Search

Introduction: Breath Volatile organic compounds (VOCs) are promising biomarkers for clinical purposes due to their unique properties. Translation of VOC biomarkers into the clinic depends on identification and validation: a challenge requiring collaboration, well-established protocols, and cross-comparison of data. Previously, we developed a breath collection and analysis method, resulting in 148 breath-borne VOCs identified. Objectives: To develop a complementary analytical method for the detection and identification of additional VOCs from breath. To develop and implement upgrades to the methodology for identifying features determined to be “on-breath” by comparing breath samples against paired background samples applying three metrics: standard deviation, paired t-test, and receiver-operating-characteristic (ROC) curve. Methods: A thermal desorption (TD)-gas chromatography (GC)-mass spectrometry (MS)-based analytical method utilizing a PEG phase GC column was developed for the detection of biologically relevant VOCs. The multi-step VOC identification methodology was upgraded through several developments: candidate VOC grouping schema, ion abundance correlation based spectral library creation approach, hybrid alkane-FAMES retention indexing, relative retention time matching, along with additional quality checks. In combination, these updates enable highly accurate identification of breath-borne VOCs, both on spectral and retention axes. Results: A total of 621 features were statistically determined as on-breath by at least one metric (standard deviation, paired t-test, or ROC). A total of 38 on-breath VOCs were able to be confidently identified from comparison to chemical standards. Conclusion: The total confirmed on-breath VOCs is now 186. We present an updated methodology for high-confidence VOC identification, and a new set of VOCs commonly found on-breath. [ABSTRACT FROM AUTHOR]

Bacterial community shapes the quality of fermented vegetables through metabolism; however, no information is available on the dynamics of the microbiota and metabolites in dry-pickled radish. Herein, the study aim to reveal the changes in bacterial communities, volatile metabolites, and nonvolatile metabolites, and to speculate how the core bacterial flora affects metabolites by high-throughput sequencing, metabolomics, and flavoromics. During the initial fermentation (d1–d14), the bacterial flora and metabolites of radish considerably changed. The relative abundance of Weissella, Lactiplantibacillus, and Staphylococcus increased, whereas that of Pseudomonas and Lactococcus considerably decreased (p < 0.05). Kyoto encyclopedia of genes and genomes (KEGG) function prediction indicated that functions related to bacterial division and proliferation were high at the start of fermentation, after which functions related to the metabolism and biosynthesis of amino acids, carbohydrates, and nucleic acids increased. Among metabolites, the contents of ethanol, dimethyl disulfide, dimethyl trisulfide, carboxylic acids and derivatives (CAAD, mainly amino acids), and fatty acyls (FAC) increased, whereas those of isothiocyanates and 1-methyl-2-pyrrolidinethione decreased significantly (p < 0.05). During the middle and final stage of fermentation (d14–d42), the bacterial flora and metabolites gradually stabilized. Weissella, Lactiplantibacillus, and Staphylococcus populations correlated positively with the contents of alcohols, sulfides, CAAD, and FAC, and negatively with the content of isothiocyanates. Therefore, Weissella, Lactiplantibacillus, and Staphylococcus may regulate the synthesis and metabolism of amino acids and organic acids by producing enzymes, such as phenylalanine hydroxylase (EC 1.14.16.1), isocitrate dehydrogenase (EC 1.1.1.41), and glutamate mutase (EC 5.4.99.1). This study provides a theoretical basis for improving and standardizing the quality of dry-pickled radish. [ABSTRACT FROM AUTHOR]

BACKGROUND: Jinmudan (JMD) is a high‐aroma variety widely cultivated in China. The current study primarily focuses on the key volatile metabolites in JMD black and oolong teas, and investigates the impact of processing technologies on the aroma quality of JMD tea. However, few studies have explored the suitability of JMD for producing a certain type of tea or the characteristic quality differences among various JMD teas using multivariate statistical analysis methods. RESULTS: The principal volatile metabolites contributing to the floral quality of JMD tea are linalool, geraniol, indole and phenethyl alcohol. In JMD black tea (BT), the key volatile metabolites include methyl salicylate, geraniol, (E)‐β‐ocimene and phenethyl alcohol. In JMD oolong tea (OT), the key volatile metabolites include indole, linalyl valerate and phenethyl alcohol. In JMD yellow tea (YT), the key volatile metabolites include methyl salicylate, geraniol and terpinolene. In JMD white tea (WT), the key volatile metabolites include methyl salicylate, geraniol and terpinolene. In JMD green tea (GT), the key volatile metabolites include (E)‐β‐ocimene, indole and geraniol. Comparative analysis and KEGG pathway enrichment analysis revealed that flavonoid biosynthesis is the primary metabolic pathway responsible for the taste differences among various tea types. GT exhibited higher levels of phloretin, dihydromyricetin and galangin. The contents of vitexin, tricetin in YT were relatively higher. The contents of aromadendrin and naringenin in BT were higher, while OT contained higher levels of kaempferol. Additionally, WT showed higher contents of 3‐O‐acetylpinobanksin and 3,5,7‐pinobanksin. CONCLUSION: This study explained the reasons for the quality differences of different JMD tea and provided a reliable theoretical basis for the adaptability of JMD tea. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: Soybean meal yogurt was prepared from soybean meal using papain and Bifidobacterium animalis subsp. lactis. A non‐targeted metabolomics approach was employed to analyze the relevance of papain to the differences in volatile and non‐volatile metabolites of soybean meal yogurt. Results: The results showed that the main up‐regulated metabolites and metabolic pathways after enzymatic digestion were dominated by amino acids and their derivatives. Conversely, the main down‐regulated metabolites and pathways were predominantly associated with flavonoid metabolism. Amino acids and their derivatives, as well as flavonoids, were found to be highly correlated with the formation of sweet, umami, astringent, and bitterness. The addition of papain enriched the content of aromatic compounds in soybean meal yogurt. Aromatic components such as 2‐heptanone, naphthalene, and p‐xylene increased in concentration. Synthetic peptide of aspartate and serine, gramine, geissospermine, N‐desmethyl vinblastine, and 3,7‐dihydroxyflavone were the major non‐volatile differential metabolites distinguishing the soybean meal yogurt. Conclusion: This study provided a comprehensive analysis of the metabolic traits of products co‐fermented by papain and Bifidobacterium animalis subsp. lactis, offering insights for the application of papain in fermented goods. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: Michelia macclurei Dandy is a traditional Chinese medicinal plant, but little is understood about the bioactive compositions and biological potential of its different parts, limiting their applications. This study aims to identify the bioactive compositions and analyze differences in accumulation patterns from different parts of Michelia macclurei (heartwood, sapwood, bark, root, leaf, and fruit) using metabolomics. It also seeks to explore their biological potential and analyze the relationship between the bioactive compositions and biological potential. RESULTS: A total of 63 volatile metabolites (VMs) were identified by gas chromatography–mass spectrometry (GC–MS) in six parts, and the VMs in each part were dominated by sesquiterpenes and their derivatives (71.40–88.32%). Six parts of Michelia macclurei contained structurally diverse non‐volatile metabolites (NVMs) with a total of 207 bioactive compounds, including 92 alkaloids, 30 flavonoids, 19 lignans, and 18 organic acids, utilizing ultra‐performance liquid chromatography–mass spectrometry (UPLC–MS) analysis. Multivariate statistical analysis showed that the accumulation patterns of bioactive compositions differed significantly among the different parts, and the 25 VMs and 72 NVMs could be considered potential markers for distinguishing the different parts of Michelia macclurei. The excellent antioxidant and enzyme inhibitory capacity of extracts of all six parts was indicated by in vitro bioactivity assays. Pearson's correlation analysis showed that the bioactive compositions in the six parts were significantly correlated with antioxidant and enzyme inhibitory activities. CONCLUSION: This study offers helpful information on the distribution of bioactive compositions in different parts of Michelia macclurei and confirms the excellent antioxidant, and enzyme inhibitory potential of its extracts, which could provide scientific evidence for its potential applications in the pharmaceutical industry, cosmetics, and functional foods. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Angelica L. has attracted global interest for its traditional medicinal uses and commercial values. However, few studies have focused on the metabolomic differences among the Angelica species. In this study, widely targeted metabolomics based on gas chromatography-tandem mass spectrometry was employed to analyze the metabolomes of four Angelica species (Angelica sinensis (Oliv.) Diels (A. sinensis), Angelica biserrata (R.H.Shan & Yuan) C.Q.Yuan & R.H.Shan (A. biserrata), Angelica dahurica (Hoffm.) Benth. & Hook.f. ex Franch. & Sav. (A. dahurica) and Angelica keiskei Koidz. (A. keiskei)). A total of 698 volatile metabolites were identified and classified into fifteen different categories. The metabolomic analysis indicated that 7-hydroxycoumarin and Z-ligustilide accumulated at significantly higher levels in A. sinensis, whereas bornyl acetate showed the opposite pattern. Furthermore, a high correspondence between the dendrogram of metabolite contents and phylogenetic positions of the four species. This study provides a comprehensive biochemical map for the exploitation, application and development of the Angelica species as medicinal plants or health-related dietary supplements. [ABSTRACT FROM AUTHOR]

