Sweet taste exposure and the subsequent acceptance and preference for sweet taste in the diet: systematic review of the published literature.

Background: There are consistent, evidence-based global public health recommendations to reduce intakes of free sugars. However, the corresponding evidence for recommending reduced exposure to sweetness is less clear. Objective: Our aim was to identify and review the published evidence investigating the impact of dietary exposure to sweet-tasting foods or beverages on the subsequent generalized acceptance, preference, or choice of sweet foods and beverages in the diet. Design: Systematic searches were conducted to identify all studies testing relations of variation in exposure to sweetness through foods and beverages with subsequent variation in the generalized acceptance, preference, or choice of sweetened foods or beverages, in humans aged >6 mo. Results: Twenty-one studies met our inclusion criteria, comprising 7 population cohort studies involving 2320 children and 14 controlled trials involving 1113 individuals. These studies were heterogeneous in study design, population, exposure, and outcomes measured, and few were explicitly designed to address our research question. The findings from these were inconsistent. We found equivocal evidence from population cohort studies. The evidence from controlled studies suggests that a higher sweet taste exposure tends to lead to reduced preferences for sweetness in the shorter term, but very limited effects were found in the longer term. Conclusions: A small and heterogeneous body of research currently has considered the impact of varying exposure to sweet taste on subsequent generalized sweet taste preferences, and this evidence is equivocal regarding the presence and possible direction of a relation. Future work should focus on adequately powered studies with well-characterized exposures of sufficient duration. This review was registered with PROSPERO as CRD42016051840, 24 November 2016.

Application of the European Test of Olfactory Capabilities in patients with olfactory impairment.

A central issue in olfaction concerns the characterization of loss of olfactory function: partial (hyposmia) or total (anosmia). This paper reports the application in a clinical setting of the European Test of Olfactory Capabilities (ETOC), combining odor detection and identification. The study included three phases. In phase 1, anosmics, hyposmics and controls were tested with the 16-items version of the ETOC. In phase 2, a short version of the ETOC was developed: patients with and controls without olfactory impairment were tested on a 6-items ETOC. In phase 3, to predict olfactory impairments in new individuals, the 16-items ETOC was administered on samples of young and older adults, and the 6-items version was applied in samples of young, elderly participants and Alzheimer patients. In phase 1, linear discriminant analysis (LDA) of ETOC scores classified patients and controls with 87.5 % accuracy. In phase 2, LDA provided 84 % correct classification. Results of phase 3 revealed: (1) 16-items ETOC: whereas in young adults, 10 % were classified as hyposmic and 90 % as normosmic, in elderly, 1 % were classified as anosmic, 39 % hyposmic and 60 % normosmic; (2) 6-items ETOC: 15 % of the young adults were classified as having olfactory impairment, compared to 28 % in the older group and 83 % in Alzheimer patients. In conclusion, the ETOC enables characterizing the prevalence of olfactory impairment in young subjects and in normal and pathological aging. Whereas the 16-items ETOC is more discriminant, the short ETOC may provide a fast (5-10 min) tool to assess olfaction in clinical settings.

Willingness to try new foods as predicted by social representations and attitude and trait scales.

The structure and predictive ability of social representation of new foods were investigated and compared with instruments measuring relevant attitudes and traits using a questionnaire quantifying these aspects, completed by 743 respondents. Based on their rated willingness to try, new foods were categorized as modified dairy products, genetically modified (GM), organic, and ethnic products (two examples, snails and passion fruit, were treated separately). The social representation (SR) consisted of five dimensions: suspicion of novelties, adherence to technology, adherence to natural food, eating as an enjoyment, and eating as a necessity. The SR dimensions were strong predictors of willingness to try GM foods (predicted by adherence to technology) and organic foods (predicted by adherence to natural foods). Low food neophobia predicted the rated willingness to try snails and passion fruit. Thus, different constructs predicted willingness to try different categories of new foods, and as a whole, SR dimensions markedly improved the prediction.

Timing of intensity perception of a polar vs nonpolar aroma compound in the presence of added vegetable fat in milk.

Differences in timing of intensity perception of the retronasal aroma of a nonpolar (linalool) vs polar (diacetyl) compound when the matrix (milk) fat content was varied (0%, 1%, 5%, or 10% rapeseed oil) were studied using a time-intensity method. Aromas were also evaluated by orthonasal means and with static headspace gas chromatography (GC). With increasing fat content, linalool was considerably retained in the matrix, while the release of diacetyl was not affected. As little as 1% fat was sufficient to significantly reduce the volatility (GC results) of linalool and orthonasal, but not retronasal, intensity. No effect of fat was found on the rate of linalool release. The linalool perception of the sample containing the greatest amount of fat lasted a shorter time than that of the samples containing less fat; however, the decrease in intensity perception was steeper in lower fat samples. The observed temporal release of linalool partly challenges the often-repeated statement that reduction of fat results in a more rapid and shorter aroma release.

