Olfactory EEG induced by odor: Used for food identification and pleasure analysis

As the need for food authenticity verification increases, sensory evaluation of food odors has become widely recognized. This study presents a theory based on electroencephalography (EEG) to create an Olfactory Perception Dimensional Space (EEG-OPDS), using feature engineering and ensemble learning to establish material and emotional spaces based on odor perception and pleasure. The study examines the intrinsic connection between these two spaces and explores the mechanisms of integration and differentiation in constructing the OPDS. This method effectively visualizes various types of food odors while identifying their perceptual intensity and pleasantness. The average classification accuracy for odor recognition in an eight-category experiment is 96.1%. Conversely, the average classification accuracy for sensory pleasantness recognition in a two-category experiment is 98.8%. The theoretical approach proposed in this study, based on olfactory EEG signals to construct an OPDS, captures the subtle perceptual differences and individualized pleasantness responses to food odors.

Machine learning based classification of yogurt aroma types with flavoromics

Traditional sensory evaluation, relying on human assessors, is vulnerable to subjective error and lacks automation. Nonetheless, the complexity of human sensation makes it challenging to develop a computational method in place of human sensory evaluation. To tackle this challenge, this study constructed logistic regression classification models that could predict yogurt aroma types based on aroma-active compound concentrations with high classification accuracy (AUC ROC > 0.8). Furthermore, indicator compounds discovered from feature importance analysis of classification models led to the derivation of classification criteria of yogurt aroma types. Through constructing and analyzing machine learning models on yogurt aroma types, this study provides an automated pipeline to monitor sensory properties of yogurts.

Perspectives on the yogurt rheology

The oral processing of yogurt is a dynamic process involving a series of deformation processes. Rheological knowledge is essential to understand the structure and flow properties of yogurt in the mouth and to explore its relationship with sensory perception. Yogurt is rheologically characterized as a non-Newtonian viscoelastic material. The rheological properties of yogurt are affected by many factors, from production to consumption. Therefore, rheological measurements are widely used to predict and control the final quality and structure of yogurts. Recent studies focus on the elucidation of the effects of cultures and processes used in production, as well as the design of different formulations to improve the rheological properties of yogurts. Moreover, the science of tribology, which dominates the surface properties of interacting substances in relative motion to evaluate the structural sensation in the later stages of eating in addition to the rheological properties that give the feeling of structure in the early stages of eating, has also become the focus of recent studies. For a detailed comprehension of the rheological properties of yogurt, this review deals with the factors affecting the rheology of yogurt, analytical methods used to determine rheological properties, microstructural and rheological characterization of yogurt, and tribological evaluations.

Influence of Chewing Rate and Food Composition on in Vivo Aroma Release and Perception of Composite Foods

This study investigated the effects of chewing rate and food composition on in vivo aroma release and perception of composite foods. Bread or sponge cake paired with varying sugar content and viscosity strawberry jams, spiked with citral and limonene, were examined. In-nose release was characterized using Proton-Transfer-Reaction-Time-of-Flight-Mass-Spectrometry (PTR-ToF-MS). Simultaneously, Time-Intensity (TI) profiling assessed citrus aroma perception (n = 8, triplicate) while fast and slow chewing protocols were applied (fast: 1.33 chews/s; slow 0.66 chews/s; each for 25 s). Chewing rate did not significantly impact the area under the curve and maximum intensity of in vivo citral and limonene release and citrus aroma perception. Faster chewing rates significantly decreased the time to reach maximum intensity of aroma release (p < 0.05) and citrus aroma perception (p < 0.001). Faster chewing rates probably accelerated structural breakdown, inducing an earlier aroma release and perception without affecting aroma intensity. Adding carriers to jams significantly (p < 0.05) increased aroma release, while perceived citrus aroma intensity significantly (p < 0.05) decreased regardless of chewing rate. In conclusion, chewing rate affects the temporality of in vivo aroma release and perception without affecting its intensity, and carrier addition increases in vivo aroma release while diminishing aroma perception.

