Effects of context and repeated exposure on food liking: The case of boar taint

This study investigated whether consumer acceptance of boar meat is overestimated by standardised situational testing and whether repeated exposure decreases liking. Thus, a home use test (HUT) followed by a central location test (CLT) was conducted to assess the acceptance of minced boar meat with approximately 14% fat either HIGH or LOW in androstenone (2.0 vs. 0.30 ppm) and skatole (0.30 vs. 0.06 ppm) in comparison to meat from castrates and gilts (CONTROL). In HUT, no significant difference (p > .05) in dislike frequency was observed between CONTROL and LOW. For HIGH, liking was strongly impaired during frying. The results indicated a masking effect of the ready-made sauce on the odour but not on the flavour. In CLT, dissatisfaction was generally higher than in HUT. Similar to HUT, HIGH boar meat was more often disliked (p < .001) compared to LOW and CONTROL in the CLT. To conclude, standardised testing did not underestimate acceptance. In contrast to anticipations, a single previous exposure to boar meat with high levels of androstenone and skatole did not affect (p > .05) liking in the follow-up CLT.     

Sensory characterisation of food and beverage stimuli containing β-ionone and differences between individuals by genotype for rs6591536

The aroma compound β-ionone is present in many fruits and vegetables and their derived products. Odour profiles at different β-ionone concentrations and perceived contributions of β-ionone to food/beverage flavour have only been partially established, and they generally do not extend to differences among individuals who vary in their sensitivity to the odour. Recent research has identified rs6591536, a single nucleotide polymorphism (SNP) located in the coding region of the odorant receptor OR5A1 as responsible for major differences in ability to detect β-ionone odour. In Study 1, using trained sensory panellists (n = 12), odour profiles were obtained for a range of β-ionone concentrations and compared across sensitivity groups defined by genotypes for rs5691536 (GG/AG or AA). A similar comparative approach was used in Studies 2 and 3, where participants (n = 104 and 158) characterised food/beverage stimuli containing added β-ionone using check-all-that-apply questions. The concentration of β-ionone required to elicit perception of the ‘floral’, ‘rose/violet’ and ‘aromatic/fragrant’ characteristics typically associated with β-ionone depended on the background fruit flavour (apple, raspberry, orange) and/or the product type (juice, jelly). It also differed among people classified as more sensitive (“sensitive”) and more insensitive (“insensitive”) to the odour of β-ionone. Perception of negative aspects of β-ionone (incl. ‘sour, acid, vinegar’, ‘sharp, pungent’, ‘soap’, ‘chemical’, ‘artificial’, ‘aftertaste’, ‘woody’) was encountered in all studies, but with varying frequency depending on concentration of added β-ionone and whether participants were “sensitive” or “insensitive” to β-ionone. There was some evidence in Study 3 that perception of β-ionone flavour was masked by the fruity flavours of the test products and that changes in ‘sweet’ and ‘fruity’ were associated with β-ionone spike concentration. Overall, this research suggests a need to consider genotype-encoded sensitivity together with other variables when measuring human flavour perception.     

Initial liking influences the development of acceptance learning across repeated exposure to fruit juices in 9–11 year-old children

