Perception of chemosensory stimuli and related responses to flavored yogurts in the young and elderly

Trigeminal Stimulus Menthol Masks Bitter Off-Flavor of Artificial Sweetener Acesulfame-K

Consumer health concerns and regulatory policies lead to a growing demand for sugar-sweetened beverage alternatives. A reduced energy content can be achieved using artificial sweeteners, which often also convey a metallic or bitter off-flavor. Therefore, the alteration of sweetness perception and masking of potential off-flavors are paramount for improving sweet beverages. Trigeminal stimuli, such as capsaicin (spicy) or menthol (cooling), have been used to influence taste perception in food items, although their use in beverages has not yet been systematically investigated. Here, the influence of menthol on sweetness perception in an aqueous solution is examined both on the sensory and psychophysiological level. The addition of menthol had no sensory effect on sweetness perception; however, psychophysiological measurements suggest a boost in the physiological response to cold perception through the addition of sugar. Moreover, menthol addition shifted the recognition threshold of unpleasant bitterness of the sweetener acesulfame-K from 21.35 to 36.93 mg/L, masking the off-flavor. These findings illuminate the complexity of trigeminal perception influences on taste. Further investigation of these effects can render trigeminal stimuli an effective tool to enhance beverage aroma and flavor.

Olfaction, ability to identify particular olfactory clusters and odors, and physical performance in community-dwelling older adults: The Yanai Study

BACKGROUND

Olfactory dysfunction is associated with poor physical performance in older adults. However, it remains unknown whether the ability to identify particular olfactory clusters and/or odors is associated with physical performance in physically independent community-dwelling older adults.

METHODS

This cross-sectional study included 130 community-dwelling older adults (70.1 ± 5.5 years). The Odor Stick Identification Test for Japanese people, consisting of 12 odors in four clusters (wood, grass, herb; sweet; spices; foul-smelling), was used to examine olfaction. Participants also completed physical performance tests (one leg standing with open eyes; aerobic capacity; lower muscle function: five-times chair stand [CS] and vertical jump; mobility: star walking and timed up and go [TUG]) and cognitive function tests.

RESULTS

Worse overall olfaction was not significantly associated with any physical performance measure. Worse performance for identifying sweet odors and an inability to identify some specific odors (menthol and rose) were associated with worse mobility and/or lower muscle function-adjusted covariates. Moreover, an inability to identify menthol and rose was associated with worse TUG (odds ratio [OR]: 0.424; 95% confidence interval [CI]: 0.215-0.836), star walking (OR: 0.714; 95% CI: 0.506-0.976), CS (OR: 0.638; 95% CI: 0.470-0.864), and vertical jump (OR: 1.12; 95% CI: 1.001-1.24) performance, even when the analysis was adjusted to exclude menthol and rose score from the overall olfaction score (p < .05 for all).

CONCLUSIONS

The current study may help to increase awareness of olfactory and physical dysfunction at an earlier stage among physically independent community-dwelling older adults.

Association between the inability to identify particular odors and physical performance, cognitive function, and/or brain atrophy in community-dwelling older adults from the Fukuoka Island City study

Background

Olfactory dysfunction is associated with severe brain atrophy and cognitive impairment in Parkinson’s disease. However, it remains unknown whether an inability to identify particular odors is associated with physical performance, cognitive function, and/or brain atrophy in community-dwelling older adults.

Methods

In this cross-sectional study, 44 community-dwelling older adults were included (14 males, 30 females; mean age: 72.4 ± 5.7 years, range: 63–85 years). The Odor Stick Identification Test for Japanese, consisting of 12 odors, was used to examine olfaction. Subjects also completed physical performance (lower limb function, balance, and gait speed) and cognitive function (global cognition, logical memory, and the Trail Making Tests). Additionally, magnetic resonance imaging was used to investigate brain atrophy in the bilateral medial temporal area (MTA) and whole gray matter using the voxel-based specific regional analysis system for Alzheimer’s disease.

