Major Volatile Compounds Research Articles

Effects of temperature and pressure on volatile compounds of black cumin seeds (Nigella sativa L.) oil extracted by supercritical carbon dioxide

AbstractThis study investigated the effects of temperature and pressure on the yield and volatile compound contents of black cumin seed oil (BCO) extracted from black cumin seeds using supercritical carbon dioxide (SCCO2). The solubility of BCO in SCCO2 increased 2.5‐fold as the pressure increased by 10 MPa. Major volatile compounds in BCO were identified using a static headspace gas chromatography–mass spectrometry (SH–GC–MS). Evidence indicated the main volatile components in SCCO2‐extracted BCO to be hexanal, p‐cymene, and thymoquinone. BCO extracted from China‐cultivated black cumin seed contained similar amounts of p‐cymene and thymoquinone. This black cumin seed is classified as the cymene/thymoquinone chemotype and is also found in Indian, Iranian, and Algerian black cumin seeds. Thymoquinone contents in BCO were more sensitive to the extraction temperature than hexanal and p‐cymene contents. The maximum oil yield of 36.28 ± 1.38 wt%, with approximately 2.0 mg of thymoquinone per milliliter of oil, was obtained at extraction temperatures of 50°C and pressures of 30 MPa. A SH–GC–MS could detect small molecules in black cumin seed oil such as hexanal. The results of this work reveal that temperature has more impact on the selectivity of volatile compounds than pressure in supercritical carbon dioxide extraction.

Dynamics and correlation between volatile compounds and microbial community in chestnut rice wine fermentation

SummaryChestnut rice wine, also called banli mijiu (BLMJ), uses Chinese chestnut (Castanea mollissima Blume) in the fermentation of traditional glutinous rice wine. This study characterised the microbial communities and volatile compounds in BLMJ and explored their correlations. Headspace solid‐phase microextraction‐gas chromatography–mass spectrometry (HS‐SPME‐GC–MS) revealed that the major volatile compounds during BLMJ fermentation include eighteen important volatile compounds (OAV > 1). High‐throughput sequencing (HTS) demonstrated that the abundance and diversity of bacteria were significantly greater than those of fungi during the fermentation process. Among them, Kropensteria and Saccharomyces were the most abundant bacteria and fungi at the genus level during the fermentation of BLMJ. Spearman's correlation analysis revealed that eighteen important volatile compounds were significantly positively correlated with seven microbial genera (|r| > 0.9, P < 0.01), including six bacterial genera (Rhodococcus, Lactococcus, Pseudomonas, Janthinobacterium, Unclassified_f_Bacillaceae and Burkholderia‐Caballeronia‐Paraburkholderia) and one fungal genus (Saccharomyces). Therefore, these bacterias and fungi may be core functional microorganisms during BLMJ fermentation. The findings may provide important reference for mediating the microbial community during fermentation to improve the flavour of BLMJ.

Analysis of differences in microorganisms and aroma profiles between normal and off-flavor pit mud in Chinese strong-flavor Baijiu

The unique cellar fermentation process of CFSB is the reason for its characteristic “cellar aroma” flavor. The types, abundance, community structure and metabolic activity of microorganisms in the pit mud directly affect the microbial balance in the white spirit production environment, promoting the formation of typical aromas and influencing the quality of CFSB. During the production process, the production of off-flavor in the cellar may occur. The aim of this study is to elucidate the differences in microbiota and flavor between normal pit mud and abnormal pit mud (pit mud with off-flavor). A total of 46 major volatile compounds were identified, and 24 bacterial genera and 21 fungal genera were screened. The esters, acids, and alcohols in the abnormal pit mud were lower than those in the normal pit mud, while the aldehydes were higher. Indole, 3-methyl-, which have been proven to be responsible for the muddy and musty flavors, were detected in both types of pit mud, and for the first time, high levels of 4-Methylanisole were detected in the pit mud. The microbial composition of the two types of pit mud showed significant differences in the bacterial genera of Sporosarcina, Lactobacillus, Garciella, Anaerosalibacter, Lentimicrobium, HN-HF0106, Petrimonas, Clostridium_sensu_stricto_12 and Bacillus, and the fungal genera of Millerozyma, Penicillium, Mortierella, Monascus, Saccharomyces, Issatchenkia, Pithoascus, Pseudallescheria, and Wickerhamomyces. While we speculate that Sporosarcina is the predominant bacterial genus responsible for the imbalance of microbiota in pit mud.

