An overview of binary taste–taste interactions

Enhancing saltiness perception in bone broth: the additive effect of oil and optimization of sodium-reduction formula for consumer acceptability

BACKGROUND

Excessive NaCl intake in liquid and semi-solid food (e.g. soup, hot pot base, sauce) poses a high risk to human health, and reducing NaCl intake is a major concern for global health.

RESULTS

Using the generalized Labeled Magnitude Scale (gLMS) method, the study verified the possibility of sodium reduction through oil addition. The compromised acceptance threshold (CAT) and hedonic rejection threshold (HRT) were determined. The gLMS results showed that the saltiness intensity of samples containing 0.36% NaCl and 2.29% sunflower seed oil was significantly higher than that of samples containing only 0.36% NaCl (P < 0.05). CAT and HRT results indicated that by adding 3.59% sunflower oil, the NaCl content could be reduced to a minimum of 0.14% without causing sensory rejection in bone broth samples. The quantitative descriptive analysis method was used to determine the effects of NaCl and oil concentrations on the sensory attributes of bone broth samples. Furthermore, it was used to analyze the consumer acceptability drivers in combination with the hedonic scale to optimize the formulation of reduced-salt bone broth products. Notably, sample E (0.36% NaCl, 2.29% fat) not only had a significant salt reduction effect with a 20% decrease in NaCl, but also had improved overall acceptability.

CONCLUSION

This study provides theoretical guidance for designing salt-reduction cuisine within the catering and food industries, including bone broth and hot pot bases. © 2024 Society of Chemical Industry.

Synergistic effect of combining umami substances enhances perceived saltiness

Umami substances have the potential to enhance the perception of saltiness and thus reduce sodium intake. Two sensory evaluation experiments were conducted, involving participants tasting salt solutions, and solutions with added umami substances at equal sodium concentrations. Umami substances included sodium glutamate (MSG), disodium inosinate (IMP), and the combination of them which has a synergistic effect and is a closer match to commonly-consumed foods. In Experiment 1, using the two-alternative forced-choice (2-AFC) method by 330 consumers, paired comparisons were conducted at three different sodium concentrations. The combination of MSG and IMP enhanced the perception of saltiness (p < .001 in the difference test), whereas presenting either umami substance in isolation failed to do so (p > .05 in the similarity test). Significant order effects occurred in paired comparisons. In Experiment 2, a two-sip time-intensity (TI) analysis with trained panellists verified these results and found that tasting MSG and IMP either simultaneously or successively enhanced saltiness perception at equal sodium concentrations. These findings indicate that the synergistic effect of umami substances may be the cause of saltiness enhancement, and represents a potential strategy for sodium reduction while satisfying the consumer demand for saltiness perception. Considering the application in food processing and in food pairing, umami substances can potentially be used to help to reduce salt intake in food consumption.

Odor and taste characteristics, transduction mechanism, and perceptual interaction in fermented foods: a review

Fermentation is a critical technological process for flavor development in fermented foods. The combination of odor and taste, known as flavor, is crucial in enhancing people's perception and psychology toward fermented foods, thereby increasing their acceptance among consumers. This review summarized the determination and key flavor compound screening methods in fermented foods and analyzed the flavor perception, perceptual interactions, and evaluation methods. The flavor compounds in fermented foods could be separated, purified, and identified by instrument techniques, and a molecular sensory science approach could identify the key flavor compounds. How flavor compounds bind to their respective receptors determines flavor perception, which is influenced by their perceptual interactions, including odor-odor, taste-taste, and odor-taste. Evaluation methods of flavor perception mainly include human sensory evaluation, electronic sensors and biosensors, and neuroimaging techniques. Among them, the biosensor-based evaluation methods could facilitate the investigation of the flavor transduction mechanism and the neuroimaging technique could explain the brain's signals that relate to the perception of flavor and how they compare to signals from other senses. This review aims to elucidate the flavor profile of fermented foods and highlight the significance of comprehending the interactions between various flavor compounds, thus improving the healthiness and sensory attributes.

Effects of theacrine on the astringency of EGCG by affecting salivary protein - EGCG interactions through different molecular mechanisms

(-)-Epigallocatechin gallate (EGCG) and theacrine are involved in imparting tea with its astringent and bitter tastes. This study investigated the effect of theacrine on the astringency of EGCG and its molecular mechanism. Sensory evaluation was used to study the astringent intensities of EGCG solutions in the presence and absence of various concentrations of theacrine. The results indicated a considerable increase in the astringency values of EGCG-theacrine solutions compared with those of EGCG solutions alone. Furthermore, dynamic light scattering (DLS) and molecular dynamics simulations (MD) were to explore the interaction mechanisms. The results revealed that theacrine increased the particle size of EGCG-proline-rich proteins (PRPs) aggregates with that of EGCG and PRPs alone. MD revealed that theacrine potentially acted as a bridge between EGCG and PRPs, promoting their interaction and intensifying the EGCG's astringency. However, theacrine could not bridge two or more mucins owing to the substantial spatial structure of mucin.

Using Cooking Schools to Improve the Pleasure of Food and Cooking in Patients Experiencing Smell Loss

Smell loss affects around 15-20% of the population, with a major effect on the quality of life. The most common complaint is the impairment of the eating experience, with around 90% of patients reporting this issue. A study conducted at a specialised Taste and Smell Clinic investigated if food and cooking can positively affect the enjoyment of food, subjective cooking skills, and quality of life in patients with smell loss. The 49 participants in the study received a 5-week cooking school course that focused on emphasizing the other senses to regain the enjoyment of food. Participants gained more confidence in cooking, and their quality of life improved significantly. Positively evaluated recipes were adjusted based on feedback and published as free e-books in Danish, German, and English. Eating and cooking are multisensory experiences, and the perception of food depends on the complex interaction of senses and surroundings. If the olfactory input is reduced or absent, both the enjoyment and cooking experience can be negatively affected. Therefore, focusing on food and cooking can have a positive impact on patients with smell loss.

