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The use of additive manufacturing is growing in multiple sectors, including food, and its scientific and technological challenges form the subject of much ongoing research. One current hurdle is the implementation of the 3D printing process for meat protein matrices. This article gives an overview of the various 3D printers used to study the printability properties of foods and presents the development of a 3D printer designed to print food protein gels. Printhead development (flow rate and temperature control) and the modifications made to the printing plate (temperature control) are described and discussed in relation to the constraints highlighted in a first prototype. A second, developed prototype was characterized and validated. This last phase showed perfect control of the prototype in the purging of the extrusion system, the flow rate, the calibration and the displacement of the printhead, along with the temperatures at both printhead and plate. A study of the printed gels also revealed good repeatability of the printed gel geometry and pointed to new ways to improve the process. In the near future, the protein gels that will be printed from this prototype will serve as a base for texturizer-free functional foods for people with chewing difficulties.

Background 3D printing or additive manufacturing (AM) now provides enormous freedom to design, manufacture and innovate in various domains, even in foodstuffs development. Given the immense potential applications related to AM, many authors are even talking about a new industrial revolution. Scope and approach In this article, we review the state of the science in applied AM methods for developing biobased products in the medical and food sectors, with these two sectors having similar points. We were therefore interested in the technological locks encountered in the various studies carried out on the subject. Consideration has also been given to the possibility of using alternative sources of protein, such as animal by-products, to address resource management and sustainable development issues. One of the strengths of 3D printing is personalization, so we chose to evaluate the impact of this technology on target populations and evaluate the possible evolutions. Key findings and conclusions In order to design food in optimal conditions, the development of new 3D printers is fundamental 1) to ensure the sanitary quality (both microbiological and chemical) of these products, and 2) to control the structure and texture of these 3D-printed foods. From there, it will be possible to propose personalized foods, adapted to different categories of population (e.g. seniors or young people …). The major challenge in the next years will be to develop, using 3D printing, meat products or products blending alternative protein sources that remain perfectly structured without having to use additives. The final step will be to garner consumer acceptance for these 3D-printed foods.

International audience; This paper presents a digital learning tool, MESTRAL (“Modélisation Et Simulation des TRansformations ALimentaires”, “Modelling and Simulating Food Processing” in English), that can provide educators with a tool to teach food processing using simulators and a broad range of models derived from research in food science & engineering. It was built using electronic knowledge books (eK-book). The eK-book represents knowledge in the form of concept maps and knowledge sheets, connected via a network of hypertext links. MESTRAL encompasses 15 modules, that cover approximately 150 h of teaching and a broad range of real systems, from a single unit operation (e.g., frying a banana) to a logistic chain (e.g., ham cold chain). Each module conveys information on a food product or a food process, and includes a simulator based on a published scientific model. Altogether, the models address various scale of systems and are based on different theoretical frameworks. For each simulator, the model inputs and outputs are stored in a database. Outputs are visualized through abacuses, which can be used for virtual practice. MESTRAL modules also include training exercises and tests to help students to assess the knowledge they have acquired during consultation of the modules. Finally, MESTRAL has already been successfully tested by different audiences according to various learning forms.

L'impression 3D offre desormais une enorme liberte de conception, de fabrication et d'innovation dans un grand nombre de domaines industriels, dont le medical et l'alimentaire. Nous analysons, ici, les recents developpements dans ces deux domaines, ainsi que l'impact de ces methodes 3D en termes de developpement durable et d'acceptabilite des consommateurs. Une reflexion est egalement amorcee concernant les aliments a fonctionnalites ciblees imprimes en 3D, ciblant differents secteurs de la population, ainsi que les perspectives de developpement de ces produits au cours de la prochaine decennie. L'impression 3D est une technologie prometteuse et, offrir des solutions nutritionnelles cle en main et sur mesure a des populations jusqu'alors exclues de certains marches en raison de leur etat de sante, de difficultes d'acces aux ressources alimentaires, ou tout simplement avec un pouvoir d'achat limite, represente une serie de problemes a surmonter. Le defi majeur pour les annees a venir sera de developper, en utilisant l'impression 3D, des produits carnes ou des produits melangeant des sources de proteines alternatives parfaitement structures sans devoir utiliser d'additifs. La derniere etape consistera a obtenir l'approbation du consommateur pour ces aliments imprimes en 3D.