Allelopathy of the essential oil of Fortunella margarita (Lour.) Swingle) in the germination on Helianthus annuus L. and Hordeum vulgare L.

Fortunella margarita known as ‘Kin-Kan or kumquat orange’ is a citrus species cultivated in South America with excellent adaptation to different climates, especially tropical. The fruits of F. margarita have a spectacular essential oil content. This study aimed to evaluate the allelopathic action of essential oil from ripe fruits of F. margarita in different concentrations on two large crops, sunflower (Helianthus annuus) and barley (Hordeum vulgare) in vitro. Ripe fruits of F. margarita were collected from an orchard in Rio Verde, Goiás, Brazil in January 2024. The skin of the fruits was removed and crushed to obtain the essential oil by Clevenger. The essential oil content obtained was expressed as a percentage (%). For the chemical profile, gas chromatography with sequential mass spectrometry (GC-MS) was used. For the allelopathic assay, varying concentrations of essential oil were produced. The allelopathic test was carried out in acrylic germination boxes and kept in a D.B.O. vegetation chamber. The results were expressed as percentage of germination µL mL-1. The radicle length was determined using a digital caliper and expressed in centimeters (cm). Seven major volatile compounds were obtained (D-Limonene 22%, β-Phellandrene 12%, β-Pinene 11%, Germacrene D 9%, Bicyclosexquiphellandrene 8%, Trans-Arbuscolene and α-Guaiene both with 5%). The essential oil demonstrated strong allelopathic activity on sunflower germination rates, especially for concentrations greater than 12.5-100 µL mL-1, between 54.40 and 12.80%. Barley seeds demonstrated resistance and a rate greater than 50% at the highest concentration (100 µL mL-1). Radicle length also showed a significant difference (P < 0.05) in all essential oil concentrations. Again, sunflower was strongly affected, with average primary roots between 0.98 and 0.11 cm and between 2.77 and 0.11 cm for barley. The essential oil from the ripe fruits of Fortunella margarita has an allelopathic action on germination and a toxic effect on the development of primary roots in sunflower and barley seeds.

Gas chromatography-stable isotope ratio mass spectrometry prior solid phase microextraction and gas chromatography-tandem mass spectrometry: development and optimization of analytical methods to analyse garlic (Allium sativum L.) volatile fraction

Garlic (Allium sativum L.) is not only appreciated for its flavour and taste, but it is also recognized for various health properties. The European Commission, through the attribution of the Protected Designation of Origin (PDO) certification mark, has officially recognized some specific varieties of garlic. To protect not only the commercial value but also the reputation of this appreciated product, effective tools are therefore required. For the first time, a new compound specific isotope analysis method based on carbon stable isotopic ratio measurement of the three major volatile garlic compounds allyl alcohol (AA), diallyl disulphide (DD) and diallyl trisulphide (DT) through head-space solid phase microextraction (HS-SPME) followed by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) was developed. A within-day standard deviation (Srwithin-day) of 0.3 ‰, 0.4 ‰ and 0.2 ‰ for δ(13C) and a between-day standard deviation (Srbetween-day) of 0.8 ‰, 1.0 ‰ and 0.6 ‰ of AA, DT and DD was estimated. For the first time, the ranges of isotopic variability for the three volatile compounds of red garlic from two neighbouring Italian regions (Abruzzo and Lazio) were defined analysing 30 samples. The same dataset was also considered in analysing the percentage composition of the previously mentioned three volatile compounds through HS-SPME followed by gas chromatography-tandem mass spectrometry (GC-MS/MS). The two analytical approaches were combined in this explorative study, aiming to provide potential parameters to discriminate garlic samples based on their geographical origin.