Progress in Multisensory Synergistic Salt Reduction

Excessive salt intake, primarily from sodium chloride prevalent in modern food processing, poses a significant public health risk associated with hypertension, cardiovascular diseases and stroke. Researchers worldwide are exploring approaches to reduce salt consumption without compromising food flavor. One promising method is to enhance salty taste perception using multisensory synergies, leveraging gustatory, olfactory, auditory, visual, tactile and trigeminal senses to decrease salt intake while preserving food taste. This review provides a comprehensive overview of salt usage in foods, mechanisms of salty taste perception and evaluation methods for saltiness. Various strategies for reducing salt consumption while maintaining food flavor are examined, with existing salt reduction methods' advantages and limitations being critically analyzed. A particular emphasis is placed on exploring the mechanisms and potential of multisensory synergy in salt reduction. Taste interactions, olfactory cues, auditory stimulation, visual appearance and tactile sensations in enhancing saltiness perception are discussed, offering insights into developing nutritious, appealing low-sodium foods. Furthermore, challenges in current research are highlighted, and future directions for effective salt reduction strategies to promote public health are proposed. This review aims to establish a scientific foundation for creating healthier, flavorful low-sodium food options that meet consumer preferences and wellness needs.

Learning enhances representations of taste-guided decisions in the mouse gustatory insular cortex

Learning to discriminate overlapping gustatory stimuli that predict distinct outcomes-a feat known as discrimination learning-can mean the difference between ingesting a poison or a nutritive meal. Despite the obvious importance of this process, very little is known about the neural basis of taste discrimination learning. In other sensory modalities, this form of learning can be mediated by either the sharpening of sensory representations or the enhanced ability of "decision-making" circuits to interpret sensory information. Given the dual role of the gustatory insular cortex (GC) in encoding both sensory and decision-related variables, this region represents an ideal site for investigating how neural activity changes as animals learn a novel taste discrimination. Here, we present results from experiments relying on two-photon calcium imaging of GC neural activity in mice performing a taste-guided mixture discrimination task. The task allows for the recording of neural activity before and after learning induced by training mice to discriminate increasingly similar pairs of taste mixtures. Single-neuron and population analyses show a time-varying pattern of activity, with early sensory responses emerging after taste delivery and binary, choice-encoding responses emerging later in the delay before a decision is made. Our results demonstrate that, while both sensory and decision-related information is encoded by GC in the context of a taste mixture discrimination task, learning and improved performance are associated with a specific enhancement of decision-related responses.

Thiazolidinediones are Partially Effective Bitter Blockers

PURPOSE

The bad bitter taste of some medicines is a barrier to overcoming noncompliance with medication use, especially life-saving drugs given to children and the elderly. Here, we evaluated a new class of bitter blockers (thiazolidinediones, TZDs).

METHODS

In this study, 2 TZDs were tested, rosiglitazone (ROSI) and a simpler form of TZD, using a high-potency sweetener as a positive control (neohesperidin dihydrochalcone, NHDC). We tested bitter-blocking effects using the bitter drugs tenofovir alafenamide fumarate (TAF), a treatment for HIV and hepatitis B infection, and praziquantel (PRAZ), a treatment for schistosomiasis, by conducting taste testing with 2 separate taste panels: a general panel (N = 97, 20-23 years, 82.5% female, all Eastern European) and a genetically informative panel (N = 158, including 68 twin pairs, 18-82 years, 76% female, 87% European ancestry). Participants rated the bitterness intensity of the solutions on a 100-point generalized visual analog scale.

FINDINGS

Person-to-person differences in drug bitterness were striking; TAF and PRAZ were weakly or not bitter for some people but moderately to highly bitter for others. Participants in both taste panels rated the bitter drugs TAF and PRAZ as less bitter on average when mixed with NHDC than when sampled alone. ROSI partially suppressed the bitterness of TAF and PRAZ, but effectiveness differed between the 2 panels: bitterness was significantly reduced for PRAZ but not TAF in the general panel and for TAF but not PRAZ in the genetically informative panel. ROSI was a more effective blocker than the other TZD.

IMPLICATIONS

These results suggest that TZDs are partially effective bitter blockers and the suppression efficacy differs from drug to drug, from person to person, and from panel to panel, suggesting other TZDs should be designed and tested with more drugs and on diverse populations to define which ones work best with which drugs and for whom. The discovery of bitter receptor blockers can improve compliance with medication use.

Mouse TMC4 is involved in the detection of chloride taste of salts

Licking behavior with various salts in transmembrane channel-like 4 (Tmc4) knockout (KO) mice was observed. In Tmc4 KO mice, a significant decrease in sensitivity to chloride salts, such as NaCl, KCl, and NH4Cl, was observed, while no significant decrease in sensitivity to Na-gluconate was observed. This finding suggests that TMC4 may be involved in the detection of chloride taste.

Study of the post-harvest processes of the peruvian chuncho cocoa using multivariate and multi-block analysis

A screening of 24 Chuncho cacao postharvest processes was carried out and three treatments were identified with the best levels of functional non-volatile metabolites and the best profile of volatile metabolites. The relationship between the sensory profile of flavor and aroma, volatile and non-volatile metabolites was investigated by multiblock analysis. The most prominent volatile metabolites were benzaldehyde (Bz), 2,3,5-trimethylpyrazine (TriMP), 2,3,5,6-tetramethylpyrazine (TetraMP), myrcene (Myr), limonene (LM), ethylphenyl acetate (EpHAc) and 2-phenylethyl acetate (pHEthAc), and functional nonvolatile metabolites were total flavonoids (Tflav), total polyphenols (TppH), catechins (Cat), epicatechin (EpCat), caffeine (Caf), and theobromine (TeoB). Sensory analysis by MFA (multiple factorial analysis) allowed checking the substrates of the metabolites and highlighting correlated flavor and aroma descriptors. Based on multiblock analysis, four new descriptors were identified for Bz, Myr, and LM, such as nut, astringent, bitter, and crude. For TetraMP the fruity flavor was identified and for TriMP it was identified as Malt flavor. For Cat, EpCat, Caf, TeoB, Tflav, and TppH, the descriptors bitter, astringent, floral, and fruity were identified. This study will allow Chuncho cocoa farmers and producers to have a cocoa paste production scheme with a high value of functional metabolites and sensory profile, and value this Peruvian accession.

Exploration of optimal preparation strategy of Chenpi (pericarps of Citrus reticulata Blanco) flavouring essence with great application potential in sugar and salt-reduced foods

To obtain flavouring essence with application potential in sugar and salt-reduced foods, the optimal strategy for extraction and microencapsulation of essential oil (EO) from Chenpi was investigated. UPLC-QTOF-MS/MS and liquid-liquid-extraction-GC-MS confirmed the selectivity for volatiles ranked in hydrodistillation > supercritical fluid extraction > solvent extraction. The aroma characteristic of Chenpi EO was distinguished by 33 key volatiles (screened out via headspace-SPME-GC-MS) and quantitative descriptive analysis. EO extracted by supercritical fluid extraction was preferred for preserving the original aroma of Chenpi and displaying more fruity, honey and floral. Chenpi flavouring essence with superior encapsulation efficiency, particle size, water dispersibility, and thermostability was obtained through optimally microencapsulating EO with gum arabic and maltodextrin (1:1) by high-pressure homogenization coupled with spray drying. Chenpi flavouring essence was able to reduce the usage of sugar and salt by 20 % via enhancing flavour perception of sweetness and saltiness. This study first developed a flavouring essence promisingly effective in both sugar and salt-reduced foods.

