Metabolomics Approach to Assess the Relative Contributions of the Volatile and Non-volatile Composition to Expert Quality Ratings of Pinot Noir Wine Quality

Tea marinating-induced improvement of quality in roasted chicken: The potential relationship between tea, flavor, and hazardous substances

The levels of flavor compounds and hazardous compounds are important indicators for evaluating high-temperature roasted food. In this paper, the effect of tea pre-marination on non-volatile compounds, volatile compounds, and hazardous compounds in roasted chicken. The results showed that the total content of key umami non-volatile compounds in roasted chicken marinated with green tea, white tea, and black tea increased by 17.43 % to 100.11 %. The content of alkenes, alcohols, aldehydes, and ketones in high-temperature roasted chicken marinated with oolong tea and yellow tea was increased. Different teas had varying inhibitory effects on hazardous compounds in high-temperature roasted chicken, while green tea exhibited the highest inhibition efficacy. The inhibition rates of green tea for ACY, 5-HMF, HCAs, and PAHs were 72.12 %, 69.87 %, 92.49 %, and 14.92 %, respectively. Flavonoids in tea may play an important role in the flavor enhancement and hazardous compounds inhibition of high-temperature roasted chicken.

Metabolomics analysis based on UHPLC-QqQ-MS/MS to discriminate grapes and wines from different geographical origins and climatological characteristics

With the proliferation of the consumer's awareness of wine provenance, wines with unique origin characteristics are increasingly in demand. This study aimed to investigate the influence of geographical origins and climatological characteristics on grapes and wines. A total of 94 anthocyanins and 78 non-anthocyanin phenolic compounds in grapes and wines from five Chinese viticultural vineyards (CJ, WH, QTX, WW, and XY) were identified by UHPLC-QqQ-MS/MS. Chemometric methods PCA and OPLS-DA were established to select candidate differential metabolites, including flavonols, stilbenes, hydroxycinnamic acids, peonidin derivatives, and malvidin derivatives. CCA showed that malvidin-3-O-glucoside had a positive correlation with mean temperature, and quercetin-3-O-glucoside had a negative correlation with precipitation. In addition, enrichment analysis elucidated that the metabolic diversity in different origins mainly occurred in flavonoid biosynthesis. This study would provide some new insights to understand the effect of geographical origins and climatological characteristics on phenolic compounds in grapes and wines.

Impact of must clarification treatments on chemical and sensory profiles of kiwifruit wine

This study examined the effect of various clarification treatments on the physicochemical properties, volatile compounds, and sensory attributes of kiwi wines produced from five different kiwifruit (Actinidia deliciosa) varieties. The degree of clarification had a minimal impact on physicochemical parameters, including the content of residual sugar, ethanol, volatile acid, titratable acidity (except for the kiwifruit variety 'Qinmei'), and the pH value. However, wines made from unclarified juices (muddy juice and pulp) displayed a higher glycerol content than those made from clarified juices. The cluster heat map and principal component analyses (PCA) demonstrated that kiwi wines produced from clarified kiwi juices possessed a higher ester content, whereas muddy juice and pulp wines contained elevated levels of higher alcohols. Quantitative descriptive analysis (QDA) indicated that clarified juice wines outperformed muddy juice and pulp wines in terms of purity, typicality, harmony, intensity, and freshness, with negligible differences in terms of palate acidity. Moreover, the clarified juice wines featured more characteristic kiwi wine aromas (kiwifruit, passionfruit, and pineapple) compared with that of the muddy juice and pulp wines, which exhibited an increased grassy flavour. Although the 100-NTU kiwifruit juice-fermented wine did not show an advantage in the cluster heat map and PCA, it presented better freshness, typicality, and intensity in the QDA, as well as a more passionfruit aroma. Based on the orthogonal partial least-squares discriminant analysis, A. deliciosa 'Xuxiang' was deemed to be the most suitable variety for vinification. This study provides crucial insights for enhancing the production of high-quality kiwi wine.

Diversity of fungal communities on Cabernet and Aglianico grapes from vineyards located in Southern Italy

Grape-associated microbial community is influenced by a combination of viticultural, climatic, pedological and anthropological factors, collectively known as terroir. Therefore, grapes of the same cultivar grown in different areas can be appreciated for their distinctive biogeographic characteristics. In our previous study, we showed that the phenotypic response of Aglianico and Cabernet grapevines from Molise and Sicily regions is significantly influenced by the prevailing pedoclimatic conditions, particularly soil physical properties. However, the scale at which microbial communities differ could be important in clarifying the concept of terroir, including whether it is linked to the grape variety present in a particular vineyard. To explore this further, in the research presented here, a comparative study on the fungal communities inhabiting the berry surfaces of Cabernet and Aglianico cultivars was conducted on different vineyards located in Southern Italy (Molise, Sicily and Campania regions, the first two of which had been involved in our previous study) by using high-throughput sequencing (HTS) and multivariate data analysis. The descriptive approach through relative abundance analysis showed the most abundant phyla (Ascomycota, Basidiomycota, and Chytridiomycota), families (Cladosporiaceae, Saccotheciaceae, Pleosporaceae, Saccharomycodaceae, Sporidiobolaceae, Didymellaceae, Filobasidiaceae, Bulleribasidiaceae, and Saccharomycetaceae) and genera (Cladosporium, Aureobasidium, Alternaria, Stemphylium and Filobasidium) detected on grape berries. The multivariate data analysis performed by using different packages (phyloseq, Vegan, mixOmics, microbiomeMarker and ggplot2) highlighted that the variable "vineyard location" significantly affect the fungal community, while the variable "grape variety" has no significant effect. Thus, some taxa are found to be part of specific vineyard ecosystems rather than specific grape varieties, giving additional information on the microbial contribution to wine quality, thanks to the presence of fermentative yeasts or, conversely, to the involvement in negative or detrimental roles, due to the presence of grape-deriving fungi implied in the spoilage of wine or in grapevine pathogenesis. In this connection, the main functions of core taxa fungi, whose role in the vineyard environment is still poorly understood, are also described.