Genetic Characterization of Gardenia jasminoides Ellis Genotypes Derived from Seeds and Selection Based on Their Morphological Traits and Flower Aromatic Substances

Gardenia jasminoides Ellis is an evergreen shrub with white fragrant flowers, and it is cultivated for its ornamental, aromatic and medicinal value. The present study aimed to select desirable genotypes for potential commercial exploitation as pot plants or use in perfumery. Thus, 32 genotypes of G. jasminoides plants derived from seedlings, whose seeds were obtained from Australia and the USA, were evaluated for their genetic diversity in relation to four commercial cultivars (‘Pelion’, ‘Joy’, ‘Grandiflora’ and ‘Kimberly’, used as reference cultivars) using ISSR and SCoT markers. A cluster analysis separated the gardenia genotypes into the following three clusters: one cluster comprised the 16 genotypes originating from Australia, one included the 16 genotypes originating from the USA, and the third cluster contained the four reference cultivars. In other words, there was a clear demarcation of the genotypes investigated according to their geographical origin. In addition, the gardenia genotypes were evaluated for their morphological and chemical characteristics. Thus, flower- and leaf-related traits with ornamental value were measured, while the volatile compounds of flower extracts were identified with GC-MS analysis. Genotype 29-5 was selected for its acceptable morphological traits and genotype 51-8 for its rich volatile compounds. The major volatile compounds responsible for the floral aroma of the various gardenia genotypes examined were α-farnesene, benzyl tiglate, cis-3-hexenyltiglate, jasminelactone and linalool.

Seasonal dynamics of the microbial community in a strong-flavor baijiu fermentation.

The microbial community plays a crucial role in Chinese strong-flavor baijiu (SFB) fermentation. However, the seasonal dynamics of the microbial community in the SFB fermentation system and its contribution to the unique flavor of SFB have not been fully elucidated. In this study, we investigated the seasonal dynamics of the microbial community through 16S rRNA and ITS gene sequencing. The results revealed significant temporal dynamics of microbial communities and environmental variables throughout the four seasons. The influence of seasons on fungal communities was found to be more significant than on bacterial communities. The diversity of bacteria was higher during the winter and summer, whereas fungal diversity was more prominent in summer and autumn. Stochastic processes maintained their dominance in microbial assembly throughout all four seasons but the significance of heterogeneous selection increased during summer for both bacteria and fungi, whereas homogeneous selection became more pronounced during winter for fungi. The pH and environmental temperature were important drivers of microbial community assembly across different seasons, primarily impacting the core genera responsible for the production of major volatile flavor compounds (VFCs), especially ethyl caproate. These findings provide new insights into the impact of seasons on microbial communities and hold promise for improving the quality-control measures for SFB brewed in different seasons. © 2024 Society of Chemical Industry.

Improvement of volatile aromatic compound levels and sensory quality of distilled soju derived from Saccharomyces cerevisiae and Wickerhamomyces anomalus co-fermentation

Distilled soju, a Korean traditional alcoholic beverage, is produced by fermenting rice with a variety of microorganisms including molds, yeasts, and lactic acid-producing bacteria, followed by distillation. Our study sought to improve the quality of distilled soju through co-fermentation with Saccharomyces cerevisiae and Wickerhamomyces anomalus, known for producing volatile aromatic compounds during the early stages of fermentation. Analysis of volatile aromatic compounds in co-fermented distilled soju revealed a substantial increase in compounds with boiling points below 200 °C. Among them, ethyl hexanoate, isobutanol, and isoamyl alcohol were identified as the major volatile aromatic compounds based on Log2 fold change analyses of the volatile aromatic compound pattern. In sensory evaluation, co-fermented distilled soju received higher scores in terms of odor and overall preference. Therefore, incorporating W. anomalus may improve the quality of distilled soju.

