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When grapes are exposed to wildfire smoke, certain smoke-related volatile phenols (VPs) can be absorbed into the fruit, where they can be then converted into volatile-phenol (VP) glycosides through glycosylation. These volatile-phenol glycosides can be particularly problematic from a winemaking standpoint as they can be hydrolyzed, releasing volatile phenols, which can contribute to smoke-related off-flavors. Current methods for quantitating these volatile-phenol glycosides present several challenges, including the requirement of expensive capital equipment, limited accuracy due to the molecular complexity of the glycosides, and the utilization of harsh reagents. To address these challenges, we proposed an enzymatic hydrolysis method enabled by a tailored enzyme cocktail of novel glycosidases discovered through genome mining, and the generated VPs from VP glycosides can be quantitated by gas chromatography-mass spectrometry (GC-MS). The enzyme cocktails displayed high activities and a broad substrate scope when using commercially available VP glycosides as the substrates for testing. When evaluated in an industrially relevant matrix of Cabernet Sauvignon wine and grapes, this enzymatic cocktail consistently achieved a comparable efficacy of acid hydrolysis. The proposed method offers a simple, safe, and affordable option for smoke taint analysis.

This study describes the sensory composition of commercial sweet almond varieties across two California growing seasons. It also discusses the relationship between sensory attributes and chemical and physical measures. Raw, whole almonds (43 samples each of 13 varieties in 2015 and 40 samples each of 10 varieties in 2016) were evaluated for their sensory profiles using descriptive sensory analysis. The 2016 samples were also analyzed for macro- and micronutrients, amygdalin, volatile composition (using gas chromatography-mass spectrometry), and physical properties, and the results were modeled with the sensory data. Independence, Sonora, and Wood Colony were harder, more fracturable, and crunchy, whereas Fritz and Monterey were more moist and chewy, reflecting their moisture contents. Aldrich and Fritz were higher in marzipan/benzaldehyde flavor, which is related to amygdalin, benzaldehyde, phenylethyl alcohol, and benzyl alcohol. New insights are provided into sweet-almond composition and the sensorial contribution of headspace volatiles. This assists almond growers and processors in describing and marketing almond varieties.

Due to their unique properties, copper-based nanopesticides are emerging in the market. Thus, understanding their effect on crop plants is very important. Metabolomics can capture a snapshot of cellular metabolic responses to a stressor. We selected maize and cucumber as model plants for exposure to different doses of Cu(OH)2 nanopesticide. GC-TOF-MS-based metabolomics was employed to determine the metabolic responses of these two species. Results revealed significant differences in metabolite profile changes between maize and cucumber. Furthermore, the Cu(OH)2 nanopesticide induced metabolic reprogramming in both species, but in different manners. In maize, several intermediate metabolites of the glycolysis pathway and tricarboxylic acid cycle (TCA) were up-regulated, indicating the energy metabolism was activated. In addition, the levels of aromatic compounds (4-hydroxycinnamic acid and 1,2,4-benzenetriol) and their precursors (phenylalanine, tyrosine) were enhanced, indicating the activation of shikimate-phenylpropanoid biosynthesis in maize leaves, which is an antioxidant defense-related pathway. In cucumber, arginine and proline metabolic pathways were the most significantly altered pathway. Both species exhibited altered levels of fatty acids and polysaccharides, suggesting the cell membrane and cell wall composition may change in response to Cu(OH)2 nanopesticide. Thus, metabolomics helps to deeply understand the differential response of these plants to the same nanopesticide stressor.

Monitoring oxidative flavor changes in almonds is possible only if the chemical and sensory profile during roasting and storage is first established. Herein, almonds roasted at two different temperatures (115 and 152 °C) were stored at 39 °C for 0 to 12 months and were analyzed by headspace solid-phase microextraction gas chromatography-mass spectrometry, descriptive analysis, and consumer hedonic analysis. Volatile profiles, descriptive sensory profiles, and consumer hedonic scores were analyzed for predictive relationships. Descriptive attributes involving Roasted and Nutty as well as consumer liking were highest in fresh almonds, while flavors typically associated with oxidative rancidity such as Cardboard, Painty/Solvent, Soapy, and Total Oxidized increased during storage. Compounds most important for predicting rancidity-related attributes were lipid oxidation products, including pentanal, hexanal, heptanal, and octanal. Consumer liking was best predicted by similar compounds to those predicting Clean Nutty flavor, including Maillard reaction products such as 2- and 3-methylbutanal, 2-methylpyrazine, and 2,5-dimethylpyrazine.

Bacillus amyloliquefaciens strain SQ-2, isolated from a cured product, has been demonstrated to exhibit a highly efficacious performance against phytopathogens, including Stemphylium solani , Fusarium moniliforme , Fusarium graminearum , and Aspergillus tubingensis . In particular, with regard to A. tubingensis , which causes summer bunch rot, SQ-2 has been observed to suppress the mycelial growth of all tested grape cultivars by over 40%. Especially on Kyoho grapes, it has the highest inhibition rate of 53%. Scanning electron microscopy (SEM) confirms that SQ-2 is an effective agent for suppressing the mycelia proliferation, differentiation, and spore formation of A. tubingensis . Furthermore, an LC/MS analysis revealed that SQ-2 produces two principal lipopeptides, namely, bacillibactin and surfactin, in addition to a polyketide, bacillaene. Further analysis through gas chromatography-mass spectrometry (GC/MS) identified 41 distinct volatile organic compounds secreted by SQ-2. Transcriptomic analysis indicated that exposure to the metabolite of SQ-2 induced substantial gene expression alterations in A. tubingensis . These data suggest that B. amyloliquefaciens strain SQ-2 exhibits promising crop protection potential of inhibiting plant pathogens through the secretion of bacillibactin, surfactin, bacillaene, and VOCs.

Halogenated polycyclic aromatic hydrocarbons (XPAHs) present potential risk owing to their greater toxicity than PAHs. This study aimed to explore their profiles in commercial salt-tolerant rice, effects of saline cultivation (0‰ and 3‰ saline conditions), and formation during home cooking. A validated SPE-GC-MS/MS method was used to analyze PAHs and XPAHs in 16 commercial salt-tolerant rice samples. The PAH24 and XPAH18 concentrations were 6.95-32.73 μg kg -1 and 0.013-0.593 μg kg -1 , respectively. Chlorinated PAHs (ClPAHs) were significantly greater in salt-tolerant rice (0.14 μg kg -1 ) than in normal rice (0.048 μg kg -1 ). During cooking, a notable increase (210-1120%) in ClPAHs and a significant correlation ( r = 0.70-0.81, p < 0.05) between newly formed ClPAHs and their parent PAHs were observed, suggesting cooking-induced chlorination of PAHs. Moreover, chlorine radical-induced chlorination of PAHs may be the primary mechanism involved. These findings highlight increased exposure to ClPAHs due to saline cultivation and cooking and provide new insight into ClPAH formation from household cooking.

