MetaboLightsapplication/xmlftp://ftp.ebi.ac.uk/pub/databases/metabolights/studies/public/MTBLS14540/m_MTBLS14540_GC-MS_positive_low-polarity_v2_maf.tsvftp://ftp.ebi.ac.uk/pub/databases/metabolights/studies/public/MTBLS14540/i_Investigation.txtftp://ftp.ebi.ac.uk/pub/databases/metabolights/studies/public/MTBLS14540/s_MTBLS14540.txtftp://ftp.ebi.ac.uk/pub/databases/metabolights/studies/public/MTBLS14540/a_MTBLS14540_GC-MS_positive_low-polarity.txtprimaryOK200ftp://ftp.ebi.ac.uk/pub/databases/metabolights/studies/public/MTBLS14540<p>Metabolite identification was performed using Compound Discoverer 3.3.SP3 software (Thermo Fisher Scientific, USA). Raw GC-MS spectra were matched against three databases: the NIST-2023 mass spectral library, the GC-Orbitrap Metabolomics Library_v2, and an in-house database constructed from standard substances and verified metabolites. Peak matching was based on mass spectral similarity and retention index (RI) consistency. Redundant peaks, noise, and derivatization-related fragments were removed. Metabolite annotations were confirmed by comparing experimental data with database entries for molecular formula, molecular weight, and characteristic fragment ions.</p>MetaboLightsPublicGas Chromatography MS - positive - low-polarity<p>Instrument and chromatographic conditions: The analysis was performed on an Orbitrap Exploris GC system (Thermo Fisher Scientific, Germany) equipped with a TG-5SILMS capillary column (30 m × 0.25 mm × 0.25 μm, Thermo Fisher Scientific). The injector temperature was 300 °C, and samples were injected in split mode with a split ratio of 20:1 and an injection volume of 1 μL. High-purity helium served as the carrier gas at a flow rate of 1.0 mL/min, with a septum purge flow of 3 mL/min. The oven temperature program started at 80 °C, ramped to 310 °C at 20 °C/min, and held at 310 °C for 8 min; the total run time was 20 min, with a solvent delay of 2 min</p>Mechanistic Insights into Lactic Acid Bacteria-Driven Biotransformation of Undaria pinnatifida: Ecological Dominance, Metabolic Reprogramming, and Quality Formation.Yingzhen WangMajorbioUndaria pinnatifidamass spectrometry assay<p>Prior to GC-MS analysis, samples were processed following an untargeted metabolomics workflow. Briefly, 50 mg of each frozen fermented Undaria pinnatifida slurry sample was accurately weighed into a 2 mL centrifuge tube. A total of 0.5 mL of methanol-water solution (4:1, v/v) containing 0.2 mg/mL ribitol as an internal standard was added, followed by one steel bead. The mixture was ground at 20 °C for 3 min at 50 Hz using a tissue grinder. Then, 200 microL of chloroform was added, and the sample was ground again for 3 min, ultrasonicated for 30 min, and kept at 20 °C for another 30 min. After centrifugation at 13,000 rcf for 15 min at 4 °C, the supernatant was transferred to a glass derivatization vial and dried under nitrogen. For derivatization, 80 microL of methoxyamine hydrochloride in pyridine (15 mg/mL) was added, vortexed for 2 min, and reacted at 37 °C for 90 min. Subsequently, 80 microL of BSTFA (with 1% TMCS) was added, vortexed for 2 min, and reacted at 70 °C for 60 min. The vial was cooled to room temperature for 30 min before GC-MS injection.