Influencing factors of plant habitat, phenophase, and organ on the essential oil composition of Agastache rugosa

AbstractAgastache rugosa (Fisch. et Mey.) O. Ktze, also known as “Suhuoxiang” (SHX), has been cultivated for more than three hundred years as a valuable aromatic edible and medicinal plant in Jiangsu Province, China. The volatile compounds of SHX from various habitats were investigated by HS-SPME-GC-MS, detecting sixty-five chemical constituents with menthone, pulegone, and estragole being the major volatile compounds. Their relative contents showed various accumulation tendencies in different growth months by GC-MS, with the relative content of menthone gradually increasing, pulegone content decreasing, as well as estragole content climbing initially before declining. This tendency was supported by quantitative experiments using samples from various habitats, which also revealed that the full-bloom stages exhibited the highest total concentrations of menthone and pulegone. The volatile composition of SHX in various plant organs differed, with palmitic acid being the main volatile component of stems, while menthone and pulegone being the core volatile components of leaves and spikes, implying that leaves and spikes should be separated from the stem to obtain higher drug contents. The current findings provide new information for SHX cultivation and applications.

Transcriptome and volatile compounds analyses of floral development provide insight into floral scent formation in Paeonia lactiflora 'Wu Hua Long Yu'.

Herbaceous peony (Paeonia lactiflora) is a well-known ornamental plant in China, celebrated for its beautiful flowers that can emit fragrances. However, exact molecular mechanisms governing synthesis of floral volatiles within herbaceous peony remain unclear. To address this gap in knowledge, our study focused on analyzing the transcriptome and the levels of floral volatile compounds in P. lactiflora 'Wu Hua Long Yu' at different stages of flower development. Using gas chromatography-mass spectrometry (GC-MS), we obtained eighteen major volatile compounds, with monoterpenes being the dominant components among them. Our transcriptome analysis, based on pooled sequencing data, revealed the most differentially expressed genes (DEGs) existed between stages S1 and S3 of flower development. Among these DEGs, we identified 89 functional genes associated with the synthesis of volatile monoterpenes, with 28 of these genes showing a positive correlation with the release of monoterpenes. Specifically, key regulators of monoterpene synthesis in herbaceous peony appear to be 1-deoxy-D-xylulose 5-phosphate synthase (DXS), geranyl pyrophosphate synthase (GPPS), and terpene synthase (TPS). Additionally, our study identified some transcription factors (TFs) that may be involved in the biosynthesis of monoterpenes. These discoveries offer invaluable illumination into the intricate molecular underpinnings orchestrating the generation of floral fragrances in herbaceous peonies, and they offer a foundation for further research to identify and utilize candidate gene resources for this purpose.

Electrospun nanofibers based on zein and red onion bulb extract (Allium cepa, L.): Volatile compounds, hydrophilicity, and antioxidant activity.

Onion is rich in bioactive and volatile compounds with antioxidant activity. However, the pungent odor of volatile compounds (VOCs) released restricts its use. The encapsulation of red onion extract by electrospinning is an alternative to mask this odor and protect its bioactive compounds. The main objective of this study was to encapsulate red onion bulb extract (ROE) in different concentrations into zein nanofibers by electrospinning and evaluate their thermal, antioxidant, and hydrophilicity properties. The major VOC in ROE was 3(2H)-furanone, 2-hexyl-5-methyl. Incorporating ROE into the polymeric solutions increased electrical conductivity and decreased apparent viscosity, rendering nanofibers with a lower average diameter. The loading capacity of ROE on fibers was high, reaching 91.5% (10% ROE). The morphology of the nanofibers was random and continuous; however, it showed beads at the highest ROE concentration (40%). The addition of ROE to the nanofibers increased their hydrophilicity. The nanofibers' antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl, nitric oxide, and hydroxyl radicals ranged from 32.5% to 57.3%. The electrospun nanofibers have the potential to protect and mask VOCs. In addition, they offer a sustainable alternative to the synthetic antioxidants commonly employed in the food and packaging industry due to their antioxidant activities.