Essential oils (EOs) are gaining importance as sustainable food antioxidants, but kinetic data on peroxyl radical trapping are missing. Thirteen EOs from 11 botanical species were studied in the inhibited autoxidation of cumene by oxygen-uptake kinetics. EOs of Juniperus oxycedrus , Syzygium aromaticum , Thymus vulgaris , Thymbra capitata , Betula alba , Pimenta racemosa , and Satureja montana , containing 23-86% phenolic components by gas chromatography/mass spectrometry (GC-MS) analysis, afforded inhibition rate constants k inh in the order of 10 4 M -1 s -1 at 30 °C similar to reference butylhydroxytoluene (2,6-di- tert -butyl-4-methylphenol) (BHT). They matched or outperformed BHT in the protection of olive oil. The EOs Daucus carota and Cedrus atlantica with <1% phenols and those of Apium graveolens and Tagetes minuta with no phenolics had no chain-breaking activity. Key components carvacrol, thymol, eugenol, dihydroeugenol, umbelliferone, conyferyl alcohol, o -cresol, m -cresol, p -cresol, 4-allylphenol, 2,3-xylenol, 2,4-xylenol, and phenol had k inh in the range of 10 3 -10 4 M -1 s -1 and, along with EOs containing them, could potentially replace BHT in the protection of food products.

The brown marmorated stink bug ( Halyomorpha halys ) poses a significant threat to hazelnut crops by affecting kernel development and causing quality defects, reducing the market value. While previous studies have identified bitter-tasting compounds in affected kernels, the impact of stink bug feeding on the hazelnut metabolome, particularly concerning aroma precursors, remains underexplored. This study aims to map the nonvolatile metabolome and volatilome of hazelnut samples obtained by caging H. halys on different cultivars in two locations to identify markers for diagnosing stink bug damage. Using a multiomic approach involving headspace solid-phase microextraction (HS-SPME), comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC-TOF MS), and liquid chromatography-high-resolution mass spectrometry (LC-HRMS), both raw and roasted hazelnuts are analyzed, with artificial intelligence (AI) and machine learning tools employed to explore data correlations. The study finds that the hazelnut metabolome and volatilome exhibit high chemical complexity with significant classes of compounds such as aldehydes, ketones, alcohols, and terpenes identified in both raw and roasted hazelnuts. Multivariate analysis indicates that the orchard location significantly impacts the metabolome, followed by damage type, with cultivar differences being less pronounced. Partial least-squares discriminant analysis (PLS-DA) models achieve high predictive accuracy for orchard location (99%) and damage type (≈80%), with the roasted volatilome showing the highest predictive accuracy. Correlation matrices reveal significant relationships between raw hazelnut metabolites and aroma compounds in roasted samples, suggesting potential markers for stink bug damage that could guide the quality assessment and mitigation strategies. Data fusion techniques further enhance classification performance, particularly in predicting damage type, underscoring the potential of integrating multiple data sets for comprehensive quality assessment.

The clustered mountain mint, Pycnanthemum muticum , is a pleasant-smelling, native North American plant. Despite its wide geographical presence across the United States and Canada, little is known about the specific odorants responsible for its pleasing aroma. Herein, 42 odorants were identified in the plant through solvent-assisted flavor evaporation (SAFE), gas chromatography-olfactometry (GC-O), and gas chromatography-mass spectrometry (GC-MS). Subsequent analysis involved determining flavor dilution (FD) factors using aroma extract dilution analysis (AEDA), quantitating 14 odorants through stable isotope dilution assays (SIDA), and calculating their odor activity values (OAVs). Several noteworthy odorants with OAV ≥ 1 included pulegone (mint, medicinal; OAV 276), 1-octen-3-one (mushroom; OAV 149), menthofuran (mint, petrol; OAV 139), nonanal (citrus; OAV 21), γ-nonalactone (coconut; OAV 13), 1,8-cineole (eucalyptus; OAV 12), mintlactone (mint, coconut; OAV 12), menthone (mint, fresh; OAV 7.3), α-pinene (pine; OAV 4), and piperitenone (mint; OAV 1.9). The study also determined the stereochemistry of various chiral odorants. An aroma simulation model was developed to validate the identification and quantitative results; upon evaluation using olfactory profile analysis, no significant differences were found between the aroma model and an aqueous infusion of P. muticum ( P > 0.05). These findings lay the foundation for future investigations into the diversity of P. muticum selections and can provide valuable insights for studies on plant hybridization for food and flavor applications.

To address the volatile markers and their biotransformation during the early stage of Zygosaccharomyces spp. contamination in acacia honey, headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and chemometric analyses were used to explore the variation of volatile compounds. A total of 36 and 35 volatile compounds were identified before and after contamination of Zygosaccharomyces rouxii and Zygosaccharomyces mellis , respectively. Methyl butyrate and 2-methyl-3-pentanone could be used as volatile markers of Z. rouxii and Z. mellis- contaminated honey, which were both specific products of the yeast's own fermentation. 2,5-Dimethylbenzaldehyde was identified as a volatile marker of Z. rouxii and Z. mellis- contaminated acacia honey, and it was a specific product resulting from the interaction of yeast and acacia honey. In addition, β-damascenone could be determined as a potential volatile marker after Z. rouxii- contaminated acacia honey. Methyl 2-methylbutyrate was used as a potential volatile marker in the high-concentration groups of Z. rouxii and Z. mellis . The content ranges of methyl butyrate, 2-methyl-3-pentanone, and 2,5-dimethylbenzaldehyde in four samples were 6.62-14.59, 3.15-5.42, and 52.52-215.19 μg/mL, respectively. The variation of volatile markers during the early stage of osmotolerant yeast contamination provided a theoretical basis for the use of HS-SPME-GC-MS for the rapid detection of acacia honey deterioration while reducing economic losses.

The presence of an oily odor in rice-made Baijiu is a unique characteristic that has not been thoroughly studied. This study qualitatively and quantitatively identified important aroma-active compounds in samples with typical and atypical oily odors using aroma extract dilution analysis (AEDA). By comparing the differences between flavor dilution (FD) and odor activity values (OAVs), nine compounds showing significant differences were selected. By combining normal-phase silica gel column and sensory analysis, these nine potential oily odor compounds were isolated from the typical oily odor sample. Addition and omission experiments confirmed that hexanal, trans -2-heptenal, trans , trans -2,4-nonadienal, (2 E )-2-decenal, trans , trans -2,4-decadienal, and γ-nonanolide are key contributors to the oily odor.