Assessment of Technological and Sensory Properties, Digestibility, and Bioactive Compounds in Polentas from Different Maize Genotypes

The sensory profile of polenta and the connections between technological attributes and varieties of maize have not been extensively studied. Thus, it is necessary to understand the possible effect of its consumption on consumers' health in terms of postprandial glucose levels and molecules associated with healthy activities. This work aims to study polenta's technological and sensory properties from different maize genotypes and evaluate their digestibility and the potential contribution of bioactive compounds on health. A commercial hybrid, two open-pollinated varieties, and three inbred lines were used. Grain physical determinations and physical-chemical semolina traits were determined. Polenta's technological quality was evaluated after simulated cooking. In vitro digestion was performed for polentas, and a sensory evaluation test was conducted. A significant correlation was found between semolina polyphenols and rapidly digestible starch (r = -0.6). Panellists characterised the genotype C6006 as having a good flavour, sandier mouthfeel, and low consistency. Also, the polenta from the hybrid exhibited sensory attributes more closely resembling commercial polenta in terms of maize odour, flavour, and consistency. The higher content of polyphenols presents in semolina affected the digestion of polenta, showing a lower proportion of rapidly digestible starch and a lower amount of bioaccessible protein fraction.

Effect of coagulation temperature on cooking integrity of heat and acid-induced milk gels

Heat and acid-induced milk gels do not melt or flow upon heating and thus show great potential as a dairy-based protein source for cooking, e.g. for stews. Understanding how processing, e.g. acidification, affects the cooking behavior of these gels is therefore of great industrial interest. The cooking integrity of gels produced by rapidly acidifying milk using citric acid at temperatures of 60, 75, and 90 °C, was determined by analyzing composition, texture, and spatial water distribution before and after cooking. Increasing the acidification temperature from 60 to75 °C resulted in a significant reduction of yield, due to decreased moisture content of the gels. With increasing content of solids, the gels grew harder and denser, as observed by texture profile analysis and low-field Nuclear Magnetic Resonance. Upon cooking the 60 °C gel lost a significant amount of moisture, due to the contraction of the porous protein network. The more compact gels, prepared at 75 and 90 °C, did not lose mass indicating good cooking integrity, i.e. a gel that keeps its structure during cooking. Acidification temperature thus greatly influenced cooking integrity. The effect was mainly ascribed to the density of the gel texture, a result of the speed of protein aggregation and calcium recovery.

In vivo aroma release and perception of composite foods using nose space PTR–ToF–MS analysis with Temporal-Check-All-That-Apply

In vivo aroma release and perception of complex food matrices have been underexplored. The aims of this study were to investigate the effects of (i) fat and sugar content of chocolate-hazelnut spreads on in vivo aroma release and perception and (ii) carrier addition (bread, wafer) on in vivo aroma release and perception of chocolate-hazelnut spread using dynamic nose space analysis (PTR-ToF-MS) and dynamic sensory analysis (TCATA). Carriers were combined with spreads varying in fat and sugar content and were spiked with five volatile organic compounds (benzaldehyde, filbertone, 2-methylpyrazine, delta-dodecalactone, isovaleraldehyde). TCATA profiles from a consumer panel without in vivo nose space analysis (n = 72) and a trained panel performing in vivo nose space analysis (n = 8, triplicate) were compared. TCATA profiles of the spread-carrier combinations obtained by both panels showed similarly that attributes related to the carriers were perceived at the beginning of consumption, whereas attributes related to the spreads were perceived after swallowing. Significant (p < 0.05) and small differences were observed for the attributes cocoa, creamy, milky, sticky and toffee between both panels. In the evaluated reformulation range, fat and sugar content of chocolate-hazelnut spreads had only a limited effect on in vivo aroma release and perception. In contrast, addition of carriers strongly affected in vivo aroma release and perception for all target molecules. The addition of carriers to spreads generally increased aroma release (duration and intensity of aroma release) and decreased aroma perception. The addition of carriers generally reduced the time to reach maximum intensity compared to when spreads were eaten alone for the five volatile organic compounds while perception decreased. We conclude that the strong effect of carrier addition on in vivo aroma release and perception of chocolate-hazelnut spreads highlights the importance of investigating toppings/spreads accompanied with carriers rather than in isolation.

Recent Trends of Microfluidics in Food Science and Technology: Fabrications and Applications

The development of novel materials with microstructures is now a trend in food science and technology. These microscale materials may be applied across all steps in food manufacturing, from raw materials to the final food products, as well as in the packaging, transport, and storage processes. Microfluidics is an advanced technology for controlling fluids in a microscale channel (1~100 μm), which integrates engineering, physics, chemistry, nanotechnology, etc. This technology allows unit operations to occur in devices that are closer in size to the expected structural elements. Therefore, microfluidics is considered a promising technology to develop micro/nanostructures for delivery purposes to improve the quality and safety of foods. This review concentrates on the recent developments of microfluidic systems and their novel applications in food science and technology, including microfibers/films via microfluidic spinning technology for food packaging, droplet microfluidics for food micro-/nanoemulsifications and encapsulations, etc.

