Sip and spit or sip and swallow: Choice of method differentially alters taste intensity estimates across stimuli

Mixed Methods Study Investigating Adolescent Acceptance and Implementation Outcomes of Serving Spicy Vegetables in School Lunch

Background

Only a few adolescents are meeting their daily vegetable requirement. At the same time, spicy food is increasingly popular and familiar across cultures.

Objectives

To explore the implementation of spicy vegetables into school meals, the primary objective is to determine adolescents' preferred degree of hot spice on steamed broccoli. Secondary objectives include estimating the appropriateness and acceptability of spicy vegetables in the National School Lunch Program and identifying strategies to promote spicy vegetables within school meals.

Methods

One hundred participants between the age 11 and 17 y sampled 4 steamed broccoli florets with varying levels of a ground red and cayenne pepper spice blend (0, 0.9, 2.0, and 4.0 g). Participants rated their likeability of each broccoli sample on a 9-point hedonic scale and answered a survey assessing chili liking, chili consumption patterns, appropriateness, and acceptability. An interview assessed perspectives on spicy vegetables within school lunch.Regression analyses assessed relationships between participant attributes and sample ratings and survey outcomes. Agglomerative hierarchical cluster analysis was conducted to cluster together participants with similar sample liking ratings.

Results

Seventy-seven percent of participants reported that chili pepper makes food taste better, and 67% consumed spicy food weekly or daily. Chili likers (n = 41) were the dominant cluster group, compared with moderates (n = 31) and chili dislikers (n = 28). Thematic analysis results suggested that most participants support incorporating spicy vegetables into school lunch but mushy vegetable texture may undermine the impact of changing school vegetable spice levels.

Conclusions

Spicy foods are commonly consumed by adolescents, and these findings support the inclusion of spicy vegetables in school lunch. Additional research is needed to identify policies and practices to improve the texture of vegetables in school meals and determine additional strategies to support cultural humility in child nutrition programs.

Predicting Perceived Hedonic Ratings through Facial Expressions of Different Drinks

Previous studies have established the utility of facial expressions as an objective assessment approach for determining the hedonics (overall pleasure) of food and beverages. This study endeavors to validate the conclusions drawn from preceding research, illustrating that facial expressions prompted by tastants possess the capacity to forecast the perceived hedonic ratings of these tastants. Facial expressions of 29 female participants, aged 18-55 years, were captured using a digital camera during their consumption of diverse concentrations of solutions representative of five basic tastes. Employing the widely employed facial expression analysis application FaceReader, the facial expressions were meticulously assessed, identifying seven emotions (surprise, happiness, scare, neutral, disgust, sadness, and anger) characterized by scores ranging from 0 to 1-a numerical manifestation of emotional intensity. Simultaneously, participants rated the hedonics of each solution, utilizing a scale spanning from -5 (extremely unpleasant) to +5 (extremely pleasant). Employing a multiple linear regression analysis, a predictive model for perceived hedonic ratings was devised. The model's efficacy was scrutinized by assessing emotion scores from 11 additional taste solutions, sampled from 20 other participants. The anticipated hedonic ratings demonstrated robust alignment and agreement with the observed ratings, underpinning the validity of earlier findings even when incorporating diverse software and taste stimuli across a varied participant base. We discuss some limitations and practical implications of our technique in predicting food and beverage hedonics using facial expressions.

Variation in TAS2R receptor genes explains differential bitterness of two common antibiotics

For pharmaceuticals to deliver their full benefits with maximum efficacy, patients need to follow recommended dosing schedules, in terms of amount and frequency. Unfortunately, the aversive taste of many drugs, especially bitterness, can reduce patient compliance in oral liquid formulations. Given common genetic differences in bitter taste receptor genes (TAS2Rs), some individuals may be at increased risk for poor compliance due to heightened bitterness that becomes a barrier to proper use. Here we report on the sensory profile of two antibiotics, chloramphenicol and ofloxacin, investigating whether bitterness intensity associates with nominally functional TAS2R variants. Participants (n = 143) rated suprathreshold intensity on a general Labeled Magnitude Scale (gLMS) for chloramphenicol and ofloxacin; propylthiouracil (PROP) was included as a control, given robust prior associations with TAS2R38 variants. The dominant sensation from chloramphenicol and ofloxacin was bitterness, falling just below “moderate” on a gLMS. TAS2R38 diplotype associated with variable bitterness of chloramphenicol and PROP, but not ofloxacin. The bitterness of ofloxacin associated with a TAS2R9 SNP (V187A). This pilot study provides novel evidence on differences in the bitterness from two antibiotics, which are associated with TAS2R variants. Improved understanding of individualized barriers to patient compliance, especially for oral formulations, can guide future efforts to optimize delivery systems for improved compliance.