Fungal secondary metabolites play a highly significant role in crop protection, which is related to their antifungal activity against agriculturally important phytopathogens. In fact, plant diseases caused by fungi including species belonging to the genera of Alternaria , Botrytis , and Fusarium have become increasingly serious affecting crop yield and quality. Hence, there is increasing awareness by the scientific community of the importance of exploiting fungal products for finding new compounds able to inhibit phytopathogens. In this study several drimane-type sesquiterpenes have been detected for the first time as products of Aspergillus xerophilus by GC-MS analysis of the organic extracts obtained from the mycelia and culture filtrates of the fungus grown on two different substrates. Seven pure drimane-type sesquiterpenes were also isolated and identified by spectroscopic methods. The inhibitory effects of the pure compounds have been investigated against three phytopathogenic fungi of agrarian crops (i.e., Botrytis cinerea , Alternaria alternata , and Fusarium oxysporum f. sp. pisi ). Among the drimane-type sesquiterpenes isolated in this study, 9,11-dihydroxy-6-oxodrim-7-ene is the most active against the three phytopathogens. Our findings also reveal the high sensitivity of A. alternata to the isolated compounds. These results pave the way for future applications in agriculture of both A. xerophilus and its metabolites.

Simultaneous detection of the dynamic distribution of long-chain fatty acid ethyl esters (LCFAEEs) during Baijiu distillation is crucial for optimizing its flavor and health attributes. In this study, we synthesized a simple, cost-effective Fe 3 O 4 @NH 2 adsorbent to simultaneously extract eight LCFAEEs from Baijiu. Through density functional theory and adsorption experiments, we elucidated 1,6-hexanediamine as a surface modifier, with the -NH 2 groups providing adsorption sites for the LCFAEEs via hydrogen-bonding interactions and van der Waals forces. Additionally, we established the magnetic solid-phase extraction-GC-MS extraction technique combined with stable isotope dilution analysis to analyze LCFAEEs. This method revealed the dynamic distribution patterns of LCFAEEs during strong aroma-type Baijiu (SAB) distillation. We observed that the concentrations of the eight LCFAEEs gradually decreased with prolonged distillation and were significantly correlated with ethanol concentration. To ensure optimal flavor and clarity in SAB, it is recommended to select the heart-stage base Baijiu with an alcohol content of 58%-63%.

New interspecific hybrid hazelnut crosses between American ( Corylus americana ) and European ( Corylus avellana ) hazelnuts are being developed to support a commercial industry in the Midwest region of the United States. In this study, volatile compounds that impact consumer aroma liking of roasted hybrid hazelnuts ( C. americana × C. avellana ) were investigated by targeted and nontargeted GC/MS flavoromics. Chemical profiles from 10 roasted hybrid hazelnut samples were modeled with consumer aroma liking scores by orthogonal partial least-squares with good fit and predictive performance ( R 2 ≥ 0.92, Q 2 ≥ 0.82, RMSE CV = 0.2). Top ranked predictors positively correlated with liking included 12 aroma compounds and 4 profiled volatiles for the targeted and nontargeted methods, respectively. Sensory recombination testing of hazelnut samples with addition of the 12 predictive odorants was preferred by consumers ( p < 0.001, Δ aroma liking = 2.2 on 9-point scale) and perceived as more roasty, nutty, and sweet compared to the control ( p < 0.05). Addition of the 4 predictive volatiles at subthreshold levels also was preferred ( p = 0.02) and perceived as less earthy and mushroom like than the control ( p < 0.05).

American-European hybrid hazelnuts ( Corylus americana × Corylus avellana ) are an emerging crop in the Upper Midwest of the United States that have been reported to have unique sensory characteristics compared to traditionally grown European hazelnuts. In this study, key odor-active compounds in a roasted hybrid hazelnut variety ( C. americana × C. avellana ) were identified and profiled across different hybrid hazelnut varietals to understand sensory differences. Gas chromatography/mass spectrometry/olfactometry analysis identified 33 odorants with high flavor dilution factors (FD ≥ 16) in the roasted hybrid hazelnut, including 2-acetylpyrazine and 2-aminoacetophenone as first reported hazelnut odorants. Descriptive sensory analysis profiles of the roasted hazelnut and an aroma recombination model consisting of 27 odorants quantified above their odor detection thresholds were not significantly different for the six evaluated attributes, confirming the aroma contribution of the identified odorants. Variation in all 33 aroma-active compounds across 12 hybrid and two European hazelnut varieties was visualized through principal component analysis and related to aroma profiles previously characterized by consumers.

Understanding volatile compound formation is critical for enhancing the flavor quality of mangoes. Integrated untargeted metabolomics and proteomics were employed to explore volatile compound formation in three different polyembryonic mango cultivars ("Ah Ping," "Rosa," and "Rosigold"). A total of 87 volatile compounds were identified using SPME-GC-MS. Untargeted metabolomics and proteomics resulted in identification of 508 metabolites and 4481 proteins, respectively. Integrative analysis revealed that the volatile compound formation was influenced by fatty acids, amino acids, pentose, and hexose, as well as terpenoid metabolisms. Specifically, upward expression of core enzymes in lipoxygenanse pathway was responsible for the higher levels of some C6 and C9 volatile compounds in "Ah Ping." The differential expression of key enzymes in fatty acid degradation facilitates the varied contents of straight-chain volatile compounds. The upregulation of glutamate decarboxylase and branched-chain amino acid aminotransferase upstream of butanoate metabolism led to the highest levels of butyl esters in "Ah Ping." Furthermore, the different levels of volatile furan and pyran compounds might be attributed to differential expression of critical enzymes in pentose and hexose metabolism. These findings established a metabolic and proteomic map unraveling the biosynthesis of specific volatile compounds and provided insights into understanding the characteristic flavor of mango.