Abstract Angelica L. has attracted global interest for its traditional medicinal uses and commercial values. However, few studies have focused on the metabolomic differences among the Angelica species. In this study, widely targeted metabolomics based on gas chromatography-tandem mass spectrometry was employed to analyze the metabolomes of four Angelica species (Angelica sinensis (Oliv.) Diels (A. sinensis), Angelica biserrata (R.H.Shan & Yuan) C.Q.Yuan & R.H.Shan (A. biserrata), Angelica dahurica (Hoffm.) Benth. & Hook.f. ex Franch. & Sav. (A. dahurica) and Angelica keiskei Koidz. (A. keiskei)). A total of 698 volatile metabolites were identified and classified into fifteen different categories. The metabolomic analysis indicated that 7-hydroxycoumarin and Z-ligustilide accumulated at significantly higher levels in A. sinensis, whereas bornyl acetate showed the opposite pattern. Furthermore, a high correspondence between the dendrogram of metabolite contents and phylogenetic positions of the four species. This study provides a comprehensive biochemical map for the exploitation, application and development of the Angelica species as medicinal plants or health-related dietary supplements. Graphical Abstract

In this study, the effect of applying different concentrations (50, 100, 150 and 200 mg/L) of 5-aminolevulinic acid (5-ALA) at the fruit swelling stage on the quality and volatile metabolites of Korla fragrant pear fruit was examined. The quality of pear fruit with and without calyx was determined at the maturity stage. Meanwhile, comprehensive quality evaluation of pear fruit under 5-ALA treatment was carried out using principal component analysis (PCA), and the optimal 5-ALA concentration for improving the fruit quality was determined. The results showed that exogenous spraying of 150 mg/L 5-ALA had the best effect on improving the quality of fragrant pear fruit. Specifically, compared with the control group, the hardness, stone cell content and titratable acid content of the fruit without calyx decreased by 13.45%, 31.03% and 42.31%, respectively, and the soluble solids content and solid/acid ratio increased by 9.95% and 90.57%, respectively; the hardness, titratable acid content and stone cell content of the fruit with calyx decreased significantly by 12.89%, 48.48% and 30.16%, and the soluble solids content, soluble sugar content and solid/acid ratio increased by 19.33%, 23.51% and 131.63%, respectively. In addition, exogenous spraying of 5-ALA significantly increased the mass fraction of volatile metabolites in both fruits, mainly including terpenoids and esters, enriching their aroma attributes such as woody, fruity, vanilla, fresh, grassy and sweet notes. The differential metabolites between the 5-ALA treatment and control groups were most enriched in the sesquiterpene and triterpenoid biosynthesis pathway. Among them, α-farnesene, 4-[((1E)-1,5-dimethyl-1,4-hexanedi-1-yl]-1-methyl-cyclohexene, δ-cadinene, (E)-1-methyl-4-(6-methylhept-5-en-2-ylidene) cyclohex-1-ene and germacrene B were annotated as key compounds to this pathway, which together endowed Korla fragrant pears with special citrus-like, lavender, lemony, astringent, thyme-like, spicy, earthy, non-medicinal and orange flower-like flavors. In conclusion, it is demonstrated that the exogenous application of 5-ALA significantly improved the quality of Korla fragrant pear fruit, the effect being most pronounced at 5-ALA concentration of 150 mg/L.

This study aimed to evaluate the characteristic aroma compounds of white tea made from ‘Fuhuang 1’, an albino mutant of ‘Fuandabaicha’, and their dynamic changes during tea processing. The types and relative contents of volatile compounds in ‘Fuhuang 1’ and ‘Fuandabaicha’ tea leaves withered for 0, 12, 24, 36 and 48 h and in white tea made from each variety were determined by headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS). A total of 560 aroma compounds were detected in all samples, among which terpenes, heterocyclic compounds, esters and hydrocarbons were the major aroma components of white tea. During the withering process, the total content of volatile metabolite in both cultivars gradually increased, reaching the highest value at 48 h. Based on their relative odor activity values (ROAVs), terpinolene, citral, 1-octen-3-one, and damascenone were identified as the key aroma components of ‘Fuandabaicha’ white tea, and these compounds together with methyl salicylate and benzaldehyde as the key aroma components of ‘Fuhuang 1’ white tea. 1-Octen-3-one and citral were accumulated in large amounts at the early stage of withering and then decreased. Terpenolene, benzaldehyde, methyl salicylate, and damascus ketone continuously increased during the whole withering process. Terpinolene, citral, 1-octen-3-one, and damascenone greatly contributed to the floral, fruity and sweet aroma of ‘Fuhuang 1’ and ‘Fuandabaicha’ white tea. 1-Octene-3-one, methyl salicylate, and benzaldehyde were the key compounds responsible for the clean and fresh aroma of ‘Fuhuang 1’ white tea. This study helps gain insights into the aroma characteristics of ‘Fuhuang 1’ white tea and provides a scientific basis for the research and development of white tea made from albino tea plant mutants.

