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Aldehydes are natural volatile aroma compounds generated by the Maillard reaction of sugars and amino acids in food and affect the flavor of food. They have been reported to exert taste-modifying effects, such as increases in taste intensity at concentrations below the odor detection threshold. The present study examined the taste-enhancing effects of short-chain aliphatic aldehydes, such as isovaleraldehyde (IVAH) and 2-methylbutyraldehyde, thus attempting to identify the taste receptors involved. The results obtained revealed that IVAH enhanced the taste intensity of taste solutions even under the condition of olfactory deprivation by a noseclip. Furthermore, IVAH activated the calcium-sensing receptor CaSR in vitro. Receptor assays on aldehyde analogues showed that C3-C6 aliphatic aldehydes and methional, a C4 sulfur aldehyde, activated CaSR. These aldehydes functioned as a positive allosteric modulator for CaSR. The relationship between the activation of CaSR and taste-modifying effects was investigated by a sensory evaluation. Taste-modifying effects were found to be dependent on the activation state of CaSR. Collectively, these results suggest that short-chain aliphatic aldehydes function as taste modulators that modify sensations by activating orally expressed CaSR. We propose that volatile aroma aldehydes may also partially contribute to the taste-modifying effect via the same molecular mechanism as kokumi substances.

This study was to understand characteristic aroma properties of kale tea made by roasting kale leaves by profiling its aroma composition and screening its aroma-active compounds. Secondary metabolites of glucosinolates such as ally isothiocyanate, 3-butenyl isothiocyanate, 3-methylthiopropyl isothiocyanate, and 5-methylthiazole were the primary aroma compounds of raw kale but were less abundant in kale tea. Dimethyl trisulfide, cyclohex-2-en-1-ol, benzeneacetaldehyde, and 4-vinylguaiacol were quantitatively major aroma compounds in kale tea. Pyrazines, aldehydes, sulfides, and 4-vinylguaiacol were newly produced only in kale tea. In particular, 2-ethyl-6-methylpyrazine exhibiting the highest flavor dilution factor was the most potent aroma-active compound of kale tea, followed by methional, 2-ethyl-5-methylpyrazine, 2,5-dimethylpyrazine, 2,6-dimethylpyrazine, two unknown compounds, dimethyl disulfide, furfural, benzaldehyde, and dimethyl trisulfide. These compounds contributed to roasted, sulfur-like/pungent, and sweet aroma characteristics, which were main aroma properties of kale tea. In addition, (E)-hex-2-enal and (Z)-hex-3-en-1-ol contributed to the green and grassy aromas of kale tea.

Aroma-active compounds in northern highbush blueberries "Bluecrop" (Vaccinium corymbosum "Bluecrop") and "Elliott" (Vaccinium corymbosum "Elliott") were isolated using solvent extraction followed by solvent-assisted flavor evaporation. The aroma-active compounds were compared by aroma extract dilution analysis (AEDA) on a polar and a chiral column and odor activity values (OAVs). The results showed that both cultivars had similar aroma-active compounds, but the flavor dilution (FD) factors and OAV values varied, responsible for the subtle aroma differences. AEDA (FD ≥ 64) suggested that the important aroma-active compounds in both cultivars could be ethyl 2-methylbutanoate, ethyl 3-methylbutanoate, (Z)-3-hexenal, 1-octen-3-one, (Z)-3-hexen-1-ol, methional, linalool, (E,Z)-2,6-nonadienal, 2-methylbutanoic acid, α-terpineol, (E,E)-2,4-nonadienal, β-damascenone, geraniol, geranyl acetone, o-cresol, eugenol, and vanillin. Different isomers can have different sensory thresholds and attributes. Enantiomer analysis revealed that although S-(+)-linalool was dominant in blueberry, R-(-)-linalool had a higher FD value and OAVs than that of the (S)-isomer. The S-(-)-α-terpineol was slightly elevated than R-(+)-α-terpineol in both cultivars.

To gain comprehensive insight into the interactions of key coffee odorants, like the Strecker aldehydes, acetaldehyde, propanal, methylpropanal, 2- and 3-methylbutanal, and methional, and the nonvolatile fraction of coffee, an untargeted metabolomics approach was applied. Ultra performance liquid chromatography (UPLC)-time of flight (TOF)-mass spectrometry (ESI-) profiling followed by statistical data analysis revealed a marker substance for a coffee beverage spiked with acetaldehyde with an accurate mass of 217.0703 [M - H]-. This compound could be identified as a reaction product of quinic acid (QA) and acetaldehyde linked by acetalization at the cis-diol function of QA. Consequently, the acetalization of aldehydes, QA, 5-O-caffeoyl quinic acid (CQA), and quinic acid γ-lactone (QAL) was investigated by means of model reactions, followed by synthesis, isolation, and structure elucidation via UPLC-TOF-MS and 1D and 2D NMR techniques. UHPLC-MS/MSMRM screening and the quantification of aldehyde adducts in coffee beverages revealed the presence of QA/acetaldehyde, -/propanal, -/methylpropanal, and -/methional reaction products and CQA/acetaldehyde, -/propanal, -/methylpropanal, -/2- and 3-methylbutanal, and -/methional and QAL/acetaldehyde adducts for the first time, in concentrations of 12-270 μg/L for QA/aldehydes, 5-225 μg/L for CQA/aldehydes, and 62-173 μg/L for QAL/acetaldehyde. The sensory characterization of the identified compounds showed bitter taste recognition thresholds of 48-297 μmol/L for CQA adducts and 658 μmol/L for QAL/acetaldehyde, while the QA adducts showed no bitter taste (