Changes in temporal sensory profile, liking, satiety, and postconsumption attributes of yogurt with natural sweeteners

Abstract

Sweetened yogurts can contain between 10 and 13% added sugar. However, studies have shown that sugar reduction or replacement can influence yogurt quality. The main objective of this research was to investigate the effects of yogurt with added natural sweeteners on temporal sensory profile, liking, satiety and postconsumption measures. Yogurt samples were prepared with iso‐sweet concentrations of sucrose (9 g/100 g of plain yogurt) using xylitol (10 g/100 g), stevia (0.15 g/100 g), and monk fruit (0.15 g/100 g). Fifty panelists evaluated the temporal sensory profile of these yogurts using multiple‐intake temporal dominance of sensations (TDS), and overall liking for each intake. In addition, satiety (hunger, thirst, and fullness) and other postconsumption attributes (healthiness, satisfaction, and purchase intent) were determined. The temporal profile of yogurt sweetened with xylitol was similar to yogurt sweetened with sucrose without any onset of negative sensory characteristics at any point in intake. Yogurt sweetened with stevia had a high dominance duration for astringency. Moreover, yogurt sweetened with monk fruit showed increased dominance of attributes bitter and astringent from the first to third intake. In terms of liking, yogurt containing xylitol was scored the highest followed by stevia and monkfruit. Sweet was a positive temporal driver of liking in yogurt sweetened with monk fruit. However, mouthcoating, sweet, and sour decreased liking in yogurt sweetened with sucrose, xylitol, and stevia respectively. In terms of perceived healthiness, satisfaction and purchase intent, yogurt sweetened with sucrose scored the highest followed by xylitol. Consumption of yogurt sweetened with xylitol, stevia, or monk fruit significantly decreased hunger compared to yogurt sweetened with sucrose.

Practical Application

The current findings will play an important role for the dairy industry in understanding how sugar replacement with natural sweeteners in yogurt can influence its sensory perception and postconsumption behavior.

The tongue map and the spatial modulation of taste perception

There is undoubtedly a spatial component to our experience of gustatory stimulus qualities such as sweet, bitter, salty, sour, and umami, however its importance is currently unknown. Taste thresholds have been shown to differ at different locations within the oral cavity where gustatory receptors are found. However, the relationship between the stimulation of particular taste receptors and the subjective spatially-localized experience of taste qualities is uncertain. Although the existence of the so-called ‘tongue map’ has long been discredited, the psychophysical evidence clearly demonstrates significant (albeit small) differences in taste sensitivity across the tongue, soft palate, and pharynx (all sites where taste buds have been documented). Biases in the perceived localization of gustatory stimuli have also been reported, often resulting from tactile capture (i.e., a form of crossmodal, or multisensory, interaction). At the same time, varying responses to supratheshold tastants along the tongue's anterior-posterior axis have putatively been linked to the ingestion-ejection response. This narrative review highlights what is currently known concerning the spatial aspects of gustatory perception, considers how such findings might be explained, given the suggested balanced distribution of taste receptors for each basic taste quality where taste papillae are present, and suggests why knowing about such differences may be important.

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The existence of the tongue map has long been discredited.

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Taste receptors in the oral cavity respond to all tastes regardless of their location.

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Human psychophysical data highlights a significant spatial modulation of taste perception in the oral cavity.

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Highly-controlled studies of taste psychophysics rarely capture the full multisensory experience associated with eating and drinking.

Why Taste Is Pharmacology

The chapter presents an argument supporting the view that taste, defined as the receptor-mediated signaling of taste cells and consequent sensory events, is proper subject matter for the field of pharmacology. The argument develops through a consideration of how the field of pharmacology itself is to be defined. Though its application toward the discovery and development of therapeutics is of obvious value, pharmacology nevertheless is a basic science committed to examining biological phenomena controlled by the selective interactions between chemicals - regardless of their sources or uses - and receptors. The basic science of pharmacology is founded on the theory of receptor occupancy, detailed here in the context of taste. The discussion then will turn to consideration of the measurement of human taste and how well the results agree with the predictions of receptor theory.