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.

Dimensions of novelty: a social representation approach to new foods.

Social representations of new foods were examined with a total of 44 subjects in nine focus groups. Each group was homogenous, defined by age, gender and educational background. Halfway through the interview, commercial packages of functional, genetically modified, organic, nutritionally modified and ethnic foods were presented as visual stimuli for discussion. Thematic and content analyses of the interview data showed that five dichotomies characterized the social representation: trust/distrust, safe/unsafe, natural/artificial, pleasure/necessity, and past/present. Many metaphors were used, with functional products being associated metaphorically with, for example, medicine and genetically modified products being associated with death and terrorism. Chronological references focused on the development of cuisine. The perceived unsafety of new foods was an important argument for women but not for men. The difference between age groups was in relating the discussion to either present time (young subjects) or past time (older subjects). Level of education affected the content of argumentation. In the context of new foods, social representations are formed to cope with the feeling of strangeness evoked by the novelties. They also have a role in cultural acceptance of new products by making them familiar. Overall, the results reflect the development of a new common sense in which popularized scientific notions are anchored in the process of urbanization.

Perception of melting and flavor release of ice cream containing different types and contents of fat.

Temporal effects of dairy and vegetable fats (0 to 18%) on perception of strawberry flavor release and melting of ice cream were studied using the time intensity sensory method. Also, aroma and flavor attributes of the ice cream samples were evaluated. Only slight effects of fat on the rate of flavor release and flavor intensity were perceived. A slightly faster flavor release from the vegetable fat compared with dairy fat was noticed. Polydextrose and maltodextrin as bodying agents in the fat-free ice cream significantly increased flavor release and melting rate of the ice cream. Increasing fat content slightly retarded melting of ice cream in the mouth. No significant effect of the fat quality on perceived melting was noticed. Significant differences in aroma and flavor attributes of the fat-free and other samples were perceived. Intensity and sharpness of the strawberry aroma and flavor were greater in fat-free samples and they were perceived as nontypical. Fattiness and creaminess were highly correlated. Maltodextrin and polydextrose increased perceived fattiness and creaminess of fat-free ice cream.

Fermented soymilk with a monoculture of Lactococcus lactis.

Lactococcus lactis strain (LL3) isolated from mothers' milk was used to produce fermented soymilk. The strain survived at levels of over 7 log cfu/ml for 3 weeks in the fermented soymilk. A consumer survey was carried out to compare the acceptability of the fermented product with a similar product made with L. lactis ATCC11545 originally isolated from cow's milk. Blind samples produced by fermentation with the two strains were rated equally attractive, whereas information on the origin of the strains significantly enhanced the pleasantness of the fermented soymilk.

Applicability of the Scandinavian Odor Identification Test: a Finnish-Swedish comparison.

The possibility of using the Scandinavian Odor Identification Test (SOIT), developed for clinical purposes for use with Swedish subjects, for assessment of another northern European population was studied by comparing test performance between 127 Finnish and 127 Swedish participants, who were matched for age (19-85 years) and gender. The results showed very similar performance between countries and demonstrated, as expected, age- and gender-related differences in performance. Test-retest reliability was as good in Finnish as in Swedish subgroups of participants and no significant difference between countries in terms of diagnostic distribution (normosmia, hyposmia and anosmia) was found when using existing cut-off scores. The findings suggest that the SOIT, with its diagnostic cut-off scores, is reliable and valid for use with Finnish populations.

Perception and pleasantness of a food with varying odor and flavor among the elderly and young.

Aging diminishes chemosensory functioning, in particular the sense of smell, thus possibly decreasing the enjoyment from food. We examined the effect of age on ortho- and retronasal perception and on pleasantness ratings of cream cheese in which 3 levels of food aromas (vanilla or basil) were combined, respectively, with 3 levels of sucrose or NaCl. The elderly (n=59, 60-85 years) and young (n=39, 21-38 years) subjects were also tested for olfactory identification ability. As expected, the young differentiated odor intensities better than the elderly. The sucrose and NaCl levels affected overall flavor intensity and pleasantness similarly in both age groups. The flavor of vanilla, but not that of basil, was favored by the elderly, suggesting that strong flavor in an appropriate context can improve the hedonic quality. The odor identification declined with age in the elderly and on average, it was lower in the elderly than in the young. Ability to identify odors was not associated with ratings of odor intensities.