Exploring UPLC-QTOF-MS-based targeted and untargeted approaches for understanding wine mouthfeel: A sensometabolomic approach

This study aimed to establish relationships between wine composition and in-mouth sensory properties using a sensometabolomic approach. Forty-two red wines were sensorially assessed and chemically characterised using UPLC-QTOF-MS for targeted and untargeted analyses. Suitable partial least squares regression models were obtained for "dry", "sour", "oily", "prickly", and "unctuous". "Dry" was positively contributed by flavan-3-ols, anthocyanin derivatives (AntD), valine, gallic acid and its ethyl ester, and peptides, and negatively by sulfonated flavan-3-ols, anthocyanin-ethyl-flavan-3-ols, tartaric acid, flavonols (FOL), hydroxycinnamic acids (HA), protocatechuic ethyl ester, and proline. The "sour" model included molecules involved in "dry" and "bitter", ostensibly as a result of cognitive interactions. Derivatives of FOLs, epicatechin gallate, and N-acetyl-glucosamine phosphate contributed positively to "oily", as did vanillic acid, HAs, pyranoanthocyanins, and malvidin-flavan-3-ol derivatives for "prickly", and sugars, glutathione disulfide, AntD, FOL, and one HA for "unctuous". The presented approach offers an interesting tool for deciphering the sensory-active compounds involved in mouthfeel perception.

Decoding the Identity of Pinot Gris and Pinot Noir Wines: A Comprehensive Chemometric Fusion of Sensory (from Dual Panel) and Chemical Analysis

Quantitative relations between the sensory overall quality (OQJ) of commercial single grape variety Pinot Gris and Pinot Noir wines, defined using specific sensory attributes, and the most influencing chemical components were investigated in commercial wines from different international origins. Multiple factor analysis (MFA) was applied to achieve a comprehensive map of the quality of the samples while multivariate regression models were applied to each varietal wine to determine the sensory attributes influencing OQJ the most and to understand how the combinations of the volatile compounds influenced the olfactory sensory attributes. For Pinot Gris wine, OQJ was positively correlated with sensory attributes, like "floral" aroma, "stone-fruit" flavor, "yellow" color, "caramelized" aroma, and "tropical fruit" aroma according to an Italian panel. For Pinot Noir wine, "licorice" aroma, "cloves" aroma, "fresh wood" aroma, "red fruit" flavor, "cherry" aroma, and "spicy" flavor were positively correlated with OQJ by the same panel. Important predictors for the wine quality of Pinot Gris could be characterized, but not for Pinot Noir. Additionally, sensory tests were also carried out by different panel compositions (German and Italian). Both the German and the Italian panels preferred (based on OQJ) a Pinot Gris wine from New Zealand (Gisborne), but for different perceived characteristics (fruity and aromatic notes by the Italian panel and acidity by the German panel). For Pinot Noir, different panel compositions influenced the OQJ of the wines, as the wines from Chile (with more spicy, red fruit and woody notes) were preferred by the Italian panel, while the German panels preferred the wines from Argentina (with light, subtle woody and red fruit notes). The profile of cyclic and non-cyclic proanthocyanidins was also evaluated in the two varietal wines. No clear effect of the origin was observed, but the wines from Italy (Sicily/Puglia) were separated from the rest and were characterized by percentage ratio chemical indexes (%C-4) and (%C-5) for both varieties.

Predicting Bordeaux red wine origins and vintages from raw gas chromatograms

Connecting chemical properties to various wine characteristics is of great interest to the science of olfaction as well as the wine industry. We explored whether Bordeaux wine chemical identities and vintages (harvest year) can be inferred from a common and affordable chemical analysis, namely, a combination of gas chromatography (GC) and electron ionization mass spectrometry. Using 12 vintages (within the 1990-2007 range) from 7 estates of the Bordeaux region, we report that, remarkably, nonlinear dimensionality reduction techniques applied to raw gas chromatograms recover the geography of the Bordeaux region. Using machine learning, we found that we can not only recover the estate perfectly from gas chromatograms, but also the vintage with up to 50% accuracy. Interestingly, we observed that the entire chromatogram is informative with respect to geographic location and age, thus suggesting that the chemical identity of a wine is not defined by just a few molecules but is distributed over a large chemical spectrum. This study demonstrates the remarkable potential of GC analysis to explore fundamental questions about the origin and age of wine.

