Cross-modal interactions as a strategy to enhance salty taste and to maintain liking of low-salt food: a review

Decoding of the enhancement of saltiness perception by aroma-active compounds during Hunan Larou (smoke-cured bacon) oral processing

The enhancement of saltiness induced by odrants perceived from the retronasal cavity during Larou oral processing was analyzed. During the oral processing of Xiangtan Larou, the smoky attribute was the dominant when chewing 0-15 times, followed by the savory (15-24 times) and meaty (24-42 times). Partial least squares analysis predicted 33 aroma compounds from the retronasal cavity significantly (p < 0.05) contributing to the aroma perception. A total of 12 aroma compounds with saltiness-enhancement ability were confirmed by odorant-NaCl mixture model experiments. Results revealed that 2-methoxy-4-vinylphenol (1.00-1000.00 μg/L) had the strongest enhancing effect on saltiness at NaCl (2969.85 mg/L), followed by diallyl sulfide (0.156-2.50 μg/L), 2,5-dimethylthiophene (0.156-50.00 μg/L), 2,6-dimethylphenol (1.00-100.00 μg/L), 2,5-dimethylpyrazine (0.391-50.00 μg/L), and 2,3-butanedione (0.50-100.0 μg/L). The sulfur-containing, nitrogen-containing, and phenolic odorants with savory, roasty, sulfide, meaty or smoky, attributes showed the better ability in saltiness enhancement.

A comprehensive review of plant-derived salt substitutes: Classification, mechanism, and application

The diseases caused by excessive sodium intake derived from NaCl consumption have attracted widespread attention worldwide, and many researchers are committed to finding suitable ways to reduce sodium intake during the dietary process. Salt substitute is considered an effective way to reduce sodium intake by replacing all/part of NaCl in food without reducing the saltiness while minimizing the impact on the taste and acceptability of the food. Plant-derived natural ingredients are generally considered safe and reliable, and extensive research has shown that certain plant extracts or specific components are effective salt substitutes, which can also give food additional health benefits. However, these plant-derived salt substitutes (PSS) have not been systematically recognized by the public and have not been well adopted in the food industry. Therefore, a comprehensive review of PSS, including its material basis, flavor characteristics, and taste mechanism is helpful for a deeper understanding of PSS, accelerating its research and development, and promoting its application.

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.

Current trends and perspectives on salty and salt taste-enhancing peptides: A focus on preparation, evaluation and perception mechanisms of salt taste

Long-term excessive intake of sodium negatively impacts human health. Effective strategies to reduce sodium content in foods include the use of salty and salt taste-enhancing peptides, which can reduce sodium intake without compromising the flavor or salt taste. Salty and salt taste-enhancing peptides naturally exist in various foods and predominantly manifest as short-chain peptides consisting of < 10 amino acids. These peptides are primarily produced through chemical or enzymatic hydrolysis methods, purified, and identified using ultrafiltration + gel filtration chromatography + liquid chromatography-tandem mass spectrometry. This study reviews the latest developments in these purification and identification technologies, and discusses methods to evaluate their effectiveness in saltiness perception. Additionally, the study explores four biological channels potentially involved in saltiness perception (epithelial sodium channel, transient receptor potential vanilloid 1, calcium-sensing receptor (CaSR), and transmembrane channel-like 4 (TMC4)), with the latter three primarily functioning under high sodium levels. Among the channels, salty taste-enhancing peptides, such as γ-glutamyl peptides, may co-activate the CaSR channel with calcium ions to participate in saltiness perception. Salty taste-enhancing peptides with negatively charged amino acid side chains or terminal groups may replace chloride ions and activate the TMC4 channel, contributing to saltiness perception. Finally, the study discusses the feasibility of using these peptides from the perspectives of food material constraints, processing adaptability, multifunctional application, and cross-modal interaction while emphasizing the importance of utilizing computational technology. This review provides a reference for advancing the development and application of salty and salt-enhancing peptides as sodium substitutes in low-sodium food formulations.

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.

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.

Could the aroma of spices produce a cross-modal enhancement of food saltiness and contribute to reducing salt intake?

