PO2/TransformON, an ontology for data integration on food, feed, bioproducts and biowaste engineering.

We are witnessing an acceleration of the global drive to converge consumption and production patterns towards a more circular and sustainable approach to the food system. To address the challenge of reconnecting agriculture, environment, food and health, collections of large datasets must be exploited. However, building high-capacity data-sharing networks means unlocking the information silos that are caused by a multiplicity of local data dictionaries. To solve the data harmonization problem, we proposed an ontology on food, feed, bioproducts, and biowastes engineering for data integration in a circular bioeconomy and nexus-oriented approach. This ontology is based on a core model representing a generic process, the Process and Observation Ontology (PO2), which has been specialized to provide the vocabulary necessary to describe any biomass transformation process and to characterize the food, bioproducts, and wastes derived from these processes. Much of this vocabulary comes from transforming authoritative references such as the European food classification system (FoodEx2), the European Waste Catalogue, and other international nomenclatures into a semantic, world wide web consortium (W3C) format that provides system interoperability and software-driven intelligence. We showed the relevance of this new domain ontology PO2/TransformON through several concrete use cases in the fields of process engineering, bio-based composite making, food ecodesign, and relations with consumer's perception and preferences. Further works will aim to align with other ontologies to create an ontology network for bridging the gap between upstream and downstream processes in the food system.

Origins of volatile compounds and identification of odour-active compounds in air-classified fractions of faba bean (Vicia faba L. minor).

Faba bean (Vicia faba L. minor) has many interests but is characterised by off-notes (negative odours/aromas) due to volatile compounds that are promoted during seed processing. Little is known about the volatile compounds of faba bean and their contribution to its odour. The purpose of this study was to determine the volatile compound origins of air-classified fractions (flour (F), starch (S) and protein (P)) from 3 faba bean cultivars and identify the odour-active compounds. Firstly, the volatile content of the fractions was extracted by solvent-assisted flavour evaporation (SAFE) and analysed by gas chromatography-mass spectrometry (GC-MS). A total of 147 volatile compounds were detected and categorised into 12 chemical classes. The P fractions had many volatile compounds from free fatty acid (FFA) oxidation and a higher lipoxygenase (LOX) activity. The volatile content suggested that cultivar 1 (C1) was confronted with a biotic stress at field whereas cultivar 2 (C2), richer in molecules from amino acid (AA) degradation, was contaminated by microorganisms in the field. Secondly, 35 odour-active compounds (OACs) were identified by GC-olfactometry (GC-O) and 12 odour-classes were used to describe the faba bean odours. The P fractions had higher detection frequency (DF) than the S and F fractions. P2 had a more complex odour profile due to important FFA and AA degradation. This work provides a better understanding of the impact of cultivar and processing steps on the faba bean volatile content. Selection of pulse-based ingredients with low volatile compounds could improve their flavour and increase their consumption.

Construction of a Generic and Evolutive Wheel and Lexicon of Food Textures.

In the context of data management and processing, food science needs tools to organize the results of diverse studies to make the data reusable. In sensory analysis, there are no classification or wheel of textural attributes that can be used to interpret the results of sensory studies. Research from the literature and databases was used to elaborate a list of attributes related to texture. With the help of a group of experts in food texture, work on these attributes and the related concepts was conducted to classify them into several categories, including intensity levels. The classification was represented as a texture wheel, completed by a generic lexicon of definitions of texture concepts. The work can be useful as a reference in texture attributes related to foods, and thanks to implementation in a general ontology based on food processing and observation, it can help query and interpret texture-related results from sensory studies.

Special Issue "Selected Papers from the 16th Weurman Flavour Research Symposium".

Since 1975, the Weurman Flavour Research Symposium has been held every three years in different European countries, and has been finally established as an international event that offers unique opportunities for distinguished scientists from academia and industry, from different disciplines, and from all over the world, to discuss trends and new paradigms in the field of flavour research [...].