Alcohol-free beers (AFBs) brewed by cold-contact fermentation exhibit a flavor reminiscent of wort which affects consumer acceptability. The aims of this study were to identify the odor-active compounds in AFB and elucidate the contribution of these to the overall aroma and worty character of the beer. Using a sensomics approach, 27 odor-active aroma compounds were identified and quantitated using gas chromatography–mass spectrometry. The most odor-active compound was methional (boiled potato-like aroma), followed by 3-methylbutanal (cocoa-like), (E)-β-damascenone (apple, jam-like), 5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone (curry, spicy-like), and phenylacetaldehyde (floral, honey-like). The important contribution of these flavor compounds to the worty and honey aroma of AFB was determined by sensory assessment of the recombinate in a beer-like matrix with omission tests. The role of 5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone in AFB aroma was reported for the first time. The outcomes from this study are of relevance for the brewing industry to design strategies for the reduction of the wortiness of AFB.

Rioja is one of the most important Spanish wine regions, and commonly produces wines with good aging potential. The quality of Rioja aged wines is well appreciated by tasters and consumers in the international wine market. In this study, the influence of the aromatic composition and oxidation on their sensory profile of different high-quality long-aged wines produced in Rioja was evaluated. The aromatic compounds that can participate actively on the aromatic profile of this type of wines have been identified. In this way, 3-methyl-2,4-nonanedione and 2-phenylacetaldehyde were the most sensory active compounds. At lesser extent, 3-methylbutanal, (E)-2-nonenal, and (E)-2-octenal were also important volatile compounds in this type of wines. Surprisingly, sotolon was only detected as active compounds in the oldest wines with lower price. Contrary, methional mainly appeared as active compound in the youngest samples of wines with higher price. 2-methylpropanal was a non-active compound in wines correctly aged and stored. This work contributes to an improved understanding about the key odorants in Rioja high-quality old wines.

Strecker aldehydes (SAs) are key determinants of wine shelf-life and can be present in unoxidized wines in odorless forms, such as hydroxyalkylsulfonates, imines or acetals. A robust and accurate method for the determination of total forms of SAs, based on the classical derivatization with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) and in the selective solid phase extraction of derivatives has been optimized and validated. Matrix effects have been solved by the use of adequate internal standards and by large-enough equilibration times under anoxic conditions. Method figures of merit are highly satisfactory in terms of detection limits ( 0.997), reproducibility (5–13%) and recoveries (RSDs, between 2 and 10%, for 3-methylbutanal, 14%). The analysis of total SAs in 108 Spanish wines revealed that between 52% and 70% of unoxidized red wines and likely a similar fraction of white wines, contain levels of SAs high enough to cause oxidative aromas if bound forms of SAs cleave., Funded by the Spanish Ministry of Economy and Compet- itiveness (MINECO) (project AGL2017-87373-C3). LAAE acknowledges the continuous support of Gobierno de Arag ́on (T29) and European Social Fund. M.B. would like to acknowledge the Spanish National Research Agency (AEI) and the Ministry of Science, Innovation, and Universities (MICIU) for her “Juan de la Cierva-Incorporaci ́on” post- doctoral grant IJC2018-037830-I. A.M.A.C. acknowledges the Depart- ment of Science, University and Knowledge Society from DGA his predoctoral grant (2020 call).

Fifteen potato genotypes were evaluated for flavor and related components using sensory analysis, metabolite analysis, and an instrumental measurement of hardness over two growing seasons. Bake and boil cooking methods were also compared. Several sensory attributes had a significant variation in both years, where positive or negative correlations to overall quality determined desirable or undesirable attributes, respectively. Desirable attributes in both years were potato-like and mealy texture, while undesirable attributes were bitter, earthy, and other off-flavors. Significant desirable attributes limited to a single season were buttery, creamy, and sweet. Significant undesirable attributes restricted to a single season were aroma intensity and woody. Relative amounts of metabolites across genotype and cooking methods were significantly different for 14 metabolites in 2015 and 30 metabolites in 2016. Metabolites consisted of hydrocarbons, terpenes, alcohols, an acid, furans, aldehydes, ketones, as well as halogenic, nitrogenous, and sulfurous compounds. Flavor is an inherently complex phenotypic trait that is difficult to assess without subjective sensory analysis, however, flavor biomarkers may enable objective high-throughput flavor phenotyping. Candidate metabolites for potato flavor biomarkers found in this study include furfural for buttery, potato-like, and umami; 2-ethylfuran, 2-pentylfuran, isomenthone, methional, 2-phenylacetaldehyde, dimethyl trisfulfide, and 2,2,3,4-tetramethylpentane for potato-like; 3-methylpentane for aroma intensity, bitter, earthy, woody, and other off-flavors; 2-methoxy-3-propan-2-ylpyrazine for aroma intensity; 3,4,5-trimethyl-2-cyclopenten-1-one for bitter; pentan-1-ol for earthy; 2-pentylfuran, (E)-hept-2-enal, pentanal, and (E)-2-methylpent-2-en-1-ol for woody; and 5-methylhexan-2-one for other off-flavors. Further, instrumental measurements of hardness were negatively correlated to mealy texture. Biomarkers, if validated, have the potential to enable objective flavor phenotyping, which would allow for more efficient flavor improvement within conventional breeding programs.