Results

Total olfaction was not significantly associated with physical performance, cognitive function, or brain atrophy. However, MTA atrophy was associated with an inability to identify Japanese orange (B: − 0.293; β: − 0.347; p < .05) after adjusting for age and sex (R²: 0.328; adjusted R²: 0.277). Subjects who were unable to identify Japanese orange (n = 30) had worse MTA atrophy than those who were able to identify Japanese orange (n = 14), even after adjusting for covariates (p < .05).

Conclusions

Total olfaction was not associated with physical performance, cognitive function, or brain atrophy. However, an inability to identify Japanese orange odor was independently associated with mild MTA atrophy among community-dwelling older adults.

Consumer Response to Cake with Apple Pomace as a Sustainable Source of Fibre

The use of apple pomace flour (APF) as a fibre enrichment strategy was investigated. The aim of this study was to evaluate consumers' response to intrinsic and extrinsic properties of a bakery premix product when using APF. Apple pomace, a by-product from the juice industry, was dried and ground. APF is high in carbohydrates (47.47%) and fibre (38.48%), and it was used to partially substitute wheat flour and sugar in a cake premix. Acceptability, health, and nutrition questions were evaluated with and without information in terms of regular and fibre-enriched cake. The regular cake score was not affected by information, while the enriched cake's score increased with information. Three clusters were identified. Cluster 1 (29%) showed high liking scores for regular cake, cluster 2 (31%) for the fibre-enriched cake, and cluster 3 (40%) showed similar liking for both. Consumers described the samples and ideal cake using a check-all-that-apply (CATA) questionnaire. Penalty analyses explained differences in acceptability among consumers. Healthiness, tastiness, and fibre content were the main reasons to buy the enriched cake for cluster 2; taste for consumers in cluster 1; and healthiness and taste for consumers in cluster 3. APF as a functional ingredient may be a consumers' choice as a sustainable use of apple pomace.

Aging and the (Chemical) Senses: Implications for Food Behaviour Amongst Elderly Consumers

The growing aging population are increasingly suffering from the negative health consequences of the age-related decline in their senses, especially their chemical senses. Unfortunately, however, unlike for the higher senses of vision and hearing, there is currently nothing that can be done to bring back the chemical senses once they are lost (or have started their inevitable decline). The evidence suggests that such chemosensory changes can result in a range of maladaptive food behaviours, including the addition of more salt and sugar to food and drink in order to experience the same taste intensity while, at the same time, reducing their overall consumption because food has lost its savour. Here, though, it is also important to stress the importance of the more social aspects of eating and drinking, given the evidence suggesting that a growing number of older individuals are consuming more of their meals alone than ever before. Various solutions have been put forward in order to try to enhance the food experience amongst the elderly, including everything from optimising the product-intrinsic food inputs provided to the remaining functional senses through to a variety of digital interventions. Ultimately, however, the aim has to be to encourage healthier patterns of food consumption amongst this rapidly-growing section of the population by optimising the sensory, nutritional, social, and emotional aspects of eating and drinking. An experimental dinner with the residents of one such home where nostalgic-flavoured healthy ice-creams were served is described.

Altered Salivary Flow, Protein Composition, and Rheology Following Taste and TRP Stimulation in Older Adults