Volatile Compounds in Pulses: A Review.

The worldwide demand for pulse-based products is increasing in the face of climate change, but their acceptability is limited due to the presence of off-flavours. Off-notes contribute to negative perceptions of pulses (beany notes). Volatile compounds belong to a large variety of chemical classes. They are mainly produced from the oxidation of unsaturated free fatty acids and the degradation of amino acids during seed development, storage, and transformation (dehulling, milling, and starch or protein production). This review aims to provide an overview highlighting the identification of these molecules in different pulses, their potential origins, and their impact on perceptions. However, data on odour-active compounds in pulses are sparse, as they are limited to those of two studies on peas and lupins. A better knowledge of the volatile compounds involved in the off-notes and their origins should allow for drawing efficient strategies to limit their impact on overall perception for more acceptable healthy food design.

Compilation of data on model cheeses composition, rheological and sensory properties, from six research projects exported from the BaGaTel database.

This paper presents data on model cheeses extracted from the BaGaTel database. The data are issued from 6 different research projects in which data on composition, rheological and sensory properties were collected. The manufacturing of the 68 different samples is described. For each model cheese, data are available on final composition (lipid, protein, water, sodium), rheological properties (uniaxial compression), sensory profile analysis (texture, taste, aroma) and for some cheeses chewing activity and in vivo sodium release were also measured. The material and methods used are detailed. Scatter plots of representation of the values for each variable and each project are plotted. Pearson correlations between variables are given for specific subsets of data. The dataset is hosted in an open access data repository. This dataset will allow a comparison of sensory properties of cheeses varying in lipid, protein water and salt content and can be used for the reformulation of cheeses made with a low salt and fat content to follow food-related health recommendations, whilst fulfilling good sensory qualities.

Exploring the Characteristics of an Aroma-Blending Mixture by Investigating the Network of Shared Odors and the Molecular Features of Their Related Odorants.

The perception of aroma mixtures is based on interactions beginning at the peripheral olfactory system, but the process remains poorly understood. The perception of a mixture of ethyl isobutyrate (Et-iB, strawberry-like odor) and ethyl maltol (Et-M, caramel-like odor) was investigated previously in both human and animal studies. In those studies, the binary mixture of Et-iB and Et-M was found to be configurally processed. In humans, the mixture was judged as more typical of a pineapple odor, similar to allyl hexanoate (Al-H, pineapple-like odor), than the odors of the individual components. To explore the key features of this aroma blend, we developed an in silico approach based on molecules having at least one of the odors-strawberry, caramel or pineapple. A dataset of 293 molecules and their related odors was built. We applied the notion of a "social network" to describe the network of the odors. Additionally, we explored the structural properties of the molecules in this dataset. The network of the odors revealed peculiar links between odors, while the structural study emphasized key characteristics of the molecules. The association between "strawberry" and "caramel" notes, as well as the structural diversity of the "strawberry" molecules, were notable. Such elements would be key to identifying potential odors/odorants to form aroma blends.

Multivariate Statistical Analysis and Odor-Taste Network To Reveal Odor-Taste Associations.

Odor-taste association has been successfully applied to enhance taste perception in foods with low sugar or low salt content. Nevertheless, selecting odor descriptors with a given associated taste remains a challenge. In the aim to look for odors able to enhance some specific taste, we tested different multivariate analyses to find links between taste descriptors and odor descriptors, starting from a set of data previously obtained using gas chromatography/olfactometry-associated taste: 68 odorant zones described with 41 odor descriptors and 4 taste-associated descriptors (sweetness, saltiness, bitterness, and sourness). A partial least square analysis allowed for identification of odors associated with a specific taste. For instance, odors described as either fruity, sweet, strawberry, candy, floral, or orange are associated with sweetness, while odors described as either toasted, potato, sulfur, or mushroom are associated with saltiness. A network representation allowed for visualization of the links between odor and taste descriptors. As an example, a positive association was found between butter odor and both saltiness and sweetness. Our approach provided a visualization tool of the links between odor and taste description and could be used to select odor-active molecules with a potential taste enhancement effect based on their odor descriptors.