Modernising Orodispersible Film Characterisation to Improve Palatability and Acceptability Using a Toolbox of Techniques

Orodispersible films (ODFs) have been widely used in paediatric, geriatric and dysphagic patients due to ease of administration and precise and flexible dose adjustments. ODF fabrication has seen significant advancements with the move towards more technologically advanced production methods. The acceptability of ODFs is dependent upon film composition and process of formation, which affects disintegration, taste, texture and mouthfeel. There is currently a lack of testing to accurately assess ODFs for these important acceptability sensory perceptions. This study produced four ODFs formed of polyvinyl alcohol and sodium carboxymethylcellulose using 3D printing. These were assessed using three in vitro methods: Petri dish and oral cavity model (OCM) methods for disintegration and bio-tribology for disintegration and oral perception. Increasing polymer molecular weight (MW) exponentially increased disintegration time in the Petri dish and OCM methods. Higher MW films adhered to the OCM upper palate. Bio-tribology analysis showed that films of higher MW disintegrated quickest and had lower coefficient of friction, perhaps demonstrating good oral perception but also stickiness, with higher viscosity. These techniques, part of a toolbox, may enable formulators to design, test and reformulate ODFs that both disintegrate rapidly and may be better perceived when consumed, improving overall treatment acceptability.

Nano Filling Effect of Nonmeat Protein Emulsion on the Rheological Property of Myofibrillar Protein Gel

Incorporation of vegetable oils through pre-emulsification has received notable attention for delivering polyunsaturated fatty acids to emulsified-type meat products. The two important influencing factors of the rheological property of composite myofibrillar protein (MP) gel are emulsion droplet size and active or inactive interaction between interface and meat proteins. Incorporation of nonmeat protein emulsion (2% protein (w/w), egg-white protein isolate (EPI), porcine plasma protein (PPP), or sodium caseinate (SC)) with different droplet sizes (nano or macro) to a model of 2% MP gel was investigated in this research. The results of drop size measurement showed that 15,000 psi homogenizing could decrease the diameter of emulsion drop from macro- to nanoscale in the range of 324.4−734.5 nm. Active fillers (PPP and EPI emulsions) with nanodroplet size did not influence the viscosity of emulsion-filled composite cold sols but caused positive filling effects on the MP gel matrix after heating, as evidenced by the density microstructure. PPP and EPI nano-emulsion-filled composite MP had a significant high storage modulus enforcement effect, which reached nearly eight times those of other treatments (p < 0.05). Similarly, the results of thermal scanning rheology and a large-deformation mechanical test showed that PPP and EPI emulsions with nanoscale droplets, other than macroscale, had the highest gel strength of heat-induced emulsion-filled composite MP gel (p < 0.05). Overall, these findings will be helpful for selecting the correct pre-emulsified protein and designing the textural properties of foods.

A new fractal structural-mechanical theory of particle-filled colloidal networks with heterogeneous stress translation

This work addresses the role of rigid inclusions in determining the elastic modulus of particle-filled colloidal networks by modifying an established fractal scaling model. The approach acknowledges the heterogeneous nature of stress distribution at length scales beyond the colloidal aggregates, while maintaining structural information at the level of individual clusters. This was achieved by introducing a scaling factor to account for system heterogeneity which contains intrinsic information about the network's capacity to form load-bearing links. Rigid fillers bound to the network induce stress concentration, but additionally serve as junction zones which introduce additional load-bearing pathways. This gives rise to the observed increase in the modulus with filler volume fraction. The proposed relationship between the load-bearing network connectivity and scaling behavior may have additional implications on the fractal dimension determined by rheological methods. Further, this model accommodates an experimentally observed correlation between the scaling behavior of the modulus associated with the addition of fillers and that arising from increasing structurant concentration. The modified fractal model thus provides an alternative view of how fillers contribute to the small- and large-deformation mechanical behavior of filled colloidal gels in a manner consistent with experimental observations.

Fundamentals of composites containing fibrous materials and hydrogels: A review on design and development for food applications

The combination of fiber and hydrogel in a system can provide substantial benefits for both components, including the development of three-dimensional structures for the fiber, followed by modifications in the rheological and mechanical properties of the hydrogel. Despite a large increase in the use of fiber-hydrogel composites (FHCs) in various sciences and industries such as biomedicine, tissue engineering, cosmetics, automotive, textile, and agriculture, there is limited information about FHCs in the realm of food application. In this regard, this study reviews the mechanism of FHCs. The force transmission between fiber and hydrogel, which depends on the interactions between them during loading, is the main reason to enhance the mechanical properties of FHCs. Moreover, articles about such FHCs that have the potential for foods or food industries have been described. Additionally, the information gaps about edible FHCs were highlighted for further research. Finally, the methods of fiber formation have been summarized.