The demand for natural Vanilla has increased rapidly, creating the need for more potential sources of high-quality Vanilla essence. Understanding the geographical influences on the aroma profile of Vanilla is essential. This study demonstrates the first comparative analysis of odorant compositions in the three most important Vanilla varieties: Vanilla planifolia , Vanilla pompona , and Vanilla tahitensis from different origins. Following the screening for odor-active molecules through gas chromatography-olfactometry and aroma extract dilution analysis (GC-O and AEDA), selected compounds were quantified using stable isotope dilution assays (SIDA) and their dose over threshold values (DoTs) were calculated. Vanillin was confirmed as the most important odor-active compound due to its highest DoT value, especially in the V. planifolia sample. Meanwhile, 4-methoxybenzyl alcohol and 4-methoxybenzaldehyde showed higher DoT factors than vanillin in V. pompona and partially in V. tahitensis samples. This indicates their role as discriminative odorants for these varieties. The heightened DoT values of 3-hydroxy-4,5-dimethyl-2(5 H )-furanone in Uganda Vanilla samples unveil geographical influences on the odorant profile within V. planifolia species. Additionally, 2-methyl-3-(methyldithio)furan was identified for the first time in Vanilla samples with diverse DoT values from different species and origins.

In recent years, there has been a need for environmentally friendly compounds for weed management in agriculture. This study is aimed to assess the phytotoxic constituents of oils obtained from oleoresins of seven Copaifera species (known as copaiba oils). Copaiba oils were separated from the resins by hydro-distillation, and the distillates were analyzed using gas chromatography-mass spectrometry (GC-MS) to characterize their chemical compositions. Multivariate analyses and molecular networking of GC-MS data were conducted to discern patterns in the chemical composition and phytotoxic activity of the oils, with the aim of identifying key compounds associated with phytotoxic activity. Seed germination bioassay revealed strong or complete germination inhibition against the monocot, Agrostis stolonifera but not the dicot Lactuca sativa . GC-MS analysis showed variations in composition among Copaifera species with some common compounds identified across multiple species. Caryophyllene oxide and junenol were associated with the observed phytotoxic effects. Automated flash chromatography was used to isolate the major compounds of the oils. Isolated compounds exhibited differing levels of phytotoxicity compared to the oils, suggesting the importance of interactions or synergism among oil components. These findings highlight the potential of copaiba oils as natural herbicidal agents and underscore the importance of considering species-specific responses in weed management strategies.

Sprouting of stored oilseeds due to improper storage can lead to quality defects of cold-pressed oils obtained from them. This study aimed to evaluate the effect of seed sprouting on volatile organic compounds (VOCs), aroma-active compounds, and the content of nonvolatile metabolites in cold-pressed false flax oil obtained from sprouted seeds. In this study, 88 unique VOCs were detected in sprouted oils, whereas only 42 were found in the control oils. The control oils were characterized by a higher abundance of alcohols, while all other groups of compounds were associated with sprouted seeds. The formation of many VOCs was reflected in changes in the nonvolatile precursors. Fifteen aroma-active compounds were identified in sprouted oil, with five compounds playing a significant role (FD ≥ 128) in aroma formation. The presented approach allowed identification of differences caused by seed sprouting, resulting in oils with a much stronger aroma and a richer profile of VOCs due to intensive metabolic changes. The origin of many VOCs can be explained by alterations in the content of nonvolatile metabolites.

We tested the ability of wood distillate (WD) to interact with urea in agricultural soil. WD is a sustainable material that has been addressed as a promising alternative to synthetic soil corroborants. However, there is little information about the effect of WD on the nitrogen cycle. In this study, soils with different amounts of WD and with/without urea were tested for ammonium, urease, nitrate/nitrite, and potential nitrification activity at different points in a 30 day time frame. High concentrations of WD (1-2%) inhibited the hydrolysis of urea and the oxidation of ammonium to nitrate. Thermal desorption coupled to GC-MS and high-performance liquid chromatography-tandem mass spectrometry characterization allowed us to reveal that WD-urea interactions mainly involve lignin-derived compounds in the distillate, such as catechol, resorcinol, and syringol. This study provides the first evidence of a strong interaction between WD and urea in soil that could be used to develop slow-release fertilizers.

The research focused on the distinctive empty cup aroma, with the aim of identifying the key aroma compounds and the formation mechanism of empty cup aroma in soy sauce aroma type baijiu (SSB). The lasting times of SSB is significantly longer than that of other types of baijiu, with an average duration of 28 days. Key compounds such as 2,3-dimethyl-5-ethylpyrazine, phenylethyl alcohol, p -cresol, sotolon, benzeneacetic acid were identified in empty cup aroma due to their highest flavor dilution factor. Molecular dynamics (MD) simulation was performed to study the mechanism of empty cup aroma on the liquid-gas interface and solid-gas interface. The results revealed the existence of hydrogen bonding and van der Waals forces between sotolon and lactic acid, a representative nonvolatile compound, which are speculated to be an important reason for the empty cup aroma.

Squalene has been proven to possess various bioactive functions that are widely present in vegetable oils. A more comprehensive understanding of the reaction behavior of squalene under oxidative conditions was achieved by studying its antioxidant capacity and thermal degradation products. The total singlet oxygen quenching rate constant ( k r + k q , and both physical and chemical quenching mechanisms equally contribute to the overall singlet oxygen quenching. Fourteen degradation products of squalene were identified at 180 °C by using gas chromatography-mass spectrometry (GC-MS). Combining with DFT calculations, the thermal degradation pathway of squalene was proposed: the aldehydes, ketones, and alcohols, and epoxy compounds were formed by the homolytic cleavage of squalene hydroperoxides to form alkoxy radicals, followed by β-scission of the alkoxyl radicals at adjacent C-C bonds or intramolecular cyclization.7 M -1 s -1 , and both physical and chemical quenching mechanisms equally contribute to the overall singlet oxygen quenching. Fourteen degradation products of squalene were identified at 180 °C by using gas chromatography-mass spectrometry (GC-MS). Combining with DFT calculations, the thermal degradation pathway of squalene was proposed: the aldehydes, ketones, and alcohols, and epoxy compounds were formed by the homolytic cleavage of squalene hydroperoxides to form alkoxy radicals, followed by β-scission of the alkoxyl radicals at adjacent C-C bonds or intramolecular cyclization.

An experimental setup was devised to investigate the permeability of cocoa bean seed coat and pulp to key volatile compounds during fermentation. Four labeled compounds (ethyl acetate- d 3, ethyl octanoate- d 15, 2-phenylethanol- d 5, linalool- d 5) and 2 unlabeled (beta-damascenone, delta-decalactone) were chosen for the investigation. The beans (cotyledons), depulped beans, or pulped beans were immersed separately in a concentrated solution of these volatile compounds at 36 or 46 °C for durations ranging from 3 to 120 h. The imbibed beans were dissected, and the cotyledons were analyzed by SPME-GC/MS. The diffusion of volatile compounds from the external solution to the seed was categorized into three groups: (1) not diffusible (ethyl octanoate- d 15); (2) semidiffusible (ethyl acetate); and (3) totally diffusible (2-phenylethanol- d 5, linalool- d 5, beta-damascenone, delta-decalactone). The impact of the yeast on volatile compound diffusion was also investigated by immerging the pulped beans into the same concentrated solution with a yeast starter. Results highlighted the positive role of yeast in the diffusion of volatile compounds. The starter positively contributed to volatile compound diffusion after a transition phase occurring at approximately 48 h of fermentation, enriching the cocoa beans with key aromatic volatile compounds.