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of the present study was to comprehensively analyze and identify the metabolites of different varieties of raw peanut, as well as provide a reference for the utilization of different varieties of peanuts. In this study, three varieties of peanuts, namely ZKH1H, ZKH13H, and CFD, were investigated via ultrahigh-performance liquid chromatography (UPLC) and widely targeted metabolomics methods based on tandem mass spectrometry (MS) and solid-phase microextraction-gas chromatography–mass spectrometry (SPME-GC–MS). In total, 417 nonvolatile and 55 volatile substances were detected. The nonvolatile substances were classified into the following 10 categories: organic acids and derivatives (28.9%); organic oxygen compounds (21.9%); lipids and lipid-like molecules (12.6%); organoheterocyclic compounds (9.9%); nucleosides, nucleotides, and analogues (9.4%); benzenoids (7.8%); phenylpropanoids and polyketides (6.1%); organic nitrogen compounds (2.7%); lignans, neolignans, and related compounds (0.5%); and alkaloids and their derivatives (0.3%). The volatile compounds (VOCs) were classified into the following eight categories: organic oxygen compounds (24.1%); organic cyclic compounds (20.4%); organic nitrogen compounds (13%); organic acids and their derivatives (13%); lipids and lipid-like molecules (11.2%); benzenoids (11.1%); hydrocarbons (3.7%); and homogeneous non-metallic compounds (3.7%). Differentially abundant metabolites among the different peanut varieties (ZKH13H vs. CFD, ZKH1H vs. CFD, and ZKH1H vs. ZKH13H) were investigated via multivariate statistical analyses, which identified 213, 204, and 157 nonvolatile differentially abundant metabolites, respectively, and 12, 11, and 10 volatile differentially abundant metabolites, respectively. KEGG metabolic pathway analyses of the differential non-VOCs revealed that the most significant metabolic pathways among ZKH13H vs. CFD, ZKH1H vs. CFD, and ZKH1H vs. ZKH13H were galactose metabolism, purine metabolism, and aminoacyl-tRNA, while the nitrogen metabolism pathway was identified as a significant metabolic pathway for the VOCs. The present findings provide a theoretical foundation for the development and utilization of these three peanut species, as well as for the breeding of new peanut varieties. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: Volatile organic compounds (VOCs) can arise from underlying metabolism and are detectable in exhaled breath, therefore offer a promising route to non-invasive diagnostics. Robust, precise, and repeatable breath measurement platforms able to identify VOCs in breath distinguishable from background contaminants are needed for the confident discovery of breath-based biomarkers. Objectives: To build a reliable breath collection and analysis method that can produce a comprehensive list of known VOCs in the breath of a heterogeneous human population. Methods: The analysis cohort consisted of 90 pairs of breath and background samples collected from a heterogenous population. Owlstone Medical's Breath Biopsy® OMNI® platform, consisting of sample collection, TD-GC-MS analysis and feature extraction was utilized. VOCs were determined to be "on-breath" if they met at least one of three pre-defined metrics compared to paired background samples. On-breath VOCs were identified via comparison against purified chemical standards, using retention indexing and high-resolution accurate mass spectral matching. Results: 1471 VOCs were present in > 80% of samples (breath and background), and 585 were on-breath by at least one metric. Of these, 148 have been identified covering a broad range of chemical classes. Conclusions: A robust breath collection and relative-quantitative analysis method has been developed, producing a list of 148 on-breath VOCs, identified using purified chemical standards in a heterogenous population. Providing confirmed VOC identities that are genuinely breath-borne will facilitate future biomarker discovery and subsequent biomarker validation in clinical studies. Additionally, this list of VOCs can be used to facilitate cross-study data comparisons for improved standardization. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Wildlife & Biodiversity (JWB) is the property of Arak University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Fixation is a necessary tea processing step that affects the quality of tea, including its aroma. However, there are no guidelines to follow whether the Cyclocarya paliurus leaves need to be fixated to produce tea. The aim of this study was to determine the volatile metabolites in fixated and unfixated C. paliuru s tea by gas chromatography-mass spectrometry in order to identify the volatile compounds that differentiate them and establish the key aroma compounds. Compared with the unfixated tea, the fixated tea had higher contents of amines, phenols, nitrogen compounds, ether, alcohol, terpenoids, ester and aromatics. A total of 147 metabolites that differentiated both types of teas were identified using principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA). Among them, 22 and 25 volatile compounds of teas processed without and with fixation, respectively, had relative odor activity values greater than 1. These metabolites had green, fruity, sweet, woody, herbal, floral, fresh, spicy, earthy and waxy odor. This study showed that fixation technology improved the quality of C. paliurus tea, which provided the basis for the production of C. paliurus tea, and promoted the standardization of the preparation technology of C. paliurus tea.

Seaweed is an increasingly recognized source of secondary metabolites with a significant role as a plant biostimulant. With the rising popularity of organic farming, there is a pressing need to investigate the utilization of organic solvents derived from natural sources for seaweed extraction. Understanding the composition of these extracts is crucial for elucidating their role as biostimulants in plant growth. Hence, the present study aimed to explore the phytochemical composition and untargeted metabolomics of four extracts of Caulerpa racemosa (SW), prepared organically using vinegar, fermented buttermilk, and cow urine, in comparison with the conventionally used solvent, water. Approximately 95 volatile metabolites that belong to 22 chemical classes were identified through GC--MS analysis. The major classes detected include benzene and its substituted derivatives (24%), fatty acyls (17%), phenols (12%), benzofurans (8%), organo-oxygen compounds (6%), steroids and steroid derivatives (5%), and indole and its derivatives (4%). A significant shift in the composition of volatile metabolites was observed among the organic extracts as determined through a combination of various statistical analyses. A principal component analysis (PCA) highlighted seven principal components (PCs), which accounted for 99.9% of the total variance. Hierarchical cluster analysis delineated two distinct clusters, which signify a clear differentiation among the organic extracts. Furthermore, partial least squares discriminant analysis (PLS-DA) highlighted 49 volatile metabolites of significant importance, evident from variable importance in projection (VIP) scores of more than 1. These results underscore the intricate and distinct metabolomes inherent in Caulerpa racemosa organic extracts, hinting at their potential as biostimulants for plant growth. This study establishes a foundation for deeper investigations into seaweed extraction utilizing easily accessible organic solvents, presenting potential benefits for farmers. [ABSTRACT FROM AUTHOR]

Introduction: Fengxiangxing Huairang Daqu (FHD) is one of the major types of Daqu in China. However, the relationship between the microbial community structure at different stages, the changes in the sensory characteristics, fermentation characteristics, volatiles, the most critical process point, and the quality formation of FHD is not clear. Methods: Based on microscopic characterization, PacBio SMRT sequencing, and HS-SPME-GC-MS volatile metabolite analysis revealed the relationship between FHD quality formation and the dynamics of Qupi. Results: The results showed that the 12th day of the culture was the most critical process point, highlighting the most significant differences in microbial community structure, sensory characteristics, fermentation characteristics, and flavor substances. Bacillus licheniformis (43.25%), Saccharopolyspora rectivirgula (35.05%), Thermoascus aurantiacus (76.51%), Aspergillus amstelodami (10.81%), and Saccharomycopsis fibuligera (8.88%) were the dominant species in FHD. S. fibuligera, A. amstelodami, and T. aurantiacus were associated with the snow-white color of the FHD epidermis, the yellow color of the interior, and the gray-white color, respectively. The abundance of T. aurantiacus, A. amstelodami, B. licheniformis, and S. rectivirgula was positively associated with the esterifying power and liquefying power of FHD. The abundance of T. aurantiacus and A. amstelodami was positively correlated with the saccharifying power of FHD. The abundance of S. fibuligera was positively related to the fermenting power of FHD. A total of 248 volatiles were detected in Qupi, mainly including alcohols, esters, aldehydes, and ketones. Of them, eleven volatiles had a significant effect on the flavor of Qupi, such as 1-butanol-3-methyl-, hydrazinecarboxamide, ethanol, phenylethyl alcohol, ethyl acetate, 2-octanone, 1-octen-3-ol, formic acid-hexyl ester, (E)-2-octen-1-ol, ethyl hexanoate, and 2(3H)-furanone-dihydro-5-pentyl-. The abundance of B. licheniformis, S. rectivirgula, T. aurantiacus, and S. fibuligera was positively correlated with the alcohols, aromatic compounds, and phenols in FHD. The abundance of S. fibuligera was positively correlated with the acids, esters, and hydrocarbons in FHD. Discussion: These results indicate important theoretical basis and technical support for controllable adjustment of FHD microbial community structure, stable control of FHD quality, and precise, effective, and large-scale guidance of FHD production. [ABSTRACT FROM AUTHOR]

