Pairing flavours and the temporal order of tasting

Smelling x as y? On (the impossibility of) multistable perception in the chemical senses

Multistable percepts are intriguing phenomena whereby an ambiguous sensory input can be perceived in one of several qualitatively different ways. In such cases, people can switch their attention to perceive the stimulus in either way, though they typically cannot maintain both interpretations in awareness simultaneously. The abundance of evidence demonstrating multistable perception in the visual and auditory modalities can be contrasted with the scarcity, if not absence, of studies reporting similar phenomena in the chemical senses (primarily olfaction and gustation), prompting an intriguing question about this apparent qualitative difference between the senses. This paper seeks to address this question by first briefly reviewing multistable perceptual phenomena in vision and audition to underscore their defining features. We then assess the limited body of research that has occasionally linked multistability to the chemical senses. While a few studies suggest loose analogies between olfactory perception and visual or auditory multistability, no compelling evidence exists for such phenomena in taste. We argue that this absence is unlikely to be explained by any single factor. Rather, it appears to stem from a confluence of constraints, including the lack of spatio-temporal structure and intrinsic dimensionality in chemosensory stimuli, as well as their distinct evolutionary functions and cognitive framing. Together, these factors may help to explain why multistable perceptual experiences seem not to emerge in the chemical senses.

Perceiving temporal structure within and between the senses: A multisensory/crossmodal perspective

The literature demonstrates that people perceive temporal structure in sequences of auditory, tactile, or visual stimuli. However, to date, much less attention has been devoted to studying the perception of temporal structure that results from the presentation of stimuli to the chemical senses and/or crossmodally. In this review, we examine the literature on the perception of temporal features in the unisensory, multisensory and crossmodal domains in an attempt to answer, among others, the following foundational questions: Is the ability to perceive the temporal structure of stimuli demonstrated beyond the spatial senses (i.e., in the chemical senses)? Is the intriguing idea of an amodal, or supramodal, temporal processor in the human brain empirically grounded? Is the perception of temporal structure in crossmodal patterns (even) possible? Does the ability to perceive temporal patterns convey any biological advantage to humans? Overall, the reviewed literature suggests that humans perceive rhythmic structures, such as beat and metre, across audition, vision and touch, exhibiting similar behavioural traits. In contrast, only a limited number of studies have demonstrated this ability in crossmodal contexts (e.g., audiotactile interactions). Similar evidence within the chemical senses remains scarce and unconvincing, posing challenges to the concept of an amodal temporal processor and raising questions about its potential biological advantages. These limitations highlight the need for further investigation. To address these gaps, we propose several directions for future research, which may provide valuable insights into the nature and mechanisms of temporal processing across sensory modalities.

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.

Exploring food and beverage pairing from a cross-cultural projective mapping

Culture is a well-known driver of food choices, and therefore, it could also impact food pairing preferences. Food pairing has been studied from different approaches; however, little cross-cultural research has been done. This work explored food and beverage pairing using projective mapping (PM) to create maps of food-beverage combinations. Four countries (Mexico, Argentina, France, and Norway), thirty foods, and six beverages were selected. PM was carried out through an online study in each country. Participants were asked to map foods together with beverages following the instruction that foods and beverages closer together represented a good combination. The coordinates of each product were analyzed through Multiple Factorial Analyses (MFA) by countries. The first four factors of each MFA were used to perform RV coefficients to test similarities in food-beverage pairings between the countries. Finally, a k-means clustering was performed on the beverage coordinates of each MFA. PM provided maps representing food and beverage pairings for each country in which the proximity between food-beverages represented a good combination according to consumers. RV coefficients between countries were low, showing that food-beverage pairings were not similar across countries, evidencing the cultural effect in food-drink combinations. Results from the k-means clustering showed some similarities and differences between countries. In general, the food-beverage pairing was effectively explored with PM, from which several differences and similarities were found within cultures.

Orthonasal olfactory influences on consumer food behaviour

It is often suggested in the popular press that food chains deliberately introduce enticing product aromas into (and in the immediate vicinity of) their premises in order to attract customers. However, despite the widespread use of odours in the field of sensory marketing, laboratory research suggests that their effectiveness in modulating people's food behaviours depends on a range of contextual factors. Given the evidence that has been published to date, only under a subset of conditions is there likely to be a measurable effect of the presence of ambient odours on people's food attitudes and choices. This narrative historical review summarizes the various ways in which food odours appear to bias people's food preferences (appetite) and food choices (food consumption and purchase). Emphasis is placed on those experimental studies that have been designed to investigate how the characteristics of the olfactory stimuli (e.g., the congruency between the olfactory cues and the foods, intensity and duration of exposure to odours, and taste properties of odours) modulate the effects of olfactory cues on food behaviour. The review also explores the moderating roles of individual differences, such as dietary restraint, Body Mass Index (BMI), genetic and cultural differences in odour sensitivity and perception. Ultimately, following a review of empirical studies on food-related olfaction, current approaches in scent marketing are discussed and a research agenda is proposed to help encourage further studies on the effective application of scents in promoting healthy foods.