Gas chromatography with electron capture negative ion mass spectrometry (GC/ECNI-MS) was used to quantify and compare halogenated natural products (HNPs) and selected anthropogenic persistent organic pollutants (POPs) in individual samples of 17 fish species from the Seychelles (Western Indian Ocean). The sum-HNP amounts (9.5-1100 ng/g lipid mass (lm)) were between 1 and 2 orders of magnitude higher than those of the sum of seven abundant polychlorinated biphenyl (PCB) congeners (0.2-15 ng/g lm) and dichlorodiphenyltrichloroethane-related compounds (DDTs) (<1.1-43 ng/g lm). Within the group of HNPs, the two tetrabrominated phenoxyanisoles (aka methoxylated diphenyl ethers, MeO-BDEs), 2'-MeO-BDE 68 ≫ 6-MeO-BDE 47, were predominant in most cases. Pearson correlation analysis showed that MeO-BDE levels were positively correlated with less abundant HNPs (2,2'-diMeO-BB 80, 2',6-diMeO-BDE 68, and Br 6 -DBP) ( p < 0.01). Accordingly, HNPs, rather than PCBs and DDTs, were the predominant polyhalogenated contaminants in the current species.

A modified aroma extract dilution approach (AEDA), followed by the determination of flavor dilution (FD) factors, a quantitative analysis and calculation of the relative flavor activity (RFA) and odor activity values (OAVs) as well as recombination experiments were conducted to evaluate the odor- and taste-relevant components of cold-pressed Citrus latifolia peel oil. A 2-fold concentration by distillation and reanalysis, compared with the original oil, revealed relevant components. Partition of the odor-active substances into four reconstitution groups according to their respective FD factors, followed by a recombination, allowed for a better understanding of the contribution of each FD-factor group to the overall aroma. Especially α-pinene, limonene, γ-terpinene, and 7-methoxycoumarin contribute significantly to the distinct aroma profile of C. latifolia . Heptadecanal (CAS 629-90-3) was described for the first time as an odor-active substance in an enriched C. latifolia peel oil. Campherenyl acetate (CAS 18530-07-9) was identified in nature for the first time and described with a herbal, minty and citrus-like odor. The odor profile of the final recombinant mixture, containing 36 components, was similar to cold-pressed C. latifolia peel oil for most descriptors, whereas the taste profile was described as more aldehydic and citral-like.

Liquor-pairing food is a common dietary combination. Baijiu and peanuts are unquestionably a classic pairing in China. But no one has explained why. Its alteration in baijiu flavor was studied using multiple sensory evaluation, as well as nontargeted proton-transfer reaction mass spectrometry coupled with GC × GC-MS. Multiple statistical analyses were used to discover the changes in the retronasal aroma and its contribution to baijiu flavor. It showed that the consumption of peanuts enhances the burst intensity of ester aroma (0.814-1.00) and Jiao aroma (0.889-0.963) but decreases the aftertaste of baijiu ( p < 0.05). Meanwhile, it increases the release intensity and advances the burst time of baijiu retronasal aroma ( p < 0.05), suppressing its aftertaste through the retention effect of the food matrix, the changes in oral processing, and cross-modal interactions. Hydrophobicity, polarity, and chemical characteristics are key factors of the uneven impact of accompanying food to aroma compounds. Esters, especially ethyl caprylate (2103 ± 927 to 51.9 ± 4.05) is most impacted by peanuts and contributes most to baijiu flavor changes. Pyrazines from peanut enhance the Qu-aroma, grain aroma, and Chen aroma in baijiu flavor. Therefore, we revealed the chemical nature of baijiu-peanut combination and help to optimize baijiu consumption experience.

Cannabis is widely used for medicinal and recreational purposes. As a result, there is increased interest in its chemical components and their physiological effects. However, current information on cannabis chemistry is often outdated or scattered across many books and journals. To address this issue, we used modern metabolomics techniques and modern bioinformatics techniques to compile a comprehensive list of >6000 chemical constituents in commercial cannabis. The metabolomics methods included a combination of high- and low-resolution liquid chromatography-mass spectrometry (MS), gas chromatography-MS, and inductively coupled plasma-MS. The bioinformatics methods included computer-aided text mining and computational genome-scale metabolic inference. This information, along with detailed compound descriptions, physicochemical data, known physiological effects, protein targets, and referential compound spectra, has been made available through a publicly accessible database called the Cannabis Compound Database (https://cannabisdatabase.ca). Such a centralized, open-access resource should prove to be quite useful for the cannabis community.

α,β-Unsaturated carbonyls are highly reactive and described as structural alerts for genotoxicity. Ten of them (either commercially available or synthesized here by combinatorial chemistry) were first investigated throughout the chocolate-making process by solvent-assisted flavor evaporation (SAFE) coupled to GC-MS/SIM. Monitored α,β-unsaturated aldehydes were formed during chocolate production, primarily through aldol condensation of Strecker aldehydes triggered by bean roasting. Notably, levels of 2-phenylbut-2-enal (up to 399 μg·kg -1 ) and 5-methyl-2-phenylhex-2-enal (up to 216 μg·kg -1 ) increased up to 40-fold. Dry conching caused evaporation of α,β-unsaturated carbonyls, while wet conching partially restored or increased their levels due to cocoa butter addition. Further analyses showed that α,β-unsaturated aldehydes also occurred in most commercial sweet snacks (up to 16 μg·kg -1 ), although often at lower concentrations than in roasted cocoa or derived chocolates. In the end, none of the monitored α,β-unsaturated aldehydes did raise a health concern compared to current maximum use levels (2-5 mg·kg -1 ). On the other hand, much higher levels of genotoxic furan-2( 5H )-one were found in crepe and cake samples (up to 4.3 mg·kg -1 ).

Freeze-dried ginger ( Zingiber officinale ) is renowned for its high quality, but it is expensive. As an alternative, spray drying can be explored for producing ginger powder. However, sugar rich feed solutions can lead to stickiness development during the process. Adding carrier materials increases costs and labeling. Accordingly, a split-stream spray-drying process was developed, where ginger fibers in their natural composition were reintroduced as a carrier material into the spray-drying process. The inlet and outlet temperatures were set at 220 and 80 °C, respectively, for optimal aroma retention. Using a stir bar sorptive extraction-gas chromatography-mass spectrometry-olfactometry, the results revealed that reintegrating ginger fibers significantly increased the concentration of eight key odorants. Although freeze-dried ginger retains more aroma, the total concentration of twenty-seven odorants in the developed spray-dried ginger was 1.9 times higher compared to frozen ginger.