Gas chromatography-olfactometry coupled with sensory analysis and partial least-squares regression (PLSR) analysis led to the identification of the odorants responsible for the different flavors of four yeast extracts. Sensory analysis showed that LA00L had an intense sulfurous attribute, and LA00 was characterized by fatty and green notes, FA31 exhibited the floral odor, while KA02 had strong phenolic, animal, fermented, roasted, and caramellic notes. A total of 37 key aroma compounds with odor activity values greater than 1 were determined. 2,4-Di-tert-butylphenol and methional were the most potent aroma compounds. In addition, the key aroma compounds in LA00L were nonanal, dimethyl disulfide, and γ-decalactone. Octanal, dimethyl disulfide, and benzeneacetaldehyde were the key aroma compounds in LA00. In FA31, styrene, benzeneacetaldehyde, and acetophenone were the key aroma compounds, while indole, 2-methoxyphenol, benzeneacetaldehyde, and p-cresol contributed significantly to the aroma of KA02. PLSR showed that p-cresol and indole were significantly responsible for the phenolic and animal notes inducing the off-flavor (yeasty odor) of yeasty extracts. More significantly, indole was first reported to have an important effect on yeasty odor.

Light-induced off-flavor compounds in Ponkan mandarin juice were investigated during its shelf-life by headspace solid-phase microextraction multidimensional gas chromatography-mass spectrometry/olfactometry (MDGC-MS/O) and a GC-MS/pulsed flame photometric detector (GC-MS/PFPD). A total of 34 aroma-active compounds with flavor dilution (FD) factors from 2 to 128 were tentatively identified by aroma extract dilution analysis-MDGC-MS/O. Among them, a light-induced off-flavor compound with a high FD factor, methional (cooked potato), was positively identified in the Ponkan mandarin juice at the end of the shelf-life. In addition, 11 volatile sulfur compounds (VSCs), including 6 screened shelf-markers (variable identification, VID > 0.80), were identified in Ponkan mandarin juice by a sulfur detector (PFPD). Four VSCs exhibited odor activity values exceeding 1. Three VSCs (methanethiol, dimethyl trisulfide, and methional) were confirmed as key light-induced off-flavor compounds in Ponkan mandarin juice based on addition/omission experiments. Furthermore, light irradiation accelerated the degradation of sulfur precursors (methionine and MMS) and the formation of these VSCs leading to an increase in off-flavor intensity.

Boiling, the most frequent edible way to hotpot seasoning (HS), exerts a significant impact on the aroma of HS. The present study employed, for the first time, a novel switchable system between GC-O-MS and GC×GC-O-MS (SGC/GC×GC-O-MS) to study the aroma compounds of HS and hotpot seasoning boiling liquid (HSBL). A total of 79 aroma compounds and 56 aroma-active compounds were identified. The aroma extract dilution analysis (AEDA) was used to analyze the differences between the key aroma-active components in the HS and HSBL. The results showed that 13 aroma-active components were significantly affected by boiling, such as D-limonene, methional, and linalool. Moreover, a total of 22 key aroma-active components were identified through the odor activity values (OAVs) calculation. Of them, (E)-2-octenal (fatty) and linalool showed a significant difference, suggesting them to be the most critical aroma-active compounds in the HSBL, and HS, respectively. Finally, the correlation between key aroma-active compounds and the sensory properties of HS and HSBL was studied. These results demonstrated that the OAVs of key aroma-active compounds could characterize the real information of samples through bidirectional orthogonal partial least squares (O2PLS). The analysis results were consistent with the sensory evaluation results.

Tamarillo is a nutrient-dense fruit with a unique aroma from its volatile compounds (VCs). In this study, we aimed to compare the volatile profiles: (i) of fresh and freeze-dried tamarillo, (ii) detected using Thermal Desorption–Gas Chromatography–Mass Spectrometry (TD–GC–MS) and Solid-Phase MicroExtraction–Gas Chromatography-Mass Spectrometry (SPME–GC–MS), (iii) of freeze-dried pulp and peel of New Zealand grown tamarillo. The possible antibacterial activity of freeze-dried tamarillo extracts was also investigated. We show that freeze-drying maintained most of the VCs, with some being more concentrated with the loss of water. The most abundant VC in both fresh and freeze-dried tamarillo was hexanoic acid methyl ester for pulp (30% and 37%, respectively), and (E)-3-Hexen-1-ol for peel (36% and 29%, respectively). With the use of TD–GC–MS, 82 VCs were detected for the first time, when compared to SPME–GC–MS. Methional was the main contributor to the overall aroma in both peel (15.4 ± 4.2 μg/g DW) and pulp (118 ± 8.1 μg/g DW). Compared to water as the control, tamarillo extracts prepared by water and methanol extraction showed significant antibacterial activity against E. coli, P. aeruginosa, and S. aureus with zone of inhibition of at least 13.5 mm. These results suggest that freeze-dried tamarillo has a potential for use as a natural preservative to enhance aroma and shelf life of food products.