Chemical pesticides help reduce crop loss during production and storage. However, the carbon footprints and ecological costs associated with this strategy are unsustainable. Here, we used three in vitro models to characterize how different Trichoderma species interact with two aflatoxin producers, Aspergillus flavus and Aspergillus parasiticus, to help develop a climate-resilient biological control strategy against aflatoxigenic Aspergillus species. The growth rate of Trichoderma species is a critical factor in suppressing aflatoxigenic strains via physical interactions. The dual plate assay suggests that Trichoderma mainly suppresses A. flavus via antibiosis, whereas the suppression of A. parasiticus occurs through mycoparasitism. Volatile organic compounds (VOCs) produced by Trichoderma inhibited the growth of A. parasiticus (34.6 ± 3.3%) and A. flavus (20.9 ± 1.6%). The VOCs released by T. asperellum BTU and T. harzianum OSK-34 were most effective in suppressing A. flavus growth. Metabolites secreted by T. asperellum OSK-38, T. asperellum BTU, T. virens OSK-13, and T. virens OSK-36 reduced the growth of both aflatoxigenic species. Overall, T. asperellum BTU was the most effective at suppressing the growth and aflatoxin B1 production of both species across all models. This work will guide efforts to screen for effective biological control agents to mitigate aflatoxin accumulation. [ABSTRACT FROM AUTHOR]

Zhoupigan (Citrus reticulata cv. Manau Gan) is a local citrus variety in China. Its peel, known as Zangju peel (ZJP). The metabolic profile and bioactivity of ZJP have not been adequately studied, resulting in underutilization of ZJP and a serious waste of resources. In this study, GC–MS identified 46 components in ZJP, which defined ZJP's distinct aroma. Furthermore, UPLC-ESI-MS/MS detected 1506 metabolites in ZJP, and the differential metabolites were primarily involved in the biosynthesis of flavonoids and phenylacetone. Additionally, 56 key differential metabolites with metabolic pathways were identified. ZJP had significant antioxidant activity and the enzyme inhibitory activity ranking as pancreatic lipase (IC50 = 3.71 mg/mL) > α-glucosidase (IC50 = 6.28 mg/mL) > α-amylase (IC50 = 8.02 mg/mL). This study aimed to evaluate the potential of ZJP as natural antioxidant and functional food source and to serve as foundation for the further development of ZJP products with specific functional attributes.

The traditional stir-fry process before pressing is crucial to manufacture Hainan camellia oil. To assess the effects of the stir-fry process on Hainan camellia oil, six samples across different stir-fry stages were analyzed. The stir-fry process modified odors, volatile metabolite profiles, and human health-promoting functions of Hainan camellia oil. Totally, 350 volatile metabolites were detected, and heterocyclic compounds were revealed as the main contributors of strong aroma. Potential indicators for monitoring the stir-fry degree were established. Eight key aroma volatile metabolites were identified, including three new ones (1-octen-3-one, 2,3-butanedione, and vanillin). Lipids degradation and the Millard reaction are probably the main pathways for aroma generation. Over-stir-fry treatment diminished the contents of some important volatile metabolites but increased the risk of arising burnt odor. Our work offered insights into the effects of the stir-fry process and over-stir-fry treatment on Hainan camellia oil, which is meaningful for improving the hot-pressing technique.

In order to study the relationship between the chemical composition of tobacco leaves of non-flue-cured tobacco varieties and the sensory quality of heated cigarettes made from them, the conventional chemical composition of four types of non-flue-cured tobacco leaf samples such as oriental tobacco, air/sun-cured tobacco, burley tobacco and cigar tobacco samples were detected. Volatile metabolite profiles were analyzed by metabolomic technique, the differential volatile metabolites in different tobacco leaves were screened by orthogonal partial least square discriminant analysis, and the correlation between them and sensory quality of heated tobacco leaves was analyzed. The results showed that the contents of total sugar and reducing sugar were higher in oriental tobacco leaves, and the contents of alkaloid and nitrogen were higher in burley tobacco, air/sun-cured tobacco and cigar tobacco leaves. The characteristics of volatile metabolites of burley tobacco, air/sun-cured tobacco and cigar tobacco were similar, but different from those of oriental tobacco. A total of 130 differential volatile metabolites were obtained from different tobacco types, mainly esters, ketones, heterocycles and terpenoids. The differential volatile metabolites were positively correlated with the attributes of the smoothness of smoke, irritancy, dry sensation and cleanliness, and negatively correlated with the attributes of unpleasant odor and strength. The results provide a reference for the formulation of heated cigarette products from non-flue-cured tobacco leaves. [ABSTRACT FROM AUTHOR]

Volatile organic compounds (VOCs) are responsible for the antagonistic activity exerted by different biological control agents (BCAs). In this study, VOCs produced by Pseudomonas synxantha strain 117-2b were tested against two kiwifruit fungal postharvest pathogens: Cadophora luteo-olivacea and Botrytis cinerea, through in vitro and in vivo assays. In vitro results demonstrated that P. synxantha 117-2b VOCs inhibit mycelial growth of C. luteo-olivacea and B. cinerea by 56% and 42.8% after 14 and 5 days of exposition, respectively. In vivo assay demonstrated significant inhibitory effects. VOCs used as a biofumigant treatment reduced skin-pitting symptoms disease severity by 28.5% and gray mold incidence by 66.6%, with respect to the untreated control. BCA volatiles were analyzed by solid-phase microextraction coupled with gas chromatography--mass spectrometry (SPME--GC/MS), and among the detected compounds, 1-butanol, 3-methyl and 1-nonene resulted as the most produced. Their efficacy as pure synthetic compounds was assayed against mycelial growth of fungal pathogens by different concentrations (0.34, 0.56, and 1.12 µL mL-1 headspace). The effect of the application of VOCs as a biofumigant was also investigated as the expression level of seven defense-related genes of kiwifruit at different exposition times. The results indicated an enhancement of the expression of almost all the genes starting from 3 h of treatment. These results described P. synxantha VOCs characteristics and their potential as a promising method to adopt for protecting kiwifruit from postharvest diseases caused by C. luteo-olivacea and B. cinerea. [ABSTRACT FROM AUTHOR]