In several studies, it has been found that repeated exposure to a novel food increases children’s acceptance of the exposure food. The present study, investigated how repeated exposure influences the acceptance of two Nordic berry juices, and whether the development depends on initial liking of the product, in 9–11 year-old children. The study had 317 participants. Two groups of children were exposed to either sea-buckthorn (n = 92) or aronia (n = 105) juice eight times, and performed two follow-up sessions 3 and 6 months after the 8th exposure. A third group (n = 120) served as controls. During pre and post-test sessions all participating children evaluated acceptance of both juices.Intake of sea-buckthorn juice increased significantly over the eight exposures (55.1 ± 7.3 till 108.8 ± 12.3) and remained high after 6 months (131.1 ± 13.2). Intake of aronia juice was only increased at follow-up sessions. Liking did not develop significantly for any of the juices across exposures. When children were grouped by their initial liking increased intake across exposures was observed regardless of initial liking of sea-buckthorn. Liking developed similarly for both juices. A significant increase was found for the ‘initial dislikers’ only. This study demonstrates how exposure effects are influenced by initial liking; it appears that changes in familiarity explain the changes seen for sea-buckthorn among ‘dislikers’. ‘Initial dislikers’ had the most benefit from repeated exposures, but did not reach ‘initial likers’ across eight exposures; more exposures in the group of ‘initial dislikers’ had possibly led to even higher liking and intake. The increased intake observed for ‘neutral likers’ and ‘initial likers’ of sea-buckthorn was not explained by increased familiarity or increased liking.     

Age and nutrition influence the concentrations of three branched chain fatty acids in sheep fat from Australian abattoirs

The characteristic mutton odour, associated with the cooked meat of older sheep, can be problematic for some consumers who find the odour disagreeable. Branch chain fatty acids (BCFAs) are considered to be the main determinants of mutton odour. In this study, the aim was to identify the factors influencing the BCFA content of animals at abattoirs in Australia. Samples of subcutaneous fat from over the chump (gluteus medius) were collected from 533 sheep carcasses at abattoirs in New South Wales, Victoria and Western Australia. The carcasses were from sheep differing in age, gender, breed and nutrition. The concentrations of three branched chain fatty acids (BCFAs); namely, 4-methyloctanoic (MOA), 4-ethyloctanoic (EOA) and 4-methylnonanoic acids (MNA), were determined. Statistical modelling showed that, with pre-slaughter nutrition in the model as a random term, BCFA concentrations could be used for discriminating the age of sheep. Fat samples from lamb carcasses had lower MOA and EOA concentrations and a higher concentration of MNA in comparison to hogget and mutton (P < 0.05). When nutrition was excluded as a random effect from the statistical model, the MOA and MNA concentrations did not differentiate between lamb, hogget and mutton whereas, for EOA, lamb had a lower concentration than mutton (P < 0.05) with hogget intermediate. An interaction existed between age and gender (P < 0.05) where female lambs had lower EOA concentrations relative to the mutton but not for castrates.     

Paired preference tests: ‘Liking’, ‘Buying’ and ‘Take Away’ preferences

Paired preference tests of liking require consumers to specify which of two foods are preferred or whether there is no preference. For ‘Buying’ preference tests, consumers specify which of two foods they are more likely to buy or whether there is no operational difference in likelihood to buy. The former test is designed to predict choice behaviour, the latter, buying behaviour. To validate the predictive ability of such tests, consumer choice and buying behaviour should be observed for several months. Another approach is to allow consumers to take away some of the foods used in the test and observe what they take. Consumers of potato chips were required to taste chips whose flavour and appearance were obviously different. A first group (N = 109) were given a traditional paired preference test of liking. A second group (N = 108) were given a preference test of buying. A third group (N = 101) were given both tests. After the test, out of sight of the experimenter, consumers were presented with two rows of plain plastic ‘snack’ bags, filled with the chips used in the test. They could take away either two bags of the same type of chip (a ‘Take Away’ preference) or one of each type (no ‘Take Away’ preference) or take neither (rejection). ‘Liking’ preferences predicted what was taken away for only 48% of consumers for the first group and 45% (third group). For ‘Buying’ preferences, the correspondence was 56% (second group) and 60% (third group). Using buying tests separately or together with liking produced some differences. More reliably, approximately 60% of consumers in all groups chose one bag of each. ‘Take Away’ preferences suggested low predictability for paired preference tests of liking and buying. ‘Take Away’ preferences are not a substitute for following a consumer for several months but they are a step in the right direction.     