Learning enhances representations of taste-guided decisions in the mouse gustatory insular cortex

Learning to discriminate overlapping gustatory stimuli that predict distinct outcomes - a feat known as discrimination learning - can mean the difference between ingesting a poison or a nutritive meal. Despite the obvious importance of this process, very little is known on the neural basis of taste discrimination learning. In other sensory modalities, this form of learning can be mediated by either sharpening of sensory representations, or enhanced ability of "decision-making" circuits to interpret sensory information. Given the dual role of the gustatory insular cortex (GC) in encoding both sensory and decision-related variables, this region represents an ideal site for investigating how neural activity changes as animals learn a novel taste discrimination. Here we present results from experiments relying on two photon calcium imaging of GC neural activity in mice performing a taste-guided mixture discrimination task. The task allows for recording of neural activity before and after learning induced by training mice to discriminate increasingly similar pairs of taste mixtures. Single neuron and population analyses show a time-varying pattern of activity, with early sensory responses emerging after taste delivery and binary, choice encoding responses emerging later in the delay before a decision is made. Our results demonstrate that while both sensory and decision-related information is encoded by GC in the context of a taste mixture discrimination task, learning and improved performance are associated with a specific enhancement of decision-related responses.

Enhancing the design of wine labels

Introduction

The knowledge accrued through research in the domain of crossmodal correspondences has had a significant influence on a diverse array of disciplines, including behavioral studies, neuroscience, computational modeling, and notably, marketing, with the objective of aligning sensory experiences to help shape patterns of consumer behavior. A study is reported that explores the extension of these principles to the communication of products having a notably complex sensory profile, specifically within the context of wine. The central aim of the project is to explore the feasibility of using crossmodal communication as a strategic tool to augment the congruence between the consumers' multisensory expectations and their sensory experiences. For consumers venturing into the realm of wine selection without the advantage of prior tasting experience, it is of paramount importance to possess a robust understanding of the mandated information. This encompasses critical elements such as the wine's origin, grape varietal(s) used, geographical indications, producer qualifications, and the potential implications of these factors on the final wine product. This level of comprehension stands as a necessary prerequisite, enabling these consumers to make informed choices that align with their preferences, even in the absence of previous sensory encounters. Nonetheless, semiotic investigations underscore the significance attributed to symbolic components such as signs, logos, colors, gestures, and linguistic cues. Research from the field performing multisensory studies, presents a counterpoint to prevailing communication paradigms, advocating for a heightened incorporation of metaphors, analogies, symbols, metonymies, and allegories. This alternative approach aims to enhance the efficacy of communication strategies, offering a more profound and evocative means of conveying intricate messages on a more holistic level.

Methods

A questionnaire was sent to a specific group of engaged wine consumers (n = 329). Besides questions regarding demographics, purchase behavior, and consumption behavior, the questionnaire included examples of multisensory communication through a selection of symbols, as well as alternative wine information.

Results

The results showed significant correlations between demographics, consumption behavior, and attitudes toward the tested multisensory symbols and alternative information, thus helping to gain a better understanding of the sensory properties that should be communicated on wine labels.

Discussion

The findings reported here highlight the effectiveness of visual crossmodal communication as a promising pathway capable of skillfully capturing consumer attributes, conveying multisensory experiences, and portraying the comprehensive timeline of taste evolution. As a result, it assumes a pivotal role as a communicative tool for intricate consumables, like wine, functioning at the crossroads of visual and sensory dimensions.

Taste-taste associations in chemotherapy-induced subjective taste alterations: findings from a questionnaire survey in an outpatient clinic

PURPOSE

Chemotherapy-induced taste alteration is a side effect that can result in malnutrition and reduced quality of life in cancer patients. However, the underlying causes of this phenomenon remain unclear, and evidence-based treatments have not been established. This study focused on patients' subjective symptoms of taste alterations aimed to explore how the sensitivity to basic tastes changes due to anticancer agents and how alterations in one taste perception are associated with changes in other tastes during chemotherapy.

METHODS

A cross-sectional questionnaire-based interview survey was conducted on 215 patients undergoing chemotherapy. The subjective sensitivity to each basic taste was assessed using a visual analog scale, and the incidence of taste alterations due to different chemotherapy regimens was calculated. Multivariate logistic regression analysis was performed to determine whether there were associations between changes in one taste sensitivity and changes in other taste sensitivities.

RESULTS

Approximately half (49.5%) of the patients experienced chemotherapy-induced taste alterations. An analysis of subjective changes in basic tastes revealed that the salt and umami taste systems were more sensitive to chemotherapy than other taste systems. Patients with altered sensitivity to sweet taste were significantly more likely to report altered sensitivity to salt, bitter, and sour tastes. Moreover, umami-salt and bitter-sour taste sensitivities were significantly related to each other.

CONCLUSION

This study suggests that changes in subjective sensitivities to one basic taste during chemotherapy may be accompanied by changes in other tastes in specific combinations. Considering taste associations in dietary guidance may help improve the nutritional status of cancer patients experiencing taste alterations due to chemotherapy.

Effect of molar mass and size of non-alcoholic beer fractions and their relevance toward palate fullness intensity

Palate fullness intensity and mouthfeel descriptors are essential sensory characteristics of non-alcoholic beers (NABs). The descriptor's perception might be influenced by the molar distribution of the non-volatile matrix in cereal-based beverages like NABs. However, only limited information is available on the molar mass of different substances in NABs. This study investigated the role of weight average molar mass (M_w) and size of NABs fractions and their relation to sensory perception. Industrialized bottom-fermented NABs (n = 28) from the German market and NABs produced by different methods were used in this study. A trained sensory panel evaluated palate fullness intensity, mouthfeel, and basic taste descriptors (as additional quality parameters). Asymmetric flow field-flow fractionation was used to fractionate NABs, while M_w was determined by multi-angle light scattering and differential refractive index detectors. The NABs were fractionated into three groups containing different substances: proteins, proteins-polyphenol complexes (P-PC) and low molar mass (non-)starch polysaccharides (LN-SP), and high molar mass (non-)starch polysaccharides (HN-SP). The M_w range of proteins was 18.3-41 kDa, P-PC and LN-SP 43-122.6 kDa, and HN-SP 0.40-2.18·10³ kDa. Harmony, defined as the sweet and sour ratio, influenced the palate fullness intensity perception. In the harmonic samples (sour/sweet sensory balanced), the size of HN-SP (> 25 nm) showed a positive correlation to palate fullness intensity. The results suggest the importance of dextrins, arabinoxylan, and β-glucan in modulating the sensory characteristics of harmonic bottom-fermented NABs.