Metallic: A Bivalent Ambimodal Material Property?

Many metallic visual stimuli, especially the so-called precious metals, have long had a rich symbolic meaning for humans. Intriguingly, however, while metallic is used to describe sensations associated with pretty much every sensory modality, the descriptor is normally positively valenced in the case of vision while typically being negatively valenced in the case of those metallic sensations that are elicited by the stimulation of the chemical senses. In fact, outside the visual modality, metallic would often appear to be used to describe those sensations that are unfamiliar and unpleasant as much as to refer to any identifiable perceptual quality (or attribute). In this review, we assess those sensory stimuli that people choose to refer to as metallic, summarising the multiple, often symbolic, meanings of (especially precious) metals. The evidence of positively valenced sensation transference from metallic serviceware (e.g., plates, cups, and cutlery) to the food and drink with which it comes into contact is also reviewed.

The Mystery of "Metal Mouth" in Chemotherapy

Of all the oral sensations that are experienced, "metallic" is one that is rarely reported in healthy participants. So why, then, do chemotherapy patients so frequently report that "metallic" sensations overpower and interfere with their enjoyment of food and drink? This side-effect of chemotherapy-often referred to (e.g., by patients) as "metal mouth"-can adversely affect their appetite, resulting in weight loss, which potentially endangers (or at the very least slows) their recovery. The etiology of "metal mouth" is poorly understood, and current management strategies are largely unevidenced. As a result, patients continue to suffer as a result of this poorly understood phenomenon. Here, we provide our perspective on the issue, outlining the evidence for a range of possible etiologies, and highlighting key research questions. We explore the evidence for "metallic" as a putative taste, and whether "metal mouth" might therefore be a form of phantageusia, perhaps similar to already-described "release-of-inhibition" phenomena. We comment on the possibility that "metal mouth" may simply be a direct effect of chemotherapy drugs. We present the novel theory that "metal mouth" may be linked to chemotherapy-induced sensitization of TRPV1. Finally, we discuss the evidence for retronasal olfaction of lipid oxidation products in the etiology of "metal mouth." This article seeks principally to guide much-needed future research which will hopefully one day provide a basis for the development of novel supportive therapies for future generations of patients undergoing chemotherapy.

The contribution of network science to the study of food recipes. A review paper

Recently, scholars have applied network science, which examines interconnected systems, to the study of food recipes. By examining the current literature, this review paper analyses the contribution of network science to recipes, and finds evidence of two main contributions. First, the pioneer studies showed the potential of network science for reducing the complexity of recipes and proposing theories to model ingredient pairings and recipe evolution. The second contribution built upon the previous theories and expanded them to cover different regions of the world as the field moved towards understanding the granularity of human culture with rich and detailed studies that examine different cuisines as more recipe datasets became available. Network science studies of recipes allowed researchers to discover insights in recipes to explain sociocultural aspects of cuisines, and include large numbers of recipes in the analysis, which would be nearly impossible using other techniques.

Engineering management of starter cultures in study of temperature of fermentation of sour-milk drink with apiproducts

The article considers the solution of problematic issues of engineering management of poly fermentation in the study of fermentation temperature of sour-milk drink with apiproducts. In the development of fermented dairy products, the components that are part of them, changes in their composition, and properties in the interconnection are considered as a technological system. The authors took into account that food technologies based on the use of the pure culture of one microorganism are limited by the capabilities of its fermentation system systems, the ultimate goal may not be achieved even by changing the conditions and parameters of cultivation. To successfully carry out fermentation processes in the technological system, a combination of cultures, associations of microorganisms with a wide range of fermentation products in contrast to one culture is promising to use. All experimental samples on a set of indicators prevailed control ones. The leader was a sample fermented with yeast with an equal ratio of cultures at a temperature of 38 – 40 °C. The authors found that the set of indicators of finished products for the production of sour-milk drinks with a complex of apiproducts, it is necessary to choose a three-strain poly fermentation product with a congruent ratio of cultures and set optimal fermentation regimes 39 ±1ºC for 5.0 ±0.3 hours.

Multisensory Flavour Perception: Blending, Mixing, Fusion, and Pairing Within and Between the Senses

This review summarizes the various outcomes that may occur when two or more elements are paired in the context of flavour perception. In the first part, I review the literature concerning what happens when flavours, ingredients, and/or culinary techniques are deliberately combined in a dish, drink, or food product. Sometimes the result is fusion but, if one is not careful, the result can equally well be confusion instead. In fact, blending, mixing, fusion, and flavour pairing all provide relevant examples of how the elements in a carefully-crafted multi-element tasting experience may be combined. While the aim is sometimes to obscure the relative contributions of the various elements to the mix (as in the case of blending), at other times, consumers/tasters are explicitly encouraged to contemplate/perceive the nature of the relationship between the contributing elements instead (e.g., as in the case of flavour pairing). There has been a noticeable surge in both popular and commercial interest in fusion foods and flavour pairing in recent years, and various of the 'rules' that have been put forward to help explain the successful combination of the elements in such food and/or beverage experiences are discussed. In the second part of the review, I examine the pairing of flavour stimuli with music/soundscapes, in the emerging field of 'sonic seasoning'. I suggest that the various perceptual pairing principles/outcomes identified when flavours are paired deliberately can also be meaningfully extended to provide a coherent framework when it comes to categorizing the ways in which what we hear can influence our flavour experiences, both in terms of the sensory-discriminative and hedonic response.