</p><p>Several control and quality control samples were prepared in parallel. A quality control (QC) sample was generated by pooling equal volumes of all 12 experimental samples and processed identically to monitor analytical reproducibility. A mixed n-alkane standard solution (C10-C33, 10 microg/mL) was prepared in hexane and analyzed alongside samples for retention index calibration. A solvent blank (methanol-water, 4:1, v/v) was included throughout extraction and derivatization to assess background contamination. All standards, blanks, and QC samples were interspersed among experimental samples during GC-MS acquisition to ensure system stability and data reliability.</p>Undaria pinnatifidahttps://www.ebi.ac.uk/metabolights/MTBLS14540Hang Qi. Dalian Polytechnic University. qihang@dlpu.edu.cn.Yingzhen Wang. Dalian Polytechnic University. wangyz2036@163.com.<p>Raw GC-MS data were processed using Compound Discoverer 3.3.SP3 software (Thermo Fisher Scientific, USA). The workflow included peak detection, peak alignment, baseline correction, and deconvolution. Metabolite identification was performed by matching mass spectra and retention indices against the NIST-2023 database, GC-Orbitrap Metabolomics Library_v2, and an in-house database. Redundant peaks and background noise were removed, and derivatization-related mass fragments were stripped from metabolite annotations. The processed data were exported as a 3D matrix (metabolite × sample × peak area) in Excel format for subsequent statistical analysis.</p>Group1049054524@qq.com<p>Frozen salted Undaria pinnatifida leaves were thawed and rinsed, then homogenized with water to prepare a slurry. After sterilization, the slurry was inoculated with lactic acid bacteria starter culture and fermented at 37°C for 48 hours. Upon completion of fermentation, all samples from each group were stored frozen.</p>MetabolomicsMetabolomicsLactic acid bacteria35–500Undaria pinnatifidauntargeted analysisBiotransformationMetabolic remodelingFlavor formationUndaria pinnatifida slurrypooled sampleMicrobial communityOrbitrap Exploris GC-MSMetabolomicsLactic acid bacteria35–500Undaria pinnatifidauntargeted analysisBiotransformationMetabolic remodelingFlavor formationUndaria pinnatifida slurrypooled sampleMicrobial communityOrbitrap Exploris GC-MS<p>The analysis was performed using an Orbitrap Exploris GC mass spectrometer (Thermo Fisher Scientific, Germany) equipped with an electron ionization (EI) source operated in positive ionization mode. The ion source temperature was set at 320 °C, electron energy at 70 eV, and emission current at 50 μA. Mass spectra were acquired in full-scan mode over the m/z range of 35-500 with an Orbitrap resolution of 30,000.