BACKGROUND

As a result of its correlation with cardiovascular diseases, salt intake must be reduced. According to multi-sensory integration, aroma plays an important role in saltiness enhancement; this could enable a food's salt content to be reduced without losing acceptance. We therefore studied the effect of three spices, Curcuma longa, Laurus nobilis L. and Petroselinum crispum L., on saltiness enhancement through sensory tests on consumers. This was followed by olfactometric analysis with the aim of relating the effect to the spices' aromatic composition.

RESULTS

According to the odour-induced salty taste enhancement (OISE) mean values, bay leaf and turmeric had the highest effect on saltiness enhancement, at a similar level to dry-cured ham aroma, wherwas parsley had a significantly lower OISE value. Only one odour-active compound (OAC), eugenol, showed a direct correlation with the spices' OISE values. Turmeric primarily had OACs with sweet aroma, whereas bay leaf had more OACs belonging to the spicy-aroma category.

CONCLUSION

The three spices, turmeric, bay leaf and parsley, investigated in the present study appear to enhance the salty taste of mashed potato with a low salt content. The results suggest that an interaction effect among OACs with different aromatic ranges may exist. Therefore, when the global OAC modified frequency value, grouped according to aroma range, was considered, the sweet range appears to counteract the effect of the spicy aroma on saltiness. © 2024 Society of Chemical Industry.

Techniques of incorporation of salty compounds, food matrix, and sodium behaviour and its effect over saltiness perception: an overview

The salty taste is usually associated with the positively charged ion sodium present in sodium chloride. Due to its relevance in the food industry, there have been several studies to determine how this ion behaves in various food matrices, or the use of techniques to improve saltiness perception to reduce the amount necessary for savoury food. Several databases were searched, and it was discovered that sodium can interact with the protein, modifying its mobility, as well as, other components of the food matrix, such as fat, that seem to interfere with saltiness perception, increasing or reducing it. Several techniques were used to identify the interaction between sodium and the food matrix, as well as sensory testing to determine the influence of different modification strategies to enhance the saltiness perception. Due to the multiple factors involved in the salty taste, understanding the effect of the technique to modify saltiness perception, the interaction of the matrix components of the food, and the sodium interaction with those components, can be of use in the developing process of foods with a reduction in the sodium content.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05861-6.

Textured soy protein with meat odor as an ingredient for improving the sensory quality of meat analog and soy burger

Even with the growing consumption of plant-based products, the consumption of soy-based products is still a limitation due to the off-flavor of soy. Thus, two studies were performed using textured soy protein (TSP) with meat odor as meat analog and as soy burger. TSP with meat odor was produced by adding thiamine (aroma precursor) to soy protein concentrate (SPC) before extrusion. Three TSP were used in each study: one without thiamine and two with thiamine but with different moisture contents of the SPC. TSP with thiamine did not affect technological or physical properties of the products. For meat analogs, the samples with thiamine showed greater odor acceptance and greater intensities of meat odor, burnt aftertaste, and aromatic in relation to the sample without thiamine, as well as lower intensity of soy odor. For soy burgers, the samples with thiamine had higher acceptances of odor and flavor and overall acceptance, and higher intensities of chicken odor and aromatic in comparison to the sample without thiamine, as well as lower intensity of soy/vegetable odor. The use of TSP with thiamine raises the sensory quality of meat analogue and soy burger, being an interesting alternative in obtaining soy-based products with lower soy odor.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05875-0.

Mushroom alcohol(1-octen-3-ol)and other 7 aroma compounds selected from Chinese dry-cured hams can enhance saltiness perception

Reducing NaCl content in food while maintaining acceptability poses a significant challenge. Odor-induced saltiness enhancement (OISE) emerges as a promising solution. This study utilized gas chromatography-olfactory (GC-O) in conjunction with gas chromatography-mass spectrometry (GC-MS) to identify 37 key volatile compounds in three representative Chinese dry-cured hams. These compounds had an odor activity value (OAV) of ≥1 or a modification frequency (MF) of ≥30%. Subsequently, quantitative descriptive analysis (QDA) identified eight odorants associated with saltiness. These included 1-octen-3-ol, nonanal, heptanal, 2-methylbutanal, 3-methyl-butanal, benzaldehyde, octanal, and 2,6-dimethylpyrazine. Remarkably, these odorants significantly intensified saltiness (P < 0.05) when added to a low-concentration NaCl solution (0.3%), compared to zero or high concentrations (0.75% and 0.8%). As a result, traditional Chinese salty meat products offer a promising source of odorants for enhancing saltiness, compensating for reduced NaCl content through OISE.