Utilization of text mining as a big data analysis tool for food science and nutrition

Big data analysis has found applications in many industries due to its ability to turn huge amounts of data into insights for informed business and operational decisions. Advanced data mining techniques have been applied in many sectors of supply chains in the food industry. However, the previous work has mainly focused on the analysis of instrument-generated data such as those from hyperspectral imaging, spectroscopy, and biometric receptors. The importance of digital text data in the food and nutrition has only recently gained attention due to advancements in big data analytics. The purpose of this review is to provide an overview of the data sources, computational methods, and applications of text data in the food industry. Text mining techniques such as word-level analysis (e.g., frequency analysis), word association analysis (e.g., network analysis), and advanced techniques (e.g., text classification, text clustering, topic modeling, information retrieval, and sentiment analysis) will be discussed. Applications of text data analysis will be illustrated with respect to food safety and food fraud surveillance, dietary pattern characterization, consumer-opinion mining, new-product development, food knowledge discovery, food supply-chain management, and online food services. The goal is to provide insights for intelligent decision-making to improve food production, food safety, and human nutrition.

On the Meaning(s) of Perceived Complexity in the Chemical Senses

Complexity is a term that is often invoked by those writing appreciatively about the taste, aroma/bouquet, and/or flavor of food and drink. Typically, the term is used as though everyone knows what is being talked about. Rarely is any explanation given, and the discussion soon moves on to other topics. However, oftentimes it is not at all clear what, exactly, is being referred to. A number of possibilities are outlined here, including physical complexity at the level of individual molecules, at the level of combinations of molecules giving rise to a specific flavor profile (e.g., as in a glass of quality wine or a cup of specialty coffee), at the level of combinations of distinct ingredients/elements (e.g., as when composing a particularly intricate dish in a high-end restaurant, say, or when pairing food with wine), and/or the number of stimuli/steps involved in the process of creation. Of course, people might also be referring to some aspect of their perceptual experience, and one of the intriguing questions in this space concerns the nature of the relationship(s) between these different ways of conceptualizing complexity in the chemical senses. However, given that physical/chemical and perceived complexity so often diverge, we argue that it is the latter notion, or rather inferred complexity, that is the most relevant when it comes to the chemical senses. Finally, we look at the role of expertise and review the evidence suggesting that inferred complexity can emerge either from a unitary taste experience that is judged to be complex, or from a tasting experience having multiple individuable elements.

Complexity on the Menu and in the Meal

Complexity is generally perceived to be a desirable attribute as far as the design/delivery of food and beverage experiences is concerned. However, that said, there are many different kinds of complexity, or at least people use the term when talking about quite different things, and not all of them are relevant to the design of food and drink experiences nor are they all necessarily perceptible within the tasting experience (either in the moment or over time). Consequently, the consumer often needs to infer the complexity of a tasting experience that is unlikely to be perceptible (in its entirety) in the moment. This paper outlines a number of different routes by which the chef, mixologist, and/or blender can both design and signal the complexity in the tasting experience.

Impact of type, size and shape of plates on hospital patients' perceptions of the quality of meals and satisfaction with foodservices

Hospital meals are important for supporting nutrition goals and the overall hospital experience. The aim of this study was to assess if patients' perceptions of quality attributes of hot meals were impacted by the type of plate on which the meal was served. Eligible patients selected from medical and/or surgical wards at a 929 bed acute care hospital were randomised to receive hot meals served on either ceramic or disposable plates at eight evening meals. Patients from a multi-centre trial of pre-packaged meals where re-thermalised meals were presented on a variety of colour and shaped disposable plates were included in a second phase. Patient assessment of meal quality was undertaken using the Meal Assessment Tool (MAT)(Hannan-Jones & Capra, 2017) with data collected by interview. In phase one, 137 eligible patients competed the MAT (response 46.8%), with results showing no significant difference in the rating of appearance, quality, expectations or satisfaction when meals were served on disposable or ceramic plates. In phase two data were collected from 6189 patients (response 47.4%). No practical difference in rating of meals was found in relation to colour and sectioning of plates, however a statistical but non-practical difference was found regarding plate shape, with meals served on oblong/rectangular plates rated more positively. Of 3078 comments made concerning the meals, 99 (3.2%) concerned the plates on which the meals were served. This study has shown that quality, appearance and taste of meals, rather than the serving ware are important to patients. Findings suggest that attending to other quality aspects of meals may be far more important than the plate itself, and deserve attention.