International audience; The oxygen transfer rate (OTR) of closures is a well-known parameter impacting the quality of Sauvignon blanc wines (SBw) within the first years of storage, but little research has been published on its long-term effects. The chemical changes in oxidation odor intensity in three SBw sealed with natural cork and other closures that had different known OTRs, ranging from

Volatile sulfur compounds in ultra-pasteurized (UP) milk are the major contributors to sulfur/burnt and eggy flavors, and these flavors are disliked by consumers. Previous research has established distinct differences in flavor profiles of fluid milk processed by high temperature, short time pasteurization (HTST) and UP by direct steam injection (DSI-UP) or indirect heat (IND-UP). An understanding of the contribution of the individual milk proteins to sulfur off-flavors would clarify the source of sulfur flavors in UP milks. The objective of this study was to determine the source of volatile sulfur compounds in fluid milk with a specific focus on the comparison of heat treatment effects on milks by HTST and UP. Formulated skim milks (FSM) were manufactured by blending micellar casein concentrate and serum protein isolate (SPI). Three different caseins as a percentage of true protein (FSM95, FSM80, and FSM60) were formulated to determine the source of sulfur/burnt and eggy flavors. Freshly processed micellar casein concentrate or SPI were blended to achieve a true protein content of about 3.2%. Raw skim milk served as a control. Skim milk and FSM were pasteurized at 78°C for 15 s (HTST) or 140°C for 2.3 s by IND-UP or DSI-UP. The experiment was replicated twice. Sensory properties of milks and FSM were documented by descriptive sensory analysis. Volatile sulfur compounds in milks and FSM were evaluated using solid-phase microextraction followed by gas chromatography-triple quadrupole mass spectrometry combined with a sulfur selective flame photometric detector. The FSM with higher SPI as a percent of true protein had higher sensory sulfur/burnt and eggy flavors along with elevated concentrations of hydrogen sulfide and carbon disulfide compared with skim milk or FSM with lower proportions of SPI. Sulfur compounds including dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide, dimethyl sulfoxide, and methional were not associated with sulfur/burnt and eggy flavors, which suggests that these compounds may not specifically contribute to the sulfur/burnt and eggy off-flavors of UP milks. Sensory panelists found higher overall aroma impact, and cooked, sulfur/burnt, and eggy flavors for DSI-UP, followed by IND-UP and HTST. The combination of sensory and instrumental methods used in the current study effectively identified that milk serum proteins are the source of sulfur compounds in milk, and further confirmed the contribution of hydrogen sulfide and carbon disulfide to eggy and sulfur/burnt flavors, respectively.

Japanese green tea is becoming increasingly popular worldwide due to its pleasant aroma. The volatiles of four types of Japanese green tea (Sencha, Matcha, Gyokuro, and Hojicha) were extracted separately by headspace solid-phase microextraction (HS-SPME) and solvent-assisted flavour evaporation (SAFE), and then analysed using gas chromatography-mass spectrometry (GC-MS). The aroma-active compounds in each type of green tea were identified by aroma extract dilution analysis (AEDA) of its SAFE extract. The odourants exhibiting the highest flavour dilution (FD) factor of 27 in Sencha were indole and methional. For Matcha, nonanal had the highest FD factor of 243. The odourant in Gyokuro with the highest FD factor of 27 was indole. For Hojicha, the odour-active compounds exhibiting high FD factor of 729 and 243 were 2,3-diethylpyrazine and 2,3-diethyl-5-methylpyrazine, respectively. Sensory evaluation was then done on the SAFE extract to understand the overall aroma profile of each type of green tea. Based on sensory evaluation results, steamed green teas (Sencha, Matcha, and Gyokuro) had leafier and higher floral notes while roasted green tea (Hojicha) showed higher roasty and woody notes. Finally, principal component analysis (PCA) of data obtained from GC-MS analysis demonstrated marked separation of these four types of Japanese green tea.

This study validates a new methodology which allows the direct quantification of 13 volatile aldehyde compounds related to oxidative off-flavours in wine. The compounds investigated were four (E)-2-alkenals ((E)-2-heptenal, (E)-2-hexenal, (E)-2-octenal and (E)-2-nonenal), four Strecker aldehydes (2-methylpropanal, 3-methylbutanal, methional and 2-phenylacetaldehyde) and five general aldehydes (hexanal, furfural, 5-methylfurfural, benzaldehyde and nonanal). This methodology involved the addition of p-benzoquinone to release the aldehydes bound to hydrogen sulfite, collection via solid phase extraction, derivatisation by o-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride and quantification by gas chromatography triple-quadrupole mass spectrometer in multiple reaction monitoring mode. Overall, the limit of detection, limit of quantification, accuracy (recovery, 98–103%) and precision (repeatability and reproducibility, RSD ≤ 15%) are sufficient to enable routine measurement of the 13 aldehyde compounds in wine. Sixteen commercial white and red wines of varied varieties and vintages were analysed with this methodology. White wines trended to have higher concentrations of the aldehyde compounds in comparison with the red wines.

Lucuma (Pouteria lucuma) is an important exportation fruit in Peru. In this work, the odour-active volatile changes during fruit ripening were studied by using a sensomics approach (GC-O in combination with GC-MS analyses). The volatile compound extracts from unripe and ripe fruits were obtained by solvent-assisted flavour extraction (SAFE) with dichloromethane. By application of the aroma extract dilution analysis (AEDA) on the ripe fruit extract, 16 odour-active compounds were detected as responsible of sweet, green, and rancid odour-notes, characteristics of this fruit. Based on odour activity value (OAV) calculation, 2,3-butanedione, methional, (Z)-3-hexenal, (E)-2-hexenal, (Z)-β-ocimene, and 3-methyl butanoic acid were identified as key-aroma compounds in this fruit. These compounds were also quantitated in the unripe fruit SAFE extract finding that their amount increased with during the ripening, such contributing to the development of characteristic odour notes.