The purpose of this study was to investigate semi-hard cheese aroma by explaining sensory characteristics of cheese by gas chromatography–olfactometry (GC–O) data obtained via intensity ratings. Sensory (13 odour attributes) and GC–O profiles obtained by trained panels were carried out on seven non-processed semi-hard cheeses. Intensity scores for significant sensory attributes and significant odour-active compounds were analysed by partial least squares to determine correlations between these datasets. A total of nine sensory attributes and 15 odour-active molecules significantly discriminated between the cheeses. There were strong correlations (89% of the sensory data was explained by 68% of the GC–O data) between sensory attributes and odour-active compounds. We observed expected correlations between the sensory sweaty-attribute and carboxylic acids, but also observed less trivial correlations suggesting that perceptual interactions could take place within the complex cheese aroma. Correlations between sensory attributes and odour-active compounds with very low-perception thresholds were also observed.

International audience; The aim of this work was to reliably identify odorous compounds of European seabass (Dicentrarchus labrax) after 1,4 and 15 days of storage in order to find markers of freshness or spoilage. For this purpose, a dynamic headspace gas chromatography olfactometry device (DH-GC-MS/8O) was used with a panel of eight sniffers for comprehensive detection of odorants. One- and two-dimensional gas chromatography (GC-GC-MS/O) coupled with olfactometry and mass spectrometry gave reliable identification. More than 144 volatile compounds were detected in seabass flesh, of which only 13 proved to be odorant (their biochemical origins are discussed): methane-thiobis, thiophene, toluene + butanoic acid ethyl ester, hexanal, 1-hexanol, 1-octen-3-one, 1-octen-3-ol, dimethyl-trisulfide, octanal, 1-nonen-3-ol, (E)-2-nonenal and 2 unknown compounds. Amongst these compounds, only thiophene, hexanal, 1-octen-3-one, dimethyl-trisulfide, and 1-nonen-3-ol are proposed as markers of seabass quality.

International audience; Indian cress (Tropaeolum majus L.) absolute was studied by GC-olfactometry (VIDEO-Sniff method) in order to identify odor-active aroma compounds. Because of its fruity-sulfury odor note, a compound that has never been identified in plant extracts before stood out: O,S-diethyl thiocarbonate, present at 0.1% (percentage of the total GC/FID area) in the extract. GCxGC-TOFMS allowed for a clean mass spectrum to be obtained, and isolation by preparative GC followed by NMR studies allowed its identification. Here, we report on the first detection of O,S-diethyl thiocarbonate in Indian cress absolute by GC-olfactometry/VIDEO-Sniff and on its isolation and identification. The synthesis and odor evaluation of its homologues are presented.

International audience; tThe assessment of the dual impact of heating treatments on food safety and aroma is a major issue for thefood sector. The aim of the present study was to demonstrate the relevance of multidimensional GC tech-niques, olfactometry and mass spectrometry for the parallel determination of process-induced toxicantsand odorants in food starting with cooked meat as a food model. PAHs were analyzed by comprehensivetwo-dimensional gas chromatography-time-of-flight mass spectrometry after extraction by acceler-ated solvent extraction (ASE-GC × GC–TOF/MS). Odour-active compounds were determined by dynamicheadspace–GC hyphenated with eightbooth olfactometry and mass spectrometry (DH–GC–MS/8O)and DH-heart-cutting multidimensional GC hyphenated with olfactometry and mass spectrometry(DH–GC–GC–MS/O). For PAH determination, the GC × GC conditions consisted of a combination of aprimary non-polar BPX-5 column and a secondary polar BPX-50 column, and a modulation period of 5 s.In terms of linearity (R2ranging from 0.985 to 0.997), recovery rate (84–111%) and limit of detection(5–65 ng/kg of cooked meat), the ASE-GC × GC–TOF/MS method was found consistent with the mul-tiresidue determination of 16 PAHs including benzo[a]pyrene in cooked meat. For aroma compounds,DH–GC–MS/8O and DH–GC–MS/O revealed 53 major meat odour-active compounds. A customizedheart-cutting GC–GC–MS/O enabled the coeluting odour zones with high odour-activity to be resolvedand revealed 15 additional odour-active compounds. Finally, these developments of multidimensionalapproaches were used to investigate the balance between 16 PAHs and 68 odour-active compoundsgenerated with different cooking techniques