This study discovered the impact of high-tunnel (i.e., unheated greenhouse) and open-field production on two industrial hemp cultivars (SB1 and CJ2) over their yield parameters, cannabinoid development, and volatile profiles. Development of neutral cannabinoids (CBD, THC, and CBC), acidic cannabinoids (CBDA, THCA, and CBCA), and total cannabinoids during floral maturation were investigated. The volatile profiles of hemp flowers were holistically compared via HS-SPME-GC/MS. Findings indicated a high tunnel as an efficient practice for achieving greater total weight, stem number, and caliper, especially in the SB1 cultivar. Harvesting high-tunnel-grown SB1 cultivars during early flower maturation could obtain a high CBD yield while complying with THC regulations. Considering the volatile profiles, hemp flowers mainly consisted of mono- and sesquiterpenoids, as well as oxygenated mono- and sesquiterpenoids. Volatile analysis revealed the substantial impact of cultivars on the volatile profile compared to the production systems.

Nasal xenobiotic metabolizing enzymes (XMEs) are important for the sense of smell because they influence odorant availability and quality. Since the major part of the human nasal cavity is lined by a respiratory mucosa, we hypothesized that this tissue contributed to nasal odorant metabolism through XME activity. Thus, we built human respiratory tissue models and characterized the XME profiles using single-cell RNA sequencing. We focused on the XMEs dicarbonyl and l-xylulose reductase, aldehyde dehydrogenase (ALDH) 1A1, and ALDH3A1, which play a role in food odorant metabolism. We demonstrated protein abundance and localization in the tissue models and showed the metabolic activity of the corresponding enzyme families by exposing the models to the odorants 3,4-hexandione and benzaldehyde. Using gas chromatography coupled with mass spectrometry, we observed, for example, a significantly higher formation of the corresponding metabolites 4-hydroxy-3-hexanone (39.03 ± 1.5%, p = 0.0022), benzyl alcohol (10.05 ± 0.88%, p = 0.0008), and benzoic acid (8.49 ± 0.57%, p = 0.0004) in odorant-treated tissue models compared to untreated controls (0 ± 0, 0.12 ± 0.12, and 0.18 ± 0.18%, respectively). This is the first study that reveals the XME profile of tissue-engineered human respiratory mucosa models and demonstrates their suitability to study nasal odorant metabolism.

Pseudococcus longispinus (Targioni-Tozzetti) (Hemiptera: Coccoidea: Pseudococcidae), a polyphagous and cosmopolitan pest native to Australia, is a highly damaging pest for numerous crops of economic importance. The sex pheromone of this species (2-(1,5,5-trimethylcyclopent-2-en-1-yl)ethyl acetate), currently used for pest monitoring purposes, was not attractive to males in field experiments conducted in Spanish persimmon orchards infested with this mealybug. The virgin and mated female volatile profiles of these P. longispinus populations were studied by the volatile collection of effluvia in Porapak-Q. The resulting extracts were analyzed by gas chromatography coupled to mass spectrometry (GC-MS), revealing a new compound specific to virgin females and different from the previously described sex pheromone. Based on GC-MS data and nuclear magnetic resonance experiments, we envisaged monoterpene 2-(1,5-dimethyl-4-methylenecyclopent-2-en-1-yl)ethyl acetate as the new sex pheromone candidate, which was synthesized and shown to be attractive in the field to P. longispinus males of the Spanish population.

Concealed damage (CD) is a brown discoloration of nutmeat that appears only after kernels are treated with moderate heat (e.g., roasting). Identifying factors that promote CD in almonds is of significant interest to the nut industry. Herein, the effect of temperature (35 and 45 °C) and moisture (

Hexanal, peroxide value, and lipid hydroperoxides are common indicators of lipid oxidation in food products. However, these markers are not always reliable as levels are dynamic and often can be detected only after significant oxidation has occurred. Changes in the volatile composition of light- and dark-roast almonds were evaluated during storage over 24 weeks at 25 or 35 °C using headspace solid phase microextraction (HS-SPME) gas chromatography-mass spectrometry (GC-MS). Several volatile changes were identified in association with early oxidation events in roasted almonds. Hexenal decreased significantly during the first 6 weeks of storage and did not increase above initial levels until 20-24 weeks of storage depending upon the degree of roast. In contrast, levels of 1-heptanol and 1-octanol increased at 16-20 weeks, depending upon the degree of roast, and no initial losses were observed. Seventeen new compounds, absent in raw and freshly roasted almonds but detectable after 6 weeks of storage, were identified. Of these, 2-octanone, 2-nonanone, 3-octen-2-one, 2-decanone, (E)-2-decenal, 2,4-nonadienal, pentyl oxirane, and especially acetic acid increased significantly (that is, >10 ng/g). The degree of roasting did not correlate with the levels of these compounds. Significant decreases in roasting-related aroma volatiles such as 2-methylbutanal, 3-methylbutanal, furfural, 2-phenylacetaldehyde, 2,3-butanedione, 2-methylpyrazine, and 1-methylthio-2-propanol were observed by 4 weeks of storage independent of the degree of roast or storage conditions.

The aim of the study was to investigate how smoke-associated flavoring substances behave during storage in Frankfurter-type sausages. The diffusion behavior of seven selected aroma substances in the sausage matrix and the influence of the packaging and the casing were examined over a storage period of 28 days. The sausages were cut into uniformly thick layers at defined time intervals and examined by headspace-solid phase microextraction-gas chromatography-mass spectrometry. In general, three different groups could be distinguished: (1) even distribution over the entire product on the first day after smoking; (2) clear concentration gradient from outside to inside on the first day of storage, which leveled out until day 28 of storage; and (3) a clear concentration gradient that remained present throughout the storage period. In addition, only small effects were found in the distribution of flavorings between two types of packaging, selected casing, or different calibers.