The study investigated compounds present in the invasive grass Hordeum murinum L. subsp. murinum and tested the allelopathic potential of this plant against common meadow species Festuca rubra L. and Trifolium repens L. Gas chromatography–mass spectrometry (GC–MS) performed separately on the ears and stalks with leaves of wall barley revealed 32 compounds, including secondary metabolites, that may play an important role in allelopathy. Two compounds, N-butylbenzenesulfonamide (NBBS) and diphenylsulfone (DDS), were described for the first time for wall barley and the Poaceae family. The presence of 6,10,14-trimethylpentadecan-2-one (TMP) has also been documented. Aqueous extracts of H. murinum organs (ears and stalks with leaves) at concentrations of 2.5%, 5%, and 7.5% were used to evaluate its allelopathic potential. Compared to the control, all extracts inhibited germination and early growth stages of meadow species. The inhibitory effect was strongest at the highest concentration for both the underground and aboveground parts of the seedlings of the meadow species tested. Comparing the allelopathic effect, Trifolium repens proved to be more sensitive. In light of the results of the study, the removal of wall barley biomass appears to be important for the restoration of habitats where this species occurs due to its allelopathic potential. [ABSTRACT FROM AUTHOR]

Celery seeds contain various bioactive compounds and are commonly used as a spice and nutritional supplement in people's daily lives. The quality of celery seeds sold on the market varies, and their regions of production are unclear. This study evaluated the metabolites of Chinese celery seeds from three production regions using HS-SPME-GC-MS, HS-GC-IMS, and UPLC-ESI-MS/MS. The results indicate that GC-IMS analysis obtained a metabolic profile different from that detected using GC-MS. Terpenoids, polyphenols, coumarins, and phthalides are the main bioactive compounds in celery seeds. The production region significantly affects the metabolic characteristics of celery seeds. Based on GC-MS data, GC-IMS data, and LC-MS data, the variation analysis screened 6, 12, and 8 metabolites as potential characteristic metabolites in celery seeds related to the production region, respectively. According to the aromatic characteristics of the characteristic metabolites, seeds from the HCQ region and HZC region have a strong herbal, woody, celery, and turpentine aroma. The concentration of secondary metabolites was highest in the seeds from the HCQ region followed by the HZC region, and it was the lowest in the JJC region. Altogether, this study investigates how geographical origins influence the metabolomic profile of celery seeds. The results can be used to guide the planting and harvesting of celery seeds in suitable regions. [ABSTRACT FROM AUTHOR]

Longjing tea is favored by consumers due to its refreshing and delicate aroma, as well as its fresh and sweet flavor. In order to study the processing technology of Longjing tea with 'Baiye 1' tea varieties, solid phase microextraction and gas chromatography–mass spectrometry were used to analyze the volatile components of Longjing tea in different process stages. The results revealed the identification of 275 aroma metabolites in the processing samples of Longjing tea. The sensory evaluation and principal component analysis revealed that the leaves of fresh (XY) and spreading (TF) were different from the leaves of first panning (YQ), second panning (EQ), final panning (HG), and fragrance enhancing (TX). The relative contents of geraniol (1199.95 and 1134.51), linalool (745.93 and 793.98), methyl salicylate (485.22 and 314.67), phenylethyl alcohol (280.14 and 393.98), 2-methylfuran (872.28 and 517.96), 2-butenal (56.01 and 154.60), and 2-hexenal (46.22 and 42.24), refreshing and floral substances in the XY and TF stages, were higher than other stages. The aroma contents of 2-methylfuran, furfural, 2-methyl-1-penten-3-one, 3-hexen-2-one, dodecane, hexanoyl hexanoate, 2,5-dimethyl-pyrazine, and methyl-pyrazine were found to be significantly positively correlated with the intensity of chestnut aroma. In conclusion, this study contributes to a better understanding of the composition and formation mechanism of chestnut-like aroma and provides new insights into the processing technology to improve the quality of albino green tea. [ABSTRACT FROM AUTHOR]

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Fusarium wilt is a destructive disease affecting Bt cotton that is caused by Fusarium oxysporum f. sp. vasinfectum. This seed and soilborne disease pose a significant risk to Bt cotton production worldwide, including India. Therefore, to cope with this problem in an eco-friendly manner, we explored the potentiality of the rhizobacterial isolate possessing antifungal activity as a natural arsenal against the fungal pathogen Fusarium wilt of Bt cotton. The rhizobacterial isolate RLS76 inhibited 85.39% of the fungal phytopathogen in the dual culture method. The RLS76 isolate's 16S rRNA partial gene sequence was determined to be Bacillus subtilis subsp. inaquosorum RLS76, with a closest phylogenetic affiliation of 99.53%. The crude extract of Bacillus subtilis subsp. inaquosorum RLS76 demonstrated 34.38% inhibition of the growth of the pathogen after a week of incubation by using an agar well diffusion method. Bacillus subtilis subsp. inaquosorum RLS76 produced volatile organic compounds that inhibited the fungal growth of phytopathogens by 54.84% in a closed environment. Also, GCMS analysis of the crude extract of Bacillus subtilis subsp. inaquosorum RLS76 identified four compounds, namely Pyrrolo[1,2-a]pyrazine-1,4- dione, hexahydro-; Pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-3-(2- methylpropyl); 2,5-cyclohexadiene-1,4-dione, 2,5-Dihydroxy-3-methoxy-6- methyl-; 9,12-Octadecadienoic acid (Z,Z)-,phenylmethyl ester. Out of four compounds, three exhibit antimicrobial activity except 2,5-Dihydroxy-3- methoxy-6-methyl. The RLS76 strain of Bacillus subtilis subsp. inaquosorum displayed a transition in hue, shifting from blue to orange, surrounding the colony on CAS medium by producing siderophore qualitatively. The quantitative siderophore produced in the crude extract was 86.06 SU after 60-72 h of incubation. The RLS76 strain of Bacillus subtilis subsp. inaquosorum also showed the ability to produce a proteolytic enzyme outside the cell. This enzyme caused a noticeable clear zone around the colony when the bacteria were grown on a skim-milk agar plate. The Bacillus subtilis subsp. inaquosorum RLS76 also exhibited phosphate solubilization activity with the clear halo around the colonies on NBRIP medium. All these results suggest that Bacillus subtilis subsp. inaquosorum RLS76 exhibits good biocontrol as well as a plant growth promoting candidate against the phytopathogen of Fusarium wilt of Bt cotton. [ABSTRACT FROM AUTHOR]

Seaweed is an increasingly recognized source of secondary metabolites with a significant role as a plant biostimulant. With the rising popularity of organic farming, there is a pressing need to investigate the utilization of organic solvents derived from natural sources for seaweed extraction. Understanding the composition of these extracts is crucial for elucidating their role as biostimulants in plant growth. Hence, the present study aimed to explore the phytochemical composition and untargeted metabolomics of four extracts of Caulerpa racemosa (SW), prepared organically using vinegar, fermented buttermilk, and cow urine, in comparison with the conventionally used solvent, water. Approximately 95 volatile metabolites that belong to 22 chemical classes were identified through GC–MS analysis. The major classes detected include benzene and its substituted derivatives (24%), fatty acyls (17%), phenols (12%), benzofurans (8%), organo-oxygen compounds (6%), steroids and steroid derivatives (5%), and indole and its derivatives (4%). A significant shift in the composition of volatile metabolites was observed among the organic extracts as determined through a combination of various statistical analyses. A principal component analysis (PCA) highlighted seven principal components (PCs), which accounted for 99.9% of the total variance. Hierarchical cluster analysis delineated two distinct clusters, which signify a clear differentiation among the organic extracts. Furthermore, partial least squares discriminant analysis (PLS-DA) highlighted 49 volatile metabolites of significant importance, evident from variable importance in projection (VIP) scores of more than 1. These results underscore the intricate and distinct metabolomes inherent in Caulerpa racemosa organic extracts, hinting at their potential as biostimulants for plant growth. This study establishes a foundation for deeper investigations into seaweed extraction utilizing easily accessible organic solvents, presenting potential benefits for farmers.