Taste and smell perceptions diminish in older age, impacting upon quality of life and nutrition, yet the causes of taste loss are largely unknown. Transient receptor potential channels (TRP) found on the oral mucosa are also involved in oral sensations including cooling and burning and may contribute to the eating experience of older people. Older adults often have reduced salivary flow and the physical properties of saliva may change, but the role of saliva in oral sensations of older adults is yet to be elucidated. Here, the effect of older age on subjective (perception) and objective (stimulated salivary response) measures of TRP stimulants, odors, and basic tastants was investigated. Whole mouth saliva was collected from younger (mean age 24 years) and older adults (mean age 72 years) following stimulation of taste [mono sodium glutamate (MSG) and caffeine], olfaction (menthol), and TRP receptors (capsaicin). Participants rated perceived intensity of each stimulus, and salivary properties were assessed. Older age was associated with 15% lower umami taste and 26% lower menthol odor perception, coupled with 17% lower salivary response to MSG. Interestingly, there were no differences for perception of TRP stimulants, so chemo-sensation was not affected by age. Younger adults had four times greater elasticity (Spinnbarkeit) with MUC7 levels almost double and 66% greater resting salivary flow rate. Stimulated salivary responses in the younger group were also higher compared to the older group, with changes in protein and viscoelasticity in response to taste and TRP stimulation. These results show the impact of older age upon taste and smell sensation which may lead to changes in the physical and compositional properties of saliva in response to taste/odor stimulation. Measurement of stimulated salivary flow and rheology provides an objective measure of taste in addition to subjective perceptions which can be influenced by participant bias. Chemo-sensation may be retained with age and trigeminal stimuli such as chili could be employed in future studies to enhance meals for an age group at risk of malnutrition. Alteration in salivary properties due to advanced age could impact on ability to taste due to poor diffusion of tastants and reduced oral surface protection.

Understanding the sensory characteristics and drivers of liking for gochujang (Korean fermented chili pepper paste)

The present study investigated the sensory characteristics of 31 types of gochujang, a Korean fermented chili paste, produced in various regions of Korea. Generic descriptive analysis was conducted to analyze the sensory properties of the samples. Among these, four samples were selected for consumer taste test based on their distinct sensory profiles. The drivers of liking for gochujang were identified when the samples were applied to four different food systems. Consumers (age range: 20's-60's) rated the acceptance of the samples. ANOVA and multivariate analyses were conducted on the data. The types of carbohydrate sources or usage of additional seasoning showed stronger influence on the sensory characteristics of gochujang than the production location. Samples with strong fermented soy and fish sauce characteristics were fairly unacceptable to the consumers. The positive drivers of gochujang were appropriate levels of spiciness and sweet odors/flavors, whereas the negative drivers were off-note and fermentation-related flavors.

Importance of consumer perceptions in fiber-enriched food products. A case study with sponge cakes

Sponge cakes enriched with fiber from different sources (maltodextrin, wheat, apple, blackcurrant and a mixture of potato and Plantago ovata) were studied.

Odor-Specific Loss of Smell Sensitivity with Age as Revealed by the Specific Sensitivity Test

The perception of odor mixtures plays an important role in human food intake, behavior, and emotions. Decline of smell acuity with normal aging could impact food perception and preferences at various ages. However, since the landmark Smell Survey by National Geographic, little has been elucidated on differences in the onset and extent of loss in olfactory sensitivity toward single odorants. Here, using the Specific Sensitivity test, we show the onset and extent of loss in both identification and detection thresholds of odorants with age are odorant-specific. Subjects of Chinese descent in Singapore (186 women, 95 men), aged 21-80 years, were assessed for olfactory sensitivity of 10 odorants from various odor groups. Notably, subjects in their 70s required 179 times concentration of rose-like odorant (2-phenylethanol) than subjects in the 20s, while thresholds for onion-like 2-methyloxolane-3-thiol only differed by 3 times between the age groups. In addition, identification rate for 2-phenylethanol was negatively correlated with age throughout adult life whereas mushroom-like oct-1-en-3-ol was equally identified by subjects across all ages. Our results demonstrated the girth of differentiated olfactory loss due to normal ageing, which potentially affect overall perception and preferences of odor mixtures with age.

Optimal preferred MSG concentration in potatoes, spinach and beef and their effect on intake in institutionalized elderly people

BACKGROUND

Elderly people may benefit from sensory stimulation to increase food intake since anorexia of ageing is prevalent among them. An optimal MSG concentration may increase the palatability of foods but this depends on the food and chemosensory status of the taster. Currently, the results on taste enhancing to increase intake are inconsistent.

OBJECTIVE

To find an optimal preferred MSG concentration in mashed potatoes, spinach and ground beef and to determine whether this concentration increases consumption of these foods among institutionalized elderly people.

DESIGN

Single blind within subject cross-over study performed at the laboratory and in the residents' own apartments.