Dynamic Instrumental and Sensory Methods Used to Link Aroma Release and Aroma Perception: A Review

Perception of flavor is a dynamic process during which the concentration of aroma molecules at the olfactory epithelium varies with time as they are released progressively from the food in the mouth during consumption. The release kinetics depends on the food matrix itself but also on food oral processing, such as mastication behavior and food bolus formation with saliva, for which huge inter-individual variations exist due to physiological differences. Sensory methods such as time intensity (TI) or the more-recent methods temporal dominance of sensations (TDS) and temporal check-all-that-apply (TCATA) are used to account for the dynamic and time-related aspects of flavor perception. Direct injection mass spectrometry (DIMS) techniques that measure in real time aroma compounds directly in the nose (nosespace), aimed at obtaining data that reflect the pattern of aroma release in real time during food consumption and supposed to be representative of perception, have been developed over the last 25 years. Examples obtained with MS operated in chemical ionization mode at atmospheric or sub-atmospheric pressure (atmospheric pressure chemical ionization APCI or proton-transfer reaction PTR) are given, with emphases on studies conducted with simultaneous dynamic sensory evaluation. Inter-individual variations in terms of aroma release and their relevance for understanding flavor perception are discussed as well as the evidenced cross-modal interactions.

Enhancing saltiness perception by chemosensory interaction: an fMRI study

Neuroimaging studies that focus on taste, odor, and their interactions can specify their capability to elicit brain regions responsible for flavor perception and reward. Such information would be useful for formulating healthy food products, such as low salt food. In this study, a sensory experiment was conducted to investigate the capability of cheddar cheese odor, monosodium glutamate (MSG), and their interactions to enhance saltiness perception and preference of NaCl solutions. The activated brain areas in response to odor-taste-taste interactions were then investigated using an fMRI study. The results of the sensory tests showed that saltiness and preference of NaCl solutions were enhanced in the presence of MSG + cheddar cheese odor. According to the fMRI study, the stimulus with a higher salty rate activated the rolandic operculum, and the stimulus with a higher preference activated the rectus, medial orbitofrontal cortex, and substantia nigra. Moreover, the activation of multiple regions, such as the orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), temporal pole, and amygdala was observed in response to (cheddar cheese odor + MSG + NaCl) minus (odorless air + NaCl).

Increasing saltiness of salts (NaCl) using mid-infrared radiation to reduce the health hazards

Table salt, rock salt, and iodized salts (composed principally of NaCl) are commonly used in many areas, such as medicine, cooking, industry, or personal care. Common fried, salty, and spicy foods contain an excess of added salt, which has detrimental health effects, especially on the kidneys. Our research aims to enhance the inherent saltiness of these three salts, which would reduce intake and thereby minimize salt's health hazards. We invented a water-based 2-6 μm of Mid-Infrared Generating Atomizer (MIRGA), which, when applied to salts, caused changes in the salts' chemistry and enhanced saltiness, thus allowing the reduction of salt intake by 25%-30%. This easy-to-use technology did not show any side effects. MIRGA was found to have enhanced the saltiness, thus allowing the reduction of salt intake by 25%-30%. MIRGA is safe, portable, highly economical, unique in the mid-IR laser technology, and possesses vast research scope in other areas of food science.

TDS Similarity: Outlier Analysis Using a Similarity Index to Compare Time-Series Responses of Temporal Dominance of Sensations Tasks

Temporal dominance of sensations (TDS) methods are used to record temporally developing sensations while eating food samples. Results of TDS tasks are typically discussed using averages across multiple trials and panels, and few methods have been developed to analyze differences between individual trials. We defined a similarity index between two time-series responses of TDS tasks. This index adopts a dynamic level to determine the importance of the timing of attribute selection. With a small dynamic level, the index focuses on the duration for attributes to be selected rather than on the timing of the attribute selection. With a large dynamic level, the index focuses on the temporal similarity between two TDS tasks. We performed an outlier analysis based on the developed similarity index using the results of TDS tasks performed in an earlier study. Certain samples were categorized as outliers irrespective of the dynamic level, whereas the categorization of a few samples depended on the level. The similarity index developed in this study achieved individual analyses of TDS tasks, including outlier detection, and adds new analysis techniques to TDS methods.