The rice blast disease caused by Pyricularia oryzae Cavara is among the most severe plant diseases in the world. The utilization of natural antagonists, such as fungal endophytes, can be a good method to control the spread of this disease. In the present study, 68 fungal isolates were obtained from 160 rice samples collected in Guilan province fields, Iran. Morphological and molecular characteristics were used for the identification of these fungi. According to the results, the fungal isolates were Alternaria citri (Penz.) Mussat, Alternaria infectoria Simmons, Aspergillus fumigatus Fresen, Fusarium verticillioides (Sacc.) Nirenberg, Trichoderma harzianum Rifai, Trichoderma virens (Mill., Giddens & Foster) Arx, Trichoderma viride Pers., Ulocladium consortiale (Thum) Simmons, and Pyricularia oryzae . Eight isolates that did not cause any plant disease were selected for biocontrol studies in vitro . The dual culture, culture filtrate, slide culture, and volatile metabolites methods were used in search of natural endophytic antagonists of Pyricularia oryzae . It was found that T. harzianum, T. virens, T. viride, A. fumigatus , and A. citri isolates caused the highest percentage of mycelial growth inhibition of P. oryzae in vitro . In the greenhouse experiments, all of the studied isolates reduced the P. oryzae disease rating, with T. harzianum isolate being the most effective antagonist (27.36% reduction in the disease rating), followed by T. virens, T. viride , and A. fumigatus (20.75%, 17.92%, and 16.98%, respectively). Furthermore, in greenhouse conditions, these antagonistic fungi increased the height, fresh weight, and dry weight of plants. The results of this research showed that there are various fungi in the natural flora of rice plants that possess potential biological properties against rice blast disease that can be implemented into practice.

Volatile organic compounds (VOCs) are responsible for the antagonistic activity exerted by different biological control agents (BCAs). In this study, VOCs produced by Pseudomonas synxantha strain 117-2b were tested against two kiwifruit fungal postharvest pathogens: Cadophora luteo-olivacea and Botrytis cinerea, through in vitro and in vivo assays. In vitro results demonstrated that P. synxantha 117-2b VOCs inhibit mycelial growth of C. luteo-olivacea and B. cinerea by 56% and 42.8% after 14 and 5 days of exposition, respectively. In vivo assay demonstrated significant inhibitory effects. VOCs used as a biofumigant treatment reduced skin-pitting symptoms disease severity by 28.5% and gray mold incidence by 66.6%, with respect to the untreated control. BCA volatiles were analyzed by solid-phase microextraction coupled with gas chromatography–mass spectrometry (SPME–GC/MS), and among the detected compounds, 1-butanol, 3-methyl and 1-nonene resulted as the most produced. Their efficacy as pure synthetic compounds was assayed against mycelial growth of fungal pathogens by different concentrations (0.34, 0.56, and 1.12 µL mL−1 headspace). The effect of the application of VOCs as a biofumigant was also investigated as the expression level of seven defense-related genes of kiwifruit at different exposition times. The results indicated an enhancement of the expression of almost all the genes starting from 3 h of treatment. These results described P. synxantha VOCs characteristics and their potential as a promising method to adopt for protecting kiwifruit from postharvest diseases caused by C. luteo-olivacea and B. cinerea.

Peels of Washington Navel (WAS), Navelina (NAV), and Vaniglia Apireno (VAN) orange fruits from Ribera (Sicily, Italy) represent abundant by-products of the Italian agro-food sector. In this work, volatile (VE) and non-volatile (NVE) extracts were obtained from fresh peels using a microwave-assisted protocol, and were characterized for their content in secondary metabolites and bioactivity. VEs exerted antibacterial activity against different pathogens, and were toxic on Caco2 cells. Their main component was limonene (>85 %). NVEs inhibited tyrosinase, amylase, and glucosidase in vitro, and exerted significant antioxidant effects on THP-1 XBlue cells. They showed also anti-inflammatory properties, by decreasing NF-κB activity in LPS-stimulated cells. Putative molecular effectors were highlighted by multivariate correlation analysis. Overall, NVEs may represent novel sustainable nutraceutical ingredients with anti-inflammatory and metabolic properties, and can be obtained by using eco-sustainable approaches. Our results will encourage the reuse of by-products of the orange processing chain and will contribute to increase its circularity in the future.

By analyzing the changes of Saccharomyces cerevisiae fortification on the microbial composition and volatile metabolites of Nong-flavour fermented grains, the disturbances of the microbial ecological network, volatile metabolites and the potential metabolic functions of the microbial community were explored. A strain of Saccharomyces cerevisiae Y1 isolated from nong -flavour fermented grains fermented was used to disturb the solid -state fermentation of fermented grains, and the composition of microorganisms and volatile metabolites were studied by high-throughput sequencing technology and headspace solid-phase microextraction-mass spectrometry technology, respectively. The random forest learning algorithm was used to calculate the biomarkers between the experimental group and the blank group, and the differences in the microbial ecological network between the experimental group and the blank group were analyzed based on the construction of a co-occurrence network model. PLS-DA analysis and Spearman correlation were used to analyze the differences of volatile flavor compounds, the correlation of differential metabolites and biomarkers, respectively. Finally, potential functional changes were analyzed by PICRUST2 functional prediction and pathway enrichment. The results showed that 5 bacteria and 15 fungi can be used as biomarkers to characterize the microbial composition of fermented grains disturbed by Saccharomyces cerevisiae, and also increased the complexity of the microbial ecological network. Meanwhile, the composition of volatile metabolites was altered, with 18 differential metabolites, and the content of some volatile metabolites was improved. The vast majority of biomarkers were significantly associated with differential metabolism. In addition, the perturbation effect of Saccharomyces cerevisiae resulted in 180 up-regulated genes and 46 down-regulated genes in the microbial community, most of which were related to the metabolism of substances. These results provide a basis for the application of Saccharomyces cerevisiae in Baijiu fermentation and the optimization of the fermentation process of fermented grains. [ABSTRACT FROM AUTHOR]

The cultivation of pecan tree [Carya illinoinensis (Wangenh.) K. Koch.] is expanding in Rio Grande do Sul state and, with that, there has been an increase in the disease reports. Among the diseases identified, there is a root rot caused by Fusarium spp. The control of phytopathogenic fungi present in the soil is difficult to obtain, and the control through antagonists such as Trichoderma spp. is a viable way of management. Thus, the objective of this work was to analyze different forms of action of Trichoderma asperellum in the control of Fusarium spp. The antagonistic action was evaluated by paring cultures, presence of volatile and non-volatile metabolites. The mycelial growth inhibition in the culture pairing ranged from 10.38% to 43.17%, while for volatile metabolites protection was lower, reaching values of a maximum of 14.54%. As for the non-volatile metabolites, a percentage of inhibition varied from zero for some treatments to 44.99% in the control of Fusarium graminearum. T. asperellum inhibited the growth of Fusarium spp. through different studied modes of action. [ABSTRACT FROM AUTHOR]