Sensory Interactions between Sweetness and Fat in a Chocolate Milk Beverage

Fat and sugar-reduced foods and beverages have become increasingly popular for a variety of reasons, mainly relating to health and wellbeing. Depending on the food or beverage, it may be difficult to reduce the fat and/or sugar content and still maintain optimal sensory properties for the specific product. One way of approaching the problem is to gain a better understanding of how a product is affected by a reduction in fat and/or sugar. This paper aims to investigate the sensory interactions between fat and sweetness perception in a chocolate-flavored milk beverage by using a descriptive analysis with a trained sensory panel. The reduction of fat significantly reduced the sweetness intensity of the chocolate milk, while the reduction of sucrose significantly decreased the cream flavor and the fruity and lactic flavor. The perception of acesulfame-K was affected by fat concentration, similarly to sucrose. These results highlight the importance of considering the effects of reducing either sugar and fat on product attributes that are not directly related to the sugar or fat.

Green label marinades: A solution to salmonella and campylobacter in chicken products?

Introduction

The presence of meat-borne pathogens entering the home remains a concern for consumers, despite advances made in improving antimicrobial interventions and systems within the processing line. Naturally antibacterial food ingredients including citrus juice and essential oils have been proven to inhibit the proliferation of microbial growth with varying success.

Aims

This study aims to investigate the antimicrobial and sensory effects of mixtures of essential oils, fruit juices and herbs at established Minimum Inhibitory Concentrations (MICs) for their biopreservative effect on general microbiota of chicken and against chicken challenged with selected pathogenic/surrogate microorganisms.

Materials and methods

Three marinade compositions were designed for use on chicken meat; lemon juice, thyme oil and black pepper (M1), lime juice, lemongrass oil and chilli paste (M2), and olive oil, oregano oil, basil oil and garlic paste (M3). These marinades were assessed for antibacterial effects against Salmonella enterica, Campylobacter jejuni and Listeria innocua on marinaded chicken drumsticks stored in aerobic conditions at 4 °C. Consumer tasting sessions were also conducted with a small focus group using selected final marinades.

Results

M1 and M2 were effective at significantly reducing initial pathogen carriage from 6 Log CFU/g to 2 Log CFU/g on refrigerated chicken meat as well as increasing the shelf-life of the product during cold-storage from 2 days to 7 days. However, consumer studies indicate that the flavours these marinades impart to treated products can be strong.

Conclusion

These findings indicate that these designed marinades have shown excellent potential to improve food safety as well as shelf-life for the consumer, particularly in settings where food safety is often compromised such as barbecuing or in care settings. However, further recipe optimisation is required to make these marinades acceptable to consumers.

Chemical Characterization, Sensory Definition and Prediction Model of the Cider Dryness from New York State Apples

Cider is a fermented drink obtained from apple juice. As a function of the used apple cultivar, cider can be classified in four different categories (dry, semi-dry, semi-sweet, sweet), distinguished by the attribute of "dryness," which reflects the sweetness and softness perceived. The dryness level is defined by scales (IRF, NYCA scales) based on the residual sugar, titratable acidity and tannin contents. Despite some adjustments, these scales show limitations in the prediction of actual perceived dryness, as they cannot consider the complicated interrelation between combined chemical compounds and sensory perception. After defining the perceived sensory dryness and its sensory description by using the quantitative descriptive analysis (QDA) method, a multivariate approach (PLS) was applied to define a predictive model for the dryness and to identify the chemical compounds with which it was correlated. Three models were developed, based on three different sets of chemical parameters, to provide a method that is easily applicable in the ordinary production process of cider. The comparison between the predicted rating and the relative scales scores showed that the models were able to predict the dryness rating in a more effective way. The multivariate approach was found to be the most suitable to study the relation between chemical and sensory data.

Inhibition of salty taste and sodium appetite by estrogens in spontaneously hypertensive rats

Estrogen has a well-known effect of reducing salt intake in rats. This mini review focuses on recent findings regarding the interaction of estradiol with brain angiotensin II to control increased sodium palatability that occurs as a result of sodium appetite in spontaneously hypertensive rats.

Sodium Replacement with KCl and MSG: Attitudes, Perception and Acceptance in Reduced Salt Soups

Sodium intake is linked to multiple negative health outcomes, particularly hypertension, the leading cause of premature death globally. Sodium intake levels in human populations are high, due in part to our desire for palatable salty-tasting foods. Two leading salt replacement strategies are the use of potassium chloride (KCl) and monosodium glutamate (MSG), the latter of which still contains some sodium, but both of which can replace some salty taste in foods while reducing net sodium levels. In this report, we employed a trained descriptive sensory panel to optimize saltiness in sodium-reduced aqueous samples using various concentrations of KCl and MSG. Following this, we assessed consumer attitudes to sodium-reduction strategies in a model food, canned soup, known to typically be high in sodium. Finally, in a large consumer test, we verified that these optimized levels of KCl and MSG did not lead to a drop in liking for the reduced-sodium soups with saltiness subsidized in this manner. Our results showed that sodium can be readily reduced in soups by 18% while actually scoring higher in liking, and in some cases being perceived as even more salty tasting, but that consumers are more open to sodium reduction in this manner when sodium replacements are not specifically highlighted, and when percentage sodium reduction is stated over absolute levels.