Biochemical characterization of gamma-ray induced mutants in mango

The volatile compound (VC) compositions of putative mutants were estimated and compared with the untreated seedlings and mother plants of mango genotype Bappakkai. Sesquiterpenes were the major VC detected in mother plants, control plants and putative mutant samples viz., BM4, BM5 and BM6, while, monoterpenes dominated the volatile fractions of other three putative mutant samples. A positive and significantly high correlation between all the mother plants, between mother plants and control seedlings as well as between the control seedlings, suggests a high level of similarity or lack of variability between mother plants and control seedlings, indicating that they might be of nucellar origin. Hence, we conclude that volatile profiling can be used as a biochemical marker for characterization and validation of putative mutants in polyembryonic mango genotypes.

Metabolic modulation of Basil (Ocimum basilicum L.): an insight into growth, metabolomics and antioxidant activity under varying temperature and light conditions

BackgroundTemperature and light are two critical environmental stimuli that greatly impact our agricultural industry. We explored the effects of varying temperature and light conditions on the metabolomics of basil, a plant widely used in cuisine and for medicinal purposes worldwide. Basil plants were subjected to elevated temperatures of 30 °C, 35 °C, and 40 °C, along with two light intensities (D11 and D23).ResultsOur results showed that the maximum shoot length (42.98 cm) was achieved at T30 and D23, the maximum leaf area (6.92 cm) at T30/D11, and the highest number of leaves (472) at T40/D11. However, at the higher temperature of T40, the number of leaves increased, but shoot length and leaf size significantly decreased (p < 0.05). Maxim shoot biomass (81 gm) and root biomass (91.2 gm) was recorded at T35/D23 treatments. Metabolomic studies of basil revealed that rosmarinic acid (RA), and linalool and eugenol were the major phenolic and volatile organic compounds (VOCs) under different growth conditions. RA levels were higher at 30 °C, correlated with elevated shikimate levels, indicating a carbon supply through the TCA cycle. In contrast, the growth conditions of 35 °C/D11 (μmol/m2/d) up-regulated the glyoxylate cycle (fumaric acid and malic acid) as part of stomatal closure, preventing ROS accumulation and resulting in increased VOC emission. Exposure to the higher temperature of 40 °C induced higher amino acid accumulation, improving temperature stresstolerance.ConclusionsThis study suggests that elevated temperature and light intensity affected the overall health of basil plants by modulating underlying growth mechanisms. Furthermore, elevated temperature plays a vital role in plant defense mechanisms by mediating the production of secondary metabolites associated with plant defense responses.Graphical

Terpene Synthase Gene Family in Chinese Chestnut (Castanea mollissima BL.) Harbors Two Sesquiterpene Synthase Genes Implicated in Defense against Gall Wasp Dryocosmus kuriphilus.

Chinese chestnut (Castanea mollissima BL.) is a well-known fruit tree that has been cultivated in East Asia for millennia. Leaves and buds of the plant can become seriously infested by the gall wasp Dryocosmus kuriphilus (GWDK), which results in gall formation and associated significant losses in fruit production. Herbivore-induced terpenes have been reported to play an important role in plant-herbivory interactions, and in this study, we show that upon herbivory by GWDK, four terpene-related compounds were significantly induced, while the concentrations of these four compounds in intact buds were relatively low. Among these compounds, (E)-nerolidol and (E, E)-α-farnesene have frequently been reported to be involved in plant herbivory defenses, which suggests direct and/or indirect functions in chestnut GWDK defenses. Candidate terpene synthase (TPS) genes that may account for (E)-nerolidol and (E, E)-α-farnesene terpene biosynthesis were characterized by transcriptomics and phylogenetic approaches, which revealed altered transcript levels for two TPSs: CmAFS, a TPS-g subfamily member, and CmNES/AFS, a TPS-b clade member. Both genes were dramatically upregulated in gene expression upon GWDK infestation. Furthermore, Agrobacterium tumefaciens-mediated transient overexpression in Nicotiana benthamiana showed that CmAFS catalyzed the formation of (E, E)-α-farnesene, while CmNES/AFS showed dual (E)-nerolidol and (E, E)-α-farnesene synthase activity. Biochemical assays of the recombinant CmAFS and CmNES/AFS proteins confirmed their catalytic activity in vitro, and the enzymatic products were consistent with two of the major volatile compounds released upon GWDK-infested chestnut buds. Subcellular localization demonstrated that CmAFS and CmNES/AFS were both localized in the cytoplasm, the primary compartment for sesquiterpene synthesis. In summary, we show that two novel sesquiterpene synthase genes CmAFS and CmNES/AFS are inducible by herbivory and can account for the elevated accumulation of (E, E)-α-farnesene and (E)-nerolidol upon GWDK infestation and may be implicated in chestnut defense against GWDK herbivores.