Second-drying has an impact on the development of flavor and aroma in black tea. However, the effect of the shape changes of the tea leaves during second-drying on the quality of black tea has yet to be evaluated. In this study, GC-TOFMS and UPLC-HRMS identified 411 volatile metabolites and 253 nonvolatile metabolites. Additionally, 107 nonvolatile compounds and 21 different volatiles were screened. Significant alterations (p < 0.01) were found in 18 amino acid derivatives, 17 carbohydrates, 20 catechins, 19 flavonoids, 13 phenolic acids, and 4 organic acids. The content of certain amino acids and carbohydrates correlated with the shape of black tea. Furthermore, sweet aroma compound formation was facilitated by hot-air second-drying while the remaining second-drying approaches encouraged the formation of the fruity aroma compound. The results of the study provide a theoretical basis and technical instructions for the accurate and precise processing of premium black tea. [ABSTRACT FROM AUTHOR]

Lactococcus lactis subsp. lactis (L. lactis subsp. lactis) is a commonly used starter cultures in fermented dairy products, contributing distinct flavor and texture characteristics with high application value. However, the strains from different isolates have different contributions to milk fermentation. Therefore, this study aimed to investigate the influence of L. lactis subsp. lactis isolated from various sources on the volatile metabolites present in fermented milk. In this study, L. lactis subsp. lactis from different isolation sources (yogurt, koumiss and goat yogurt) was utilized as a starter culture for fermentation. The volatile metabolites of fermented milk were subsequently analyzed by headspace solid phase microextraction gas chromatography-mass spectrography (HS-SPME-GC-MS). The results indicated significant differences in the structure and abundance of volatile metabolites in fermented milk produced with different isolates (R2Y = 0.96, Q2 = 0.88). Notably, the strains isolated from goat yogurt appeared to enhance the accumulation of ketones (goat yogurt vs yogurt milk: 50 %; goat yogur vs koumiss: 27.3 %)and aldehydes (goat yogurt vs yogurt milk: 21.4 %; goat yogurt vs koumiss: 54.5 %) in fermented milk than strains isolated from koumiss and yogurt milk. It significantly promoted the production of 8 flavor substances (1 substance with OAV ≥ 1 and 6 substances with OAV > 0.1) and enhanced the biosynthesis of valine, leucine, and isoleucine. This study provides valuable insights for the application of Lactococcus lactis subsp. lactis isolated from different sources in fermented dairy production and screening of potential starter cultures.

Existing research on the post-heating processing of fermented milk has primarily focused on single post-heating treatments and the texture, while research on how changes in metabolites during different post-heating treatments affect flavor and sensory properties is limited. This study investigates the changes in volatile metabolites in fermented milk treated at different post-heating temperatures to determine the characteristic aroma types and analyzes the changes in non-volatile metabolites associated with aroma-active compounds or their precursors to clarify the causes of the altered flavor and sensory properties. The results showed that in the 65 °C and 75 °C treatments, 63 volatile compounds were produced by Strecker degradation, lipid oxidation and esterification to produce ketones and aldehydes. Significantly higher odor activity values for 2,3-butanedione, hexanoic acid, and esters and significantly lower odor activity values for 2-heptanone enhanced the frankincense odors and creaminess of the post-heated fermented milk. With temperatures increasing to 95 °C, the increased ketones were primarily 2-heptanone, 2-nonanone, and 2-undecanone that originated from the oxidative decomposition of unsaturated phospholipids at high temperatures. The Maillard reaction of dipeptides produces nitrogenous heterocycles that trigger a caramelized flavor, while organic acids interact with proteins to form complexes that produce astringent flavors. These increase the oxidative off-flavors and reduce the overall palatability. These findings provide a scientific basis for optimizing the post-heating temperature process of fermented milk.

Tropical forests are complex ecosystems characterized by rich biodiversity and intricate interspecies interactions. One of the less understood aspects of these ecosystems is the role of volatile metabolites in shaping the eco-physiological responses of native species. This article explores how variations in spatial and temporal distributions of Volatile Organic Compounds (VOCs) influence the physiological and ecological responses of a selected native plant species in a tropical forest. We conducted field studies to analyze VOC emissions and their correlation with environmental parameters, assessing the impact on plant growth, stress responses, and interactions with pollinators and herbivores. Our findings highlight the adaptive significance of volatile metabolites and suggest that fluctuations in these compounds could be critical in understanding plant resilience in a changing environment. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to analyze the fermentation quality, microbial community, and volatile metabolites of oat silage harvested at two different stages, while examining the correlation between microorganisms and volatile metabolites. Methods: Oats were harvested at two growth stages (pre-heading [PRH] and post-heading [POH] stages), followed by 90 days of natural fermentation, with 6 replicates per treatment. Pre- and post-silage samples were randomly selected for nutrient composition, fermentation parameters, microbial population, and high-throughput sequencing analysis. Volatile metabolomics analysis was also performed on samples after 90 days of fermentation to detect differences in flavor quality after silage. Results: The effect of growth stage on the nutrient content of oats was significant, with pre-heading oats having higher crude protein and post-heading oats having higher water soluble carbohydrates content (p < 0.05). Following a 90-day fermentation period, the pH and ammonia nitrogen/total nitrogen levels in the PRH-90 (silage from pre-heading oats after 90 days of fermentation) group demonstrated a significant decrease (p < 0.05), whereas the lactic acid content was notably higher compared to the POH-90 (silage from post-heading oats after 90 days of fermentation) group (p <0.05). Lactiplantibacillus dominated in the PRH-90 group and Enterococcus dominated in the POH-90 group, with abundances of (> 86%) and (> 87%), respectively. The differential volatile metabolites of the two treatment groups were dominated by esters and terpenoids, and the differences in flavor were mainly concentrated in sweet, green, and fruity odors. The results of Kyoto encyclopedia of genes and genomes pathway enrichment analysis demonstrated three major metabolic pathways: phenylpropanoid biosynthesis, phenylalanine metabolism, and biosynthesis of secondary metabolites. Specific microorganisms were significantly correlated with flavor indicators and flavor metabolites. Lactiplantibacillus was significantly positively correlated with flavor substances indicating sweet and fruity flavors, contributing to good flavor, while Enterococcus was significantly and positively correlated with flavor substances indicating bad flavors. Conclusion: In summary, growth stage had significant effects on nutritional components, fermentation parameters and flavor quality of oats, with the fermentation process dominated by Lactiplantibacillus leading to good flavor, while the fermentation process dominated by Enterococcus led to the development of poor flavor. [ABSTRACT FROM AUTHOR]

