Tasting spoons: Assessing how the material of a spoon affects the taste of the food

This study investigated the effect that the taste of certain metals has on the perception of food. Four spoons plated with different metals (gold, copper, zinc, and stainless steel) were used to taste cream samples having different tastes: sweet, sour, bitter, salty, and plain. The results revealed that the zinc and copper spoons, in addition to transferring a somewhat metallic and bitter taste, enhanced to a greater or lesser extent, each cream’s dominant taste. Contrary to our expectations, the metallic taste of the copper and zinc spoons did not seem to affect the pleasantness of the samples significantly. These findings reveal that the effect that the metals from which cutlery can be made have on food perception differs from that found when the metal salts are added to the composition of the food itself.     

Water quality and taste sensitivity for basic tastes and metallic sensation

The aim of the study was to investigate the influence of water quality on taste sensitivity for basic tastes and metallic sensation. To familiarize subjects with sensory analysis, they were asked to recognize tastes, distinguish between different concentrations of basic tastes, and realize their own taste sensitivity. The International Standard ISO 3972 describes a set of tests to measure taste sensitivity. A “neutral, tasteless, still and odourless water, preferably of known hardness” is recommended for preparing the dilutions and for rinsing the mouth. The standard also recommends a series of dilutions for acid (citric acid), bitter (caffeine), salty (sodium chloride), sweet (sucrose), umami (monosodium glutamate) and metallic (iron(II)sulfate). The question arises if water quality affects taste sensitivity.MethodsTwenty-three female subjects (mean age: 22), who were recruited at the University of Applied Sciences Hamburg, Faculty of Life Sciences, were tested. Deionized water, spring water and tap water were used for taste dilutions. In each experiment, subjects were initially familiarized with the basic tastes.ResultsIn comparison to taste thresholds in spring water, the recognition thresholds are higher using tap water, and lower using deionized water. When using deionized water, sour was detected by all subjects at the lowest concentrations. Iron(II)sulfate could best be matched to metallic sensation in deionized water. Results indicate that taste sensitivity is influenced by water quality.     

Impact of Prior Consumption on Sour,Sweet, Salty,and Bitter Tastes

Food sensory tests generally require panelists to abstain from food or beverage consumption 30 min to an hour before a tasting session. However, investigators do not have a complete control over panelists' intentional or unintentional consumption prior to a tasting session. Currently, it is unclear how prior consumption impacts the results of the tasting session. The aim of this study was to determine the effects of temporary and lingering mouth irritation caused by the consumption of coffee, orange juice, and gum within 1, 15, or 30 min prior to the tasting session on the perception of 4 basic tastes: sweet, salty, sour, and bitter. Fifty‐two panelists were served a beverage (orange juice, coffee, and water) or were asked to chew a piece of gum, and then, remained in the waiting room for 1, 15, or 30 min. They were then asked to report taste intensities using 15‐cm unstructured line scales. Mean intensities of all tastes were not significantly different when orange juice was a primer at 1, 15, and 30 min when compared to water. Mean intensities of bitter were significantly lower when coffee was a primer at 1, 15, and 30 min than when water was a primer. Mean intensities of sweet were significantly lower when gum was a primer at 1 and 15 min than when water was a primer. The findings showed that it is necessary for 30 min or more waiting period of no food or beverage consumption prior to sensory testing.     

Naming and identification of tastes in aqueous solutions

Several taste substances were tested in aqueous solutions; tannic and tartaric acids were found unsuitable as a standard substance for the taste identification. Monosodium glutamate, sodium hydrogen carbonate and potassium chloride were often identified as salty substances even when the subjects were able to distinguish between the tastes. They probably identified the taste as salty owing to the lack of proper terms, and unsufficient experience with tasting monosodium glutamate and sodium hydrogen carbonate as substances possessing defined tastes different from the salty taste.     

Naming and identification of tastes in aqueous solutions.