Metabolomics and genetics of reproductive bud development in Ficus carica var. sativa (edible fig) and in Ficus carica var. caprificus (caprifig): similarities and differences

In figs, reproductive biology comprises cultivars requiring or not pollination, with female trees (edible fig) and male trees (caprifig) bearing different types of fruits. Metabolomic and genetic studies may clarify bud differentiation mechanisms behind the different fruits. We used a targeted metabolomic analysis and genetic investigation through RNA sequence and candidate gene investigation to perform a deep analysis of buds of two fig cultivars, 'Petrelli' (San Pedro type) and 'Dottato' (Common type), and one caprifig. In this work, proton nuclear magnetic resonance (¹H NMR-based metabolomics) has been used to analyze and compare buds of the caprifig and the two fig cultivars collected at different times of the season. Metabolomic data of buds collected on the caprifig, 'Petrelli', and 'Dottato' were treated individually, building three separate orthogonal partial least squared (OPLS) models, using the "y" variable as the sampling time to allow the identification of the correlations among metabolomic profiles of buds. The sampling times revealed different patterns between caprifig and the two edible fig cultivars. A significant amount of glucose and fructose was found in 'Petrelli', differently from 'Dottato', in the buds in June, suggesting that these sugars not only are used by the ripening brebas of 'Petrelli' but also are directed toward the developing buds on the current year shoot for either a main crop (fruit in the current season) or a breba (fruit in the successive season). Genetic characterization through the RNA-seq of buds and comparison with the literature allowed the identification of 473 downregulated genes, with 22 only in profichi, and 391 upregulated genes, with 21 only in mammoni.

Identification of Oak-Barrel and Stainless Steel Tanks with Oak Chips Aged Wines in Ningxia Based on Three-Dimensional Fluorescence Spectroscopy Combined with Chemometrics

With the increased incidence of wine fraud, a fast and reliable method for wine certification has become a necessary prerequisite for the vigorous development of the global wine industry. In this study, a classification strategy based on three-dimensional fluorescence spectroscopy combined with chemometrics was proposed for oak-barrel and stainless steel tanks with oak chips aged wines. Principal component analysis (PCA), partial least squares analysis (PLS-DA), and Fisher discriminant analysis (FDA) were used to distinguish and evaluate the data matrix of the three-dimensional fluorescence spectra of wines. The results showed that FDA was superior to PCA and PLS-DA in classifying oak-barrel and stainless steel tanks with oak chips aged wines. As a general conclusion, three-dimensional fluorescence spectroscopy can provide valuable fingerprint information for the identification of oak-barrel and stainless steel tanks with oak chips aged wines, while the study will provide some theoretical references and standards for the quality control and quality assessment of oak-barrel aged wines.

Untargeted metabolomics analysis based on LC-IM-QTOF-MS for discriminating geographical origin and vintage of Chinese red wine

Identifying wine geographical origin and vintage is vital due to the abundance of fraudulent activity associated with wine mislabeling of region and vintage. In this study, an untargeted metabolomic approach based on liquid chromatography/ion mobility quadrupole time-of-flight mass spectrometry (LC-IM-QTOF-MS) was used to discriminate wine geographical origin and vintage. Wines were well discriminated according to region and vintage with orthogonal partial least squares-discriminant analysis (OPLS-DA). The differential metabolites subsequently were screened by OPLS-DA with pairwise modeling. 42 and 48 compounds in positive and negative ionization modes were screened as differential metabolitesfor the discrimination of different wine regions, and 37 and 35 compounds were screened for wine vintage. Furthermore, new OPLS-DA models were performed using these compounds, and the external verification trial showed excellent practicality with an accuracy over 84.2%. This study indicated that LC-IM-QTOF-MS-based untargeted metabolomics was a feasible tool for wine geographical origin and vintage discrimination.

Integrative analysis of sensory evaluation and non-targeted metabolomics to unravel tobacco leaf metabolites associated with sensory quality of heated tobacco

INTRODUCTION

Heated tobacco (Nicotiana tabacum L.) products are heating tobacco plug at a temperature of 350°C and produce different emissions in aerosol and sensory perceptions of tobacco leaf compared with combustible tobacco. Previous study assessed different tobacco varieties in heated tobacco for sensory quality and analyzed the links between sensory scores of the final products and certain chemical classes in tobacco leaf. However, contribution of individual metabolites to sensory quality of heated tobacco remains largely open for investigation.

METHODS

In present study, five tobacco varieties were evaluated as heated tobacco for sensory quality by an expert panel and the volatile and non-volatile metabolites were analyzed by non-targeted metabolomics profiling.

RESULTS

The five tobacco varieties had distinct sensory qualities and can be classified into higher and lower sensory rating classes. Principle component analysis and hierarchical cluster analysis showed that leaf volatile and non-volatile metabolome annotated were grouped and clustered by sensory ratings of heated tobacco. Orthogonal projections to latent structures discriminant analysis followed by variable importance in projection and fold-change analysis revealed 13 volatiles and 345 non-volatiles able to discriminate the tobacco varieties with higher and lower sensory ratings. Some compounds such as β-damascenone, scopoletin, chlorogenic acids, neochlorogenic acids, and flavonol glycosyl derivatives had strong contribution to the prediction of sensory quality of heated tobacco. Several lyso-phosphatidylcholine and lyso-phosphatidylethanolamine lipid species, and reducing and non-reducing sugar molecules were also positively related to sensory quality.

