about-right (JAR) scales. Penalty analysis was conducted to assess the effects of non-JAR ratings on acceptability scores. Situations arose where JAR ratings and penalty analyses could yield different recommendations, including large groups with low penalties and small groups with high penalties. Opposing groups with moderate to high penalties on opposite sides of the same JAR scale were also seen. Strategies for dealing with these observances are discussed.

Taste properties of potassium chloride alone and in mixtures with sodium chloride using a check-all-that-apply method.

As consumers try to reduce their sodium consumption for health purposes, the food industry seeks ways to reduce the sodium content in products while maintaining palatability. One potential solution for lowering sodium content is using potassium chloride (KCl) as a substitute. However, many people find KCl to have unpleasant off-tastes, which limits its effectiveness to replace sodium chloride (NaCl). This study examined the taste properties of KCl using a check-all-that-apply (CATA) ballot. The objectives were to see which terms people use to describe KCl and in what ways this changes in various combinations with NaCl. Panelists were served mixtures of varying NaCl and KCl concentrations, and evaluated them using a set of predetermined terms on a CATA ballot. Frequency counts were taken, and binomial and McNemar tests were performed to see which stimuli changed the most between samples. Results showed that adding KCl increased salt perception slightly, and salty was chosen more frequently when in combination with NaCl. Adding NaCl in a mixture with KCl decreases unpleasant side tastes associated with KCl, such as bitter, chemical, and metallic.

Recovery of subsampled dimensions and configurations derived from napping data by MFA and MDS.

Napping is a multivariate sensory method in which participants physically place stimuli on a large sheet of paper and orient them so that the distance between pairs represents a measure of dissimilarity. The two-dimensional nature of the task may be a limitation to the ability of this and similar methodologies to recover information about complex stimuli. In the first investigation, eight simulated three-dimensional stimuli were created with two different levels for each attribute. Simulated napping experiments had groups of participants attend to two of the dimensions with different probabilities. Multiple factor analysis (an analytical multivariate statistical procedure that can be thought of as a principle components analysis on the individuals) and MDS-INDSCAL (a variation on multidimensional scaling that finds a common configuration through reducing a stress measure associated with lack of fit) recovered full dimensionality from these data, although MFA had trouble when attention was the most unbalanced. In the second experiment, a human napping experiment was designed using custom three-dimensional stimuli: shapes with two levels each of size, color, and shape attributes. This experiment confirmed the results of Experiment 1, as both MDS-INDSCAL and MFA analyses again recovered the full dimensionality of the stimuli.

Effects of Nasal Occlusion and Oral Contact on Perception of Metallic Taste from Metal Salts.

Iron and copper salts have complex olfactory and gustatory properties including a metallic flavor component that is decreased by nasal occlusion. To examine the sensory properties of ferrous sulfate and copper sulfate, a trained descriptive panel evaluated these compounds at equal molarity and perceived equal intensity with and without nasal occlusion. Ferrous sulfate exhibited a metallic taste and metallic aftertaste and copper sulfate exhibited a more pronounced metallic aftertaste. Metallic sensations were decreased by nasal occlusion, which in the absence of any orthonasal metallic smell, implies that the sensations were retronasally perceived volatiles in the nose open condition. Ferrous sulfate showed a larger effect of nasal occlusion. A second experiment isolated ferrous sulfate solutions from oral contact via a plastic barrier. In comparison to a condition in which oral contact was allowed, intensity ratings were decreased. This result is consistent with the hypothesis that rinses with solutions of metal salts, particularly ferrous sulfate, generate volatile lipid oxidation products in the mouth that are perceived retronasally as metallic flavors.

A direct comparison of the taste of electrical and chemical stimuli.

Three multidimensional scaling studies were conducted to compare the taste qualities evoked from electrical and chemical stimulation, including ferrous sulfate as a typical "metallic" taste stimulus. Bipolar, anodal, and cathodal stimulation were delivered by 1.5- or 3-V batteries applied to the tongue. Solutions of chemical stimuli including prototypical tastes and binary mixtures were evaporated on small metal disks to provide tactile impressions similar to those of the battery stimuli and avoid any potential response biases induced by the subjects' knowledge of the form of the stimulus. Multidimensional unfolding was performed to place stimuli and verbal descriptors in common perceptual spaces. Bipolar, anodal, and cathodal stimuli were tested in separate experiments but generated very similar perceptual spaces and were differentiated from the chemical stimuli. Electrical stimuli were associated with descriptors, such as metallic, copper penny, and iron nail, regardless of the polarity of stimulation. Taste qualities evoked by electric stimuli may not be fully described by commonly used taste stimuli or their binary mixtures and appear most adequately described by a unique metallic taste.