Several taste substances were tested in aqueous solutions; tannic and tartaric acids were found unsuitable as a standard substance for the taste identification. Monosodium glutamate, sodium hydrogen carbonate and potassium chloride were often identified as salty substances even when the subjects were able to distinguish between the tastes. They probably identified the taste as salty owing to the lack of proper terms, and unsufficient experience with tasting monosodium glutamate and sodium hydrogen carbonate as substances possessing defined tastes different from the salty taste.     

Quality assessment of corn snacks enriched with soybean ferritin among young healthy people and patient with Crohn’s disease: the effect of extrusion conditions

Fortified extruded snacks are convenient products to supplement malnourished patients’ diet, e.g. suffering from Crohn’s disease. The snacks were extruded with different additions of iron-biofortified sprouts under varying process conditions (temperature and humidity). The sensory profiling showed the correlation between extrusion temperature and snack stickiness (R = 0.835), crispiness (R = 0.727), hardness (R=−0.485), as well as the intensity of corn (R = 0.888), powder (R=−0.795), metallic (R=−0.606) and bitter (R=−0.901) tastes. The sprouts addition affected metallic taste (R = 0.606) and aroma (R = 0.666) intensity. The product desirability was compared between healthy people (HP) and Crohn’s patients (CP). Overall desirability positively correlated with taste desirability in both groups. In the HP group, taste desirability was associated with metallic taste (R=−0.857) and Fe(III) content (R=−0.717). Also, aroma desirability (connected with pyrazines) was more significant to HP. Higher tolerance of CP to metallic and bitter flavours was observed. This confirms that the taste and aroma preferences of CP and HP are different.     

The ability of 10–11-year-old children to identify basic tastes and their liking towards unfamiliar foods

The involvement of children in sensory evaluation and consumer research continues to increase and has become crucial in the food industry, as children sensory perceptions differ from adults. Research on basic taste sensitivity in children provides contradictory results, with most of the studies not considering the familiarity aspect of the food samples. Familiarity can lead children to memories of the food which are able to influence their taste perception and liking. This study aims to investigate the ability of 10 to 11-year old children in identifying sweetness, saltiness, sourness, and bitterness in unfamiliar food samples. The taste identification data was collected from 98 children using 19 food samples representing the four basic tastes of sweet, sour, salty, and bitter. For each food sample, the children evaluated their familiarity, the basic taste(s) they perceived using the check-all-that-apply (CATA) method and scored their liking. Their basic taste identification ability was investigated by comparing their results to trained panellists as a reference. The food samples were unfamiliar to most of the children (never tasted by 85% of the children on average). Correspondence Analysis (CA) showed that children were able to identify the basic tastes of sweet, sour, salty, and bitter in the unfamiliar foods, with a high congruency to the trained panellists. However, children’s identification ability was lower when combinations of dominant basic tastes occurred. Principal Component Analysis (PCA) demonstrated a positive correlation between the presence of sweet taste and the children’s liking while sour and bitter tastes showed the opposite.     

The role of congruency in taste–odor interactions

The present study investigated the role that congruency between tastes and odors plays in two types of taste–odor interactions: retronasal odor enhancement by taste and retronasal odor referral to the mouth. In the first experiment, subjects rated (1) the intensities of sweetness, sourness, bitterness, and specific odor of aqueous samples of 3 tastants (sucrose, citric acid, caffeine) and 2 odorants (citral, coffee odor), both alone and in taste–odor mixtures, and (2) the degree of congruency of all possible taste–odor pairs. The results showed that only sucrose significantly enhanced the perceived intensities of citrus and coffee odors (Tukey’s test, p < 0.05), while citric acid and caffeine failed to enhance or even suppressed the odors. In the second experiment, the returning subjects were asked (1) to report the perceived locations of the odors after inhaling 3 odorants (citral, “sweet” and “bitter” coffee odors) through the mouth alone or in the presence of either water or various tastes in the mouth, and (2) to rate the degree of congruency between tastes and odors. The data showed that a highly congruent taste or taste mixture significantly increased localization of odors to the mouth (χ², p < 0.05). These findings suggest that taste–odor congruency is a necessary but not sufficient condition for retronasal odor enhancement. In contrast, taste–odor congruency is a critical component for retronasal odor referral, and the degree of congruency modulates the degree of odor referral to the mouth. The results and implications of the study findings are discussed in terms of cognitive and perceptual factors of flavor perception.     