Gouda cheese was produced from pasteurized milk and ripened for 30 weeks (PM-G). By application of gas chromatography/olfactometry and an aroma extract dilution analysis on the volatiles isolated by extraction/SAFE distillation, 25 odor-active compounds in the flavor dilution (FD) factor range from 16 to 4096 were identified. Butanoic acid, 2- and 3-methylbutanoic acid, and acetic acid showed the highest FD factors, and 2-phenylethanol, δ-decalactone, and δ-dodecalactone were most odor-active in the neutral-basic fraction. Quantitations by stable isotope dilution assays followed by a calculation of odor activity values (OAVs) revealed acetic acid, 3-methylbutanoic acid, butanoic acid, and butane-2,3-dione with the highest OAVs. Finally, an aroma recombinate prepared based on the quantitative data well agreed with the aroma profile of the PM-G. In Gouda cheese produced from raw (nonpasteurized) milk (RM-G), qualitatively the same set of odor-active compounds was identified. However, higher OAVs of butanoic acid, hexanoic acid, and their corresponding ethyl esters were found. On the other hand, in the PM-G, higher OAVs for 3-methylbutanoic acid, 3-methylbutanol, 3-methylbutanal, and butane-2,3-dione were determined. The different rankings of these key aroma compounds clearly reflect the aroma differences of the two Gouda-type cheeses. A higher activity of lipase in the RM-G and higher amounts of free l-leucine in PM-G on the other side were responsible for the differences in the concentrations of some key aroma compounds.

Terpenes and pentene dimers are less studied volatile organic compounds (VOCs) but are associated with specific features of extra virgin olive oils (EVOOs). This study aimed to analyze mono- and sesquiterpenes and pentene dimers of Italian monovarietal EVOOs over 3 years (14 cultivars, 225 samples). A head space-solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) method recently validated was used for terpene and pentene dimer quantitation. The quantitative data collected were used for both the characterization and clustering of the cultivars. Sesquiterpenes were the molecules that most characterized the different cultivars, ranging from 3.908 to 38.215 mg/kg; different groups of cultivars were characterized by different groups of sesquiterpenes. Pentene dimers (1.336 and 3.860 mg/kg) and monoterpenes (0.430 and 1.794 mg/kg) showed much lower contents and variability among cultivars. The application of Kruskal-Wallis test-PCA-LDA-HCA to the experimental data allowed defining 4 clusters of cultivars and building a predictive model to classify the samples (94.3% correct classification). The model was further tested on 33 EVOOs, correctly classifying 91% of them.

This study developed a novel nanocomposite colorimetric sensor array (CSA) to distinguish between fresh and moldy maize. First, the headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC/MS) method was used to analyze volatile organic compounds (VOCs) in fresh and moldy maize samples. Then, principal component analysis and orthogonal partial least-squares discriminant analysis (OPLS-DA) were used to identify 2-methylbutyric acid and undecane as key VOCs associated with moldy maize. Furthermore, colorimetric sensitive dyes modified with different nanoparticles were employed to enhance the dye properties used in the nanocomposite CSA analysis of key VOCs. This study focused on synthesizing four types of nanoparticles: polystyrene acrylic (PSA), porous silica nanospheres (PSNs), zeolitic imidazolate framework-8 (ZIF-8), and ZIF-8 after etching. Additionally, three types of substrates, qualitative filter paper, polyvinylidene fluoride film, and thin-layer chromatography silica gel, were comparatively used to fabricate nanocomposite CSA combining with linear discriminant analysis (LDA) and K-nearest neighbor (KNN) models for real sample detection. All moldy maize samples were correctly identified and prepared to characterize the properties of the CSA. Through initial testing and nanoenhancement of the chosen dyes, four nanocomposite colorimetric sensitive dyes were confirmed. The accuracy rates for LDA and KNN models in this study reached 100%. This work shows great potential for grain quality control using CSA methods.

This study explores the antipathogenic properties of volatile organic compounds (VOCs) produced by Bacillus velezensis LT1, isolated from the rhizosphere soil of Coptis chinensis . The impact of these VOCs on the mycelial growth of Sclerotium rolfsii LC1, the causative agent of southern blight in C. chinensis , was evaluated using a double Petri-dish assay. The biocontrol efficacy of these VOCs was further assessed through leaf inoculation and pot experiments. Antifungal VOCs were collected using headspace solid-phase microextraction (SPME), and their components were identified via gas chromatography-mass spectrometry (GC-MS). The results revealed that the VOCs significantly inhibited the mycelial growth and sclerotia germination of S. rolfsii LC1 and disrupted the morphological integrity of fungal mycelia. Under the influence of these VOCs, genes associated with chitin synthesis were upregulated, while those related to cell wall degrading enzymes were downregulated. Notably, 2-dodecanone and 2-undecanone exhibited inhibition rates of 81.67% and 80.08%, respectively. This research provides a novel approach for the prevention and management of southern blight in C. chinensis , highlighting the potential of microbial VOCs in biocontrol strategies.

Mead was analyzed by using the concept of molecular sensory science for the identification of key odorants. A total of 29 odor-active compounds were identified in mead by using gas chromatography olfactometry (GCO). Flavor dilution (FD) factors of identified compounds ranged from 1 to 16,384, compounds with FD factors ≥32 were quantitated by using stable isotopically substituted odorants as internal standards or external standard method, and odor activity values (OAVs) were calculated. Fifteen compounds showed OAVs ≥1: aldehydes (2-phenylacetaldehyde, 3-(methylsulfanyl)propanal), 4-hydroxy-3-methoxybenzaldehyde), esters (ethyl 3-methylbutanoate, ethyl propanoate, ethyl octanoate), alcohols (2-phenylethan-1-ol, 3- and 2-methylbutan-1-ol, 3-(methylsulyfanyl)propan-1-ol), furanons (4-hydroxy-2,5-dimethylfuran-3(2 H )-one, 3-hydroxy-4,5-dimethylfuran-2(5 H )-one), acids (3- and 2-methylbutanoic acid, acetic acid), 1,1-diethoxyethane, and 4-methylphenol. 2-Phenylacetaldehyde (OAV, 3100) was suggested as the compound with the biggest influence on the aroma of mead, followed by 4-hydroxy-2,5-dimethylfuran-3(2 H )-one (OAV, 1900), 3-(methylsulfanyl)propanal (OAV, 890), and 2-phenylethan-1-ol (OAV, 680). Quantitative olfactory profile analysis revealed strong honey, malty, and alcoholic impressions. Omission experiments revealed that 3-(methylsulfanyl)propanal, 2-phenylethan-1-ol, 4-hydroxy-2,5-dimethylfuran-3(2 H )-one, ethyl propanoate, ethyl 3-methylbutanoate, 2-phenylacetaldehyde, 3- and 2-methylbutanoic acid, 3-hydroxy-4,5-dimethylfuran-2(5 H )-one, and 4-hydroxy-3-methoxybenzaldehyde were the key odorants in the mead. Determining concentrations of key odorants in important production steps showed that the fermentation and maturation stages had the strongest effect on the formation of mead aroma.