Water-in-Oleogel Emulsions—From Structure Design to Functionality

The development of water-in-oleogel (W/Og) emulsions is highlighted, with focus placed on the key properties dictating the structuring ability of both the continuous oleogelled and dispersed phases present. The gelling ability of oleogelators is distinguished by the formation of crystalline structures, polymeric strands, or tubules. Once a dispersed aqueous phase is introduced, droplet stabilization may occur via oleogelator adsorption onto the surface of the dispersed droplets, the formation of a continuous gel network, or a combination of both. Surface-active species (added or endogenous) are also required for effective W/Og aqueous phase dispersion and stabilization. Processing conditions, namely temperature-time-shear regimes, are also discussed given their important role on dispersed droplet and oleogel network formation. The effects of many factors on W/Og emulsion formation, rheology, and stability remain virtually unknown, particularly the role of dispersed droplet size, gelation, and clustering as well as the applicability of the active filler concept to foods. This review explores some of these factors and briefly mentions possible applications of W/Og emulsions.

Measurement of molten chocolate friction under simulated tongue-palate kinematics: Effect of cocoa solids content and aeration

The perception of some food attributes is related to mechanical stimulation and friction experienced in the tongue-palate contact during mastication. This paper reports a new bench test to measure friction in the simulated tongue-palate contact. The test consists of a flat PDMS disk, representing the tongue loaded and reciprocating against a stationary lower glass surface representing the palate. The test was applied to molten chocolate samples with and without artificial saliva. Friction was measured over the first few rubbing cycles, simulating mechanical degradation of chocolate in the tongue-palate region. The effects of chocolate composition (cocoa solids content ranging between 28 ​wt% and 85 ​wt%) and structure (micro-aeration/non-aeration 0–15 ​vol%) were studied. The bench test clearly differentiates between the various chocolate samples. The coefficient of friction increases with cocoa solids percentage and decreases with increasing micro-aeration level. The presence of artificial saliva in the contact reduced the friction for all chocolate samples, however the relative ranking remained the same.

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Development of a reciprocating sliding friction test to mimic tongue-palate motion.

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Variations in friction coefficient depending on chocolate composition and structure.

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Higher cocoa content samples had higher friction coefficient.

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Friction coefficient decreased with aeration (0–15% vol).

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The presence of an artificial saliva film reduced chocolate friction.

WITHDRAWN: Reinforcing the rheological and mechanical properties of WPI nanocomposite hydrogels with birefringence morphologies

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New insights into food hydrogels with reinforced mechanical properties: A review on innovative strategies

Enhancement on the mechanical properties of hydrogels leads to a wider range of their applications in various fields. Therefore, there has been a great interest recently for developing new strategies to reinforce hydrogels. Moreover, food gels must be edible in terms of both raw materials and production. This paper reviews innovative techniques such as particle/fiber-reinforced hydrogel, double network, dual crosslinking, freeze-thaw cycles, physical conditioning and soaking methods to improve the mechanical properties of hydrogels. Additionally, their fundamental mechanisms, advantages and disadvantages have been discussed. Important biopolymers that have been employed for these strategies and also their potentials in food applications have been summarized. The general mechanism of these strategies is based on increasing the degree of crosslinking between interacting polymers in hydrogels. These links can be formed by adding fillers (oil droplets or fibers in filled gels) or cross-linkers (regarding double network and soaking method) and also by condensation or alignment of the biopolymers (freeze-thaw cycle and physical conditioning) in the gel network. The properties of particle/fiber-reinforced hydrogels extremely depend on the filler, gel matrix and the interaction between them. In freeze-thaw cycles and physical conditioning methods, it is possible to form new links in the gel network without adding any cross-linkers or fillers. It is expected that the utilization of gels will get broader and more varied in food industries by using these strategies.