Taste Perception of Nutrients Found in Nutritional Supplements: A Review.

Nutritional supplements are prescribed when one's nutritional status is not conducive to good health. These foodstuffs constitute concentrated sources of nutrients such as vitamins, minerals, amino acids, and fatty acids. For nutritional supplements to be effective, patients must consume the amount that has been prescribed for the recommended period of time. Therefore, special attention must be given to the sensory attributes of these products. Indeed, the presence of active compounds can cause an off-taste or aftertaste. These negative sensations can lead to a reduction in the consumption of nutritional supplements and reduce the effectiveness of the treatment. In this manuscript, we provide an overview of the sensory characteristics and the sensing receptor mechanism of the main compounds present in oral nutritional supplements, such as amino acids, minerals, fatty acids, and vitamins. Part of this article is devoted to the development of new masking strategies and the corresponding potential influence at the industrial level.

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

Salt reduction in foods is becoming an important challenge to protect population health from severe diseases as recommended by different health agencies worldwide. Among the reduction strategies already evaluated in order to lower sodium salt content in foods, the use of cross-modal interactions between taste and odour, regardless of saltiness, was revealed to be a very promising method to improve saltiness perception. Cross-modal odour-taste interactions, as means to enhance salty taste in foods, is reviewed. Salt-related odours can enhance salty taste in water solutions containing a low level of sodium chloride through odour-induced changes in taste perception. Odour-induced saltiness perception enhancement (OISE) depends on salt concentration (intensity). OISE was also found to be effective in low salt content solid model cheese but was texture- and composition-dependent. A significant enhancement in saltiness perception induced by Comté cheese and sardine odours was observed only in model foods with soft textures. In ternary odour-sour-salty solutions, sourness additively enhanced saltiness perception with salt-related odours. Finally, in cream-based food systems, a strategy combining OISE and heterogeneous distribution of stimuli was found to compensate for a greater than 35% decrease in salt content without significant loss of acceptability. However, variation in the composition of the food matrix influenced aroma and salt release and consequently the overall saltiness perception. A better knowledge of the mechanisms involved in cross-modal perceptual interactions at the central level should allow for the optimization of their use as salt reduction strategies for healthier food design.

Publisher Correction: Ex vivo real-time monitoring of volatile metabolites resulting from nasal odorant metabolism.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

Assessment Wine Aroma Persistence by Using an in Vivo PTR-ToF-MS Approach and Its Relationship with Salivary Parameters.

To better understand wine aroma persistence, the nasal cavity of nine volunteers was monitored by Proton Transfer Reaction-Time of Flight-Mass Spectrometry (PTR-ToF-MS) after they rinsed their mouths with three rosé wines (one control and the same wine supplemented with two tannin extracts) during four minutes. Wines were aromatised with a mixture of five target aroma compounds. Results showed that wine aroma persistence was highly compound-dependent: while esters disappeared very fast, other compounds such as linalool remained in the oral cavity for longer times after wine expectoration. A low effect of tannins (at 50 mg/L) on nasal cavity parameters was observed, with the exception for the compound ethyl decanoate that was significantly higher released in the presence of tannins. Strong interindividual differences on aroma persistence were also found. Significant positive correlations with the salivary total protein content and negative with the salivary flow were observed for specific compounds. This work has studied for the first time in vivo wine aroma persistence in real time from an analytical perspective.

Ex vivo real-time monitoring of volatile metabolites resulting from nasal odorant metabolism.