Bitterness quantification and simulated taste mechanism of theasinensin A from tea

Theasinensin A is an important quality chemical component in tea, but its taste characteristics and the related mechanism are still unclear. The bitterness quantification and simulated taste mechanism of theasinensin A were researched. The results showed that theasinensin A was significantly correlated with the bitterness of tea. The bitterness threshold of theasinensin A was identified as 65 μmol/L for the first time. The dose-over-threshold (DOT) value of theasinensin A was significantly higher than that of caffeine in black tea soup. The concentration-bitterness curve and time-intensity curve of theasinensin A were constructed. The bitterness contribution of theasinensin A in black tea was higher than in oolong and green tea. Theasinensin A had the highest affinity with bitterness receptor protein TAS2R16, which was compared to TAS2R13 and TAS2R14. Theasinensin A was mainly bound to a half-open cavity at the N-terminal of TAS2R13, TAS2R14, and TAS2R16. The different binding capacity, hydrogen bond, and hydrophobic accumulation effect of theasinensin A and bitterness receptor proteins might be the reason why theasinensin A presented different bitterness senses in human oral cavity.

Chloride ions evoke taste sensations by binding to the extracellular ligand-binding domain of sweet/umami taste receptors

Salt taste sensation is multifaceted: NaCl at low or high concentrations is preferably or aversively perceived through distinct pathways. Cl^- is thought to participate in taste sensation through an unknown mechanism. Here, we describe Cl^- ion binding and the response of taste receptor type 1 (T1r), a receptor family composing sweet/umami receptors. The T1r2a/T1r3 heterodimer from the medaka fish, currently the sole T1r amenable to structural analyses, exhibited a specific Cl^- binding in the vicinity of the amino-acid-binding site in the ligand-binding domain (LBD) of T1r3, which is likely conserved across species, including human T1r3. The Cl^- binding induced a conformational change in T1r2a/T1r3LBD at sub- to low-mM concentrations, similar to canonical taste substances. Furthermore, oral Cl^- application to mice increased impulse frequencies of taste nerves connected to T1r-expressing taste cells and promoted their behavioral preferences attenuated by a T1r-specific blocker or T1r3 knock-out. These results suggest that the Cl^- evokes taste sensations by binding to T1r, thereby serving as another preferred salt taste pathway at a low concentration.

Effect of Piperine on Saltiness Perception

Chemical irritants, like piperine, have the potential to increase human perception of tastes and odours, including saltiness. This cross-modal interaction could help the food industry develop new salt-reduced food products that maintain their salty taste. The objective of this study was: firstly, to determine the detection threshold of piperine (n = 72), secondly to evaluate piperine's influence on saltiness perception in model solutions (n = 78), and lastly to identify piperine's effect on sensory perception of low sodium soup using temporal check-all-that-apply (TCATA; n = 75). The group mean of the individual threshold was 0.55 ± 0.15 ppm. Piperine increased the saltiness perception of the model solutions, but it also increased the bitterness and decreased the sweetness of the solutions. The piperine significantly increased the saltiness intensity of the soups (evaluated using a generalized labelled magnitude), but during the TCATA task, the salty attribute was selected less for the soup with piperine than the control (based on the average proportion of selection). The TCATA indicated that the peppery attribute dominated the participants' perception of the soup with piperine. More studies are needed to assess piperine's cross-modal interactions.

Acids in brewed coffees: Chemical composition and sensory threshold

Coffee brewed on light, and very light-roast coffee beans have emerged as a recent trend among specialty coffee drinkers. The acidity of such light-roast coffee, and coffee in general, is an important sensory characteristic, as there is demonstrated a clear correlation between the roast level and perceived acidity in brewed coffee. The acidity is believed to be strongly linked to the content and composition of organic acids in coffee. Still, there is limited literature on acid content in brewed coffee and on the relevance of specific acid concentrations to sensory perception. In this study, we determined concentrations of acids and sugars in French-press brewed specialty coffee. We used varying roast degrees in the light to very light range using five coffees from different geographical locations (Brazil, Bolivia, and Kenya) and determined the sensory detection threshold and recognition for selected acids. The concentration of all individual acids except one (formic) either significantly decreased (citric, malic, and chlorogenic acid) or increased (acetic, lactic, phosphoric, quinic, and glycolic acid) systematically with an increasing roast degree, while no systematic trends were found between the different coffee samples. The sugar content decreased with an increasing roast degree. The sensory detection threshold for malic, acetic, and lactic acid was determined to be above the actual concentration of said acids in the coffee and just below for phosphoric acid, indicating that these compounds are unlikely to individually be perceived in coffee. Only citric acid can be clearly detected in the threshold test (not identified by experts in coffee) in concentrations above the measured concentrations, as the detection threshold was below (<0.16 g/L) the concentration found in the investigated coffees (0.23-0.60 g/L). The measured citric acid concentration was found to be much higher for the Brazil coffees (0.49 ± 0.08 g/L) compared to the Bolivia coffee (0.40 ± 0.11 g/L), and the Kenya coffees (0.30 ± 0.07 g/L). Furthermore, none of the acids added to the coffee were correctly recognized by coffee experts when spiked with measured average concentrations. Combined, the results question the direct relation between individual organic acids and acidity in coffee and point towards a more complex understanding of perceived acidity.

Trial Analysis of the Relationship between Taste and Biological Information Obtained While Eating Strawberries for Sensory Evaluation

This paper presents a trial analysis of the relationship between taste and biological information obtained while eating strawberries (for a sensory evaluation). This study used the visual analog scale (VAS); we collected questionnaires used in previous studies and human brain activity obtained while eating strawberries. In our analysis, we assumed that brain activity is highly correlated with taste. Then, the relationships between brain activity and other data, such as VAS and questionnaires, could be analyzed through a canonical correlation analysis, which is a multivariate analysis. Through an analysis of brain activity, the potential relationship with "taste" (that is not revealed by the initial simple correlation analysis) can be discovered. This is the main contribution of this study. In the experiments, we discovered the potential relationship between cultural factors (in the questionnaires) and taste. We also found a strong relationship between taste and individual information. In particular, the analysis of cross-loading between brain activity and individual information suggests that acidity and the sugar-to-acid ratio are related to taste.

Fermentation Conditions Affect the Synthesis of Volatile Compounds, Dextran, and Organic Acids by Weissella confusa A16 in Faba Bean Protein Concentrate

Fermentation with Weissella confusa A16 could improve the flavor of various plant-based sources. However, less is known about the influence of fermentation conditions on the profile of volatile compounds, dextran synthesis and acidity. The present work investigates the synthesis of potential flavor-active volatile compounds, dextran, acetic acid, and lactic acid, as well as the changes in viscosity, pH, and total titratable acidity, during fermentation of faba bean protein concentrate with W. confusa A16. A Response Surface Methodology was applied to study the effect of time, temperature, dough yield, and inoculum ratio on the aforementioned responses. Twenty-nine fermentations were carried out using a Central Composite Face design. A total of 39 volatile organic compounds were identified: 2 organic acids, 7 alcohols, 8 aldehydes, 2 alkanes, 12 esters, 3 ketones, 2 aromatic compounds, and 3 terpenes. Long fermentation time and high temperature caused the formation of ethanol and ethyl acetate and the reduction of hexanal, among other compounds linked to the beany flavor. Levels of dextran, acetic acid, and lactic acid increased with increasing temperature, time, and dough yield. Optimal points set for increased dextran and reduced acidity were found at low temperatures and high dough yield. Such conditions would result in hexanal, ethyl acetate and ethanol having a relative peak area of 35.9%, 7.4%, and 4.9%, respectively.