DISCUSSION

Taken together, these discriminating volatile and non-volatile metabolites support the role of leaf metabolites in affecting the sensory quality of heated tobacco and provide new information on the types of leaf metabolites that can be used to predict applicability of tobacco varieties for heated tobacco products.

Cross-modal interactions caused by nonvolatile compounds derived from fermentation, distillation and aging to harmonize flavor

Chinese liquor (Baijiu), unique liquor produced in China and among the six world-renowned distilled liquors, is never a follower of others. Flavor is the essential characteristics of Baijiu which largely affect consumers' acceptance and selection. Though the flavor of Baijiu has been widely explored, the majority of research and review mainly focused on the volatile compounds in Baijiu. The research status on detection, source and flavor contribution of nonvolatile compounds in Baijiu is clarified in the article based on available literatures and knowledge. The nonvolatile composition of Baijiu is the result of contributions of different degrees from each step involved in the production process. Gas chromatography-mass spectrometry combined with derivatization and ultra-high performance liquid chromatography coupled to mass spectrometry is the generally adopted methods for the characterization of nonvolatile compounds in Baijiu. Certain nonvolatile compounds are taste-active compounds. Cross-modal interactions caused by nonvolatile composition could affect the aroma intensity of flavor compounds in Baijiu. The work provides numerous incompletely explored but useful points for the flavor chemistry of Baijiu and lays a theoretical foundation for the better understanding of Baijiu flavor and rapid development of Baijiu industry.

Elucidating the effects of Lactobacillus plantarum fermentation on the aroma profiles of pasteurized litchi juice using multi-scale molecular sensory science

Three Lactobacillus Plantarum (LP), namely LP28, LP226 and LPC2W, were employed to investigate the effect on the aroma profiles of pasteurized litchi juice using E-nose, GC-IMS, GC-MS, and sensory evaluation. The E-nose results showed that pasteurization weakened the flavor profile of litchi juice, while LP fermentation effectively promoted flavor formation. The GC-MS analysis demonstrated that pasteurization significantly reduced the content of alcohols (28.51%), especially geraniol and citronellol, which give litchi juices a fruity and floral aroma. Different LP fermentation enhances the characteristic aroma and produces some new compounds that give it a strong fruity and citrus-like aroma. Moreover, 37 aroma-active compounds (OAV>1) indicated that the linalool (OAV 7504) was the highest, followed by (Z)-rose oxide (OAV 4265), 1-octen-3-ol (OAV 1055) and geraniol (OAV 764), which jointly form the main characteristic flavor. More esters were identified by GC-IMS, indicating the advantage of the combined approach for a better understanding of the impact of pasteurization and fermentation on the litchi juice. The sensory evaluation confirmed that the aroma attributes of fruity, citrus-like, floral, sweet and litchi-like were stronger for the samples fermented by LP28 than those for the other samples. The combination strategy used in this study would facilitate the awareness of litchi juice aroma and broaden our insight into the deep processing of litchi.

Characterization of wine volatile compounds from different regions and varieties by HS-SPME/GC-MS coupled with chemometrics

HS-SPME/GC-MS and aroma descriptive analysis were used to gain insights into the volatile and sensory details of 99 red wine samples collected from four varieties in five regions. The general volatile fingerprints of Cabernet Sauvignon and Merlot wine samples in Xinjiang and Ningxia regions were similar, even though chemometric models could not discriminate between them. The main drivers of the diversity were secondary metabolites of grape such as terpenes, benzene-derivatives, and ketones. Fermentation-derivatives (esters and alcohols) were also responsible for region and variety-related differences in wines. Analysis of volatile compounds also showed that the primary factor accounting for diversity in wines in this study was region rather than variety. These results highlight the sensory attributes and volatiles of different regions and varieties, and provide a quantitative basis for screening for differential metabolites and potential markers in wines.

Flavor Profiling Using Comprehensive Mass Spectrometry Analysis of Metabolites in Tomato Soups

Trained sensory panels are regularly used to rate food products but do not allow for data-driven approaches to steer food product development. This study evaluated the potential of a molecular-based strategy by analyzing 27 tomato soups that were enhanced with yeast-derived flavor products using a sensory panel as well as LC-MS and GC-MS profiling. These data sets were used to build prediction models for 26 different sensory attributes using partial least squares analysis. We found driving separation factors between the tomato soups and metabolites predicting different flavors. Many metabolites were putatively identified as dipeptides and sulfur-containing modified amino acids, which are scientifically described as related to umami or having "garlic-like" and "onion-like" attributes. Proposed identities of high-impact sensory markers (methionyl-proline and asparagine-leucine) were verified using MS/MS. The overall results highlighted the strength of combining sensory data and metabolomics platforms to find new information related to flavor perception in a complex food matrix.