The aim of this study was to evaluate the potential of Curie point pyrolysis–mass spectrometry (CpPy–MS) to estimate the collagen and lipids contents and the texture of lamb meat. The work was carried out using the longissimus muscle from 120 commercial lambs originating from different European countries and from contrasting production systems. Meat characteristics varied largely between animals, e.g. 582 (S.D. ± 124) μg hydroxyproline g −1 for collagen content and 22.5 (S.D. ± 9.6) mg g −1 for lipid content, and 2.9 (S.D. ± 1.2) kg cm −2 for shear force value. Non-linear models of prediction were calculated by Artificial Neural Networks (ANNs). The results showed that it is possible to evaluate lipid and collagen contents and meat texture from CpPy–MS fingerprints. The best predictions obtained with test samples were for lipids ( r = 0.89; mean prediction error = 10%), for collagen ( r = 0.85; mean prediction error = 11%) and for texture ( r = 0.78; mean prediction error = 12%).

International audience; This study shows that thiamine plays a major role in the formation of three key odorants of cooked ham: 2-methyl-3-furanthiol, 2-methyl-3-methyldithiofuran, and bis(2-methyl-3-furyl)disulphide. Analyses revealed that under identical cooking conditions, the productions of these three aroma compounds increase in a closely intercorrelated way when the dose of thiamine increases. Using a specific 2-methyl-3-furanthiol extraction-quantification method, it was possible to relate the amounts of thiamine added in model cooked hams to the amounts of 2-methyl-3-furanthiol produced in the cooking process. Sensory analyses highlighted the role of thiamine as a precursor of cooked ham aroma.

Absolutes isolated from Viola odorata leaves, valuable materials for the flavor and fragrance industry, were studied. Violets are mainly cultivated in France and Egypt and extracted locally. The absolutes of the two origins showed different olfactory profiles both in top and heart notes, as evidenced by sensory analysis. The aims of this study were i) to characterize the volatile compounds, ii) to determine the odorant-active ones, and iii) to identify some markers of the plant origin. Two complementary analytical methods were used for these purposes, i. e., headspace solid-phase microextraction (HS-SPME) using different fiber coatings followed by GC/MS analysis and gas chromatography - olfactometry/mass spectrometry (GC-O/MS) applied to violet leaf extracts. From a total of 70 identified compounds, 61 have never been reported so far for this species, 17 compounds were characterized by both techniques (with seven among them known from the literature), 23 compounds were solely identified by HS-SPME GC/MS (among them only two being already mentioned as components of violet absolutes in the literature), and, finally, 30 compounds were only identified by GC-O/MS. According to the HS-SPME GC/MS analyses, ethyl hexanoate and (2E, 6Z)-nona-2,6-dienol were specific volatile compounds of the sample with French origin, while (E, E)-hepta-2,4-dienal, hexanoic acid, limonene, tridecane, and eugenol were specific of the samples with Egyptian origin. Additional compounds that were not detected by HS-SPME GC/MS analysis were revealed by GC-O analyses, some of them being markers of origin. Pent-1-en-3-ol, 3-methylbut-2-enal, 2-methoxy-3-(1-methylethyl) pyrazine, 4-ethyl-benzaldehyde, beta-phenethyl formate, and 2-methoxy-3-(2-methylpropyl) pyrazine revealed to be odorant markers of the French sample, whereas cis-rose oxide, trans-rose oxide, and 3,5,5-trimethylcyclohex-2-enone were odorant markers of the Egyptian samples.