PARTICIPANTS

33 elderly and 29 young people in the sensory study and 53 elderly people in the intake study.

MEASUREMENTS

Pleasantness of the foods was rated of the foods each with 0, 0.5, 0.8, 1.3 and 2.0 g of MSG/100g. Intake was measured by weighing back leftovers of 2 meals with MSG (0.5% in mashed potatoes, 2% in spinach and ground meat) and without MSG.

RESULTS

0.5% MSG (p < 0.05) was preferred in mashed potatoes but no optimal preferred concentration was found for spinach and ground beef, possibly because of their complex taste. Intake was not different between the foods with and without MSG or the total meal (all p > 0.68).

CONCLUSION

MSG (0.5% and 2%) does not guarantee a higher intake among elderly. The chemosensory heterogeneity of the elderly population requires more individual flavor enhancement to improve the dietary intake and sensory experience.

Compensation for age-associated chemosensory losses and its effect on the pleasantness of a custard dessert and a tomato drink

Differences between elderly subjects (n=52, 60-85 years) and young subjects (n=55, 18-35) in their food liking and their olfactory capability were investigated. Two food systems were used: custard desserts and tomato drinks. Flavor enhancement/enrichment, textural change, and/or irritant addition were incorporated as compensatory strategies into these foods. The addition of low concentrations of both cherry flavor and cream flavor to the custard desserts influenced their pleasantness for the majority of the elderly. The addition of cream topping increased the pleasantness of the custard desserts for both the elderly and the young. The elderly equally liked the tomato drinks with no or with low irritant addition, whereas the young generally disliked an irritant addition. However, the food liking of the elderly was not generally increased by these different compensatory strategies. Instead, subgroups were observed for each compensatory strategy, in which applied compensatory strategies led to an increase in product pleasantness. Age-associated losses in olfactory capabilities did not sufficiently explain differences in food liking, as only elderly with similar olfactory capabilities to the young demonstrated a liking of enhanced flavor. The present study does not support the assumption that age-associated impairment in olfactory capability will inevitably lead to changes in food liking.

Exposure, health information and flavour-masking strategies for improving the sensory quality of probiotic juice

Probiotics are live microbial food supplements, which have been shown to exert numerous health benefits. Research has identified that probiotics cause perceptible off-flavours that often contribute to consumer dissatisfaction. This research consisted of three objectives. Firstly, to confirm whether probiotics have a significant effect on the sensory quality and the consumer acceptance of juices. Secondly, to evaluate whether the addition of tropical juices masks probiotic off-flavours, thereby increasing consumer liking. Thirdly, to determine whether non-sensory factors (i.e., repeated exposure, and health information) have an impact on consumer liking. Three orange juice products were manufactured for analysis; Control juice, juice containing probiotics, and juice containing probiotics and tropical fruit juices (10% v/v). Descriptive sensory analysis using a trained panel (n=8) determined that probiotic juices possessed unique 'medicinal' characteristics. Using labelled affective magnitude scales, consumers (n=116) evaluated their 'overall liking' of the three juices in a randomised order in the laboratory. Once assigned into one of three balanced exposure groups, each consumer took home seven, 100mL bottles of one of the juices, and consumed one bottle each day for 7 days. After each in-home consumption, consumers evaluated their 'overall liking' to familiarize themselves with the juice. Furthermore, half of the consumers were provided with information about the presence and the health benefits of probiotics, while the other half of consumers received no information. After 7 days of in-home usage, consumers returned to the laboratory for post-exposure sensory testing, where they re-evaluated their 'overall liking' of the three juices in a randomised order. Results showed that tropical juices were effective in masking the off-flavours associated with probiotic ingredients, and that consumer liking for the probiotic juice containing tropical juice flavours was maintained over the 7-day exposure period. Exposure and information had significant effects on the 'overall liking' of juices containing probiotic cultures. A significant interaction between exposure and information was observed. Therefore, exposure, health information and flavour-masking techniques can have a positive effect on the hedonic qualities of probiotic juices.