Future foods: a manifesto for research priorities in structural design of foods

A number of major challenges facing modern society are related to the food supply. As the global population grows, it will be critical to feed everyone without damaging the environment. Advances in biotechnology, nanotechnology, structural design, and artificial intelligence are providing farmers and food manufacturers will new tools to address these problems. More and more people are migrating from rural to urban environments, leading to a change in their dietary habits, especially increasing consumption of animal-based products and highly-processed foods. Animal-based foods lead to more greenhouse gas production, land use, water use, and pollution than plant-based ones. Moreover, many animal-based and highly-processed foods have adverse effects on human health and wellbeing. Consumers are therefore being encouraged to consume more plant-based foods, such as fruits, vegetables, cereals, and legumes. Many people, however, do not have the time, money, or inclination to prepare foods from fresh produce. Consequently, there is a need for the food industry to create a new generation of processed foods that are desirable, tasty, inexpensive, and convenient, but that are also healthy and sustainable. This article highlights some of the main food-related challenges faced by modern society and how scientists are developing innovative technologies to address them.

Dynamic Oral Texture Properties of Selected Indigenous Complementary Porridges Used in African Communities

Child malnutrition remains a major public health problem in low-income African communities, caused by factors including the low nutritional value of indigenous/local complementary porridges (CP) fed to infants and young children. Most African children subsist on locally available starchy foods, whose oral texture is not well-characterized in relation to their sensorimotor readiness. The sensory quality of CP affects oral processing (OP) abilities in infants and young children. Unsuitable oral texture limits nutrient intake, leading to protein-energy malnutrition. The perception of the oral texture of selected African CPs (n = 13, Maize, Sorghum, Cassava, Orange-fleshed sweet potato (OFSP), Cowpea, and Bambara) was investigated by a trained temporal-check-all-that-apply (TCATA) panel (n = 10), alongside selected commercial porridges (n = 19). A simulated OP method (Up-Down mouth movements- munching) and a control method (lateral mouth movements- normal adult-like chewing) were used. TCATA results showed that Maize, Cassava, and Sorghum porridges were initially too thick, sticky, slimy, and pasty, and also at the end not easy to swallow even at low solids content—especially by the Up-Down method. These attributes make CPs difficult to ingest for infants given their limited OP abilities, thus, leading to limited nutrient intake, and this can contribute to malnutrition. Methods to improve the texture properties of indigenous CPs are needed to optimize infant nutrient intake.

Relating Food Engineering to Cooking and Gastronomy

Modern consumers are increasingly eating meals away from home and are concerned about food quality, taste, and health aspects. Food engineering (FE) has traditionally been associated with the industrial processing of foods; however, most underlying phenomena related to FE also take place in the kitchen during meal preparation. Although chemists have positively interacted with acclaimed chefs and physicists have used foods as materials to demonstrate some of their theories, this has not been always the case with food engineers. This review addresses areas that may broaden the vision of FE by interfacing with cooking and gastronomy. Examples are presented where food materials science may shed light on otherwise empirical gastronomic formulations and cooking techniques. A review of contributions in modeling of food processing reveals that they can also be adapted to events going on in pots and ovens, and that results can be made available in simple terms to cooks. Industrial technologies, traditional and emerging, may be adapted to expand the collection of culinary transformations, while novel equipment, digital technologies, and laboratory instruments are equipping the 21st-century kitchens. FE should become a part of food innovation and entrepreneurship now being led by chefs. Finally, it is suggested that food engineers become integrated into gastronomy's concerns about safety, sustainability, nutrition, and a better food use.

Impact of different sequences of mechanical and thermal processing on the rheological properties ofPorphyridium cruentumandChlorella vulgarisas functional food ingredients

Different processing sequences result in specific rheological properties of these microalgae as functional food ingredients.

Structuring and calorie control of bakery products by templating batter with ultra melt-resistant food-grade hydrogel beads

We report the use of a temperature insensitive, food-grade hydrogel to reduce the caloric density of pancakes that were prepared at temperatures much higher than the boiling point of water. This cheap, facile method utilises a mixed agar-methylcellulose hydrogel, which was blended to produce a slurry of hydrogel microbeads. The pancake batter was mixed with a controlled volume percentage of slurry of hydrogel beads and cooked. From bomb calorimetry experiments, the composites were found to have a reduced caloric density that reflects the volume percentage of hydrogel beads mixed with the batter. Using this procedure, we were able to reduce the caloric density of pancakes by up to 23 ± 3% when the volume percentage of hydrogel beads initially used was 25%. The method is not limited to pancakes and could potentially be applied to various other food products. The structure and morphology of the freeze-dried pancakes and pancake-hydrogel composites were investigated and pores of a similar size to the hydrogel beads were found, confirming that the gel beads maintained their structure during the cooking process. There is scope for further development of this method by the encapsulation of nutritionally beneficial or flavour enhancing ingredients within the hydrogel beads.