Odorant-metabolizing enzymes are critically involved in the clearance of odorant molecules from the environment of the nasal neuro-olfactory tissue to maintain the sensitivity of olfactory detection. Odorant metabolism may also generate metabolites in situ, the characterization and function of which in olfaction remain largely unknown. Here, we engineered and validated an ex vivo method to measure odorant metabolism in real-time. Glassware containing an explant of rat olfactory mucosa was continuously flushed with an odorant flow and was coupled to a proton transfer reaction-mass spectrometer for volatile compound analysis. Focusing on carboxylic esters and diketone odorants, we recorded the metabolic uptake of odorants by the mucosa, concomitantly with the release of volatile odorant metabolites in the headspace. These results significantly change the picture of real-time in situ odorant metabolism and represent a new step forward in the investigation of the function of odorant metabolites in the peripheral olfactory process. Our method allows the systematic identification of odorant metabolites using a validated animal model and permits the screening of olfactory endogenously produced chemosensory molecules.

Saliva and Flavor Perception: Perspectives.

This paper reports the main trends and perspectives related to the current understanding of the relationships between saliva and flavor perception. Saliva is a key factor in flavor perception and controls the transport of flavor molecules to their receptors, their adsorption onto the mouth surfaces (i.e., oral mucosa), their metabolism by enzymatic modification, and the friction force in the oral cavity. The proteins in free saliva or in the mucosal pellicle contribute to flavor perception by interacting with or metabolizing flavor compounds. Most of these reactions were observed when using fresh whole saliva; however, they were absent or less frequently observed when using artificial saliva or depleted/frozen whole saliva. There is a need to better understand the role of protein aggregates in flavor perception. Within humans, there is great interindividual variation in salivary composition, which has been related to differences in flavor perception. However, the relative role of salivary proteins and the microbiota should be deeply investigated together with the impact of their composition on individual perception during life. Finally, future results must also consider cross-modal interactions at the brain level.

Understanding fat, proteins and saliva impact on aroma release from flavoured ice creams.

The release profile of fourteen aroma compounds was studied in ice cream samples varying in fat and protein, both in level and type. In vitro aroma release was monitored by solid phase micro-extraction gas chromatography using an innovative saliva reactor, which imitated human chewing under temperature control. The results showed that the effect of the fat type on aroma release was smaller than that of fat level. Ice creams with low fat level released more hydrophobic aroma compounds than ice creams with high fat level. At low fat level more aroma compounds were released from ice creams with lower protein content. At high fat level a small increase of aroma release was observed by the addition of saliva, which was explained by a salting out effect, due to the presence of proteins and salts in the saliva. These findings confirmed that the interactions between salivary proteins and aroma compounds occurring in aqueous solutions are not observed in emulsions.

Selecting odorant compounds to enhance sweet flavor perception by gas chromatography/olfactometry-associated taste (GC/O-AT).

Gas chromatography/olfactometry-associated taste (GC/O-AT) analysis combined with mass spectrometry allowed identification of odorant compounds associated with taste attributes (sweet, salty, bitter and sour) in a multi-fruit juice. Nine compounds were selected for their odor-associated sweetness enhancement in a multi-fruit juice odor context using Olfactoscan and for their odor-induced sweet taste enhancement in sucrose solution and sugar-reduced fruit juice through sensory tests. Sweetness of the fruit juice odor was significantly enhanced by methyl 2-methylbutanoate, ethyl butanoate, ethyl 2-methylbutanoate and linalool; sweet perception was significantly enhanced in 7% sucrose solution by ethyl 2-methylbutanoate, furaneol and γ-decalactone, and in 32% sugar-reduced fruit juice by ethyl 2-methylbutanoate. GC/O-AT analysis is a novel, efficient approach to select odorants associated with a given taste. The further screening of taste-associated odorants by Olfactoscan helps to identify the most efficient odorants to enhance a target taste perception and may be used to find new ways to modulate taste perception in foods and beverages.

Impact of fruit texture on the release and perception of aroma compounds during in vivo consumption using fresh and processed mango fruits.