Toxic trace metals in food. I. A new voltammetric procedure for toxic trace metal control of wines.

A new highly sensitive and particularly reliable analytical procedure for the precise determination of the most relevant toxic trace metals cadmium, lead and copper in wine is presented. It consists of a simple and convenient sample pretreatment by UV irradiation (1,5 h, 500-W-Hg-lamp) to release the toxic trace metals bound by organic substances and subsequent voltammetry (DPASV) of cadmium and lead simultaneously at a mercury film electrode (MFE) formed in situ on a vitreous carbon carrier and of copper on a gold electrode. Particular emphasis has been placed on the efficient exclusion of interference due to contamination. Only special wines, with more than 10% of sugar, require substitution of UV irradiation by a wet digestion also described. The procedure may be easily expanded to include the determination of mercury and zinc.     

The role of sour and bitter perception in liking,familiarity and choice for phenol-rich plant-based foods

Among factors influencing food preferences and choices, individual differences in taste perception play a key role in defining eating behaviour. In particular, sour and bitter responsiveness could be associated with the acceptance and the consumption of phenol-rich plant-based foods recommended for a healthy diet. The aim of this study was to investigate, in a large population sample, the associations among sour and bitter responsiveness and liking, familiarity and choice for plant-based foods characterized by these target tastes. Adults aged 18 to 60 years (n = 1198; 58% women) were tested for their sour and bitter responsiveness both in water solutions and in food models (pear juice-based beverages modified in citric acid content to induce different levels of sourness: 0.5, 2.0, 4.0 and 8.0 g/kg; chocolate pudding samples modified in sucrose content to induce different levels of bitterness: 38, 83, 119, 233 g/kg). Familiarity, stated liking and choice for fruit juices and vegetables varying for sour/bitter taste (high in bitter/sour taste: e.g. grapefruit juice and cauliflower; low in bitter/sour taste: e.g. zucchini and pineapple juice) were measured. Results showed a significant positive correlation between bitter and sour taste perception in water solutions and model foods, as well as a positive correlation between the perceived intensity of the two taste stimuli. Subjects characterized by high responsiveness to the two target stimuli were found to give lower liking scores to foods characterized by sour/bitter tastes and tended to choose less sour/bitter foods compared to less responsive subjects.Thus, food choice for phenol rich plant-based products could be associated with a reduced responsiveness to bitter and sour tastes and a consequent higher acceptance of food products characterized by these taste qualities.     

Bitter taste in cassava roots correlates with cyanogenic glucoside levels

Cassava roots contain cyanogenic glucosides. Malawian farmers classify cultivars into two groups based on the perceived danger of eating raw roots that they associate with bitterness. In the vernacular, cultivars that produce roots with bitter taste are called vyakubaba (bitter), whereas those yielding non‐bitter roots are called vyakuzizra (cool). In the scientific literature they are distinguished as ‘bitter’ or ‘sweet’. Roots from ‘bitter’ cultivars are processed prior to consumption. We studied the ability of farmers to predict the cyanogenic glucoside levels of 492 roots from the 10 most commonly grown cultivars. Twenty‐eight farmers predicted the taste of each of the cultivars that they grew, and scored bitterness on a five‐point scale by tasting the root tip. Thereafter cyanogenic glucosides were determined on half of the root, while a taste panel scored the taste of the other half. The mean cyanogenic glucoside level in 132 roots from ‘cool’ cultivars was 29 mg HCN eq kg^?1 fresh weight (CI 25–33, range 1–123) and in 360 roots from ‘bitter’ cultivars was 153 mg HCN eq kg^?1 fresh weight (CI 143–163, range 22–661). Farmers' distinction of ‘cool’ and ‘bitter’ cultivars predicts glucoside levels. The tasting of the tip of the root improved the farmers' prediction of toxicity. Scoring of bitterness by a trained taste panel showed a stronger correlation with glucoside levels (r² = 0.67). This suggests that cyanogenic glucosides confer the bitter taste, notwithstanding the probability of additional modifying intrinsic factors. Copyright © 2004 Society of Chemical Industry     