The taste & affect music database: Subjective rating norms for a new set of musical stimuli

Music is a ubiquitous stimulus known to influence human affect, cognition, and behavior. In the context of eating behavior, music has been associated with food choice, intake and, more recently, taste perception. In the latter case, the literature has reported consistent patterns of association between auditory and gustatory attributes, suggesting that individuals reliably recognize taste attributes in musical stimuli. This study presents subjective norms for a new set of 100 instrumental music stimuli, including basic taste correspondences (sweetness, bitterness, saltiness, sourness), emotions (joy, anger, sadness, fear, surprise), familiarity, valence, and arousal. This stimulus set was evaluated by 329 individuals (83.3% women; Mage = 28.12, SD = 12.14), online (n = 246) and in the lab (n = 83). Each participant evaluated a random subsample of 25 soundtracks and responded to self-report measures of mood and taste preferences, as well as the Goldsmiths Musical Sophistication Index (Gold-MSI). Each soundtrack was evaluated by 68 to 97 participants (Mdn = 83), and descriptive results (means, standard deviations, and confidence intervals) are available as supplemental material at osf.io/2cqa5 . Significant correlations between taste correspondences and emotional/affective dimensions were observed (e.g., between sweetness ratings and pleasant emotions). Sex, age, musical sophistication, and basic taste preferences presented few, small to medium associations with the evaluations of the stimuli. Overall, these results suggest that the new Taste & Affect Music Database is a relevant resource for research and intervention with musical stimuli in the context of crossmodal taste perception and other affective, cognitive, and behavioral domains.

Sodium reduction in foods: Challenges and strategies for technical solutions

In many parts of the world, sodium consumption is higher than recommended levels, representing one of the most important food-related health challenges and leading to considerable economical costs for society. Therefore, there is a need to find technical solutions for sodium reduction that can be implemented by food producers and within food services. The aims of this review are to discuss the barriers related to sodium reduction and to highlight a variety of technical solutions. The barriers relate to consumer perception, microbiology, processing, and physicochemistry. Existing technical solutions include inhomogeneous salt distribution, coated salt particles, changing particle sizes and forms, surface coating, multisensory combinations, sodium replacements, double emulsions, adapted serum release by microstructure design, and adapted brittleness by microstructure design. These solutions, their implementation and the associated challenges, and applicable product categories are described. Some of these solutions are ready for use or are in their early development stages. Many solutions are promising, but in most cases, some form of adaptation or optimization is needed before application in specific products, and care must always be taken to ensure food safety. For instance, further research and innovation are required in the dynamic evolution of saltiness perception, consumer acceptance, the binding and migration of sodium, juiciness, microbiological safety, and the timing of salt addition during processing. Once implemented, these solutions will undoubtedly support food producers and food services in reducing sodium content and extend the application of the solutions to different foods.

Development of an Effective Protocol for Evaluating the Saltiness Intensity Enhancement of Umami Compounds

Reducing sodium intake without decreasing saltiness perception remains an important target in the food industry. This study developed an effective protocol for evaluating the saltiness perception enhanced by umami compounds. Two sodium chloride solutions (2.00 and 6.00 g/L) were the preferred concentrations for consumers. Two-alternative forced-choice evaluation results confirmed that at a concentration of 2.00 g/L (sodium concentration), the highest replacement ratios of monosodium glutamate and l-alanine (Ala) were 10 and 20% in sodium chloride solution without saltiness intensity decrease, respectively. The highest replacement ratios of l-glycine (Gly) and Ala were 10 and 20% compared to 6.00 g/L, respectively. Temporal dominance of sensations analysis figured out that gum Arabic (GA) could compensate for the decrease of the retention time and increase the overall saltiness perception in the sodium-reduced sample. Quartz crystal microbalance with dissipation results showed that Ala and Gly could inhibit the binding of Na⁺ to mucin, thereby increasing the saltiness perception. GA exhibited the best saltiness enhancement effect in sodium-reduced solution by producing the nanoparticles from GA, decreasing the stability of the solution system, enhancing the loading effect of mucin on Na⁺, and prolonging the saltiness perception.