The choice of fat-free vs. regular-fat fudge: the effects of liking for the alternative and the restraint status.

Non-restrained and restrained American women (N=157) chose a portion of a fat-free or regular-fat hot fudge, to be eaten on a portion of fat-free or regular-fat (depending on the experimental condition) ice cream. The subjects had tasted and rated samples of both fudge and ice cream earlier in the same session and, prior to the choice, they were informed of their own hedonic ratings of both fudges and of the respective fat contents ("fat-free" vs. "regular-fat"). The higher the hedonic difference (fat-free minus regular-fat) between hot fudge samples and the higher the individual restraint score, the more likely was the choice of the fat-free option. Also, the less hungry the subjects were prior to testing, the more likely they were to choose the fat-free version. On average, the hedonic difference between the hot fudge samples was roughly -0.5 for those choosing the fat-free option, while the corresponding value for subjects choosing the regular-fat version was -3 (9-point scale). The type of ice cream did not affect the choice. The data demonstrate the effects of a food (its hedonic quality), person (restrained status), and context (perceived hunger) on food choice.

Differences in health and taste attitudes and reported behaviour among Finnish, Dutch and British consumers: a cross-national validation of the Health and Taste Attitude Scales (HTAS).

The Health and Taste Attitude Scales (HTAS) developed by Roininen, Lähteenmäki and Tuorila in 1999 measure the importance of health and taste aspects of foods in the food choice process. These multi-item scales consist of sets of statements, ranging from "strongly disagree" to "strongly agree", which further divide into three Health (General health interest, Light product interest and Natural product interest) and three Taste (Craving for sweet foods, Using food as a reward and Pleasure) sub-scales. Finnish (N=467), Dutch (N=477), and British (N=361) respondents completed a questionnaire which contained four components: the HTAS, a separate "paper and pencil task" of choosing a food for a snack; pleasantness, healthiness and frequency of consumption of eight foods; and the Restraint Eating Scale of the Dutch Eating Behaviour Questionnaire (DEBQ). The latter three components were included in order to validate various aspects of the HTAS. The factor structure of HTAS was found to be equal in all three countries. However, there were some minor differences in factor loadings among countries, e.g. the Natural product interest and Pleasure sub-scale items had lower factor loadings in the UK than in Finland and The Netherlands. Finnish respondents had the most positive attitude towards light products. Dutch and British respondents scored higher on all Taste sub-scales than their Finnish counterparts. Respondents' health-related attitudes were good predictors of their "healthy food choices" in the snack task and self-reported consumption. Two of the Taste sub-scales (Craving for sweet foods and Using food as a reward) predicted well respondents' self-reported consumption of, for example, full-fat chocolate bars. All the Health and two of the Taste sub-scales proved to be useful tools for characterizing consumer attitudes within and between countries.

Measurements of consumer attitudes and their influence on food choice and acceptability (AIR-CAT).

A changing European food market demands insight into consumer attitudes and their influence on food choice and acceptability. This multidisciplinary area needs to bring together scientists from all regions of Europe and with very different scientific backgrounds. The primary objectives of this concerted action have been: to establish a base with state of the art methods for measurements of consumer attitudes; to review and test existing methods in practical applications in collaboration with European food industries; to perform comparative studies between laboratories on food products, where attitudes play different roles for consumer behaviour in the community countries, such as transgenic foods, irradiated foods, foods with different additives, declarations and process technologies, foods with different origin declarations, ecological foods and foods with strong health connotations (such as high-fat foods). The members of the action have published more than 130 publications related to aspects of how consumer attitudes can be measured and how food choice behaviour is related to acceptability, during the last four years. Studies have been conducted in relation to methodological aspects as well as particular studies related to specific food items and regions for food production. The paper will give a brief selection of relevant results from experiments reported through the action. During 2001 a textbook called "Food, People and Society, in a European Perspective", will be published. The book was initiated during the action and is later supported with additional authors. Altogether 29 chapters will cover the whole spectrum of topics from consumer food choice and acceptability to market perspectives and risk analysis.

Quantification of consumer attitudes to health and hedonic characteristics of foods.