Recent Progress in the Study of Taste Characteristics and the Nutrition and Health Properties of Organic Acids in Foods

Organic acids could improve the food flavor, maintain the nutritional value, and extend the shelf life of food. This review summarizes the detection methods and concentrations of organic acids in different foods, as well as their taste characteristics and nutritional properties. The composition of organic acids varies in different food. Fruits and vegetables often contain citric acid, creatine is a unique organic acid found in meat, fermented foods have a high content of acetic acid, and seasonings have a wide range of organic acids. Determination of the organic acid contents among different food matrices allows us to monitor the sensory properties, origin identification, and quality control of foods, and further provides a basis for food formulation design. The taste characteristics and the acid taste perception mechanisms of organic acids have made some progress, and binary taste interaction is the key method to decode multiple taste perception. Real food and solution models elucidated that the organic acid has an asymmetric interaction effect on the other four basic taste attributes. In addition, in terms of nutrition and health, organic acids can provide energy and metabolism regulation to protect the human immune and myocardial systems. Moreover, it also exhibited bacterial inhibition by disrupting the internal balance of bacteria and inhibiting enzyme activity. It is of great significance to clarify the synergistic dose-effect relationship between organic acids and other taste sensations and further promote the application of organic acids in food salt reduction.

Detection of Bitterness in Vitamins Is Mediated by the Activation of Bitter Taste Receptors

Vitamins are known to generate bitterness, which may contribute to an off-taste or aftertaste for some nutritional supplements. This negative sensation can lead to a reduction in their consumption. Little is known about the bitter taste threshold and taste sensing system for the bitter taste detection of vitamins. To better understand the mechanisms involved in bitterness perception, we combined taste receptor functional assays and sensory analysis. In humans, bitter taste detection is mediated by 25 G-protein-coupled receptors belonging to the TAS2R family. First, we studied the bitterness of thirteen vitamins using a cellular-based functional taste receptor assay. We found four vitamins that can stimulate one or more TAS2Rs. For each positive molecule-receptor combination, we tested seven increasing concentrations to determine the half-maximal effective concentration (EC₅₀) and the cellular bitter taste threshold. Second, we measured the bitter taste detection threshold for four vitamins that exhibit a strong bitter taste using a combination of ascending series and sensory difference tests. A combination of sensory and biological data can provide useful results that explain the perception of vitamin bitterness and its real contribution to the off-taste of nutritional supplements.

Neurosensory development of the four brainstem-projecting sensory systems and their integration in the telencephalon

Somatosensory, taste, vestibular, and auditory information is first processed in the brainstem. From the brainstem, the respective information is relayed to specific regions within the cortex, where these inputs are further processed and integrated with other sensory systems to provide a comprehensive sensory experience. We provide the organization, genetics, and various neuronal connections of four sensory systems: trigeminal, taste, vestibular, and auditory systems. The development of trigeminal fibers is comparable to many sensory systems, for they project mostly contralaterally from the brainstem or spinal cord to the telencephalon. Taste bud information is primarily projected ipsilaterally through the thalamus to reach the insula. The vestibular fibers develop bilateral connections that eventually reach multiple areas of the cortex to provide a complex map. The auditory fibers project in a tonotopic contour to the auditory cortex. The spatial and tonotopic organization of trigeminal and auditory neuron projections are distinct from the taste and vestibular systems. The individual sensory projections within the cortex provide multi-sensory integration in the telencephalon that depends on context-dependent tertiary connections to integrate other cortical sensory systems across the four modalities.

Insights into the flavor perception and enhancement of sodium-reduced fermented foods: A review

Salt (sodium chloride, NaCl) is a vital ingredient in fermented foods, which affects their safety, texture, and flavor characteristics. Recently, the demand for reduced-sodium fermented foods has increased, as consumers have become more health-conscious. However, reducing sodium content in fermented foods may negatively affect flavor perception, which is a critical quality attribute of fermented foods for both the food industry and consumers. This review summarizes the role of salt in the human body and foods and its role in the flavor perception of fermented foods. Current sodium reduction strategies used in the food industry mainly include the direct stealth reduction of NaCl, substituting NaCl with other chloride salts, and structure modification of NaCl. The odor-induced saltiness enhancement, application of starter cultures, flavor enhancers, and non-thermal processing technology are potential strategies for flavor compensation of sodium-reduced fermented foods. However, reducing sodium in fermented food is challenging due to its specific role in flavor perception (e.g., promoting saltiness and volatile compound release from food matrices, inhibiting bitterness, and changing microflora structure). Therefore, multiple challenges must be addressed in order to improve the flavor of low-sodium fermented foods. Future studies should thus focus on the combination of several strategies to compensate for the deficiencies in flavor resulting from sodium reduction.

Effect of Monosodium Glutamate on Salt and Sugar Content Reduction in Cooked Foods for the Sensory Characteristics and Consumer Acceptability

Three different types of typical Korean foods were studied to investigate the effect of monosodium glutamate (MSG) on the sensory characteristics and hedonic perception of sodium- or sugar-reduced samples. The first consumer test (n = 300) was conducted to evaluate the overall liking (OL) of the samples containing four different levels of salt and sugar contents without added MSG, while the second consumer test (n = 300) was designed to examine the effects of MSG on the samples containing reduced salt and sugar contents with the lowest observed OL in the first consumer test. The results showed that the intensity of the umami taste and saltiness of the samples increased, whereas sourness and bitterness were suppressed with added MSG. The samples with the lowest salt contents were observed to be acceptable to consumers after MSG addition, indicating a 23% reduction in sodium intake. Bitterness was partially masked, while sweetness, umami taste, and saltiness were the main factors affecting the OL after MSG addition. However, no consistent results of added MSG on the sensory attributes of samples with reduced sugar contents were observed, possibly indicating that the effect of umami taste on sweetness depends on the MSG concentration used or the type of food studied. This study could be beneficial to researchers who want to know the optimal level of MSG required to reduce the sodium or sugar contents in cooked food.