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.

The influence of dough kneading time and flour particle size distribution on white bread structure, glycemic response and aspects of appetite

BACKGROUND & AIMS

White bread is widely consumed in many countries despite being a high-glycemic index (GI) food. It has been shown that the "food matrix effect" may help with diabetes and obesity management through lowering GI and appetite. This study aimed at investigating the effects of dough kneading time and flour particle size on white bread structure, glycemic response, and aspects of appetite.

METHODS

A two-phase randomized cross-over design was used in 10 healthy subjects over the course of 2 h. In phase 1, Texture Profile Analysis (TPA) attributes, Scanning Electron Microscope (SEM) image, glycemic response, and appetite aspects of white bread made with a 15-min dough kneading time (K15) were compared with white bread made with a 10-min dough kneading time (K10). In phase 2, TPA, SEM image, glycemic response, and satiety score of white bread made with coarse flour (CF) were compared to white bread made with fine flour (FF).

RESULT

With increasing hardness (force required to compress a food between the molars to a given deformation), total blood glucose IAUC in K15 (IAUC = 119 ± 12; GI = 66) was significantly (p < 0.05) lower than in K10 (IAUC = 154 ± 10; GI = 81). No marked difference was observed between K15 and K10 on aspects of appetite except for hunger. There was no significant (p > 0.05) difference in glycemic response between CF (IAUC = 126 ± 18; GI = 64) and FF (IAUC = 147 ± 12; GI = 81). Similarly, no discernible difference in satiety between CF and FF.

CONCLUSION

Changes in processing conditions can improve blood glucose response relalated to white bread consumption.

Role of Aromatic Herbs and Spices in Salty Perception of Patients with Hyposmia

Herbs and spices represent a possibility for the improvement of anosmia and ageusia. In this work we evaluated the role of Mediterranean aromatic herbs and spices in the salty taste perception of patients with hyposmia compared to healthy controls. To this goal, the salty taste perception in response to pure salt and different types of commercial flavored sea salt was assessed in patients with hyposmia, with or without a post-acute coronavirus syndrome, and healthy controls. Myrtle berries and leaves, a mixture of Mediterranean herbs and plants such as helichrysum, rosemary, liquorice, fennel seeds and myrtle leaves, oranges and saffron were used as salt flavoring ingredients. Differences in gustatory perception between 57 patients with hyposmia and 91 controls were evaluated considering the rate of the gustatory dimensions of pleasantness, intensity, and familiarity, using a 7-point hedonic Likert-type scale. At a dose of 0.04 g/mL, saline solutions of flavored salts, with an average 15% less NaCl, were perceived by patients with hyposmia as equally intense but less familiar than pure salt solution, with similar scores in the pleasantness dimension. Our study highlighted the central role of Mediterranean aromatic plants in the enhancement of salty perception in patients with hyposmia.

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.

Behavioural Nudges, Physico-Chemical Solutions, and Sensory Strategies to Reduce People’s Salt Consumption

This narrative historical review examines the wide range of approaches that has been trialled/suggested in order to reduce the consumption of salt. While sodium is an essential micronutrient, there is widespread evidence that high levels of consumption are leading to various negative health outcomes. This review summarises the evidence relating to the various approaches that have been put forward to date to help reduce salt consumption over the years, while also highlighting a number of important questions that remains for future research. Solutions to reducing salt consumption include everything from the gradual reduction in salt in foods through to the reduction in the number/size of holes in saltshakers (what one might consider a behavioural nudge). Physico-chemical solutions have included salt replacers, such as monosodium glutamate (MSG) through to the asymmetric distribution of salt in processed (e.g., layered) foods. A wide range of sensory approaches to modulating expected and perceived saltiness have also been suggested, including the use of salty aromas, as well as suggesting the use of colour cues, sonic seasoning, and even textural primes. It is currently unclear whether different salty aromas can be combined to increase odour-induced taste enhancement (OITE) effectiveness. In the years ahead, it will be interesting to assess how long such solutions remain effective, as well as whether different solutions can be combined to help reduce salt consumption without having to compromise on taste/flavour

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.