The production and microbiological status of skin-on sheep carcasses

There is a demand by certain ethnic consumer groups in the United Kingdom for skin-on, singed carcasses, primarily from older sheep, but their production is illegal under current EU legislation. The aim of this study was to devise a protocol to produce carcasses having the desired ‘smoked’ colour and odour and an acceptable microbiology. A successful result could form the basis of a case to revise the legislation. Three key steps in the selected procedure were carcass singeing using specially designed gas burner equipment, pressure washing to clean the carcass and then evisceration. It was shown that a second heat application, termed ‘toasting’, if applied after evisceration, significantly (P < 0.001) reduced Enterobacteriaceae and TVC counts on carcasses before chilling. Microbiological quality was also improved when toasting was the final step, following carcass splitting and inspection. Carcasses produced in this way had significantly (P < 0.001) lower Enterobacteriaceae and TVC counts before chilling than conventionally dressed sheep carcasses produced in the same abattoir.     

The influence of recent tasting experience on expected liking for foods

Expected liking is an important determinant of food choice and there is some suggestion that liking expectations are stable over time. Here we examine the impact that a recent ‘disappointing’ hedonic experience has on expected liking. In Study 1, we examine if a disappointing experience results in changes to expected liking one day after tasting and one week after tasting. In Study 2, we examine whether past frequency of eating a food determines whether a disappointing hedonic experience results in changes to expected liking. In Study 1, expected liking for a food was reduced 1 day after a disappointing experience, but not 1 week afterwards. In Study 2, past frequency of eating moderated whether expected liking for a food was reduced 1 week after a disappointing experience: expected liking of a infrequently eaten food was reduced, but not expected liking of a frequently eaten food. Liking expectations can be influenced by disconfirmatory hedonic experiences with a food product, but these effects are dependent upon the recency of the experience and the past frequency with which the food is eaten.     

The consumer acceptance of novel vegetable-enriched bread products as a potential vehicle to increase vegetable consumption

Currently UK fruit and vegetable intakes are below recommendations. Bread is a staple food consumed by approximately 95% of adults in western countries. In addition, bread provides an ideal matrix by which functionality can be delivered to the consumer in an accepted and convenient food. Therefore, enriching bread with vegetables may be an effective strategy to increase vegetable consumption. This study evaluated bread enriched with red beetroot, carrot with coriander, red pepper with tomato or white beetroot (40 g vegetable per 100 g) compared to white control bread (0 g vegetable) for consumer acceptance. Consumers (n = 120) rated their liking of the breads overall, as well as their liking of appearance, flavour and texture using nine-point hedonic scales. Product replacement and purchase intent of the breads were rated using five-point scales. The effect of providing consumers with health information about the breads was also evaluated. There were significant differences in overall liking (P < 0.0001), as well as liking of appearance (P < 0.0001), flavour (P = 0.0002) and texture (P = 0.04), between the breads. However, the significant differences resulted from the red beetroot bread which was significantly (P < 0.05) less liked compared to control bread. There were no significant differences in overall liking between any of the other vegetable-enriched breads compared with the control bread (no vegetable inclusion). The provision of health information about the breads did not increase consumer liking of the vegetable-enriched breads. In conclusion, this study demonstrated that vegetable-enriched bread appeared to be an acceptable strategy to increase vegetable intake, however, liking depended on vegetable type.     

The acceptability of the New Nordic Diet by participants in a controlled six-month dietary intervention

A healthy and palatable ‘New Nordic Diet’ (NND) has been designed with the aim to improve public health in Denmark. In order to explore barriers and possibilities for acceptance of the NND by the wider population this study analyzes acceptance of the NND and a control diet labeled the ‘Average Danish Diet’ (ADD) among participants in a randomized controlled intervention study of the two diets’ health effects. Based on questionnaires presented before (N = 197) and after (N = 147) the intervention, an eating acceptance index expressing eating qualities and a practical acceptance index expressing practical implications of the diet in everyday life were developed. Variations in practical and eating acceptance in relation to key background variables were explored.The NND had high eating acceptance and low practical acceptance when measured after the intervention. The ADD had low eating acceptance but high practical acceptance. NND participants already exhibiting healthy eating habits before the intervention showed the highest eating acceptance of the NND. The ADD had the highest eating acceptance among ADD participants exhibiting less healthy eating habits before the intervention. In spite of high eating acceptance, low practical acceptance may hinder broader public acceptance of the New Nordic Diet.     