A comparison of two electric taste stimulation devices.

Electrical stimulation of the tongue, commonly used in clinical evaluations of taste dysfunction, can produce a variety of sensations including reports of metallic taste. Two studies compared responses to a fabricated electrical stimulator (a 1.6 V battery, anode side exposed) and a clinical electrogustometer (Rion TR-06). Batteries placed on the anterior dorsal tongue surface produced sensations similar in intensity and quality to those produced by the clinical electrogustometer, with equal intensity on the tongue tip for the 1.6 V battery in the range of 33-56 microA from the electrogustometer. A second study examined responses on three areas of the tongue on each side. Responses declined for areas lower in fungiform papillae for both devices, but at different rates. Higher current levels were required to match the battery in lower density areas, indicating spatial summation for the larger battery surface area. A consistent pattern of lateral differences was seen in only one subject. Quality descriptions were similar in frequency whether or not a word list was provided, with metallic, sour, pain and bitter being the most frequently mentioned words for both electric stimuli. Similarities in response to the battery device and electrogustometer were evident in intensity, qualities evoked, lack of a laterality effect and decreasing response in areas with lower fungiform papillae density. The battery device may provide an inexpensive portable alternative to an electrogustometer for use in clinical testing of taste.

Retronasal smell and detection thresholds of iron and copper salts.

Iron and copper salts, when placed in the mouth, may give rise to odorous compounds which complicate their functioning as chemical stimuli. The contribution of retronasal smell to perception of these metal salts at threshold has not been determined. Detection thresholds of the sulfate and chloride salts of ferrous iron and copper, and sodium chloride (as a control) were determined using a modified forced-choice ascending method of limits, with and without nasal occlusion. Threshold values were calculated from geometric means of individual estimates, and from interpolation on logistic regression and percent correct plots. Nasal occlusion raised thresholds for iron salts and copper but not sodium. The geometric mean detection thresholds with the nose open were 30, 64, 7.8, and 8.2 microM for FeSO(4), FeCl(2), CuSO(4), CuCl(2), respectively but rose to 160, 227, 24.6 and 15.6 with the nose closed. Metal salts of both iron and copper create a retronasally perceived olfactory stimulus at low concentration levels, probably arising from lipid oxidation products generated in the mouth.

Multidimensional scaling of ferrous sulfate and basic tastes.

The status of metallic sensations as a primary or basic taste category is controversial. Ferrous sulfate (FeSO4) has been suggested as a prototypical metallic chemosensory stimulus. At least part of the metallic sensation from FeSO4 arises from a metallic retronasal smell. The quality of this sensation was studied via multidimensional scaling (MDS) of taste similarities, with and without nasal closure to eliminate retronasal olfactory sensations. The metallic stimulus was embedded in a series containing classical "basic taste" stimuli, alum and monosodium glutamate. With olfaction available, the metallic stimulus plotted away from basic tastes and taste mixtures. Scaled ratings of sensory properties related to metallic taste (iron-nail, copper-penny-like, aftertaste) of FeSO4 decreased with nasal closure. Results are consistent with the idea that ferrous sulfate produces a distinctly different sensation from the traditional basic tastes, which includes both olfactory and oral sensations.

Identification of metallic-smelling 1-octen-3-one and 1-nonen-3-one from solutions of ferrous sulfate.

Taste threshold tests of ferrous sulfate (FeSO4) solutions have been confounded by the presence of putative odorants. To detect the presence of odorants released from these solutions solid-phase microextraction (SPME) was used to collect volatiles in the headspace above FeSO4 solutions. Gas chromatography-olfactometry of samples collected over three time periods (1, 5, and 16 h) and at two temperatures (22 and 37 degrees C) revealed the presence of several metallic-smelling odorants in the headspace. Using authentic standards, two of the odorants were conclusively identified as 1-octen-3-one and 1-nonen-3-one. Trace levels of other odorants were also detected, but dilution experiments indicated that 1-nonen-3-one was at least 10 times more potent than anything else released from the solutions. 1-Octen-3-one and 1-nonen-3-one are excellent candidates for the metallic odor responses often observed in threshold testing of solutions of FeSO4.