In this study, the effects of Danisco mixed lactic acid bacteria and single Bifidobacterium lactis HCS04-001 fermentation on metabolites in soy yogurt were investigated. The main volatile metabolites in sample D fermented by Danisco mixed lactic acid bacteria were aldehydes, followed by alcohols and ketones. In contrast, the main flavor substances in sample SQ fermented by single Bifidobacterium lactis HCS04-001 were alcohols followed by aldehydes. L-Arginine, S-Adenosylhomocysteine, Glutamyltyrosine, Gly-Trp, Ser-Trp, Ile-Ser-Leu, Pro-Val-Leu etc. and D-Ornithine, Citrulline, Glutamylproline, organic acid were the main non-volatile differential metabolites that distinguished the soy yogurt samples. Arginine biosynthesis and glutathione metabolism were important pathways leading to differences in metabolic profiles. This study provides detailed insight into the metabolic properties of commercial Danisco mixed lactic acid bacteria and single Bifidobacterium lactis HCS04-001 fermentations, which will contribute to the development of soy yogurt with good nutritional and sensory qualities. [ABSTRACT FROM AUTHOR]

Plum (Prunus salicina Lindl.) is an important stone fruit crop in Sichuan that is increasingly in demand by consumers owing to its flavor and outstanding nutraceutical properties. The physicochemical characteristics, antioxidant capacity, and volatile profiles of five traditional and new plum cultivars in Sichuan were determined using high-performance liquid chromatography and gas chromatography time-of-flight mass spectrometry. The results showed that all plums exhibited an appropriate quality profile for fresh consumption; the new cultivar 'ZH' exhibited the highest soluble solids content, sugar–acid ratio, total phenolic content, total flavonoid content, and antioxidant capacity. High sugar–low acid properties were observed in five plum cultivars. Sucrose was the main sugar, while quinic acid and malic acid were the main organic acids. The plums were rich in volatile compounds and had specific volatile characteristics. A total of 737 volatiles were identified in the plum fruit, and orthogonal partial least-squares discriminant analysis was employed to screen 40 differential volatiles as markers for cultivar distinction. These findings offer comprehensive information on the physicochemical characteristics, antioxidant capacity, and volatile profiles of plums. [ABSTRACT FROM AUTHOR]

The losses of harvested sweet potato is large due to postharvest disease, among which black spot, caused by Ceratocystis fimbriata is one of the most important. In this study, the antimicrobial activities of Bacillus amyloliquefaciens (JK) and Klebsiella pneumoniae (GK) screened in the previous research with strong antagonistic effect on C. fimbriata were analyzed. The volatile antifungal components of the two antagonistic bacteria were analyzed by gas chromatography-ion mobility spectrometry (GC-IMS) and gas chromatography-mass spectrometry (GC-MS). It was found that fumigation sweet potato with fermentation of the two antagonistic bacteria delayed the onset time of black spot and effectively controlled the development of the disease spot. The volatile components were ketones, alkanes, alcohols, esters, aldehydes and so on. In all of them, 1-hexanol, 2-ethyl-, hexanal, 2-nonanone and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate had strong inhibitory effects on C. fimbriata by plate test. After the two safety gas components hexanal and 2-nonone were mixed in the ratio of 1:1, the growth of C. fimbriata could be completely inhibited when the concentration of the mixtures reached 200 µL/L. This study would provide a reference for the application of antagonistic microorganisms in postharvest fruits and vegetables.

Common bean (Phaseolus vulgaris L.) is one of the most important crops in human food production. The occurrence of diseases, such as white mold, caused by Sclerotinia sclerotiorum can limit the production of this legume. The use of Trichoderma has become an important strategy in the suppression of this disease. The aim of the present study was to evaluate the effect of volatile organic compounds (VOCs) emitted by Trichoderma azevedoi CEN1241 in five different growth periods on the severity of white mold in common bean. The in vitro assays were carried out in double-plate and split-plate, and the in vivo assays, through the exposure of the mycelia of S. sclerotiorum to the VOCs of T. azevedoi CEN1241 and subsequent inoculation in bean plants. Chemical analysis by gas chromatography coupled to mass spectrometry detected 37 VOCs produced by T. azevedoi CEN1241, covering six major chemical classes. The profile of VOCs produced by T. azevedoi CEN1241 varied according to colony age and was shown to be related to the ability of the biocontrol agent to suppress S. sclerotiorum. T. azevedoi CEN1241 VOCs reduced the size of S. sclerotiorum lesions on bean fragments in vitro and reduced disease severity in a greenhouse. This study demonstrated in a more applied way that the mechanism of antibiosis through the production of volatile compounds exerted by Trichoderma can complement other mechanisms, such as parasitism and competition, thus contributing to a better efficiency in the control of white mold in bean plants.

The reasons for the change in volatile metabolites and aroma of black tea during storage remain unclear. Therefore, we used HS-SPME and GC–MS methods to analyze the aroma compounds of new tea (2021) versus aged tea groups (2015, 2017, and 2019). A total of 109 volatile components were identified. During storage, 36 metabolites mainly with floral and fruity aromas decreased significantly, while 18 volatile components with spicy, sour, and woody aromas increased significantly. Linalool and beta-ionone mainly contributed to sweet and floral aromas of freshly-processed and aged black tea, respectively. Isovaleric acid and hexanoic acid mainly caused sour odor of aged black tea. The monoterpene biosynthesis and secondary metabolic biosynthesis pathways might be key metabolic pathways leading to changes in the relative content of metabolites during storage of black tea. Our study provides theoretical support for fully understanding the changes in the aroma quality of black tea during storage.

Shaking is an innovative technology employed in black tea processing to enhance flavor. However, the effects of shaking on the evolutionary mechanisms of volatile metabolites (VMs) remain unclear. In this study, we compared the effects of a shaking–withering method with those of traditional withering on the flavor and VMs transformation of black tea. The results showed that black tea treated with shaking exhibited excellent quality with floral and fruity aroma. Based on gas chromatography-tandem mass spectrometry, 128 VMs (eight categories) were detected. Combining variable importance projection with odor activity value analysis, eight key differential VMs were identified. Shaking could promote the oxidative degradation of fatty acids and carotenoids and modulate the biosynthesis of terpenoids to facilitate the formation of floral/fruity VMs (such as (Z)-hexanoic acid-3-hexenyl ester, ethyl hexanoate, trans-β-ionone, and decanal). Our findings provide theoretical guidance for the production of high-quality black tea with floral and fruity aromas.

The effects of reduced glutathione (GSH) on non-volatile and volatile metabolites of Chardonnay wine during storage under simulated oxidation were investigated. The metabolites of GSH, which play a key role in the storage of white wine, were identified. In this study, GSHs at 0, 10, and 20 mg/L were added to wine samples and stored at 45 °C for 45 days. Wine samples supplemented with 0 mg/L GSH were used as controls (CK). The samples stored for 45 days were analyzed via ultra-high performance liquid chromatography–tandem mass spectrometry and gas chromatography–tandem mass spectrometry. A total of 1107 non-volatile metabolites were detected, and 617 volatile metabolites were identified. Variable Importance in Projection (VIP) of >1.0 and Fold Change (FC) of ≧2.0 were used to screen differential metabolites. A total of 59 important non-volatile and 39 differential volatile metabolites were screened. Among the non-volatile metabolites, 17 substances were down-regulated, whereas 16 substances were up-regulated. Among the volatile metabolites, 3 substances were down-regulated, while 19 substances were up-regulated. After analysis, some lipids were found to play an important role in the changes to non-volatile substances. This study provides theoretical support for further application of GSH in increasing the oxidation stability of white wine. [ABSTRACT FROM AUTHOR]