Evaluation of the Perceptual Interaction among Ester Odorants and Nonvolatile Organic Acids in Baijiu by GC-MS, GC-O, Odor Threshold, and Sensory Analysis

By applying the aroma extract dilution analysis, 13 esters were found to have high FD factors in the Laobaigan flavor type of Baijiu. These were then quantified using GC-MS. In addition, 35 nonvolatile organic acids were quantified by a derivatization method combined with GC-MS. The perceptual interactions of lactic acid and ethyl lactate and that of lactic acid and ethyl acetate were studied through the olfactory threshold. The S curve was used to evaluate the changes in the olfactory thresholds. After adding lactic acid (1142, 20 000, and 53 703 mg/L), the olfactory thresholds of ethyl lactate (1000, 724, and 295 mg/L) and ethyl acetate (398, 324, and 257 mg/L) decreased obviously, which revealed that lactic acid gave additive or synergistic odor effects for the two esters. Furthermore, it was discovered that as the concentrations of lactic acid increased, the extent of the interaction among these compounds was also greater in the mixture.

Characterization of Bitter Compounds in Shaoxing Huangjiu by Quantitative Measurements, Taste Recombination, and Omission Experiments

Excessive and uncoordinated bitterness of Shaoxing Huangjiu, a traditional Chinese rice wine, reduces its acceptance by consumers. To determine the compounds responsible for this bitterness, gas chromatography-mass spectrometry and high-performance liquid chromatography were performed on four types of Shaoxing Huangjiu (Yuanhong, Huadiao, Shanniang, and Xiangxue wine) for targeted quantitation of candidate compounds known to contribute to bitterness. Calculations of dose-over-threshold factors revealed that isoamyl alcohol, 1-hexanol, phenylethanol, ethyl butyrate, ethyl lactate, furfural, histidine, and arginine were important bitter compounds. Taste recombination experiments demonstrated that a recombination model constructed using the screened known bitter compounds showed good similarity with the original sample in bitter taste. Furthermore, omission experiments revealed that isobutanol, isoamyl alcohol, 1-hexanol, phenylethanol, ethyl acetate, ethyl butyrate, ethyl lactate, furfural, arginine, and valine were the compounds affecting the bitter taste perception. This study provides a certain guiding effect on the bitterness control and taste improvement of Shaoxing Huangjiu.

Analysis of Microbial Community Diversity on the Epidermis of Wine Grapes in Manasi’s Vineyard, Xinjiang

Epiphytic microbial communities significantly impact the health and quality of grape berries. This study utilized high-performance liquid chromatography and high-throughput sequencing to explore the epiphytic microbial diversity and physicochemical indicators in nine different wine grape varieties. In total, 1,056,651 high-quality bacterial 16S rDNA sequences and 1,101,314 fungal ITS reads were used for taxonomic categorization. Among the bacteria, Proteobacteria and Firmicutes were the dominant phyla, and Massilia, Pantoea, Pseudomonas, Halomonas, Corynebacterium, Bacillus, Anaerococcus, and Acinetobacter were the dominant genera. Among the fungi, Ascomycota and Basidiomycota were the dominant phyla, and Alternaria, Filobasidium, Erysiphe, Naganishia, and Aureobasidium were the dominant genera. Notably, Matheran (MSL) and Riesling (RS) exhibited the highest microbial diversity among the nine grape varieties. Moreover, pronounced differences in epiphytic microorganisms in red and white grapes suggested that the grape variety significantly influences the structure of surface microbial communities. Understanding the composition of epiphytic microorganisms on the grape skin can provide a direct guide to winemaking.

Effects of Short-Chain Peptides on the Flavor Profile of Baijiu by the Density Functional Theory: Peptidomics, Sensomics, Flavor Reconstitution, and Sensory Evaluation

The effect of peptides on the flavor profile of Baijiu is unclear as a result of their trace concentrations in the complex matrix, and therefore, the study involving the interaction mechanism between peptides and flavor compounds is limited. In this study, short-chain peptides (amino acid number between 2 and 4, SCPs) associated with the Feng-flavor Baijiu (FFB) were comprehensively analyzed by a dedicated workflow using ultra-high-performance liquid chromatography Q Orbitrap high-resolution mass spectrometry, flavor reconstitution experiments, sensory analysis, and density functional theory (DFT) analysis. The concentrations of 96 SCPs intimately related with six different grades of honey aroma intensity in FFB were quantified (0.12-155.01 μg L^-1) after multivariable analysis, Spearman's correlation analysis (ρ ≥ 0.7), and confirmation with synthetic standards, and 32 dominant odorants with an odor activity value of ≥1 in FFB with the highest intensity of honey aroma were quantified by gas chromatography-mass spectrometry and gas chromatography-flame ionization detection analyses. The results of flavor reconstitution experiments and sensory analysis indicated that the SCPs can obviously influence the honey aroma with amplifying the fruity, sweet, and flora flavor odor characters (p < 0.05) while significantly reducing the acidic character (p < 0.001), which could be attributed to the most stable complex structure between SCPs and odor-active compounds calculated by DFT being butanoic acid, followed by β-damascenone, 3-methylbutanal, and ethyl hexanoate, and the multiple sites as a hydrogen bond donor or acceptor in SCPs can form a stable ternary structure with water and ethanol inside the peptide chain or carboxyl terminal of SCPs, consequently improving the stability of the Baijiu system. The results highlighted the important role of SCPs on the volatiles in Baijiu and laid the foundation for further facilitating the sensory quality of Baijiu products.