Odour and taste sensitivity is associated with body weight and extent of misreporting of body weight

BACKGROUND

Sensory factors are important determinants of appetite and food choices but little is known about the relationship between body weight and sensory capabilities.

OBJECTIVE

To investigate the relationship between measured body weights, misreporting of body weight and sensory capabilities.

DESIGN

In a cross-sectional sensory study, body weight was assessed by measured and self-reported body weight in healthy men (n=130) and women (n=181). Sensory capabilities were assessed as odour detection and identification, and detection for salty, sweet, sour and bitter taste.

RESULTS

Odour detection, odour identification and taste perception scores were lower in subjects with a BMI >or=28 kg/m(2) than in subjects with a BMI <28 kg/m(2) in the age group <65 years whereas in subjects >or=65 years scores were higher in subjects with a BMI >or=28 kg/m(2) than in subjects with a BMI <28 kg/m(2) (BMI*age group: P=0.015, 0.053 and 0.015, respectively). Independent of age, scores were highest in under reporters of body weight (P=0.008, 0.001 and 0.017). Differences in taste perception could be attributed to sour (P=0.015) and bitter (P=0.026) perception, but not to salty or sweet perception.

CONCLUSION

Relationship between sensory capabilities and body mass is age dependent. Compared to overweight subjects, the sensory capabilities of normal weight individuals appear to be higher (<65 years) and lower (>or=65 years). At any age, however, subjects who under reported their body weight show higher sensory capabilities.

Correspondence between three olfactory tests and suprathreshold odor intensity ratings

OBJECTIVES

The capability of three olfactory tests (European Test of Olfactory Capabilities, Sniffin' Sticks and Cross-Cultural Smell Identification Test) to similarly classify subjects as normosmics, hyposmics and anosmics as well as the relation between test performance and suprathreshold ortho- and retronasal odor intensity ratings were examined.

MATERIAL AND METHODS

A total of 48 subjects (age range 15-84 years; mean age 49.5 years) completed the 3 olfactory tests, rated aqueous solutions of vanilla (0-0.31%) and lemon aroma (0-0.17%) for odor and flavor intensity and filled in a background questionnaire. Ten subjects had case histories indicating anosmia, with the remainder having subjectively normal olfaction.

RESULTS

The test results were highly correlated and differentiated anosmic, hyposmic and normosmic subjects. At an individual level, some discrepancy was seen in the olfactory diagnoses given by the three tests. In principal component analysis, olfactory measurements were loaded on three components: (i) odor detection, discrimination and identification; (ii) suprathreshold intensity ratings; and (iii) threshold for n-butanol. Advanced age was related to impaired olfactory performance.

CONCLUSIONS

Although the three olfactory tests diagnosed the individuals slightly differently, all were considered to be valid for clinical evaluation of olfactory capabilities. The tests separated anosmics and normosmics highly significantly, and permitted an assessment of hyposmia. The suprathreshold odor intensity ratings reflected a different dimension of olfaction than the three olfactory tests.

Flavor enhancement as a tool for increasing pleasantness and intake of a snack product among the elderly

A yogurt-like fermented oat bran product, flavored with regular and heightened concentrations of red currant aroma, was tested in two tasting sessions (side-by-side) and, between these, in a six-day home-use (monadic testing daily, 3+3 packages of the snack) by the elderly (n=50, mean age 73.7, range 63-85 years) and the young (n=58, mean age 23.1, range 18-34 years). The subjects rated the odor and flavor intensity and pleasantness and also conducted an odor detection and identification test. In home-use, the subjects reported the quantity consumed, willingness to eat, buy or recommend the snack. The young outperformed the elderly in the olfactory test. The heightened aroma samples were initially rated as less pleasant by both age groups, but among the elderly, the ratings given to the two samples merged during exposure. For the young, the large difference in perceived odor and flavor intensities reflected marked differences in pleasantness, while the elderly were less responsive to intensity differences in their pleasantness ratings. Overall, both age groups ate less of the heightened aroma sample. Despite the impaired olfactory capabilities of the elderly, no clear indication of benefit of the enhanced flavor was found for either pleasantness or intake.