Volatile flavor compounds created in the mixture of enzymatic hydrolysates of soy sauce residue and defatted soybean by reaction flavor technology (RFT) were analyzed and compared using solid phase micro-extraction/gas chromatography/mass selective detector to develop a seasoning sauce. Using response surface methodology analysis, RFT was performed by adding 0.50% fructose, 0.33% glutamic acid, 0.68% arginine, 0.37% methionine, and 0.86% glycine in the base and reaction conditions at 93°C for 120 min. A total of 57 compounds, 43 in RFT and 45 in control, were detected, including 8 aldehydes and ketones, 6 aromatic hydrocarbons, 3 acids, 12 alcohols, 6 esters, 4 furans, 9 nitrogen-containing compounds, 4 sulfur-containing compounds, and 5 miscellaneous. In RFT samples, aldehydes and ketones, aromatic hydrocarbons, alcohols, esters, and S-containing compounds were significantly increased. Sulfur-containing compounds were increased by 687 fold compared to control samples (P

Background To evaluate the impact of cold fermentation time on bagel rolls, the key aroma-active compounds in the volatile fractions obtained from three different bagel rolls through solvent assisted flavor evaporation (SAFE) were sequentially characterized by an aroma extract dilution analysis (AEDA), quantified by stable isotope dilution and analyzed by odor activity values (OAVs) respectively. Results Findings revealed 40 aroma-active compounds with flavor dilution (FD) factor ranges of 2–1024. Of these, 22 compounds (FD ≥ 16) were quantified by stable isotope dilution assays (SIDA). Subsequent analysis of the 22 compounds by odor activity values (OAVs) revealed 14 compounds with OAVs ≥ 1 and the highest concentrations were obtained for 2,3-butanedione, 2-phenylethanol, 3-methylbutanal and acetoin respectively. Two recombination models of the bagels (i.e. 24 h and 48 h bagels) showed similarity to the corresponding bagels. Omission tests confirmed that 2,3-butanedione (buttery), acetoin (buttery), 2-acetyl-1-pyrroline (roasty), 5-methyl-2-furanmethanol (bread-like), (Z)-4-heptenal (biscuit-like) and 4-hydroxy-2,5-dimethyl-3(2H)-furanone, were the key aroma compounds. Additionally, acetic acid, butanoic acid, 2-phenylethanol (honey-like), 3-methylbutanoic acid, 2/3-methylbutanal, vanillin, 3-methylbutanol, methional were also important odorants of the bagel. Conclusion Whilst the long, cold fermented bagels exhibited roasty, malty, buttery, baked potato-like, smoky and biscuit-like notes, the control bagels produced similar but less intense odor notes.

Naturally fermented soy sauce is one of the few globally valued food condiments. It is complex in its substrate, manufacturing processes, and chemical profile of salts and organic compounds, resulting from spontaneous, enzymatic and biochemical reactions. The overall chemical character of soy sauce has a few rivals relative to its chemical and bioactive complexity. Resulting from this complexity are unique sensory attributes contributing to the characteristic soy sauce flavor as well as potentiating other sensory sensations. Soy sauce is susceptible to deterioration after bottling during storage. This work examined soy sauces over an eight-month period using descriptive sensory methods and the discovery of metabolomic biomarkers with high resolution mass spectrometry, wherein samples were derivatized to enable volatility and identification of polar analytes. While several thousand metabolites were detected, only organic acids, amino acids, and various glycosylated metabolites were statistically defensible biomarkers of storage time. The relationships between sensory and metabolomic data were assessed using Kendall rank-based correlations to generate Kendall Tau correlation coefficients. A second approach filtered the data based on correlation significance and grouped molecules based on hierarchical clustering. Mass spectrometry analyses discovered several thousand unique analyte peaks with relevant changes denoted as significant relative to the fresh samples using volcano depictions of p values versus changes in compound abundances. We present a metabolomic approach for the analysis of complex food systems capable of differentiating a quantifiable extrinsic variable, which is, in this case, storage time with a correlation coefficient of 0.99. We further demonstrate that changes in soy sauce resulting from storage are characterized by sensory decreases in fruity/grape and nutty/sesame aroma and increases in methional/potato aroma and astringent attributes with concomitant changes in the concentrations of several key biomarkers.

Polyphenolic fractions from Garnacha, Tempranillo, and Moristel grapes were reconstituted to form model wines of identical pH, ethanol, amino acid, metal, and varietal polyfunctional mercaptan (PFM) contents. Models were subjected to a forced oxidation procedure at 35 °C and to an equivalent treatment under strict anoxia. Polyphenolic profiles significantly determined oxygen consumption rates (5.6-13.6 mg L-1 day-1), Strecker aldehyde (SA) accumulation (ratios max/min around 2.5), and levels of PFMs remaining (ratio max/min between 1.93 and 4.53). By contrast, acetaldehyde accumulated in small amounts and homogeneously (11-15 mg L-1). Tempranillo samples, with highest delphinidin and prodelphinidins and smallest catechin, consume O2 faster but accumulate less SA and retain smallest amounts of PFMs under anoxic conditions. Overall, SA accumulation may be related to polyphenols, producing stable quinones. The ability to protect PFMs as disulfides may be negatively related to the increase in tannin activity, while pigmented tannins could be related to 4-methyl-4-mercaptopentanone decrease., Funded by the Spanish Ministry of Economy and Competitiveness (MINECO) (project AGL2017-87373-C3). LAAE acknowledges the continuous support of Gobierno de Aragón (T29) and European Social Fund. EB has received funding from the Spanish Government grant no FPU2017/ 03410.