Differentiation through E-nose and GC-FID data modeling of rosé sparkling wines elaborated via traditional and Charmat methods.

The growing demand for rosé sparkling wine has led to an increase in its production. Traditional or Charmat wine-making influence the aromatic profiles in wine. An analysis such as gas chromatography makes an accurate assessment of wines based on volatile detection but is resource intensive. On the other hand, the electronic nose (E-nose) has emerged as a versatile tool, offering rapid, cost-effective discrimination of wines, and contributing insights into quality and production processes because of its aptitude to perform a global aromatic pattern evaluation. In the present study, rosé sparkling wines were produced using both methods and major volatile compounds and polyols were measured. Wines were tested by E-nose and predictive modelling was performed to distinguish them. Volatile profiles showed differences between Charmat and traditional methods, especially at 5 months of aging. A partial least square discriminant analysis (PLS-DA) was carried out on E-nose detections, obtaining a model that describes 94% of the variability, separating samples in different clusters and correctly identifying different classes. The differences derived from PLS-DA clustering agree with the results obtained by gas-chromatography. Moreover, a principal components regression model was built to verify the ability of the E-nose to non-destructively predict the amount of different volatiles analyzed. Production methods of Rosé sparkling wine affect the final wine aroma profiles as a result of the differences in terms of volatiles. The PLS-DA of the data obtained with E-nose reveals that distinguishing between Charmat and traditional methods is possible. Moreover, predictive models using gas chromatography-flame ionization detection analysis and E-nose highlight the possibility of fast and efficient prediction of volatiles from the E-nose. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Free and glycosidically bound volatile compounds in quince (Cydonia oblonga Mill) from Kashmir, India

The study reports the presence of 87 free and glycosidically bound volatile compounds in two quince fruit cultivars (Round and Oblong). The major free volatile compounds were ethyl acetate,ethyl (E)-2-butenoate, hexyl butanoate, hexyl 2-methylbutanoate, ethyl 3- phenyl propanoate, α-farnesene, hexanal, 1-hexanol, dihydo-beta-ionol and linalool oxide. The major bound volatiles were ethyl acetate, hexyl pentafluoro propanoate, ethyl hexanoate, γ-elemene, cyclocitral, megastigmatrienone-II and dihydo-beta-ionol. Among all the volatiles, γ-elemene (in glycosidically bound form), cyclocitral, (E)-β-damascenone (in both free and bound form), were found for the first time in quince fruit. Odour activity values (OAVs) of most potent volatiles were calculated for both free and bound volatiles, with 11 compounds having an OAV above 1. Volatiles with higher OAVs in two varieties were β-ionone, (E)-β-damascenone, (Z, E)-α-farnesene, ethyl 2-methyl butanoate and hexanal, with the highest being 425 for (E)-β-damascenone as free form in ‘Round’ variety. In addition, the off-flavours released from quince juice after enzyme treatment or cooking were identified. In particular, megastigmatrienone-II was identified to contribute tobacco flavour. Thus, it can be concluded that variation in free and bound volatiles between the two quince cultivars resulted in the different organoleptic properties, which would assist consumers in selection of the desired quince cultivar.