Reducing Sodium Content in Cheeses While Increasing Salty Taste and Fat Perception Using Aroma

Excess salt (NaCl) and fat intake are major causes of chronic diseases, but reducing such components without affecting acceptability is a major challenge. Here, we set out to examine whether added aroma in lower salt cheese can enhance saltiness and fat perception. Low-salt cheese samples were grated through a homogenizer, and then aroma solution, sardine aroma (salt-associated), butter aroma (fat-associated) and a mix of sardine and butter aromas were added. The results confirmed that grating changes cheese texture, leading to induced taste perception. In addition, a significant saltiness enhancement was induced by sardine aroma and to a lesser extent by butter aroma, while significant fat perception enhancement was only induced by blended aroma. These findings show that aroma addition can be a strategy to compensate for sodium reduction in commercial cheese. Concerning fat perception, the addition of aroma can be a good strategy to compensate for low-fat in commercial cheeses. However, the mechanisms involved seem complex and need to be elucidated.

Characterizing Adolescents' Dietary Intake by Taste: Results From the UK National Diet and Nutrition Survey

The taste of foods is a key factor for adolescents' food choices and intakes, yet, exploring taste characteristics of adolescents' diet is limited. Using food records for 284 adolescents (10–19 years old) from the National Diet and Nutrition Survey (NDNS), year 9 (2016–2017), we classified diets according to taste. Tastes for each food consumed were generated from a previous survey that asked participants to allocate one main taste to each food. Responses from that survey were processed and included in a Hierarchical Cluster Analysis (HCA) to identify taste clusters. The resulting tastes were then applied to the adolescents' food records in the NDNS. For each individual, the total weight of food per day for each taste was calculated. A linear regression model was used to explore dietary intakes from each taste. Findings reveal that adolescents' daily energy intake was highest (34%) from foods that taste sweet. Sweet foods were the main calorie contributors at breakfast and daytime snacking, while energy intake from neutral-tasting foods was higher at lunch and dinner. Sweet food intake was significantly positively associated with higher energy, sugar, and fat intakes. For each percentage increase in sweet foods, energy increased by 10 kcal/d (95% CI 6, 15; P &lt; 0.01). Savory food intake was lower in carbohydrates and sugars; with neutral food consumption inversely associated with energy, carbohydrate, sugars, saturated and total fat. Higher salty food intake was linked to higher saturated fat as well as sodium consumption. Sweet and neutral foods dominate the UK adolescent diet, followed by savory tastes. Balancing the contributions of different tasting foods could assist in improving adolescent diet quality.

Comparison of Sweet–Sour Taste Interactions between Cold Brewed Coffee and Water

Most beverages are complex matrices. Different taste compounds within these matrices interact, and thus affect the perception of the tastes. Sweetness and sourness have generally been known to suppress each other, but often such investigations have focused on aqueous solutions. Investigations into what happens when these known interactions are transferred to more complex solutions are scarce. In this study, we investigated the differences in taste interactions between an aqueous matrix and a cold-brewed coffee matrix. Two sub-studies were conducted. In one, six aqueous samples were evaluated by 152 naïve consumers; in the other six cold-brewed coffee samples were evaluated by 115 naïve consumers. In both studies participants tasted samples with no addition or with addition of either sucrose, citric acid, tartaric acid, or a mix of sucrose and either of the acids. Results showed that the sweetness of sucrose was suppressed by both citric acid and tartaric acid in both matrices. The sourness of both citric acid and tartaric acid was suppressed in the aqueous matrix, but only the sourness of tartaric was suppressed in the coffee matrix. Generally, the suppression was lower in the coffee matrix compared to the aqueous matrix. In conclusion, results from taste interaction studies conducted on aqueous matrices can to some extent, with caution, be interpolated to more complex matrices. Importantly, suppression effects might diminish with an increase in matrix complexity.

Biohybrid Tongue for Evaluation of Taste Interaction between Sweetness and Sourness

The past decade has witnessed tremendous progress achieved in taste research, while few studies focus on interactions among taste compounds. Indeed, sweeteners and acidulants are commonly used food additives, and sweet-sour mixtures always provide improved tastes. For example, sensory studies have shown that sourness suppresses sweetness. However, the degree of sweetness suppression by sourness is difficult to evaluate quantitatively and objectively. Therefore, we propose a biohybrid tongue that is constructed by integrating mammalian gustatory epithelium with a microelectrode array chip. The taste quality and intensity information is coded in time-frequency patterns of local field potential. Different response patterns evoked by sweet and sour stimuli are observed, and the response is dose-dependent. Then, interaction effects of sourness against sweetness are quantified. The results indicate that suppression of sweetness by sourness occurs by increasing sourness concentrations. In summary, this study provides a powerful new tool for quantitative evaluation of sweet, sour, and their binary taste interactions that mimic the mammalian taste system.

Modification of milk resulting in low potassium and minimal electrolyte changes with minimal changes in taste

The objective of this research communication was to produce low potassium milk in which other electrolyte changes and changes in taste were minimized. To reduce potassium concentrations, several studies have reported batch methods of directly mixing milk or formula with sodium polystyrene sulfonate, which can exchange cations such as potassium for sodium. However, they also reported increases in sodium content, decreases in calcium and magnesium content, and changes in taste, because sodium polystyrene sulfonate exchanged other substances such as calcium and magnesium for sodium. In the present study, a method of dialyzing whole cow's milk using both sodium polystyrene sulfonate and a small amount of water through cellophane membranes was developed. A batch method for comparison was also performed. Each milk sample was evaluated biochemically and analyzed for taste and aroma in a sensory analysis. We showed that the potassium concentration in the dialyzed milk was reduced to 38% of that in unreacted milk. It was also shown that changes in sodium (increased) as well as calcium and magnesium (decreased) in the dialyzed milk were less than half of those in the batch method milk. Sensory analysis showed that minimal changes occurred in the taste of the dialyzed milk.