Qualitative differences of divalent salts: multidimensional scaling and cluster analysis.

Sensations from salts of iron, calcium, magnesium, and zinc with different anions were studied using a sorting task and multidimensional scaling (MDS). Ten divalent salts were adjusted in concentrations such that the mean intensity ratings were approximately equal. Stimuli were sorted on the basis of similarity to minimize any semantic influence and were examined with and without nasal occlusion to eliminate retronasal cues. Compounds representing the four primary tastes and astringency were also sorted. Similarity estimates were derived from sorting and were submitted to MDS. Divalent salts fell outside the area of the space defined by the four primary tastes. The nose-open condition showed that some of the divalent salts have unique metallic sensations along with astringency. The groupings obtained were corroborated using single-linkage cluster analysis. An iron group was most distinctive in metallic sensations; calcium and magnesium salts were primarily bitter; and zinc salts were characterized by astringency. When nasal cues were not available, the sensations from the divalent salts were mainly explained by bitterness and astringency. Results were consistent with a previous evaluation of divalent salts using descriptive analysis.

Oral sensations from iron and copper sulfate.

In previous work, retronasal smell was an important cue for perceiving metallic sensations from ferrous sulfate (FeSO4). The purpose of this study was to examine whether FeSO4 produced oral sensations as well as retronasal cues and whether astringency contributed to the oral sensations. In the first study, discrimination of FeSO4 from water was confirmed at concentrations at or above 5 mM without retronasal flow. A second study examined whether FeSO4 and CuSO4 could be detected on a non-gustatory region by tactile sensations. Astringency was perceived when the copper sulfate solution was applied to non-gustatory surfaces between the gum and the upper lip with or without retronasal cues. However, rated astringency for FeSO4 was less than that for CuSO4, and not significantly different from water. Other gustatory or tactile sensations from iron salts may contribute to their oral sensations and the possibility remains that at least one part of metallic sensation may be a metallic taste.

Metallic taste from electrical and chemical stimulation.

A series of three experiments investigated the nature of metallic taste reports after stimulation with solutions of metal salts and after stimulation with metals and electric currents. To stimulate with electricity, a device was fabricated consisting of a small battery affixed to a plastic handle with the anode side exposed for placement on the tongue or oral tissues. Intensity of taste from metals and batteries was dependent upon the voltage and was more robust in areas dense in fungiform papillae. Metallic taste was reported from stimulation with ferrous sulfate solutions, from metals and from electric stimuli. However, reports of metallic taste were more frequent when the word 'metallic' was presented embedded in a list of choices, as opposed to simple free-choice labeling. Intensity decreased for ferrous sulfate when the nose was occluded, consistent with a decrease in retronasal smell, as previously reported. Intensity of taste evoked by copper metal, bimetallic stimuli (zinc/copper) or small batteries (1.5-3 V) was not affected by nasal occlusion. This difference suggests two distinct mechanisms for evocation of metallic taste reports, one dependent upon retronasal smell and a second mediated by oral chemoreceptors.

DESCRIPTIVE ANALYSIS OF DIVALENT SALTS.

Many divalent salts (e.g., calcium, iron, zinc), have important nutritional value and are used to fortify food or as dietary supplements. Sensory characterization of some divalent salts in aqueous solutions by untrained judges has been reported in the psychophysical literature, but formal sensory evaluation by trained panels is lacking. To provide this information, a trained descriptive panel evaluated the sensory characteristics of 10 divalent salts including ferrous sulfate, chloride and gluconate; calcium chloride, lactate and glycerophosphate; zinc sulfate and chloride; and magnesium sulfate and chloride. Among the compounds tested, iron compounds were highest in metallic taste; zinc compounds had higher astringency and a glutamate-like sensation; and bitterness was pronounced for magnesium and calcium salts. Bitterness was affected by the anion in ferrous and calcium salts. Results from the trained panelists were largely consistent with the psychophysical literature using untrained judges, but provided a more comprehensive set of oral sensory attributes.

Metallic taste and retronasal smell.