The contribution of free amino acids and thiamine to the production of potent meat aroma compounds in nitrite-reduced, dry-fermented sausages inoculated with a D. hansenii strain was the objective of this study. For this, three different sausage formulations were manufactured; a control and two formulations reduced by half in nitrate and nitrite and one of them inoculated with D. hansenii. Free amino acids, thiamine content and savoury volatile compounds were analysed. Eleven savoury volatile compounds were quantitated. Among them, the most potent compounds above their odour thresholds were 2-methyl-3-furanthiol, 2-acetyl-1-pyrroline, methional, dimethyl trisulfide and methyl-2-methyl-3-furyl disulfide. Their generation was affected by D. hansenii inoculation as shown by the decrease in methional and methyl 2-methyl-3-furyl disulfide content, and the increase of methionol. Nitrate and nitrite reduction did not significantly affect amino acid and thiamine contents., Financial support from RTI2018-098074-B-I00 (MCIU/AEI/FEDER, UE)

Volatiles, key odorants, phenolics and antioxidant properties of raw, boiled and oven-cooked champignon and oyster mushrooms were investigated. Total concentration of the volatiles was drastically reduced by both cooking treatments and the lowest contents were found in the oven-cooked sample. Alcohols and terpenes were the dominant aroma groups in the raw champignon and oyster sample, respectively. The highest FD factor (FD = 2048) was found for 1-octen-3-one and methional in raw and boiled champignon samples while the same FD factor was determined in 1-octen-3-ol and methional in raw and boiled oyster samples. It was determined that the phenolics were more abundant in champignon samples than the oyster samples and that the boiling process caused a decrease while oven-cooking resulted in an increase in the amount of phenolics in both varieties. It was revealed that cooking was a crucial factor for the key odorants and phenolics in champignon and oyster mushrooms.

Aging is an essential step for enriching the aroma profiles of Chinese vinegar. This study aimed to track the volatile flavor changes in the same batch of Chinese vinegar for the first time during two years of aging with the aid of HS-SPME-GC-MS. The aroma-active compounds were characterized at 0, 6, and 12 months of aging using GC-O coupled with a modified frequency method. A total of 67 volatile compounds and 30 aroma-active compounds were identified during the different stages of aging. Most alcohols, esters, ketones, acids, and phenols decreased during the aging from 628.4, 105.4, 132.1, 22.1, and 21.4 µg/L at 0 month to 228.7, 7.2, 9.69, 17.24, and 11.6 µg/L at 24 months separately, except aldehydes and pyrazines, which showed slight increases. Many aroma-active compounds were generated during the aging, such as methional, trimethylpyrazine, acetophenone, and 2-acetyl-3-ethylpyrazine, while pyrazines were formed during 24 months of aging. Three aroma-active compounds with high odor activity values (OAVs) showed significant contributions to the aroma profile of vinegar, which included isovaleric acid (2743, 340, and 3139), 4-ethylguaiacol (580, 429, and 516), and γ-nonalactone (324, 640, and 442) at 0, 6, and 12 months of aging, respectively.

International audience; This work investigated the influence of grape variety, vineyard location, and grape harvest maturity, combined with different oxygen availability treatments, on red wine composition during bottle aging. Chemometric analysis of wine compositional data (i.e., wine color parameters, SO 2 , metals, and volatile compounds) demonstrated that the wine samples could be differentiated according to the different viticultural or bottle-aging factors. Grape variety, vineyard location, and grape maturity showed greater influence on wine composition than bottle-aging conditions. For most measured wine compositional variables, the evolution patterns adopted from the viticultural factors were not altered by oxygen availability treatment. However, contrasting evolution patterns for some variables were observed according to specific viticultural factors, with examples including dimethyl sulfide, phenylacetaldehyde, maltol, and β-damascenone for vineyard locations, 2-methylbutanal, 1,4-cineole, and linalool for grape variety, and methanethiol, methional, and homofuraneol for grape maturity.

Chicken liver is a main protein source to prepare attractant for dog food. However, animal proteins are costly. Seeking high quality and low-cost protein sources has been a goal for the industry. Mushroom Lentinus edodes (L. edodes) and Mealworm Tenebrio molitor (T. molitor) are novel protein sources, showing high potential as raw material of attractants. In this paper, chicken liver, L. edodes, and T. molitor were used as three different protein sources to prepare attractants. Their palatability to dogs were then compared. Firstly, the enzymatic hydrolysis process of three proteins was optimized, with a degree of hydrolysis of 54.82%, 36.10% and 30.14% for chicken liver, L. edodes, and T. molitor respectively. Secondly, volatile compounds of three attractants were identified by HS-SPME/GC-MS and SDE/GC-MS. Using OAV and PLRS method, it was found that bis(2-methyl-3-furyl) disulfide, indole, methional, 2-(methyl thio) phenol, γ-butyrolacton, furfuryl alcohol, acetic acid and isovaleraldehyde were the key components. Although both T. molitor and L. edodes attractant showed less palatability than that of chicken liver, they could be readily improved via adding key palatable volatile compounds. The ingestion rate of dog food with attractant showed a similar trend and was higher than that of food without attractant., Food analysis; Attractant; Palatability; Flavour analysis; Different protein sources.