Proteomics and Metabolomics Profiling of Pork Exudate Reveals Meat Spoilage during Storage

Previous studies have evaluated pork quality by omics methods. However, proteomics coupled with metabolomics to investigate pork freshness by using pork exudates has not been reported. This study determined the changes in the profiles of peptides and metabolites in exudates from pork stored at different temperatures (25, 10, 4, and −2 °C). Multivariate statistical analysis revealed similar changes in profiles in exudates collected from pork stored at −2 and 4 °C, and additional changes following storage at higher temperatures. We identified peptides from 7 proteins and 30 metabolites differing in abundance between fresh and spoiled pork. Significant correlations between pork quality and most of the peptides from these 7 proteins and 30 metabolites were found. The present study provides insight into changes in the peptide and metabolite profiles of exudates from pork during storage at different temperatures, and our analysis suggests that such changes can be used as markers of pork spoilage.

Metabolomic Study of Dactylis glomerata Growing on Aeolian Archipelago (Italy)

The Aeolian Islands (Italy) are a volcanic archipelago in the Tyrrhenian Sea comprising seven main islands, among which are two active volcanoes. The peculiar geological features and the wide variety of environments and soils have an important impact on native plants, and in particular, the Aeolian populations of Dactylis glomerata (a perennial cool-season bunchgrass) exhibit remarkable phenotypic variability. Considering that environmental drivers also strongly affect the production of plant metabolites, this work aimed at comparing the metabolomic profiles of D. glomerata (leaves) harvested at different altitudes on four islands of the Aeolian archipelago, namely: Lipari, Vulcano, Stromboli and Panarea. Samples were analyzed by ¹H NMR profiling, and data were treated by PCA. Samples collected on Stromboli were very different from each other and from the samples collected in the other islands. Through an Orthogonal Partial Least Squares (OPLS) model, using altitude as the y variable, it emerged that the concentration of proline, glycine betaine, sucrose, glucose and chlorogenic acid of D. glomerata growing on Stromboli decreased at increasing altitude. Conversely, increasing altitude was associated with an increment in valine, asparagine, fumaric acid and phenylalanine.

Mixtures of Macro and Micronutrients Control Grape Powdery Mildew and Alter Berry Metabolites

Powdery mildew caused by the fungus Erysiphe necator is a major grape disease worldwide. It attacks foliage and berries and reduces yield and wine quality. Fungicides are mainly used for combating the disease. Fungicide resistance and the global requisite to reduce pesticide deployment encourage the use of environment-friendly alternatives for disease management. Our field experiments showed that the foliar application of the potassium phosphate fertilizer Top-KP+ (1-50-33 NPK) reduced disease incidence on leaves and clusters by 15-65% and severity by 75-90%, compared to untreated vines. Top-KP+ mixed with Nanovatz (containing the micronutrients boron (B) and zinc (Zn)) or with TruPhos Platinum (a mixture containing N, P₂O₅, K₂O, Zn, B, Mg, Fe, Mn, Cu, Mo, and CO) further reduced disease incidence by 30-90% and disease severity by 85-95%. These fertilizers were as effective as the fungicide tebuconazole. Tank mixtures of fertilizers and tebuconazole further enhanced control efficacy in the vineyards. The modes of action of fertilizers in disease control were elucidated via tests with grape seedlings, microscopy, and berry metabolomics. Fertilizers applied preventively to the foliage of grape seedlings inhibited powdery mildew development. Application onto existing mildew colonies plasmolyzed mycelia and conidia and arrested the development of the disease. Berries treated with fertilizers or with a fungicide showed a significant increase in anti-fungal and antioxidant metabolites. Twenty-two metabolites, including non-protein amino acids and carbohydrates, known for their anti-fungal and bioactive effects, were significantly upregulated in grapes treated with fertilizers as compared to grapes treated with a fungicide, suggesting possible indirect activity against the pathogen. Esters and organic acids that contribute to wine quality were also upregulated. We conclude that integrating macro and micronutrients in spray programs in commercial vineyards shall control powdery mildew, reduce fungicide deployment, delay the buildup of fungicide resistance, and may improve wine quality.

Identification of characteristic volatiles and metabolomic pathway during pork storage using HS-SPME-GC/MS coupled with multivariate analysis

Previous researches have been conducted evaluating the volatile compounds of pork. However, data regarding the changes in volatiles and metabolic pathways during pork storage were inadequately investigated. Herein, a headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC/MS) coupled multivariate analysis was proposed for characterizing the profiles of volatile compounds and metabolic pathways during pork storage. A total of 37 metabolites, including aldehydes, ketones, alcohols etc. were successfully identified. Multivariate statistical analysis revealed a substantial variation in metabolite phenotype among samples over the pork storage period, with 12 characteristic metabolites and 5 potential characteristic metabolites screened as biomarkers. Moreover, three metabolomic pathways analysis and transformation between each other (thermal reactions, lipid metabolism and amino acid metabolism) reveals the underlying mechanisms of metabolites change of pork. Therefore, the present study may provide insight into future understanding of the variation in the pork metabolite profiles.