Citrus fruits have been known and valued for their aroma in food and perfume ever since humans have maintained written records. Often described as the "champagne" of citrus oils, especially cold pressed lime peel oils have raised attention. Particularly peel oils of Citrus latifolia exhibit a pleasant coumarinic, sweet, and balsamic aroma in comparison to its close relative, the Citrus aurantifolia . Those coumarinic notes have not been completely understood until today. Thus, this study aimed to identify the responsible substances and elucidate their contribution and impact on the aroma of cold-pressed lime oil. By combining distillation, fractionation, olfactory detection, and structure elucidation, the responsible key aroma components were identified. A combination of coumarins and their corresponding saturated analogs have been identified to significantly contribute to the typical coumarinic-like aroma, including three new flavor compounds that have not yet been described in the literature as lime oil constituents: 7-methoxy-2-chromanone (3,4-dihydro-7-methoxy-2 H -1-benzopyran-2-one; CAS 20921-02-2), 5,7-dimethoxy-2-chromanone (3,4-dihydro-5,7-dimethoxy-2 H -1-benzopyran-2-one; CAS 82243-01-4) and 5,6-dihydrobergaptene (5,6-dihydro-4-methoxy-7 H -furo[3,2- g ][1]benzopyran-7-one; CAS 29050-61-1). The sensorial evaluation of the impact of these components on the lime aroma profile has shown flavor-modulating effects and the ability to enhance aldehydic-peely, juicy, and fruity notes as well as their importance in reproducing the authentic, typical coumarin-like notes.

Some truffles are expensive and, therefore, are prone to food fraud. A particular problem is the differentiation of high-priced Tuber magnatum truffles from cheaper Tuber borchii truffles, both of which are white truffles with similar morphological characteristics. Using an untargeted approach, the volatiles isolated from samples of both species were screened for potential marker compounds by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOFMS) and statistical analysis of the obtained semiquantitative data. Results suggested bis(methylsulfanyl)methane and furan-2(5 H )-one as compounds characterizing T. magnatum and T. borchii , respectively. Exact quantitation of both volatiles by conventional one-dimensional gas chromatography-mass spectrometry in combination with stable isotopologues of the target compounds as internal standards confirmed both as marker compounds. The method is suitable to be used in the routine analysis for the objective species differentiation of T. magnatum and T. borchii .

The determination of odor threshold values can be performed in various matrices, including air, and serves as a parameter to compare the potencies of odorous compounds. Typically, the odor thresholds in air are determined by gas chromatography-olfactory (GC-O) and referenced to an internal standard, most often ( E )-dec-2-enal. Herein, a direct gas chromatography-flame ionization detector-olfactory analysis method for the determination of odor thresholds in air is reported. As model substrates for this novel approach, naturally occurring substances ( R )-1- p -menthene-8-thiol as well as (3 S ,3a S ,6 R ,7a S )-3,6-dimethyl-3a,4,5,6,7,7a-hexahydro-3 H -1-benzofuran-2-one were used. The latter compound was synthesized from (-)-isopulegol and exhibited an extremely low odor recognition threshold of 1.9 × 10 -6 ng L -1 air, the lowest value reported for a fungal aroma compound thus far.

Bacillus has been widely studied for its potential to protect plants from pathogens. Here, we report the whole genome sequence of Bacillus subtilis H2, which was isolated from the tea garden soil of Guiyang Forest Park. Strain H2 showed a broad spectrum of antagonistic activities against many plant fungal pathogens and bacteria pathogens, including the rice blast fungus Magnaporthe oryzae , and showed a good field control effect against rice blast. The complete genome of B. subtilis H2 contained a 4,160,635-bp circular chromosome, with an average G + C content of 43.78%. Through the genome mining of strain H2, we identified 7 known antimicrobial compound biosynthetic gene clusters (BGCs) including sporulation killing factor, surfactin, bacillaene, fengycin, bacillibactin, subtilosin A, and bacilysin. Palmitic acid (PA), a secondary metabolite, was detected and identified in the H2 strain through genome mining analysis and gas chromatography-mass spectrometry (GC-MS). Additionally, we propose, for the first time, that the type II fatty acid synthesis (FAS) pathway in Bacillus is responsible for PA biosynthesis. This finding was confirmed by studying the antimicrobial activity of PA and conducting reverse transcription-quantitative polymerase chain reaction (RT-qPCR) experiments. We also identified numerous genes associated with plant-bacteria interactions in the H2 genome, including more than 94 colonization-related genes, more than 34 antimicrobial genes, and more than 13 plant growth-promoting genes. These findings contribute to our understanding of the biocontrol mechanisms of B. subtilis H2 and have potential applications in crop disease control.

The leaf skeletonizer, Pyrausta machaeralis (Lepidoptera: Crambidae), is a serious insect pest of teak ( Tectona grandis ) in China. The application of insect pheromones is widely applied as an environmentally friendly technology for integrated pest management (IPM). In the present study, crude extracts of sex pheromone glands of calling P. machaeralis females were collected and then analyzed using gas chromatography/electroantennographic detection (GC/EAD) and gas chromatography-mass spectrometry (GC-MS). The combination of infrared spectroscopy (IR) and nuclear magnetic resonance (NMR) spectrometry was used for structure identification. Afterward, their electrophysiological and behavioral activity was evaluated in the laboratory and field. Herein, we eventually determined two active components, E -11-tetradecenyl acetate ( E 11-14:Ac) and Z- 11-tetradecenyl acetate ( Z 11-14:Ac), at a ratio of 96:4, as the sex pheromone of P. machaeralis . The identification of sex pheromones would facilitate the development of efficient strategies for monitoring and controlling the field populations of P. machaeralis .

The impact of the oxidation of linoleic acid cannot be overlooked in daily food consumption. This study used gas chromatography-mass spectrometry (GC-MS) to identify both nonvolatile oxidation products and volatile oxidation products of methyl linoleic acid at 180 °C and density function theory to investigate oxidation mechanisms. An analysis of nonvolatile oxidation products revealed the presence of three primary oxidation products. The three primary oxidation products were identified as hydroperoxides, peroxide-linked dimers, and heterocyclic compounds in a ratio of 2.70:1:3.69 (mmol/mmol/mmol). The volatile components of secondary oxidation products were found including aldehydes (40.77%), alkanes (19.89%), alcohols (9.02%), furans (6.11%), epoxides (0.46%), and acids (2.50%). DFT calculation proved that the secondary oxidation products mainly came from peroxides (77%). Finally, we look forward to our research contributing positively to lipid autoxidation and human health.