The key aroma constituents in the volatile fractions isolated FROM two differently processed fry breads by solvent-assisted flavor evaporation were characterized by an aroma extract dilution analysis (AEDA). Twenty-two compounds were identified with flavor dilution (FD) factor ranges of 2&ndash, 516. Among them, 13 compounds (FD &ge, 16) were quantified by stable isotope dilution assays and analyzed by odor activity values (OAVs). Of these, 11 compounds had OAVs &ge, 1, and the highest concentrations were determined for &delta, decalactone and 2,3-butanedione. Two recombination models of the fry breads showed similarity to the corresponding fry breads. Omission tests confirmed that aroma-active constituents, such as &delta, decalactone (oily/peach), 2-acetyl-1-pyrroline (roasty/popcorn-like), 3-methylbutanal (malty), methional (baked potato-like), 2,3-butanedione (buttery), phenyl acetaldehyde (flowery), (E,E)-2,4-decadienal (deep-fried), butanoic acid, and 3-methylbutanoic acid, were the key aroma constituents of fry bread. In addition, 3-methoxy-4-vinylphenol (smoky) and 4-hydroxy-2,5-dimethyl-3(2H)-furanone were also identified as important aroma constituents of fry bread.

In this study, gas chromatography coupled to an ion mobility spectrometry (GC–IMS) was used for analyzing some volatile components and flavor fingerprint in samples from Jingyuan lambs of different ages (2, 6, and 12 months). The data obtained from ion mobility were processed using laboratory analysis view processing software for fingerprint recognition, and the principal component analysis (PCA) was performed. GC–IMS provided information on the characteristics and strength of 66 volatile flavor compounds (monomers and dimers). The differences in flavoring substances between lambs of different ages were observed. The compounds with higher intensity peaks in the lamb meat samples were alcohols (1-octen-3-ol, ethanol, (E)-2-hexen-1-ol, 1-pentanol, and 2-propanol), ketones (2-pentanone, 2-heptanone, 3-hydroxy-2-butanone, 2-hexanone, 2-butanone, 2-propanone, and 4-methyl-2-pentanone), aldehydes (n-nonanal, octanal, heptanal, 3-methylbutanal, hexanal, pentanal, 2-methylbutanal, (E)-2-octenal, (E)-2-nonenal, methional, and phenylacetaldehyde), esters (methyl benzoate), furan (2-pentylfuran), and thiazole (trimethylthiazole). The results showed that the flavor fingerprint in samples from Jingyuan lambs of different ages (2, 6, and 12 months) can be established by GC–IMS and PCA based on the identified volatile compounds. This method might be used for the rapid and comprehensive analysis of volatile components in lamb meat.

Changes of volatile flavor compounds of watermelon juice by heat treatment were investigated by gas chromatography-olfactometry-mass spectrometry. Although the major volatile compounds in watermelon juice, three aldehydes, three alcohols, and one ketone, did not increase significantly by heat treatment, dimethylsulfide and methional increased in heated juice. These two sulfides were suggested to contribute to the off-flavors in heated watermelon juice.

Sesame oil is a traditional and delicious edible oil in China and Southeast Asia with a high price. However, sesame oil essence was often illegally added to cheaper edible oils to counterfeit sesame oil. In this study, a rapid and accurate headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) method was proposed to detect the counterfeit sesame oil where the other cheap oils were adulterated with essence. Combined with chemometric methods including principal component analysis (PCA), orthogonal partial least squares discriminant analysis (OPLS-DA) and random forest (RF), authentic and counterfeit sesame oils adulterated with sesame essence (0.5%, w/w) were easily separated into two groups. More importantly, 2-methylbutanoic acid, 2-furfurylthiol, methylpyrazine, methional, and 2,5-dimethylpyrazine were found to be markers of sesame essence, which were used to directly identify the sesame essence. The determination of volatile compounds based on HS-GC-IMS was proven to be an effective method for adulteration detection of essence in sesame oil.

The sensory and aroma quality of 30% (w/w) sucrose reduced sponge cakes incorporating clean-label replacers were investigated. The sensory quality of the reformulated sponge cakes varied, with those containing apple pomace powder (APP) showing the greatest difference to the control (SC100). Volatile profiles mainly differed in relation to compounds derived from the Maillard reaction, caramelisation and lipid oxidation. Thrity six aroma active volatile compounds were identified in the SC100, APP and oligofructose (OLIGO) sponge cakes by olfactometry. Furfural 'spicy bready' contributed most to the overall aroma of all samples, with factor dilution values differing the most for heptanal 'fatty cake crust', methional 'potato damp', and 2,5-dimethylpyrazine 'cake crust, nutty'. This study provides an in-depth insight into the impact of sugar reduction reformulation on the sensory perception of sponge cakes and demonstrates how this approach can be used to improve the sensory perception of reduced sucrose sponge cakes.