Characterization of bitter-tasting and antioxidant activity of dry-hopped beers

BACKGROUND

Bitter flavors and antioxidant activities are critical characteristics and indicators, respectively, of beer quality. To gain a better understanding of dry-hopped beer's bitterness, this work comprehensively evaluated the perceived bitterness intensity and bitterness attributes from aspects of beer aroma and non-volatile bitter compounds using sensory analysis under two conditions: (i) with and (ii) without nose clips. To quantify bitter and volatile compounds, the work conducted chromatographic analyses: high-performance liquid chromatography (HPLC), ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) and gas chromatography-mass spectrometry (GC-MS). Simultaneously, this work assessed the antioxidant activity of commercially dry-hopped beers.

RESULTS

First, dry-hopped beer in this study contained abundant non-volatile bitter compounds (hop bitter acids, polyphenols and flavonoids), and aroma was validated using HPLC, UPLC-MS and GC-MS methods. Moreover, the bitter-tasting perception test findings demonstrated that many dry-hopped beers had a higher bitterness intensity when evaluated without a nose clip, whereas this phenomenon was adverse in several ale beers. Additionally, the 'lingering' and 'harsh' characteristics were diminished when beer aroma was blocked out (with nose clip) for dry-hopped beer. Meanwhile, most dry-hopped beers had greater antioxidant activity than ale beers (P < 0.05).

CONCLUSION

This work revealed the bitterness complexity of dry-hopped beer; besides non-volatile bitter compounds, beer aroma had an impact on the perceived bitterness intensity and attributes, and dry-hopped beer had a relatively intense antioxidant capacity. This study facilitated the development of a detailed knowledge about the assessment of bitter-tasting perceptions in dry-hopped beers and provided a basis for the development of functional beer benefiting human health. © 2022 Society of Chemical Industry.

Impact of cooking on the sensory perception and volatile compounds of Takifugu rubripes

Takifugu rubripes is well-known for its unique flavour but can also develop a putrid off-note. To eliminate off-note and promote desirable flavour, four cooking processes (boiling, steaming, microwave-heating and roasting) were explored to determine their effects on cooked T. rubripes. The temperature and water dynamics, physico-chemical properties were analysed and correlated with sensory qualities. The changes of centre temperature dynamics during cooking decreased the water mobility and led to varied sensory properties. Six out of ten orthonasal aroma attributes and four out of five mouthfeel attributes were significantly different among samples (p < 0.05). Based on partial least squares regression analysis, orthonasal aroma attributes "roasted" and "earthy/putrid fish" highly correlated with the volatile compounds generated from Maillard reaction and lipid oxidation, respectively; meanwhile mouthfeel attributes of chewy/fibre and tender/juicy were highly associated with water loss and moisture, respectively. This study provides insights for optimising cooking conditions to create desirable fish flavour.

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.

Impact of a Shorter Brine Soaking Time on Nutrient Bioaccessibility and Peptide Formation in 30-Months-Ripened Parmigiano Reggiano Cheese

Reducing the salt content in food is an important nutritional strategy for decreasing the risk of diet-related diseases. This strategy is particularly effective when applied to highly appreciated food having good nutritional characteristics, if it does not impact either upon sensory or nutritional properties of the final product. This work aimed at evaluating if the reduction of salt content by decreasing the brine soaking time modifies fatty acid and protein bioaccessibility and bioactive peptide formation in a 30-month-ripened Parmigiano Reggiano cheese (PRC). Hence, conventional and hyposodic PRC underwent in vitro static gastrointestinal digestion, and fatty acid and protein bioaccessibility were assessed. The release of peptide sequences during digestion was followed by LC–HRMS, and bioactive peptides were identified using a bioinformatic approach. At the end of digestion, fatty acid and protein bioaccessibility were similar in conventional and hyposodic PRC, but most of the bioactive peptides, mainly the ACE-inhibitors, were present in higher concentrations in the low-salt cheese. Considering that the sensory profiles were already evaluated as remarkably similar in conventional and hyposodic PRC, our results confirmed that shortening brine soaking time represents a promising strategy to reduce salt content in PRC.