International audience; The aim of this work was to identify and gain further knowledge on the origin of sulfur compounds present in the volatile fraction of cooked ham, and on their role in the aroma of this product. To this end, we performed analyses by one- and two-dimensional gas chromatography coupled with mass spectrometry, and olfactometry. Among the odorant sulfur compounds identified, three furans present in trace amounts proved to have very intense odours responsible for the "meaty, cooked ham" notes of this pork product. They were 2-methyl-3-furanthiol, 2-methyl-3-(methyldithio)furan and bis(2-methyl-3-furyl) disulphide. Addition of thiamine or cysteine also enabled us to study the effect of these odour precursors on the formation of odorant furans during the cooking of ham. The results revealed a direct link between the thermal degradation of thiamine and the formation of these compounds. By contrast, addition of cysteine in the presence of fructose or xylose did not appreciably increase their production

The lipids of subcutaneous fat tissues from 120 lambs were analysed by Curie point Pyrolysis - Mass Spectrometry (Py-MS) after extraction of the lipids with hexane. The animals came from six European countries with different production sys- tems. The classification of the fat tissues according to the predominant type of feed the lambs consumed (milk, concentrate or pasture) was obtained by Discriminant Analysis (DAs) and Artificial Neural Networks (ANNs). The classification models were validated by "leave-one-out"-type cross-validations. The results showed that the Py-MS spectra of the fat tissue lipids permitted recognition of feed type. The percentages of correct classifications determined by cross-validation were 78 % by DA and 92 % by ANNs.

International audience; The aim of this work was to identify and characterize the volatile compounds formed during the cooking of a model cheese. Particular attention was paid to the generation of the odour-active volatile fraction, which can contribute to the sensory characteristics of cheeses. To this end we used various analytical methods including two-dimensional gas chromatography coupled with time-of-flight mass spectrometry and chromatography—olfactometry. The changes observed in the volatile fraction enabled us to follow several markers of lipid oxidation, caramelization and Maillard reaction mechanisms during cooking. Maltol and furaneol, though present in only trace amounts, gave rise to "overcooked" odour defects in the cheese matrices.

International audience; The aim of this work was to reliably identify odour-active compounds in dry-cured ham using powerful analysis methods for the volatile fraction. For this purpose, dynamic headspace gas chromatography combined with eight-way olfactometry using a panel of eight sniffers was used. One- and two-dimensional gas chromatography coupled with mass spectrometry and (or) olfactometry were also used. More than 600 compounds from the volatile fraction of dry-cured ham were identified and their biochemical origins are discussed. They covered a wide diversity of structures and chemical functions. Only 29 of them proved odour-active. Comparison of the results of GC–O analysis with those obtained by orthonasal sniffing of the dry-cured ham helped to gain a better understanding of how these substances contributed to the overall aroma of the product. Thus, “Fruity–Floral”, “Green–Vegetable” or “Plastic–Chemical” odours intensively perceived by GC–O have been poorly perceived by orthonasal sniffing. By contrast, “Animal–Meat products” or “Butter–Lactic–Cheesy” odours have been much better perceived by orthonasal sniffing. These results indicate that to understand the interactions between odour-active compounds, experimental doping with carefully selected odour-active compounds will be necessary.

International audience; Indian cress (Tropaeolum majus L.) has been consumed in salad or soup for decades, but its odor's detailed molecular composition is still unknown. Here we report on the study of the odorant profile and odor-impact compounds of Indian cress absolute by GC-olfactometry/vocabulary-intensity-duration of elementary odors by sniffing (GC-O/VIDEO-Sniff) on an eight-way multiport system, combined with GCxGC-MS analyses for the identification of odorant trace constituents. Odor impact compounds of Indian cress absolute were determined by GC-O, and the overall influence of sulfury and fruity notes stood out. Forty-four odorant compounds were identified among which 22 (50% of the identified odorant molecules) were identified by using comprehensive two-dimensional GC coupled to a time-of-flight-mass spectrometer (TOFMS). These trace compounds were not detected by 1D-qMS or could only be found with specific searches once they were detected by comprehensive 2D-GC, although they were well perceived by the judges in GC-O. This was amongst others the case for the two molecules having the highest odor impact, (E)-hex-2-enal (fruity) and diethyl trisulfide (alliaceous, sulfury, cabbage). A powerful sulfur-containing odor compound whose first identification in cress was recently reported by the authors was detected by GC-O: O,S-diethyl thiocarbonate (fruity/red fruit and sulfury odor)