Potential of Solid Gel Formulation of Kaffir Lime Peel Extract Against Postharvest Pest Sitophilus Zeamais on Stored Rice

Maize weevil, Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae) is a primary pest on maize, rice, wheat, sorghum, and other cereal grains. The purpose of this study was to determine the effectiveness of using kaffir lime peel extract in solid gel formulation as a plant-based insecticide. This study used five treatments, untreated (control), 0.5%, 1%, 1.5%, and 2%. The results of this study are the treatments tested had effects on adult mortality and repellency. The 2% concentration showed the highest adult mortality and repellency. The major volatile organic compounds contained in kaffir lime peel were α-fernesene, α-sinensal, D-citronellol, and citronellal.

Dynamics of microbial communities, flavor, and physicochemical properties of kombucha-fermented Sargassum fusiforme beverage during fermentation

In this study, a novel kombucha-fermented Sargassum fusiforme beverage was prepared, and physicochemical properties, volatile flavor compounds, and microbial communities during the beverage fermentation were investigated. The results indicated that after fermentation, the pH decreased to 2.77 ± 0.05, titratable acid content increased to 4.42 ± 0.20 mg/mL, organic acids content increased and acetic acid became the main organic acid, values for total sugar content decreased and the reducing sugar content increased during fermentation. The clearance rates of DPPH radicals, hydroxyl radicals, superoxide anion radicals, and ABTS radicals increased after fermentation. In addition, the results of high-throughput sequencing showed that Zygosaccharomyces was the main fungi, and Komagataeibacter and Acetobacter were the main genera of bacteria in kombucha-fermented S. fusiforme beverage. Gas chromatography-ion migration spectrometry results showed that ethanol, acetic acid, acetone, and ethyl acetate were the main volatile flavor compounds. The correlation results between the dominant microbial community and the major volatile flavor compounds indicated that Pichia, Aspergillus, Zygosaccharomyces, Acetobacter, and Ralstonia had a positive effect on the flavor formation of beverages, which provided the direction for the later development and accurate screening of flavorous functional microorganisms.

GC-IMS and GC/Q-TOFMS analysis of Maotai-flavor baijiu at different aging times

There's a Chinese saying that the older the baijiu, the better it is. This study is an exploration of why baijiu are getting better during storaging. The aging mechanism of baijiu is still in the exploratory stage; therefore, this study used gas chromatography-ion mobility spectroscopy (GC-IMS) coupled with chemometrics and gas chromatography-quadrupole time-of-flight mass spectrometry (GC/Q-TOF MS) to analyze the volatile components of Maotai-flavor baijiu (MFB) at different aging times. Moreover, GC/Q-TOF MS was combined with a machine learning model to analyze the volatile components of MFB with different aging times to gain a deeper understanding of its aging mechanism. Nine major basal volatile organic compounds (VOCs) and 14 differential VOCs of MFB during the aging process were obtained using GC-IMS combined with visual mapping and differential analyses, and data refinement was performed using the GC/Q-TOF MS assay. With aging time, the total esters, except long-chain esters, decreased, and the total acid content increased. Based on these results, 21 characteristics were identified by combining random forest, support vector machine, and logistic regression models. These models were used to discriminate MFB with different aging times, which demonstrated the successful combination of multivariate analysis using multiple detection methods.

Comprehensive characterization of physicochemical, thermal, compositional, and sensory properties of cold-pressed rosehip seed oil

In this study, cold-pressed rosehip seed oil was fully characterized. Acidity and oxidation levels were near the limit values or slightly exceeded them and improvement in the storage conditions was suggested. The oil started to crystallize at -45.25 °C, and melt at -25.56 °C. Linoleic acid (51.1%), β-sitosterol (84.6%), γ-tocopherol (773.76 µg/g) and rosmarinic acid (31.38 µg/g) were determined as major fatty acid, sterol, tocopherol and phenolic compound, respectively. For the first time, aromatic volatile compounds and sensory descriptive terms were determined for cold-pressed rosehip seed oil. Sixty-seven volatile compounds were detected and L-limonene was found to be a major volatile compound. According to the sensory analysis, timber/kindling and raw vegetable tastes/aromas were found to be relatively dominant. Consequently, it is thought that rosehip seeds can be used as a raw material for edible and nutritionally-rich cold-pressed oil production and/or as source oil for functional food preparations.