</p>PsicofuranoseSorbitolD-Glucuronic AcidL-Rhamnose3-Ethyl-3-MethyldecaneDothiepin SulfoxideSucroseEthyl[(Oxolan-2-Yl)Methyl]Amine3-Methyl-3-(1-Methylethoxy)-1-PentyneFumaric Acid, Decyl 3-Heptyl Ester3-Alpha-MannobioseCis-3-Methyl-Endo-Tricyclo[5.2.1.0(2.6)]Decane2,2-DimethyloctaneN-Butyl-N-(4-Aminophenylsulfonyl)BenzamideGlucopyranoseHexadecaneErythritolD-Xylose1,2-EthenediolMethyl[(1-Methyl-2,3-Dihydropyrrol-3-Yl)Methyl]Amine2,2-Dimethylpentane1-Dodecyl-2-PyrrolidinoneIsopropyl Beta-D-GlucopyranosideIsofucosterolPhenanthrene-10-Ethanamine, 3-Bromo-Beta-Hydroxy-N,N-Diheptyl-, O,O-DiphenylphosphateTert-ButyldimethylsilanolThreonineMethylvinyl(2,4-Dimethylpent-3-Yloxy)(Methylvinylheptyloxysilyloxy)-SilanePhytol6-O-Beta-D-Galactopyranosyl-D-GalactoseGlycine, 2-Cyclohexyl-N-(But-3-En-1-Yl)Oxycarbonyl-, Octyl Ester2,3-DihydroxybutanedihydrazideO-(2-Furoyl)-O'-(Isobutoxycarbonyl)-1,2-Benzenediol(Z)-9-OctadecenamideTrimethyl(3,3-Difluoro-2-Propenyl)SilaneL-ArabinitolPaeoniflorinOxalic Acid, Allyl Hexadecyl Ester1,3-PropanediolL-Sorbose2,2'-(Hexadecylazanediyl)Bis(Ethan-1-Ol)Butyraldehyde OximeN-(Furan-2-Ylmethyl)-1-(1,2,3,4-Tetrahydroisoquinoline-3-Carbonyl)Piperidine-4-CarboxamideDl-Glutamic Acid4-O-[6-Deoxy-2,3,4-Trihydroxy-Alpha-L-Mannopyranosyl]-D-GlucoseTrehaloseLactuloseHydroxyproline8-Hexadecyne3,3-Dimethylbutanamide(Z)-Docos-9-EnenitrileGlycineD-Mannose8,11,14-Eicosatrienoic Acid, Methyl EsterLevoglucosanOctadecanamideSebacamideLinoleamide2,3-Dimethyl-1-Pentene2-Butyl-3,4,5,6-Tetrahydropyridine(2S,3R,4R)-2,3,4,5-TetrahydroxypentanalInositol 1-PhosphateHeptadecanenitrileAlanineD-(+)-CellobiosePhenylalanineL-(-)-Sorbofuranose2,3-Dihydro-1-(1-Methylpropyl)-1H-Indole6-[(3,4-Dimethoxyphenyl)(4-Morpholinyl)Methyl]-1,3-Benzodioxol-5-OlIsomaltoseBicyclo[2.1.0]Pentane-5-Carboxylic Acid, 1-Methyl-, Ethyl Ester1-MonopalmitinDl-Alanyl-Dl-NorvalineN-(2-Methoxyphenyl)-2-Nitrobenzenecarbothioamide(3S,4S,5R)-1,3,4,5,6-Pentahydroxyhexan-2-OneStephasunoline4-Thiouridine1,1',3-Tribenzoyl-2,3-Dihydro-2,2'-Biimidazole3,3,5-Trimethyl-1-HexeneSuccinic Acid, Di(2-Fluoroethyl) Ester(E)-2-Methyl-2-Butenyl Angelate3-OctadecyneStearidonic AcidAsparagine2-Hydroxy-Pentanedioic Acid1,4A,7-Trimethyl-7-[2-[3,4,5-Trihydroxy-6-(Hydroxymethyl)Oxan-2-Yl]Oxyethyl]-3,4,4B,5,6,8,10,10A-Octahydro-2H-Phenanthrene-1-Carboxylic Acid[5-(Hydroxymethyl)-2,2-Dimethyl-1,3-Dioxolan-4-Yl]MethanolUracil1-Ethylhexyl I(2)-D-Glucopyranoside(R,S,R)-D-(+)-Ribono-1 4-LactoneTromethamine1-Aminocyclopentanecarboxylic Acid, 3-Chloropropoxycarbonyl-, Octyl Ester1-Aminocyclopentanecarboxylic Acid, 3-Chloropropoxycarbonyl-, Dodecyl Ester1-Isocyanato-Hexane2,2'-Dithiodibenzoic AcidTert-Leucine, N-Methoxycarbonyl-, Pentadecyl Ester4,6,8-Trimethyl-1-NonenePropylene GlycolAspartic AcidEicosapentaenoic AcidJuniperoside IiiOxydipropyl DibenzoateGalactaric Acid2-Methyl-7-OctadecyneL-5-OxoprolineN-(4-(Dimethylamino)Butyl)Acetamide3,3-Dimethyl-HexaneQuinic AcidHexadecanenitrileCitric Acid1-(2-Fluoro-Ethyl)-Piperidin-4-Ylamine2-(Ethylamino)Acetic AcidOleonitrileGlycerol MonostearateMethyl Beta-D-GalactopyranosideN-Methylformamide4-Hydroxyphenyllactic AcidMaltoseDiacetone AlcoholMalic AcidPsoracorylifol A1-Aminocyclopentanecarboxylic Acid, 3-Chloropropoxycarbonyl-, Undecyl Ester4,4-Dimethyl-Pent-2-YnalOctamethyl-CyclotetrasiloxaneGallic AcidAcetaldehyde Trans-2-Hexenyl Pentyl AcetalStearonitrilePyruvic AcidGluconolactone3-Methyl-3-Hydroxy-Pentanedioic Acid2,6-Dimethyl-L-Tyrosine1-Phenyl-4,5-Dihydro-1H-Pyrazol-3-Yl Methyl(2-Methyl-1,3-Dioxo-2,3-Dihydro-1H-Isoindol-4-Yl)CarbamateD-Glucose1-Aminocyclopentanecarboxylic Acid, 3-Chloropropoxycarbonyl-, Nonyl