Reconstitution of the Flavor Signature of Laobaigan-Type Baijiu Based on the Natural Concentrations of Its Odor-Active Compounds and Nonvolatile Organic Acids

Nonvolatile organic acids (NVOAs) associated with the Laobaigan flavor type of Baijiu were analyzed by a derivatization method, and 37 NVOAs were quantified. In addition, 33 odorants were judged to have high flavor dilution factors by application of aroma extract dilution analysis and quantification by gas chromatography coupled with mass spectrometry (GC-MS) and GC combined with quadrupole time-of-flight MS. The quantitative data obtained for the odorants and NVOAs were used to recombine the overall flavor of Baijiu. The odor of the reconstitution of the odor-active volatiles and the NVOAs was more similar to that of the original Baijiu sample than the sample that only contained odor-active volatiles, and the alcoholic and sweety flavor odor characters were reduced, while others, that is, fruity, acidic, floral, jujube and grain, were amplified. It was shown for the first time that NVOAs have effects on the volatiles in Baijiu and might obviously influence the intensity of certain aroma qualities.

LC-MS-Based Metabolomics Discriminates Premium from Standard Chilean cv. Cabernet Sauvignon Wines from Different Valleys

Cabernet Sauvignon grapes in Chile, mainly grown between the 30° S and 36° S, account for more than 30% of Chilean wine production, and yield wines with different characteristics which influence their quality. The aim of this study was to apply a liquid chromatography – mass spectrometry (LC–MS)-based metabolomic protocol to investigate the quality differentiation in a sample set of monovarietal wines from eight valleys covering 679 km of the north-south extension. All samples were produced using a standardized red winemaking process and classified according to a company categorization in two major groups: premium and standard, and each group in two subcategories. The results pointed out that N-containing metabolites (mainly small peptides) are promising biomarkers for quality differentiation. Moreover, the premium wines were characterized by higher amounts of anthocyanins and other glycosylated and acetylated flavonoids, as well as phenolic acids; standard quality wines, on the other hand, presented stilbenoids and sulfonated catabolites of tryptophan and flavanols.

Investigation of Volatile Compounds, Microbial Succession, and Their Relation During Spontaneous Fermentation of Petit Manseng

Petit Manseng is widely used for fermenting sweet wine and is popular among younger consumers because of its sweet taste and attractive flavor. To understand the mechanisms underlying spontaneous fermentation of Petit Manseng sweet wine in Xinjiang, the dynamic changes in the microbial population and volatile compounds were investigated through high-throughput sequencing (HTS) and headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography-mass spectrometry (GC-MS) technology, respectively. Moreover, the relationship between the microbial population and volatile compounds was deduced via multivariate data analysis. Candida and Mortierella were dominant genera in Petit Manseng wine during spontaneous fermentation. Many fermentative aroma compounds, including ethyl octanoate, isoamyl acetate, ethyl butyrate, ethyl decanoate, isoamyl alcohol, ethyl laurate, isopropyl acetate, hexanoic acid, and octanoic acid, were noted and found to be responsible for the strong fruity and fatty aroma of Petit Manseng sweet wine. Multivariate data analysis indicated that the predominant microorganisms contributed to the formation of these fermentative aroma compounds. Hannaella and Neomicrosphaeropsis displayed a significantly positive correlation with the 6-methylhept-5-en-2-one produced. The current results provide a reference for producing Petit Manseng sweet wine with desirable characteristics.

Metabolomics as a marketing tool for geographical indication products: a literature review

Geographical indication (GI) is used to identify a product's origin when its characteristics or quality are a result of geographical origin, which includes agricultural products and foodstuff. Metabolomics is an “omics” technique that can support product authentication by providing a chemical fingerprint of a biological system, such as plant and plant-derived products. The main purpose of this article is to verify possible contributions of metabolomic studies to the marketing field, mainly for certified regions, through an integrative review of the literature and maps produced by VOSviewer software. The results indicate that studies based on metabolomics approaches can relate specific food attributes to the region’s terroir and know-how. The evidence of this connection, marketing of GIs and metabolomics methods, is viewed as potential tool for marketing purposes (e.g., to assist communication of positive aspects and quality), and legal protection. In addition, our results provide a taxonomic categorization that can guide future marketing research involving metabolomics. Moreover, the results are also useful to government agencies to improve GIs registration systems and promotion strategies.