Consumers’ sensory acceptability of pork from immunocastrated male pigs

Boar taint is the off-odour or off flavour of cooked pork. Currently, the most common method of controlling boar taint is surgical castration. However, immunocastration has been used in some parts of the world as an alternative to surgical castration. The aim of this study was to evaluate the sensory acceptability of meat from immunocastrated pigs (IM) compared with meat from females (FE), surgically castrated (CM) and entire males (EM). Twenty animals of each type were evaluated by 201 consumers in 20 sessions. Longissimus thoracis muscle of the different animals was cooked in an oven at 180 °C for 10 min. Consumers scored the odour and the flavour of the meat in a 9-point category scale without an intermediate level. There were no significant differences in consumer’s evaluation of meat from IM, CM, and FE. In contrast, EM meat presented a higher percentage of dissatisfied scores and was significantly (P < 0.05) less accepted than meat from CM, IM and FE. Consumers’ acceptability of EM meat was always lower, independently of its androstenone levels. However meat with low levels of androstenone was more accepted that meat with medium or high levels of this substance. It can be concluded that immunocastration produced pork that was accepted by the consumers, and was indistinguishable from pork from CM or FE.     

Acquisition of liking for spinach products

This research investigated whether consumers acquire a liking for spinach through tasting it many times (repeated exposure) or in association with something which is better-liked (associative learning). The research focused on women who ate spinach infrequently or did not eat spinach at all, did not have a strong liking or disliking for spinach and were prepared to try the vegetable again. The experiment consisted of three phases; a pre-test, followed by a learning phase and finally a post-test. Two hundred and twenty-three consumers participated in a pre- and post-test evaluation of plain spinach at a central location. They were divided into five different groups for the learning phase, with approximately 40 consumers in each. A ‘control’ group of consumers was not given a product. The other consumers were given the same product (either peas, spinach type 1, spinach type 2 or a cream spinach recipe, containing cheese and spices) once a week for five weeks to prepare at home according to specified instructions and consume as an accompaniment to a hot meal. Acquisition of liking was found; repeated consumption of plain spinach did result in an increased liking for plain spinach overall (p = 0.02) and specifically for spinach dislikers (p < 0.05). At an overall level, flavour–flavour pairing effects were not demonstrated. However, consumers who initially disliked spinach showed an increased liking (p < 0.05) for spinach after having repeatedly eaten it in the learning phase as part of a recipe with cream, cheese and spices.     

Sensory profiles and consumer acceptability of a range of sugar-reduced products on the UK market

Current UK intake of non-milk extrinsic sugars (NMES) is above recommendations. Reducing the sugar content of processed high sugar foods through reformulation is one option for reducing consumption of NMES at a population level. However, reformulation can alter the sensory attributes of food products and influence consumer liking. This study evaluated consumer acceptance of a selection of products that are commercially-available in the UK; these included regular and sugar-reduced baked beans, strawberry jam, milk chocolate, cola and cranberry & raspberry juice. Sweeteners were present in the reformulated chocolate (maltitol), cola (aspartame and acesulfame-K) and juice (sucralose) samples. Healthy, non-smoking consumers (n = 116; 55 men, 61 women, age: 33 ± 9 years; BMI: 25.7 ± 4.6 kg/m²) rated the products for overall liking and on liking of appearance, flavor and texture using a nine-point hedonic scale. There were significant differences between standard and reduced sugar products in consumers' overall liking and on liking of each modality (appearance, flavor and texture; all P < 0.0001). For overall liking, only the regular beans and cola were significantly more liked than their reformulated counterparts (P < 0.0001). Cluster analysis identified three consumer clusters that were representative of different patterns of consumer liking. For the largest cluster (cluster 3: 45%), there was a significant difference in mean liking scores across all products, except jam. Differences in liking were predominantly driven by sweet taste in 2 out of 3 clusters. The current research has demonstrated that a high proportion of consumers prefer conventional products over sugar-reduced products across a wide range of product types (45%) or across selected products (27%), when tasted unbranded, and so there is room for further optimization of commercial reduced sugar products that were evaluated in the current study. Future work should evaluate strategies to facilitate compliance to dietary recommendations on NMES and free sugars, such as the impact of sugar-reduced food exposure on their acceptance.     