Two fresh (fresh cubic pieces, fresh puree) and two dried (dried cubic pieces, dried powder) products were prepared from a homogenous mango fruit batch to obtain four samples differing in texture. The aromatic profiles were determined by SAFE extraction technique and GC-MS analysis. VOCs released during consumption were trapped by a retronasal aroma-trapping device (RATD) and analysed by GC-MS. Twenty-one terpenes and one ester were identified from the exhaled nose-space. They were amongst the major mango volatile compounds, 10 of which were already reported as being potential key flavour compounds in mango. The in vivo release of aroma compounds was affected by the matrix texture. The intact samples (fresh and dried cubic pieces) released significantly more aroma compounds than disintegrated samples (fresh puree, dried powder). The sensory descriptive analysis findings were in close agreement with the in vivo aroma release data regarding fresh products, in contrast to the dried products.

Modified proton transfer reaction mass spectrometry (PTR-MS) operating conditions for in vitro and in vivo analysis of wine aroma.

With proton transfer reaction-mass spectrometry standard operating conditions, analysis of alcoholic beverages is an analytical challenge. Ethanol reacts with the primary ion H3 O+ leading to its depletion and to formation of ethanol-related ions and clusters, resulting in unstable ionization and in significant fragmentation of analytes. Different methods were proposed but generally resulted in lowering the sensitivity and/or complicating the mass spectra. The aim of the present study was to propose a simple, sensitive, and reliable method with fragmentation as low as possible, linearity within a realistic range of volatile organic compounds concentrations, and applicability to in vivo dynamic aroma release (nosespace) studies of wines. For in vitro analyses, a reference flask containing a hydro-alcoholic solution (10% ethanol) was permanently connected to the PTR-MS inlet in order to establish ethanol chemical ionization conditions. A low electric field strength to number density ratio E/N (80 Td) was used in the drift-tube. A stable reagent ion distribution was obtained with the primary protonated ethanol ion C2 H5 OH2+ accounting for more than 80% of the ionized species. The ethanol dimer (C2 H5 OH)2 H+ accounted for only 10%. Fragmentation of some aroma molecules important for white wine flavor (various esters, linalool, cis-rose oxide, 2-methylpropan-1-ol, 3-methylbutan-1-ol, and 2-phenylethanol) was studied from same ethanol content solutions connected alternatively with the reference solution to the instrument inlet. Linear dynamic range and limit of detection (LOD) were determined for ethyl hexanoate. Fragmentation of the protonated analytes was limited to a few ions of low intensity, or to specific fragment ions with no further fragmentation. Association and/or ligand switching reactions from ethanol clusters were only significant for the primary alcohols. Interpretation of the mass spectra was straightforward with easy detection of diagnostic ions. These results made this ethanol ionization method suitable for direct headspace analyses of model wines and to their nosespace analyses.

The basal free fatty acid concentration in human saliva is related to salivary lipolytic activity.

Fat perception during eating is a complex sensation that involves various sensory modalities, such as texture, aroma and taste. Taste is supported by the discovery of fatty acid receptors in the tongue papillae. Dietary fat is mainly composed of esterified fatty acids, whereas only free fatty acids can bind to taste receptors. Some authors have mentioned the necessity and efficiency of salivary lipolytic activity to hydrolyse the esterified fatty acids present in foods and enable fat perception. Our hypothesis is that salivary lipolytic activity is also involved in regulating the basal level of salivary fatty acids in humans. To test this hypothesis, total fatty acid (TFA) and free fatty acid (FFA) concentrations and selected salivary characteristics (such as lipolytic activity) were analysed in the resting saliva of 54 subjects. The results show differences in the TFA and FFA profiles, with TFA and FFA concentrations of 8.99 and 3.56 µg/mL of saliva, respectively. Interestingly, lipolytic activity had a significant positive correlation with FFA concentration (0.51, p < 0.01). This result highlights a possible physiological role of salivary lipolytic activity in the regulation of the basal FFA concentration. This regulation could be involved in fat taste sensitivity.