Aroma characteristics of traditional Huangjiu produced around Winter Solstice revealed by sensory evaluation, gas chromatography-mass spectrometry and gas chromatography-ion mobility spectrometry

Traditional Huangjiu (a kind of traditional Chinese rice wine) produced around Winter Solstice has higher quality and a more harmonious aroma than those produced during other periods. To determine the specific differences in aroma characteristics, sensory evaluation, gas chromatography-mass spectrometry (GC-MS) and gas chromatography-ion mobility spectrometry (GC-IMS) were used to analyze the volatile profiles of the traditional Huangjiu samples produced under different ambient temperature conditions. The sensory evaluation results showed that the aroma attributes of wheat, sweet, ester, alcoholic and sauce were stronger for the samples fermented near Winter Solstice than those for the other samples. GC-MS combined with heatmap analysis showed that with the decrease in average ambient temperature, the contents of esters such as diethyl succinate and ethyl butanoate gradually increased, and the contents of alcohols such as phenylethyl alcohol, 2-methylpropanol and 3-methylbutanol gradually decreased. Some key aroma compounds, such as ethyl butyrate (OAV: 97-151), nonanal (OAV: 189-200), ethyl octanoate (OAV: 859-1134) and ethyl phenylacetate (OAV: 307-353), were more abundant in the samples fermented near Winter Solstice than the other samples. The visualization of GC-IMS suggested that isoamyl acetate, 2-methylpropyl acetate, ethyl 3-methylbutyrate, and ethyl 2-methylbutanoate were enriched near Winter Solstice. Together, the results suggested that the traditional Huangjiu produced around Winter Solstice contained more flavor volatiles and had better aroma quality than those produced during other periods.

A Statistical Workflow to Evaluate the Modulation of Wine Metabolome and Its Contribution to the Sensory Attributes

A data-processing and statistical analysis workflow was proposed to evaluate the metabolic changes and its contribution to the sensory characteristics of different wines. This workflow was applied to rosé wines from different fermentation strategies. The metabolome was acquired by means of two high-throughput techniques: gas chromatography–mass spectrometry (GC-MS) and liquid chromatography–mass spectrometry (LC-MS) for volatile and non-volatile metabolites, respectively, in an untargeted approach, while the sensory evaluation of the wines was performed by a trained panel. Wine volatile and non-volatile metabolites modulation was independently evaluated by means of partial least squares discriminant analysis (PLS-DA), obtaining potential markers of the fermentation strategies. Then, the complete metabolome was integrated by means of sparse generalised canonical correlation analysis discriminant analysis (sGCC-DA). This integrative approach revealed a high link between the volatile and non-volatile data, and additional potential metabolite markers of the fermentation strategies were found. Subsequently, the evaluation of the contribution of metabolome to the sensory characteristics of wines was carried out. First, the all-relevant metabolites affected by the different fermentation processes were selected using PLS-DA and random forest (RF). Each set of volatile and non-volatile metabolites selected was then related to the sensory attributes of the wines by means of partial least squares regression (PLSR). Finally, the relationships among the three datasets were complementary evaluated using regularised generalised canonical correlation analysis (RGCCA), revealing new correlations among metabolites and sensory data.

Recent trends in the chromatographic analysis of volatile flavor and fragrance compounds: Annual review 2020

The chromatographic analysis of volatile flavor and fragrance compounds is performed routinely in several industries and in many fields of scientific research. Typical applications include food-, environmental-, essential oil- and cosmetics analysis. Even though the analysis of flavors and fragrances have become increasingly standardized during the past decade, there are still a large variety of techniques that can be used for their extraction, chemical analysis, and sensory analysis. Moreover, there are certain less commonly used techniques that are now being used with increased frequency and that are showing the potential of being used as alternatives to the existing standard techniques. In this annual review, the techniques that were most commonly used in 2020 for the investigation of these volatile compounds are discussed. In addition, a number of emerging trends are discussed, notably the use of solvent assisted flavor evaporation (SAFE) for extraction, GC ion mobility spectrometry (IMS) for volatile compound analysis and electronic senses, that is, E-noses and E-tongues, for sensory analysis. Miscellaneous hyphenated techniques, advances in stationary phase chemistry and a number of interesting applications are also highlighted.

Metabolomic Study of Sorghum (Sorghum bicolor) to Interpret Plant Behavior under Variable Field Conditions in View of Smart Agriculture Applications

To tackle the urgency of smarter crop management, the complex nature of agricultural ecosystems needs to be better understood, employing and combining different techniques and technologies. In this study, untargeted metabolomics and agro-meteorological survey were coupled to study the variation of Sorghum bicolor (L.) Moench metabolome during crop development, in response to environmental and anthropic factors. Twelve crop fields in the Emilia-Romagna region, Italy, were monitored and sampled at different stages, seedling (Ss), advanced vegetative (Sv), and ripening (Sr), and subjected to ¹H NMR-based metabolomics. The analytical method developed resulted to be successful to quickly analyze different sorghum organs. Dhurrin, a cyanogenic glucoside, resulted to be a biomarker of crop quality and development, and several insights into its turnover and functions were obtained. In particular, p-glucosyloxy-2-hydroxyphenylacetic acid was identified, for the first time, as the main metabolite accumulated in sorghum at Sr, after gradual dhurrin neutralization. During plant life, fertilization and biotic and abiotic stress reflected peculiar metabolomic profiles. Water supply and soil features (i.e., clay content) were correlated to metabolomic variations, affecting dhurrin (and related metabolites), amino acids, organic acids, and carbohydrate content. Increase in chlorogenic acid was registered in consequence of predator attacks. Moreover, grain from three fields presented traces of dhurrin and the lowest antioxidant potential, which resulted in poor grain quality. Metabolomics turned out to be a promising tool in view of smart agriculture for monitoring plant growth status and applying appropriate agricultural practices since the early stage of crop development.