Odour and flavour perception in flavoured model systems: Influence of sodium chloride,umami compounds and serving temperature

The effects of salt (0% or 0.5% of NaCl) and umami compounds (0% or 0.3% of monosodium glutamate (MSG) + 0.15% of disodium salts of ribonucleotides) on odour and flavour attributes of beef broth model systems (BG) were studied at two serving temperatures (25 and 50 °C). Flavoured BG samples were prepared using 1-octen-3-ol (35 mg l^?1) and 2,6-dimethylpyrazine (100 mg l^?1) alone (BGO and BGD) or in combination (BGOD). A noticeable odour and flavour potentiator effect of NaCl on flavour intensities (overall, broth-like and saltiness in all samples; mushroom flavour in BGO and BGOD samples; nutty and cocoa flavour in BGD and BGOD samples), partly related to a “salting out” phenomenon, was found. Compared to 2,6-dimethylpyrazine, 1-octen-3-ol provided a less congruent flavour, which could explain the absence of a potentiator effect of umami compounds on mushroom flavour intensity. Cocoa and nutty flavour intensities increased with serving temperature in both BGD and BGOD model systems. However, mushroom odour and flavour increased in BGOD model systems but not in BGO samples, as a result of the likely enhancement effect displayed by the presence of 2,6-dimethylpyrazine. Salting-out phenomenon on particular aroma-active volatile compounds was established using sensory analysis. The potentiator flavour effect of MSG and NaCl was dependent on the characteristics of the model systems.     

Effects of an evoked refreshing consumption context on hedonic responses to apple juice measured using best–worst scaling and the 9-pt hedonic category scale

Awareness of the need to consider a product’s consumption context when measuring consumer hedonic response of a product is increasing among consumer sensory researchers. This study investigated the effects of evoking a consumption context using a written scenario on hedonic response measured using best–worst scaling and the 9-pt hedonic category scale. Hedonic responses for four apple juices with relatively large sensory differences were compared when measured in the evoked context ‘when having something refreshing to drink’ using best–worst hedonic scaling (n = 65) and the 9-pt hedonic scale (n = 48). Best–worst scaling discriminated between the four apple juices when a refreshing context was evoked (p < 0.01), while the juices were equally liked using the 9-point scale (p = 0.41) when the same context was evoked. Consumers perceived best–worst scaling to be more difficult than the 9-pt scale, however there was no difference between the two methods for consumers perceived accuracy of their liking information. The present study highlights that the effect of an evoked context on hedonic response may not be universal for hedonic methods. Further research is needed to understand the effect of evoking context on the liking of products, and to determine whether this measure reflects product liking in an actual consumption context.     