Untargeted LC-MS based identification of Rebaudioside A degradation products impacting flavor perception during storage

Untargeted LC-MS flavoromics chemical profiling was used to identify compounds predictive of Rebaudioside A (Reb A) flavor instability in an acidified beverage after 6 weeks at 35 °C. High-quality orthogonal partial least squares analysis models were developed from the chemical data and d' values from tetrad sensory panel testing with good predictive ability. The top four highly predictive compounds were selected and identified as Reb A (negatively correlated) and three Reb A degradation compounds (positively correlated), which included a rearrangement, hydration, and an epoxidation/rearrangement of Reb A, termed compounds 1, 2, and 3, respectively. The concentrations of compounds 1-3 in the aged beverages were determined to be below the sensory recognition threshold values. However, sensory recombination testing of compounds 1-3 as a tertiary mixture revealed a perceivably significant flavor change that was aligned with the aged beverage.

The Challenge of Measuring Sweet Taste in Food Ingredients and Products for Regulatory Compliance: A Scientific Opinion

The Codex Alimentarius Commission, a central part of the joint Food and Agricultural Organization/World Health Organizations Food Standards Program, adopts internationally recognized standards, guidelines, and code of practices that help ensure safety, quality, and fairness of food trade globally. Although Codex standards are not regulations per se, regulatory authorities around the world may benchmark against these standards or introduce them into regulations within their countries. Recently, the Codex Committee on Nutrition and Foods for Special Dietary Uses (CCNFSDU) initiated a draft revision to the Codex standard for follow-up formula (FUF), a drink/product (with added nutrients) for young children, to include requirements for limiting or measuring the amount of sweet taste contributed by carbohydrates in a product. Stakeholders from multiple food and beverage manufacturers expressed concern about the subjectivity of sweetness and challenges with objective measurement for verifying regulatory compliance. It is a requirement that Codex standards include a reference to a suitable method of analysis for verifying compliance with the standard. In response, AOAC INTERNATIONAL formed the Ad Hoc Expert Panel on Sweetness in November 2020 to review human perception of sweet taste, assess the landscape of internationally recognized analytical and sensory methods for measuring sweet taste in food ingredients and products, deliver recommendations to Codex regarding verification of sweet taste requirements for FUF, and develop a scientific opinion on measuring sweet taste in food and beverage products beyond FUF. Findings showed an abundance of official analytical methods for determining quantities of carbohydrates and other sweet-tasting molecules in food products and beverages, but no analytical methods capable of determining sweet taste. Furthermore, sweet taste can be determined by standard sensory analysis methods. However, it is impossible to define a sensory intensity reference value for sweetness, making them unfit to verify regulatory compliance for the purpose of international food trade. Based on these findings and recommendations, the Codex Committee on Methods of Analysis and Sampling agreed during its 41st session in May 2021 to inform CCNFSDU that there are no known validated methods to measure sweetness of carbohydrate sources; therefore, no way to determine compliance for such a requirement for FUF.

Temporal Sensory Profiles of Regular and Sodium-Reduced Foods Elicited by Temporal Dominance of Sensations (TDS) and Temporal Check-All-That-Apply (TCATA)

Temporal sensory methods can be used to highlight the impact of sodium reduction on the dynamic sensory profile of foods targeted for sodium reduction. Study aims were to compare the temporal sensory attribute profiles of regular and sodium-reduced food products elicited by TDS and TCATA, over single and multiple oral intakes. A total of 20 semi-trained participants evaluated commercially available regular and sodium-reduced canned corn, cooked ham (single intakes), potato chips and cream of mushroom soup (5 intakes) using both TDS and TCATA. Regular and sodium-reduced products differed in not only salty but also other sensory attributes, noticeably dry for chips, sweet for corn, bitter and metallic for ham, thick, creamy, sweet, and starchy for soup. TDS and TCATA provided comparable information for the key sensory attributes characterizing and differentiating the regular and sodium-reduced products. TDS profiled significant differences between samples for a larger number of attributes than TCATA, while TCATA profiles were more consistent across intakes. Multiple intakes changed the duration of attribute dominance but not the number of significantly dominant attributes in TDS profiles. The current findings provide insight for applications of temporal profiling to other food products and development of sodium-reduced foods with attribute profiles acceptable to consumers.

Sodium Reduction in Bouillon: Targeting a Food Staple to Reduce Hypertension in Sub-saharan Africa

Bouillon cubes are a staple ingredient used in Sub-saharan African countries providing flavor enhancement to savory foods. Bouillon has been identified as a vehicle for fortification to overcome micronutrient deficiencies in Sub-saharan Africa. However, bouillon has a high sodium content (and in addition with other foods) contributes to dietary sodium intake above recommended guidelines. High dietary sodium intake is a key risk factor for hypertension and cardiovascular disease (CVD). Africa has the highest rates of hypertension and CVD globally with nearly half the adult population above 25 years affected. This review presents current state of research on sodium reduction strategies in bouillon. The key challenge is to reduce sodium levels while maintaining optimal flavor at the lowest possible production cost to ensure bouillon continues to be affordable in Sub-saharan Africa. To produce lower sodium bouillon with acceptable flavor at low cost will likely involve multiple sodium reduction strategies; direct reduction in sodium, sodium replacement and saltiness boosting flavor technologies. Efforts to reduce the sodium content of bouillon in Sub-saharan Africa is a worthwhile strategy to: (i) lower the overall sodium consumption across the population, and (ii) deliver population-wide health benefits in a region with high rates of hypertension and CVD.

Effects of phenolic acids and quercetin-3-O-rutinoside on the bitterness and astringency of green tea infusion

Phenolic acids are important taste components in green tea. The aim of this study was to analyze the taste characteristics of phenolic acids and their influence on the bitterness and astringency of green tea by sensory evaluation and chemical determination. The major tea phenolic acids and quercetin-3-O-rutinoside (Que-rut) were significantly positively correlated with the bitterness (r = 0.757, p < 0.01; r = 0.605, p < 0.05) and astringency (r = 0.870, p < 0.01; r = 0.576, p < 0.05) of green tea infusion. The phenolic acids have a sour and astringent taste, whereas Que-rut has a mild astringent taste. Phenolic acids and Que-rut can increase the bitterness of epigallocatechin gallate (EGCG). However, these components behaved differently for astringency on EGCG. Gallic acid (GA) enhances the astringency throughout all the concentrations in this study. While it seemed to be double effects of caffeic acid (CA), chlorogenic acid (CGA), and Que-rut on that, i.e., the inhibition at lower concentrations (CA: 0–0.2 mM; CGA: 0–0.2 mM; Que-rut: 0–0.05 mM) but enhancement at higher ones. The phenolic acids and Que-rut interacted synergistically with tea infusion and as their concentration increased, the synergistic enhancement of the bitterness and astringency of tea infusion increased. These findings help provide a theoretical basis for improving the taste of middle and green tea.