Temporal aspects of consumer preferences

Layered food designs to create appetizing desserts: A proof-of-concept study

Creating layers in foods is a culinary technique commonly used to diversify sensory experiences, but it has not been reported scientifically on its effect on hedonic and appetitive responses. This study aimed to investigate the use of dynamic sensory contrasts in layered foods to stimulate liking and appetite, using lemon mousse as a model. A sensory panel evaluated the perceived sour taste intensity of lemon mousses acidified by various amounts of citric acid. Bilayer lemon mousses with unequal distribution of citric acid across the layers to deliver higher levels of intraoral sensory contrast were developed and evaluated. A consumer panel evaluated the liking and desire to eat lemon mousses (n = 66), and a selection of samples was further investigated in an ad libitum food intake setting (n = 30). In the consumer study, bilayer lemon mousses with a layer of low acidity (0.35% citric acid w/w) on top and higher acidity (1.58 or 2.8% citric acid w/w) at the bottom showed consistently higher liking and desire scores than their corresponding counterparts with identical acid levels equally distributed in a monolayer. In the ad libitum setting, the bilayer mousse (top: 0.35; bottom: 1.58% citric acid w/w) had a significant 13% increase in intake compared to its monolayer counterpart. Modulating sensory properties across food layers with different configurations and layer compositions can be further explored as a tool to design appetizing foods for consumers at risk of undernutrition.

Time-intensity and reaction-time methodology applied to the dynamic perception and liking of bitterness in relation to body mass index

There are very few studies which have considered perception temporality when relating perceived intensity and hedonic responses in relation to body mass index (BMI; kg/cm²). The aim of the present study was to determine the relationship between BMI with the dynamic perception and liking of bitter tasting solutions. For this purpose, two different categories of bitter products were applied: 6-n-propilthiouracil (PROP) solutions (0.010, 0.032 and 0.060 mmol/L) and commercial beverages (coffee, yerba mate infusion and grapefruit juice). The proposed methodology to evaluate perception and hedonic response was based on the measurement of reaction-time (R-T) and multiple-sip time-intensity (T-I) registers in people with a high BMI (25 < BMI < 30; overweight group) and a normal BMI (<25; normal-weight control group). The multiple-sip evaluation to describe perception of PROP solutions and liking of beverages was used as a more ecologically valid laboratory methodology to simulate a situation of usual consumption. In this sense, working with a multiple-sip design helped confirm that bitter taste has a cumulative effect since in every case the sip effect was significant when evaluating the maximum intensity; this effect was more important as the bitterness increased. Regarding the body weight group comparisons, the normal BMI group perceived bitter taste more intensely and the time to react to it was shorter (faster reaction) for both PROP solutions and the three beverages. Interestingly, even though the high BMI group rated the bitter taste as less intense, they had a lower level of acceptance than normal BMI. This result suggests that the hedonic rather than the sensory component might be playing a crucial role in the perception of bitter taste in individuals with high BMI.

Sensory evaluation of dark origin and non-origin chocolates applying Temporal Dominance of Sensations (TDS)

Dark chocolates are rich sources of polyphenols, widely acknowledged for eliciting several beneficial health effects. However, these compounds are key inducers of bitter taste and astringency, potentially limiting consumers' acceptance of chocolates with higher cocoa contents. In order to gain better insight in consumers' choices, the present study investigated the temporal profile of bitterness and astringency as well as sweet taste as covering agent, during the testing period in 5 dark origin (OR) (66.8-80.1% cocoa) and 6 non-origin (N-OR) (54.5-80.0% cocoa) chocolates with different cocoa contents, applying Temporal Dominance of Sensations (TDS). The temporal profile of the evaluated OR chocolates was characterized by the dominance of bitterness independent of cocoa contents (%cc), reaching maximum dominance rates (DR%) between 60.0 and 80.0% over approximately 75.0% of the testing period, i.e. prior to swallowing. After swallowing, astringency dominated, mostly not significantly. DR (%) of sweetness reached the level of significance only in one sample (OR 67.4%cc). N-OR chocolates with 54.5-60.0%cc were characterized by significant dominances of sweet taste along the entire evaluation period, reaching maximum DR% between 90 and 95%. The increase of cocoa contents was combined with higher DR% of bitter taste. Astringency dominated in N-OR samples at the end of the evaluation period presumably after swallowing. Finally, in N-OR chocolates, cc% highly affected the dominance of the evaluated attributes. This impact was found to be rather minor or absent in OR chocolates. Thus, the TDS-parameters showed variations in attribute's dominance in OR and N-OR chocolates indicating a strong influence of cocoa bean variety and local conditions (environmental and farming conditions as well as post-harvest treatment practices) in addition to cocoa contents.

How Does Food Taste in Anorexia and Bulimia Nervosa? A Protocol for a Quasi-Experimental, Cross-Sectional Design to Investigate Taste Aversion or Increased Hedonic Valence of Food in Eating Disorders

Background: Despite on-going efforts to better understand dysregulated eating, the olfactory-gustatory deficits and food preferences in eating disorders (ED), and the mechanisms underlying the perception of and responses to food properties in anorexia nervosa (AN) and bulimia nervosa (BN) remain largely unknown; both during the course of the illness and compared to healthy populations. It is, therefore, necessary to systematically investigate the gustatory perception and hedonics of taste in patients with AN and BN. To this end, we will examine whether aversions to the taste of high-calorie food is related to the suppression of energy intake in restricting-type AN, and whether an increased hedonic valence of sweet, caloric-dense foods may be part of the mechanisms triggering binge-eating episodes in BN. In addition, the role of cognitions influencing these mechanisms will be examined.

Method: In study 1, four mixtures of sweet-fat stimuli will be presented in a sensory two-alternative forced-choice test involving signal detection analysis. In study 2, a full-scale taste reactivity test will be carried out, including psychophysiological and behavioral measures to assess subtle and covert hedonic changes. We will compare the responses of currently-ill AN and BN patients to those who have recovered from AN and BN, and also to those of healthy normal-weight and underweight individuals without any eating disorder pathology.

Discussion: If taste response profiles are differentially linked to ED types, then future studies should investigate whether taste responsiveness represents a useful diagnostic measure in the prevention, assessment and treatment of EDs. The expected results on cognitive mechanisms in the top-down processes of food hedonics will complement current models and contribute to the refinement of interventions to change cognitive aspects of taste aversions, to establish functional food preferences and to better manage food cravings associated with binge-eating episodes. No trial registration was required for this protocol, which was approved by the Swiss ethics committee (CER-VD, n° 2016-02150) and the Ethics Review Panel of the University of Luxembourg.