Dynamic aspects of liking: post-prandial persistence of sensory specific satiety

The time dependence of the liking of foodstuffs was investigated in a study with 25 subjects, consisting of three parts: (1) on day one, a sensory specific satiety study, which was extended until 125 min after consumption; (2) on days two to seven, a repeated in home taste and evaluation study; (3) on day eight, a second sensory specific satiety study as in 1.In parts 1 and 3, subjects were asked to eat either cheese biscuits or pears in light syrup to satiety. The change in liking of both foodstuffs, after eating one of the two foodstuffs to satiety, was followed during 125 min. In part 2, the same subjects were asked to taste and evaluate each product at home, every day for six days.In the sensory specific satiety studies (parts 1 and 3) a significant decrease in liking was observed for the product eaten to satiety, as long as 125 min after consuming that product to satiety. For both products contrast effects were observed: the liking of the uneaten product increased after eating the other product to satiety, while the liking of the eaten product decreased. This contrast effect lasted longer after eating cheese biscuits to satiety, than after eating pears to satiety.In the in home taste and evaluation study, a significant and linear decrease in liking was observed for both products during six days. There was a significant effect (p < 0.05) of eating cheese biscuits to satiety in the sensory specific satiety study on day 1, on the liking ratings of the in home consumption study. No such effect was observed for the pears.The results indicate that sensory specific satiety is relatively strong for more than 2 h after consumption and can have effects on liking ratings for more than 24 h. These effects were different for the products tested. Based on these results, we suggest that combining eating a product to satiety and in home evaluation over several days, could possibly be useful as an accelerated method to predict changes in liking upon repeated consumption.     

Consumer acceptability of coffee as affected by situational conditions and involvement

For understanding consumer behaviors more closely to what would be observed in real-life, “situational” tests has been widely studied using two main approaches: ‘physical environment’ or ‘cognitive evocation’. Both approaches have shown advantages in adopting consumption context in consumer tests. However, it has not been investigated whether either one of the approaches may be more effective or whether using these approaches together would be more advantageous than using each solely in terms of bring in consumption context. The aims were to understand the effects of evocation in different environmental settings on consumers liking and to explore the differences of these effects based on consumer involvement levels. Consumers participated in one of the 4 contextual conditions of 2 × 2 factorial design, consisting of ‘evocation’ factor (with vs. without evocation instruction) and ‘environment’ factor (booth vs. simulated café), respectively. Consumers evaluated liking for two coffee samples and responded to a coffee involvement questionnaire. The results showed that both factors have influenced on consumer liking. These effects were different according to coffee types differing in hedonic levels. Vividness of evocation lasted longer in the simulated café setting, implying physical cues reinforcing cognitive evocation. When consumers were classified according to involvement scores, liking score of the high involvement group was little affected by either situational factors, while low involvement group was highly affected by the ‘environment’ factor. The findings of the study provide important perspectives to be considered for researches into “situational” tests, including which situational approach to apply as well as consumer involvement.     

The influence of product preparation,familiarity and individual traits on the consumer acceptance of insects as food

Insects are highly valued as food in many cultures but have only recently gained interest in the West as a sustainable alternative to reduce the environmental impact of meat production. Despite the growing consumer interest in insect consumption, there is still a great disparity between curious trying and actual acceptance. The aim of this study was to examine how the product preparation, familiarity and individual traits (e.g. food neophobia) influence the consumer acceptance of insects as food. Dutch consumers (n = 976) evaluated 8 mealworm product images on 4 acceptability measures (product appropriateness, expected sensory-liking, willingness to buy, willingness to try). Product images varied according to mealworm visibility (visible/invisible), carrier flavour (savoury/sweet) and carrier origin (Western/Asian). High product acceptability was not simply achieved by adding mealworms to familiar foods. Acceptability depended very much on the perceived appropriateness of mealworms as food and the perceived appropriateness of the product combination. However, mealworm products were always expected to be inferior to the carrier products, even when visually identical. Familiarity with mealworms and individual traits played a relatively minor role, and influenced the willingness to try more than the other acceptability measures. We conclude that appropriate product design is important but insufficient to achieve consumer acceptance of insects as food in the West. Additional incentives are required to encourage acceptance beyond the mere willingness to try. We discuss the complexities underlying the consumer acceptance of insects as food and reflect on how acceptance might be increased in the future.