Characterization of the Aroma-Active Compounds in Banana (Musa AAA Red green) and Their Contributions to the Enhancement of Sweetness Perception

"Hongmeiren" bananas are popular because of their red peel. Two extraction methods solvent-assisted flavor evaporation and headspace solid-phase microextraction, combined with gas chromatography-olfactometry and gas chromatography-mass spectrometry (GC-MS), were used to analyze the volatile components of "Hongmeiren" bananas. A total of 86 aroma compounds were identified by GC-MS, 62 of which were identified as the major aroma-active compounds with an odor activity value ≥ 1 or modified frequency ≥ 30%. Ethyl (E)-2-butenoate, 4-undecanone, and α-phellandrene were found in bananas for the first time. Sensory experiments showed that eight sweet-associated odorants could significantly achieve the sweetness enhancement effect at 30 g/L sucrose solution by odor-induced changes in taste perception. These experiments suggest that selected odorants can achieve sugar reduction, but with consideration of the sugar concentration. The study of the sweetness enhancement effect of individual compounds provides a more direct theoretical support for sugar reduction in the food industry.

Dysgeusia: A review in the context of COVID-19

Background

Taste disorders in general, and dysgeusia in particular, are relatively common disorders that may be a sign of a more complex acute or chronic medical condition. During the COVID-19 pandemic, taste disorders have found their way into the realm of general as well as specialty dentistry, with significance in screening for patients who potentially may have the virus.

Types of Studies Reviewed

The authors searched electronic databases (PubMed, Embase, Web of Science, Google Scholar) for studies focused on dysgeusia, ageusia, and other taste disorders and their relationship to local and systemic causes.

Results

The authors found pertinent literature explaining the normal physiology of taste sensation, proposals for suggested new tastes, presence of gustatory receptors in remote tissues of the body, and etiology and pathophysiology of taste disorders, in addition to the valuable knowledge gained about gustatory disorders in the context of COVID-19. Along with olfactory disorders, taste disorders are one of the earliest suggestive symptoms of COVID-19 infection.

Conclusions

Gustatory disorders are the result of local or systemic etiology or both. Newer taste sensations, such as calcium and fat tastes, have been discovered, as well as taste receptors that are remote from the oropharyngeal area. Literature published during the COVID-19 pandemic to date reinforces the significance of early detection of potential patients with COVID-19 by means of screening for recent-onset taste disorders.

Practical Implications

Timely screening and identification of potential gustatory disorders are paramount for the dental care practitioner to aid in the early diagnosis of COVID-19 and other serious systemic disorders.

Metacognition and Crossmodal Correspondences Between Auditory Attributes and Saltiness in a Large Sample Study

Mounting evidence demonstrates that people make surprisingly consistent associations between auditory attributes and a number of the commonly-agreed basic tastes. However, the sonic representation of (association with) saltiness has remained rather elusive. In the present study, a crowd-sourced online study ( n = 1819 participants) was conducted to determine the acoustical/musical attributes that best match saltiness, as well as participants' confidence levels in their choices. Based on previous literature on crossmodal correspondences involving saltiness, thirteen attributes were selected to cover a variety of temporal, tactile, and emotional associations. The results revealed that saltiness was associated most strongly with a long decay time, high auditory roughness, and a regular rhythm. In terms of emotional associations, saltiness was matched with negative valence, high arousal, and minor mode. Moreover, significantly higher average confidence ratings were observed for those saltiness-matching choices for which there was majority agreement, suggesting that individuals were more confident about their own judgments when it matched with the group response, therefore providing support for the so-called 'consensuality principle'. Taken together, these results help to uncover the complex interplay of mechanisms behind seemingly surprising crossmodal correspondences between sound attributes and taste.

Chromatographic Fingerprinting Strategy to Delineate Chemical Patterns Correlated to Coffee Odor and Taste Attributes

Coffee cupping includes both aroma and taste, and its evaluation considers several different attributes simultaneously to define flavor quality and therefore requires complementary data from aroma and taste. This study investigates the potential and limits of a data-driven approach to describe the sensory quality of coffee using complementary analytical techniques usually available in routine quality control laboratories. Coffee flavor chemical data from 155 samples were obtained by analyzing volatile (headspace-solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS)) and nonvolatile (liquid chromatography-ultraviolet/diode array detector (LC-UV/DAD)) fractions, as well as from sensory data. Chemometric tools were used to explore the data sets, select relevant features, predict sensory scores, and investigate the networks between features. A comparison of the Q model parameter and root-mean-squared error prediction (RMSEP) highlights the variable influence that the nonvolatile fraction has on prediction, showing that it has a higher impact on describing acid, bitter, and woody notes than on flowery and fruity. The data fusion emphasized the aroma contribution to driving sensory perceptions, although the correlative networks highlighted from the volatile and nonvolatile data deserve a thorough investigation to verify the potential of odor-taste integration.