Exploring the hedonic and incentive properties in preferences for bitter foods via self-reports,facial expressions and instrumental behaviours

Preferences for and consumption of bitter foods such as vegetables and fruit are important in addressing the epidemic of obesity as healthy dietary patterns contribute to its prevention. However, few studies have been undertaken to understand the preference for bitter-tasting foods. A generally accepted but not proven explanation is that these acquired preferences involve changes in affective and motivational processes in order to overcome the innate rejection of bitter tastes. To examine this issue we compared the hedonic and incentive responses to bitter substances among bitter likers and dislikers. In addition, the effects of hunger, stress and weight concern on bitter preferences were also explored. Fifty-nine healthy adults (age = 24.8 ± 6.3; body mass index = 22.0 ± 2.8) were divided into bitter likers and bitter dislikers according to their food preferences. Both groups sampled the unreinforced flavours of coffee, beer, chocolate and grapefruit under four motivational states induced by static pictures (neutral, food, stressor and obesity) at the time of testing. The results showed that the bitter solutions elicited less aversive responses (higher hedonic ratings and less intense disgust reactions) and fewer avoidance behaviours (slower response time and lower amount of water for rinsing) in bitter likers after viewing neutral images. On the other hand, likers exhibited a further reduction in disgust to coffee after viewing stressor pictures, and also drank more water after tasting chocolate following the obesity pictures, compared with the dislikers. The expression of disgust increased in bitter likers, as well as the amount of water used to rinse the mouth, after tasting chocolate following pictures showing obesity compared with pictures showing food. These results show, for the first time, not only the implication of affective and incentive components in reversal of the predisposition to reject bitterness but also the motivational modulation of the expression of rejection of bitter tastes in humans.     

Do facial reactions add new dimensions to measuring sensory responses to basic tastes?

Basic taste solutions induce sensory perceptions via taste receptors and give rise to specific facial reactions. Many of these have been shown to be innate. The aim of this study was to explore relationships between the sensory perception of basic taste solutions at different concentrations and facial reactions.Basic taste solutions each at three levels plus water were served to a panel. The assessors individually identified quality, intensity and pleasantness. They were recorded during tasting and their facial reactions (based on FACS) were coded and analysed.Facial reactions indicated both quality and concentration of the stimuli. The intensity of most facial reactions increased with increasing stimulus concentration, most pronounced for sourness (lips) and bitterness (eyes and forehead). Pleasantness ratings decreased with increasing concentrations of all basic tastes. Water and the lowest sucrose concentration were perceived as the most pleasant samples and gave rise to the lowest intensity of facial reactions. The study showed that a combination of sensory analyses and facial expressions was successful in adding further insight to the knowledge of perception of basic tastes.     

感官评定方法确定麻竹笋苦涩味物质成分及与口感的关系

通过分析测定麻竹笋苦涩味物质含量与感官评定方法确定竹笋苦涩味物质成分及与口感的关系。麻竹鲜笋在100℃纯净水中分别进行0、30、90、150 s和420 s 5个时间梯度水煮处理,并测定煮后笋汤、笋渣的可溶性单宁、草酸和游离苦味氨基酸(Phe、Val、Arg、Met和Leu)含量,感官评定小组对其涩味、苦味强度评定,并通过对食品级草酸、单宁标准样品配制的不同质量浓度溶液进行苦涩味感官评定,建立单宁、草酸、单宁和草酸混合液的质量浓度与滋味强度的特征曲线函数。结果表明,影响麻竹笋苦涩味的主要物质是可溶性单宁,竹笋苦味和涩味均与单宁含量呈极显著关系,相关系数分别达0.896和0.867;竹笋涩味与草酸含量呈显著关系,相关系数为0.448,而竹笋苦味与草酸含量无显著关系;竹笋苦涩味与游离苦味氨基酸含量均无显著关系。利用单宁特征曲线函数对竹笋苦涩味偏重的成因进行了分析,对9个笋渣、笋汤的分析结果表明,单宁特征曲线函数对竹笋涩味的解释程度达60.6%~136.4%,对竹笋苦味的解释程度达63.4%~132.0%,较高的可溶性单宁含量是引起麻竹笋苦涩味偏重的主要原因。     