A series of experiments investigated the nature of metallic taste reports and whether they can be attributed to the development of a retronasal smell. Two studies showed that the metallic sensation reports following oral stimulation with solutions of FeSO4 were reduced to baseline when the nose was occluded. No such reduction was seen for CuSO4 or ZnSO4, which were more bitter and astringent, respectively, and less metallic. A discrimination test based on weak but equi-intense levels of FeSO4 and CuSO4 showed that FeSO4 could be discriminated from water with the nose open but not when occluded, but that discrimination of CuSO4 from water was not impaired by nasal occlusion. A discrimination test demonstrated that the headspace over solutions of FeSO4 was not different from water, although some subjects could discriminate FeSO4 solutions from water in the mouth when the nose was occluded, perhaps by tactile or astringent cues. These results confirm that metallic taste reports following oral stimulation with FeSO4 are likely due to development of a retronasal smell, possibly following a lipid oxidation reaction in the mouth. However, metallic taste reports may arise from different mechanisms with copper and zinc salts.

Effect of citric acid and citric acid-sucrose mixtures on swallowing in neurogenic oropharyngeal dysphagia.

The ability of sour and sweet-sour mixtures to improve swallowing in 11 nursing home residents with neurogenic oropharyngeal dysphagia was investigated using fiberoptic endoscopic evaluation of swallowing. Citric acid (2.7%) significantly reduced aspiration and penetration compared with water. Teaspoon delivery of liquids significantly reduced aspiration and penetration compared with natural cup drinking. Subjects tended to appropriately self-regulate the cup volume they consumed after the first trial. A significant increase in spontaneous dry swallows was observed after both taste stimuli. The mechanisms for improved swallowing due to citric acid are not understood but may be due to increased gustatory and trigeminal stimulation of acid to the brainstem in neurologically impaired subjects.

Gender, age, vessel size, cup vs. straw sipping, and sequence effects on sip volume.

Two experiments were performed to examine the effects of cup size, gender, age, and parameters of sipping (cup vs. straw and sequence) on sip volume. Increasing the size of the vessel from 150 to 600 ml increased the volume of a sip by about 15%. Males took larger sips and had significantly larger maximum oral capacities than females. However, in a second group of taller females and shorter males, the difference in sip size between genders was minimized. A second experiment examined sip size from a cup and straw drinking, the effects of sequential sipping (one to five sips), personal characteristics (height, weight), age, and gender on sip volume. Height was a good predictor of individual differences in sip volume. Cup drinking produced larger sip volumes than straw drinking, but only in a group of adults and not in an elderly group. Volume per sip decreased across sips. A reasonable guide for cup sipping is about 25 ml per sip for males and 20 ml for females. However, this rule should be modified as a function of cup size, straw sipping, and sequential sipping.

Turbidity as a measure of salivary protein reactions with astringent substances.

Binding of tannins to proline-rich proteins has been proposed as an initial step in the development of astringent sensations. In beer and fruit juices, formation of tannin-protein complexes leads to the well-known effect of haze development or turbidity. Two experiments examined the development of turbidity in human saliva when mixed with tannins as a potential in vitro correlate of astringent sensations. In the first study, haze was measured in filtered human saliva mixed with a range of tannic acid concentrations known to produce supra-threshold psychophysical responses. The second study examined relationships among individual differences in haze development and the magnitude of astringency ratings. Mostly negative correlations were found, consistent with the notion that high levels of salivary proteins protect oral tissues from the drying effects of tannic acid.

Bitter taste of saccharin and acesulfame-K.

The relationships among suprathreshold taste responses to acesulfame-K, Na-saccharin and 6-n-propylthiouracil (PROP) were examined in two studies. In the first study, the labeled magnitude scale was used with the high anchor labeled as 'strongest imaginable oral sensation' and in the second study, it was labeled as 'strongest imaginable sensation of any kind'. Results from the two procedures were similar. Individual differences among 65 subjects were seen in bitter responses to acesulfame-K and saccharin. Bitter responses to acesulfame-K ands accharin were positively correlated, but showed no significant relationship with responses to PROP bitterness or with PROP taster groups. Saccharin and acesulfame-K may share a common mechanism for bitter taste reception and transduction, one that varies across individuals and is different from mechanisms mediating bitter responses to PROP. Changing the instructions of the labeled magnitude scale induced a context effect. Ratings of sweetness referenced to the 'strongest imaginable sensationof any kind' were lower than ratings referenced to just oral sensations.