Salt and Aroma Compound Distributions Influence Flavour Release and Temporal Perception While Eating Hot-Served Flans

To counteract the negative effect of salt overconsumption on health, strategies have been developed to reduce the salt content in food products. Among them, two promising strategies based on odour-induced saltiness enhancement and the heterogeneous distribution of flavour compounds were combined and assessed in four-layer cream-based snacks. To investigate the relationship between saltiness enhancement, temporal release and perception of flavour compounds in hot snacks with heterogeneous distribution of salt and aroma compounds, complementary techniques were used: nose space PTR-Tof-MS (Proton Transfer Reaction-Time of Flight–Mass Spectrometry) to assess the release of aroma compounds in vivo, and ATI (Alternate Time-Intensity) and TDS Temporal Dominance of Sensations) to evaluate perception as a function of time. The obtained results confirmed that the strategy of concentrating salt in the outer layer of a multilayer product was the optimal solution with respect to taste intensity. Heterogeneous salt distribution decreased aroma compound release and consequently aroma intensity but in different ways according to both salt and added aroma distribution in the food matrix. The salty taste enhancement could be due to the initial strong dominance of the salty sensation at the very beginning of the eating process. The involved mechanisms rely on a combination of physico-chemical and perceptual effects which are not clear yet.

Strategies for Reducing Salt and Sugar Intakes in Individuals at Increased Cardiometabolic Risk

Non-communicable diseases (NCDs) are the first causes of death worldwide. Reduction in the dietary intake of salt and sugars is important lifestyle advice that is useful for NCD prevention. However, the simple recommendations of reducing salt and sugars by healthcare professionals are often ineffective; innovative strategies are therefore necessary. This review aimed at describing the current knowledge about the strategies to reduce dietary salt and sugar intake, including both strategies for the food industry to reduce the salt or sugar of its products and recommendations for health professionals in a clinical context, such as the replacement with substitutes in foods, the gradual reduction to allow a progressive consumer adaptation towards less intense taste, and the different spatial distribution of tastants within the food matrix with taste intensity enhancement. In addition, the cross-modal interaction between two or more different sensory modalities as an innovative strategy for enhancing sweetness and saltiness perception was described. Finally, the dietary tips for salt and sugar reduction were summarized in order to create a comprehensive guide of dietary advices for healthcare professionals for optimizing the management of patients at increased cardiometabolic risk.

Enhancement of saltiness perception by odorants selected from Chinese soy sauce: A gas chromatography/olfactometry-associated taste study

Odor-taste interaction has become a popular salt reduction method. In this study, the odorants associated with saltiness in soy sauce were selected by gas chromatography/olfactometry-associated taste (GC/O-AT), and their ability to induce saltiness/umami enhancement was verified by sensory evaluation. A total of 30 taste-associated odorants were perceived, including 5 saltiness-associated and 2 umami-associated odorants. Among them, 3-(methylthio)propanal, 1-octen-3-ol, 3-(methylthio)-1-propanol, and 2,5-dimethylpyrazine could significantly enhance saltiness of 0.3% NaCl solution (p < 0.05). Furthermore, 3-(methylthio)propanal, maltol, 2,5-dimethyl-4-hydroxy-3(2H)-furanone (HDMF), dimethyl trisulfide, 3-(methylthio)-1-propanol and 1-octen-3-ol could also enhance the umami taste in 0.3% monosodium glutamate solution. Compared with zero or strong-salt-content (0.8%) solution, the saltiness of weak-salt-content (0.3%) was enhanced significantly by adding the odorant. These results suggest that salty food is an efficient source for selecting saltiness-enhancing odorants, which could be used to compensate NaCl reduction in food.