To determine the odor-active compounds in Cheddar cheeses with different ripening times (6, 10, and 14 mo), 39 potent odorants of Cheddar cheeses were identified with a flavor dilution factor range between 1 and 512 by aroma extract dilution analysis. To further determine their contribution to the overall aroma profile of Cheddar cheeses, odor activity values of 38 odorants with flavor dilution factors ≥1 were calculated. A Cheddar cheese matrix was developed to determine the concentrations and the odor thresholds of these key aroma compounds. The result of the aroma recombinant experiment prepared by mixing the key aroma compounds in the concentrations in which they occurred in Cheddar cheeses showed that the overall aroma profile of the recombinant sample was very similar to that of Cheddar cheese. The main different compounds in Cheddar cheese with different ripening time were acetic acid, butanoic acid, dimethyl trisulfide, methional, hexanal, (E)-2-nonenal, acetoin, 1-octen-3-one, δ-dodecalactone, furaneol, hexanoic acid, heptanal, and ethyl caproate. This study could provide important information for researching and developing Cheddar cheese-related products.

Changes in volatile compounds of fermented minced pepper (FMP) during natural fermentation (NF) and inoculated fermentation (IF) process were analyzed by the headspace–gas chromatography–ion mobility spectrometry (HS‐GC‐IMS). A total of 53 volatile compounds were identified, including 12 esters, 17 aldehydes, 13 alcohols, four ketones, three furans, two acids, one pyrazine, and one ether. Generally, fermentation time played an important role in volatile compounds of FMP. It was found that most esters, aldehydes, and alcohols obviously decreased with the increase in fermentation time, including isoamyl hexanoate, methyl octanoate, gamma‐butyrolactone, phenylacetaldehyde, methional, and E‐2‐hexenol. Only a few volatile compounds increased, especially for 2‐methylbutanoic acid, 2‐methylpropionic acid, linalool, ethanol, and ethyl acetate. However, no significant difference in volatile compounds was found between NF and IF samples at the same fermentation time. In addition, the fermentation process in all samples was well discriminated as three stages (0 days; 6 day; and 12, 18, and 24 days), and all volatile compounds were divided into two categories (increase and decrease) based on principal component analysis and heat map., Changes in volatile compounds of FMP during NF and IF process were analyzed by HS‐GC‐IMS. Fermentation time played an important role in volatile compounds of FMP. Most esters, aldehydes, and alcohols obviously decreased, and only a few volatile compounds increased during NF and IF, especially for acids. NF and IF posed little effect on volatile compounds of FMP.

A potent unpleasant aroma presenting a pickle-like off-odor in Moutai-aroma type Baijiu was studied by comparative aroma extract dilution analysis (AEDA). Two Moutai-aroma type Baijiu samples, one having no off-odor (A) and the other one presenting pickle-like off-odor (B), were selected for chemical analysis and sensory evaluation. The aroma compounds were isolated by headspace solid-phase microextraction and liquid-liquid extraction. AEDA, quantitative analysis, and odor activity value calculation were performed in both the A and B samples. The main differences between the two samples were obtained for 12 compounds, presenting significantly higher concentrations in the off-odor sample. A total of 30 Moutai-aroma type Baijiu samples having different intensities of pickle-like sensory defect were analyzed to confirm the differences. An aroma addition test indicated that the 12 compounds with higher concentrations contributed to the pickle-like off-odor when spiked into sample A. Finally, a triangle test involving omission of the aroma compounds from the spiked A sample proved that 2-methyl-3-furanthiol, methional, methyl 2-methyl-3-furyl disulfide, dimethyl trisulfide, 2-furfurylthiol, methanethiol, dimethyl disulfide, and bis(2-methyl-3-furyl)disulfide with higher concentrations were generally responsible for the pickle-like off-odor in Moutai-aroma type Baijiu.

The off-flavor produced after thermal stabilization of mandarin (Citrus reticulata, Blanco) juices has limited the production of commercial juices. Methanethiol, a putrid-smelling sulfur volatile, has been identified for the first time in heated mandarin juices. Identification was achieved using a combination of capillary gas chromatography with two dissimilar columns and a dual sulfur-specific pulsed flame photometric detector and selected ion mass spectrometry detection. Static headspace solid-phase microextraction quantitation found that average odor activity values (OAVs) in heated juices were 25.5 for methanethiol compared to 10.8 for dimethyl sulfide. OAVs for methanethiol and dimethyl sulfide in fresh juices were ND (not detected) and 5.5, respectively. Hydrogen sulfide, carbonyl sulfide, carbon disulfide, and dimethyl disulfide were also identified and quantitated. Thermal decomposition studies of nonvolatile sulfur-containing potential precursors indicated that methionine was the major source of methanethiol. Additional heating studies with model juices demonstrated that ascorbic acid greatly accelerated the formation of methanethiol and methional, as well as dimethyl di and tri sulfides.

peer-reviewed The full text of this article will not be available in ULIR until the embargo expires on the 20/05/2021 BACKGROUND: Recently, a new process concept has been proposed to selectively adsorb wort offflavours, i.e. aldehydes, from alcohol-free beers with hydrophobic zeolites. RESULTS: In this work, we investigated the uptake of a mixture of wort flavour compounds (2-methylpropanal, 2-methylbutanal, 3methylbutanal, furfural and methional), from a model solution onto binderless, hydrophobic ZSM-5 zeolite granules in order to quantify mass transfer parameters and identify bottlenecks. Subsequently, the homogenous solid diffusion model was employed to regress the effective diffusion coefficients for each molecule and experimental condition, which ranged between 10-15 and 10-13 m2/s, indicating strong intraparticle mass transfer limitation. Furthermore, it was found that the effective diffusion coefficient is inversely correlated to the molecules’ hydrophobicity, expressed as the logD value and its isotherm affinity constant. CONCLUSION: These results give valuable insight to design and improved adsorbent material and an off-flavour removal unit for industrial scale.