International audience; Odor impact compounds of Tagetes minuta L. essential oil were studied by gas chromatography (GC)-olfactometry using aroma extract dilution analysis (AEDA) and vocabulary-intensity-duration of elementary odors by sniffing (VIDEO-Sniff). AEDA was conducted by direct injection and revealed the presence of 43 odorant zones. Highest flavor dilution (FD) values were obtained for ethyl 2-methylpropanoate, ethyl 3-methylbutanoate, (E)-ocimenone, two tentatively identified thiols, and two yet unknown compounds. VIDEO-Sniff was realized by dynamic headspace sampling (D-HS) combined with 8W-GC-olfactometry where eight sniffers simultaneously detect volatile compounds obtained from a single chromatographic separation and revealed the presence of 42 odorant zones. Odorant trace compounds detected by GC-O that were present in quantities inferior to the GC-qMS system’s detection limit and those subject to coelutions were identified by GC×GC-time-of-flight mass spectrometry (TOFMS). A total amount of 37 odorant components could be identified by VIDEO-Sniff, and the strong influence of the fruity notes of numerous esters stood out. Highest olfactory signals were obtained for ethyl 2-methylpropanoate, ethyl 2- and 3-methylbutanoate, and oct-1-en-3-one. Both methods hence come to the conclusion that ethyl 2-methylpropanoate and ethyl 2- and 3-methylbutanoate are among the main odorants in Tagetes minuta L. essential oil. Differences, advantages, and drawbacks of both GC-O methods are discussed.

Cantal cheese was made with either raw or pasteurized milk from cows fed either pasture or a hay and concentrate diet, and was analyzed after 3- and 6-month aging. The cheese aroma was rather mild for pasteurized-milk cheese and rather strong for raw-milk cheese, and was little affected by the cows’ feeding patterns. Gas chromatography of the volatile compounds coupled with a new 8-way olfactometry device revealed 42 odorous peaks. The major odour-active compounds were butanoic acid, 2,3-butanedione, 3-methylthio-propanal, hexanal, acetic acid, isobutanoic acid, and 1-octen-3-ol. The intensity of butanoic acid was much stronger in raw-milk than pasteurized-milk cheese. The intensities of isobutanoic acid, pentanal, E-2-hexenal, cyclohexanone, tetramethylpyrazine and γ-heptalactone were lower in the 6-month-aged than the 3-month-aged cheeses, and only ethylbenzene intensity was higher. Isopentanoic acid odour was weaker when the milk had been obtained from cows fed a pasture diet.

The aim of this work was to devise a novel fully computerised chromatography–olfactometry system where eight sniffers detect volatile compounds obtained from a single chromatographic separation. The technical options taken to implement this system are described in detail. The new methods and software developed and applied to analyse data obtained by gas chromatography–olfactometry and mass spectrometry (GC–O/MS) are presented. We found that 46 odorous zones could be detected by a panel of eight sniffers during the 35 min of the analysis of the volatile compounds extracted from a cheese by purge-and-trap. Synchronisation of olfactometry and mass spectrometry data enabled us to propose 44 structures to account for 44 out of these 46 odorous zones.

This study describes a rapid method to characterize cheeses by analysis of their volatile fraction using dynamic headspace-mass spectrometry. Major factors governing the extraction and concentration of the volatile components were first studied. These components were extracted from the headspace of the cheeses in a stream of helium and concentrated on a Tenax TA trap. They were then desorbed by heating and injected directly into the source of a mass spectrometer via a short deactivated silica transfer line. The mass spectra of the mixture of volatile components were considered as fingerprints of the analyzed substances. Forward stepwise factorial discriminant analysis afforded a limited number of characteristic mass fragments that allowed a good classification of the batches of cheeses studied.

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