Health and Taste Attitudes Questionnaires were developed to assess consumers' orientations toward the health and hedonic characteristics of foods. Items were generated in a qualitative study. The original 37 items on health and 44 on taste were rated from "strongly disagree" to "strongly agree" by a representative sample of 1005 Finnish adults (18-81 years). The number of items was reduced using factor and item analysis, resulting in 20 health- and 18 taste-related statements. Three health-related and three taste-related factors were extracted. The health-related factors were labelled as "General health interest", "Light product interest", and "Natural product interest". The taste-related factors were named "Craving for sweet foods", "Using food as a reward", and "Pleasure". Cronbach's alphas of the multi-item scales, based on the statements loading highly on each factor, ranged from 0.67 to 0.89. Age and gender affected the responses. Females were more interested in the health and taste aspects of foods than were males. Younger respondents were less concerned with health but more interested in taste than were older respondents. A preliminary test of predictive validity was conducted by analysing subjects' responses to foods with weak and strong connotations of health and taste, and currently the questionnaires are being validated with further behavioural tests.

Predicting the intent to purchase unfamiliar and familiar cheeses: the effects of attitudes, expected liking and food neophobia.

The attitude model of the theory of reasoned action (TRA) has been applied mainly to predicting the choice of familiar foods; however, the choice of unfamiliar foods may be governed by distinct factors. In the present study, 92 females rated their attitudes and subjective norms about the purchase intentions of two familiar and two unfamiliar cheeses, and the expected and actual pleasantness of them. They also completed the food neophobia scale, which measures the tendency to avoid novel foods. Neophobic persons rated the attitudes and expected and actual taste pleasantness lower than neophilics for all cheeses, except for the most familiar, mild cheese. This suggests that food neophobia also indicates the tendency not only to avoid, but also to dislike novel foods. Before tasting, attitudes and subjective norms together predicted the intent to purchase familiar cheeses better (R2=0.54 and 0.58) than for novel cheeses (R2=0.24 and 0.35); thus, the basic TRA model was not as useful in predicting intent to purchase unfamiliar as familiar cheeses. The predictions especially for the novel cheeses were clearly improved by including expected pleasantness ratings in the model. The usefulness of the food neophobia score as an additional predictor was not clearly supported. Attitudes and subjective norms measured before tasting were poor predictors of purchase intents after tasting, which implies the importance of taste and direct product experience in food choice.

Ad libitum mixing in a taste memory task: methodological issues.

Ad libitum mixing, an application of the method of adjustment in food research, was investigated and evaluated for the purpose of taste memory research. The difference between ascending and descending runs in mixing was studied using a wide range of prefill concentrations lower and higher than standard. The effect of training was studied by comparing subjects with two or 10 replications in the first session where a standard was present as a reference. Results showing higher reproduced concentrations after a 25 h time interval than those produced immediately are consistent with earlier results from within-subject designs. Thus, the difference in recall performance did not depend on the design of the study. No difference between ascending and descending runs in the mixing was observed, thus the prefill concentrations did not affect the reproduction of a given standard. There was no significant difference between produced concentrations after two and 10 replications, although a non-significant trend towards improved performance following 10 replications was observed after the 25 h time interval.

Serum leptin, food intake and preferences for sugar and fat in obese women.

OBJECTIVE: To examine the association of leptin with food intake and preferences for sugar and fat in obese humans. METHOD: Food intake and preferences for sugar and fat were measured in 35 obese women by a four-day food record and three hedonic tests, respectively. RESULTS: High fasting serum leptin concentration adjusted for body fat mass and dietary underreporting was associated with low dietary energy and fat intakes. In addition, trends towards lower preference for chocolate as well as for the taste of high-fat, low-sugar mixture were observed in those with higher leptin concentration. CONCLUSION: High serum leptin concentration could be associated in obese women with lower dietary energy and fat intakes, and possibly with the lower preference for fat. These findings need to be verified in further human studies.

Recalling sweet taste intensities in the presence and absence of other tastes.

Memory for sweet taste intensities in different media during 125 h was investigated using three concentrations (w/w) of sucrose: 4.21% (0.125 M), 8.28% (0.25 M) and 16.06% (0.5 M). Sucrose was dissolved in four media [water with no tastant and water with 0.73% (0.125 M) sodium chloride, 0.04% (0.002 M) citric acid and 0.04% (0.002 M) caffeine] as standard stimuli. Subjects (n = 39) were assigned into four groups, each group performing the memory task in one medium only. After tasting each standard the subjects reproduced the subjective taste intensity immediately and after 12 min and 1, 5, 25 and 125 h by mixing portions of low (0%) and high (29.75%; 1 M) concentrations (w/w) of sucrose and by tasting and retasting (ad libitum procedure). The produced sucrose concentrations increased significantly from the first session to the 125 h time interval. There was a significant difference between immediately reproduced standard concentrations and concentrations produced after all time intervals. Relative differences from standard (delta i/i) differed only between concentrations produced immediately and after 125 h time interval. The low (4.21%) concentration showed larger differences from standard than the high (16.06%) concentration. The added tastant had no effect on the results.