Effect of edible oils and oil emulsions on the perception of basic tastes

The intensity of sweet, bitter or astringent tastes is reduced by con-sumption of edible oil or oil emulsions immediately before the inges-tion of test solutions. The basic taste substances were dissolved in 30% aqueous ethanol, flavoured with plant extracts. The time-intensity dependence was influenced similarly. The sensitivity of taste receptors returned to the original value within 15—20 min. Intensities of acidic or salty tastes were not affected.     

Taste of Water-Soluble Extracts Obtained from Over-Fermented Tempe

Over-fermented tempe, known as tempe semangit, is popular in Indonesian culture, especially in Java, as an umami seasoning in traditional foods. The objective of this study was to characterize taste-active compounds in water soluble extracts of over-fermented tempe. Over-fermented tempe was prepared from fresh tempe in which the fermentation was prolonged (0 to 96 h). Free amino acids in the water soluble extract were analyzed and characterized for their taste activity values. Water soluble extracts contained umami and bitter tasting free amino acids at relatively high concentrations. Their umami and bitter taste activity values were higher than the taste threshold concentration. Water soluble extract from 72 h over-fermentation had a higher umami taste activity value than bitter taste activity, exhibiting the highest umami taste dilution factor. The high-performance liquid chromatography profile of water soluble extract fractions obtained using Sephadex G-25 gel filtration chromatography demonstrated that fractions having higher umami taste intensity had more hydrophilic components than hydrophobic components.     

Taste transduction: Linkage between molecular mechanisms and psychophysics

Taste transduction is initiated when taste stimuli interact with receptor sites on the exposed apical microvilli of receptor cells. The interaction leads to an increase in intracellular Ca⁺⁺ and transmitter release from the taste cell. Recent studies have revealed that taste cells utilize a diversity of mechanisms for transduction. Ionic taste stimuli, such as salts and acids, interact directly with apically located ion channels to depolarize taste cells. In contrast, amino acids, sweeteners and most bitter tasting stimuli bind to specific membrane receptors that are usually coupled to G proteins and second messenger systems. This review summarizes recent progress in understanding the initial events in taste transduction. Commonalities of molecular mechanisms for different taste stimuli may help explain psychophysical interactions of taste stimuli.     

On the localization of tastes and tasty products in 2D space

People map different sensory stimuli, and words that describe/refer to those stimuli, onto spatial dimensions in a manner that is non-arbitrary. Here, we evaluate whether people also associate basic taste words and products with characteristic tastes with a distinctive location (e.g., upper right corner) or a more general direction (e.g., more right than left). Based on prior research on taste and location valence, we predicted that sweetness would be associated with higher vertical spatial positions than the other basic tastes. The results of Experiments 1 and 2 support the view that participants do indeed locate the word “sweet” higher in space than the word “bitter”. In Experiment 2, the participants also positioned products that are typically expected to be sweet (cupcake and honey) or bitter (beer and coffee) spatially. Overall, the sweet-tasting products were assigned to higher locations than were the bitter-tasting products. In order to test whether taste/location congruency would also affect product evaluations, a third experiment was conducted. The results of Experiment 3A (between participants) and 3B (within participants) failed to provide any evidence for the existence of consistent taste/location congruency effects. However, in Experiment 3B, the participants evaluated the sweet products as looking more appetizing when presented in upper relative to lower shelf locations. In none of the three studies was an association found between tastes and positions along the horizontal axis. Taken together, these results suggest that sweet and bitter tastes are differentially located in vertical, but not horizontal, space. The potential implications of these findings for both our understanding of the crossmodal correspondences, as well as for taste evaluation, and product placement are discussed.