Chemosensory Changes from Cancer Treatment and Their Effects on Patients' Food Behavior: A Scoping Review

Individuals undergoing treatment for cancer can experience changes in taste or smell that are often assumed to affect constructs related to food behavior, although this relationship is rarely measured directly. To ascertain the extent to which measured changes in taste and smell during and after cancer treatment affect food behavior, we conducted a scoping review and completed a comparative analysis for studies that met our criteria, which were: they directly measured cancer patients’ (a) psychophysical response to taste and/or olfactory stimuli, and (b) food behavior (including food enjoyment, food preference, dietary intake) in people affected by cancer. Eleven studies met these criteria and were included in the review. All 11 studies evaluated taste and five also measured smell. A comparative analysis exploring taste and food behavior shows that a reduced sweet taste function (decreased sensitivity) was associated with a reduced intake of a variety of different macro and micro nutrients, reduced appetite, and overall lower energy intake. One out of six studies that measured smell and food measured observed changes in olfactory function following cancer treatment. There were no significant relationships reported between olfactory measures and food behavior. Taste changes that arise from cancer treatment appear to have a direct effect on food behavior, although there is a need for more research using standardized measures and larger sample sizes. A better understanding of taste alterations and their implications for dietary intake and food enjoyment will support optimal nutritional health by identifying strategies to help patients eat well during and after cancer treatment.

Quantifying Sweet Taste Liker Phenotypes: Time for Some Consistency in the Classification Criteria

Taste hedonics is a well-documented driver of food consumption. The role of sweetness in directing ingestive behavior is largely rooted in biology. One can then intuit that individual differences in sweet-liking may constitute an indicator of variations in the susceptibility to diet-related health outcomes. Despite half a century of research on sweet-liking, the best method to identify the distinct responses to sweet taste is still debated. To help resolve this issue, liking and intensity ratings for eight sucrose solutions ranging from 0 to 1 M were collected from 148 young adults (29% men). Hierarchical cluster analysis (HCA) revealed three response patterns: a sweet-liker (SL) phenotype characterized by a rise in liking as concentration increased, an inverted U-shaped phenotype with maximum liking at 0.25 M, and a sweet-disliker (SD) phenotype characterized by a decline in liking as a function of concentration. Based on sensitivity and specificity analyses, present data suggest the clearest discrimination between phenotypes is seen with 1.0 M sucrose, where a liking rating between -15 and +15 on a -50/+50 scale reliably distinguished individuals with an inverted U-shaped response from the SLs and the SDs. If the efficacy of this approach is confirmed in other populations, the discrimination criteria identified here can serve as the basis for a standard method for classifying sweet taste liker phenotypes in adults.

Activity of frontal pole cortex reflecting hedonic tone of food and drink: fNIRS study in humans

Cognitive and hedonic aspects of taste have been studied using different neuroimaging techniques in humans. However, the methods used are unsuitable for easy monitoring of hedonics induced by intake of foods and beverages. Here we have tried to monitor changes in oxygenated hemoglobin (oxyHb) levels in the anterior prefrontal cortex (aPFC, frontopolar cortex, Brodmann area 10) in response to intake of hedonically different edibles in healthy adults. When subjects tasted sweet and bitter solutions freely without any particular instruction, cortical activation varied greatly among subjects and between the two stimuli, and no consistent results were obtained. Subjects then ate or drank preferred (hedonically positive) and disliked (hedonically negative) edibles. Although these stimuli differed among subjects, hedonically positive stimuli decreased oxyHb, whereas hedonically negative stimuli increased oxyHb, particularly in the ventral aPFC. When subjects tasted 4 kinds of jellies with different flavors and evaluated the degree of pleasantness, oxyHb level in the ventral region correlated negatively with pleasantness score. These results revealed that pleasant and unpleasant edibles tended to elicit decreased and increased oxyHb levels, respectively, within the ventral aPFC, suggesting that monitoring of oxyHb in this region may prove useful for objective evaluation of pleasantness of food and drink.

Dose-Response Relationships for Vanilla Flavor and Sucrose in Skim Milk: Evidence of Synergy

Regarding cross-modality research, taste-aroma interaction is one of the most studied areas of research. Some studies have reported enhancement of sweetness by aroma, although it is unclear as to whether these effects actually occur: depending on the cognitive strategy employed by panelists, the effects may disappear, e.g., forcing panelists into an analytical strategy to control for dumping may not be able to reveal perceptual interactions. Previous studies have largely focused on solutions and model foods, and did not test stimuli or concentrations relevant to real food applications. This study addresses these gaps: 18 vanilla flavored sucrose milks, varying between 0–0.75% (w/w) two-fold vanilla, and 0–5% (w/w) sucrose, were rated by 108 panelists for liking and perceived sweetness, vanilla flavor, milk flavor, and thickness. Interactions between vanilla and sucrose were measured using deviations of real mixtures from additive models (via the isobole method), indicating vanilla aroma does enhance perceived sweetness. However, the sweetness enhancing effect of vanilla aroma was not as pronounced as that of sucrose on vanilla flavor. Measurable cross-modal interactions occur despite using an analytical cognitive strategy. More work is needed to investigate the influence of perceptual strategy on the degree of taste-aroma interactions in real foods.