Ester2-Deoxy-3,4,5-Trihydroxy-Erythro-Pentonic AcidMaleic AcidSerineGlycerophosphoric AcidHexadecanamide2,2-Dichloro-N-[3-Fluoro-1-Hydroxy-1-(4-Methylsulfonylphenyl)Propan-2-Yl]AcetamideAdipic Acid, 2-Decyl Isobutyl EsterChiro-InositolDl-3-Phenyllactic Acid5-NonanolBeta-D-Galactofuranose(Z)-11-Octadecenoic AcidLoliolide3-Hydroxy-3-Buten-2-One5-Hydroxypipecolic AcidOctanoic AcidAdenosineN,N-Diheptyl-2-(2-Thiophenyl)-EthylamineLactic Acid2-Ethylhexan-1-Ol1-Methylbutyl 6-O-(Beta-D-Glucopyranosyl)-Beta-D-GlucopyranosideIbotenic AcidSulfurous Acid, 2-Ethylhexyl Isohexyl Ester1-(2-Aminopropoxy)-2-Methoxyethane2,4,6-TrimethyloctaneD-RibosePentadecanenitrile5-Methyl-2,4-Dihydroxy-Pyrimidine3-Methyl-3-Morpholin-4-Yl-1-Oxido-4-Phenyl-4,4A,5,6,7,8-Hexahydro-2,1-Benzoxazin-1-Ium3-(1-Methyl-2-Propenyl)-1,5-CyclooctadieneTerephthalic Acid, 2,6-Dimethoxyphenyl Propyl EsterfalseMechanistic Insights into Lactic Acid Bacteria-Driven Biotransformation of Undaria pinnatifida: Ecological Dominance, Metabolic Reprogramming, and Quality FormationUndaria pinnatifida, a representative brown macroalga, is limited in high-value food applications due to its dense cell wall structure, pronounced marine odor, and inefficient conventional processing. In this study, a controlled fermentation strategy was established using different lactic acid bacterial starters with Undaria pinnatifida slurry as the substrate. Milk starter fermentation exhibited a predominance of Streptococcus, with annotated enrichment in propanoate metabolism and branched-chain amino acid degradation. These metabolic signatures coincided with higher abundances of esters and methyl-branched volatiles correlated with roasty and fruity sensory notes. In comparison, kimchi starter fermentation was abundant in Lactiplantibacillus, where starch–sucrose and arginine–proline metabolic pathways were enriched. The observed accumulation of furanones and hexenal was closely associated with caramel-like sweetness. This study characterizes lactic acid bacteria–correlated metabolic patterns underlying the formation of quality, offering valuable references for the controlled bioprocessing of brown macroalgae.2026-05-202026-05-20MTBLS14540HMDB0000258;PW_C000177HMDB0000247;HMDB0250766;PW_C000168HMDB0062251HMDB0002117HMDB0001266HMDB0000156;PW_C000592HMDB0000639;LMFA01170107HMDB0000126;HMDB0252849HMDB0000094;PW_C000063HMDB0012273;LMFA08010009HMDB0000187HMDB0000150;PW_C000097HMDB0001851HMDB0000975;PW_C000776HMDB0250791HMDB0000283;PW_C000191HMDB0002019;LMPR0104010002HMDB0000122;PW_C000077HMDB0000849HMDB0251512HMDB0000640HMDB0002994HMDB0000169;PW_C000111HMDB0034146;LMFA08010003HMDB0000243;LMFA01060077;PW_C000164HMDB0002374;LMST01040145HMDB0000725;HMDB0243901HMDB0062656;LMFA08010008HMDB0000050;HMDB0247583;PW_C000034HMDB0000176HMDB0240288HMDB0005807HMDB0000300;PW_C000204HMDB0000123;PW_C000078HMDB0031511HMDB0000213HMDB0246588HMDB0001881;PW_C001252HMDB0062786HMDB0033792;LMFA11000577HMDB0251596HMDB0000482;LMFA01010008HMDB0031231;LMFA05000703HMDB0001122HMDB0000163HMDB0003072HMDB0002923HMDB0000098HMDB0000740HMDB0001999;PW_C001337HMDB0041945HMDB0253330HMDB0302428HMDB0256075HMDB0006547;LMFA01030357;PW_C002804HMDB0000127;PW_C000082LMFA09000006LMFA09000007LMFA11000678