Search Results (102)

Discovering new yeast species can be crucial for creating new types of beers. In this study, we investigated three new yeast species, Saccharomyces bayanus, Schizosaccharomyces japonicus and Schizosaccharomyces pombe var. malidevorans, which have not been previously used in the brewing industry. Colour, total acidity, bitterness, aroma profile, total phenolic, flavonoid, mineral content and organoleptic characteristics of beers fermented by these strains were analysed to discover their applicability in the brewing industry. They did not significantly affect the nutritional value and colour of the beers, but showed increased acidity compared to the control Saccharomyces cerevisiae. GC-MS (Gas Chromatography-Mass Spectrometry) analysis revealed 33 aroma compounds, some of which were identical and some unique. S. cerevisiae and S. bayanus produced a similar number (19–20) of aroma compounds, while S. japonicus produced the fewest, including some undesirable compounds. Isobutyl alcohol, isoamyl alcohol, acetol, dimethylpyrazine, acetic acid, 4-cyclopentene-1,3-dione, butyrolactone, 2-furanmethanol, phenylethyl alcohol, maltol and pyranone that provide desired aromas in beers could be found in every sample. The new yeasts significantly increased polyphenols and decreased flavonoid content. Based on the results above and the taste scores, the strains S. bayanus and S. pombe var. malidevorans may be suitable for brewing, while S. japonicus is less or only suitable for combined fermentation. Full article

Current research on chili powder and oil has predominantly focused on cultivar selection and oil temperature, while the impact of thermal pretreatment methods on their quality and flavor profiles remains underexplored. In this study, the flavor profiles of raw untreated, stir-fried, oven-baked, and microwaved chili powders (RC, SC, OC, and MC) and their corresponding chili oils obtained through secondary flavor activation (RCO, SCO, OCO, and MCO) were analyzed using E-nose, GC-IMS, HS-SPME-GC-MS, LC-MS/MS, and sensory evaluation techniques. E-nose and GC-IMS 2D topographic plots revealed that thermal treatment increased the concentration of volatile flavor compounds. HS-SPME-GC-MS further detected 220 and 207 volatile compounds in chili powders and oils, respectively, with 74 and 35 identified as differential volatile compounds. Aldehydes ((E,E)-2,4-heptadienal, benzaldehyde), alcohols (1-nonanol, 2-furanmethanol), Maillard reaction products (ethyl pyrazine, 2,3-dimethylpyrazine, and 2-ethyl-6-methylpyrazine), and methyl acetate were significantly enhanced in SC, OC, and MC and their corresponding chili oils. Among them, OC and OCO showed the greatest increase in differential flavor substances. Additionally, all three treatments enhanced the release of taste-active substances and improved sensory overall acceptability. These findings provide new insights for the food industry in optimizing chili product processing. Full article

The aim of this study was to investigate the metabolites in Aspergillus subramanianii 1901NT-1.40.2 extract using UPLC-MS, isolate and elucidate the structure of individual compounds, and study the antimicrobial and cytotoxic activities of the isolated compounds. The structures of two previously unreported ergostane triterpenoid aspersubrin A (1) and pyrazine alkaloid ochramide E (2) were established using NMR and HR ESI-MS. The absolute configuration of 1 was determined using quantum chemical calculations. Moreover, the known polyketides sclerolide (3) and sclerin (4); the indolediterpene alkaloid 10,23-dihydro-24,25-dehydroaflavinine (5); the bis-indolyl benzenoid alkaloids kumbicin D (6), asterriquinol D dimethyl ether (7), petromurin C (8); and the cyclopentenedione asterredione (9) were isolated. The effects of compounds 3-9 on the growth and biofilm formation of the yeast-like fungus Candida albicans and the bacteria Staphylococcus aureus and Escherichia coli were investigated. Compounds 5 and 6 inhibited C. albicans growth and biofilm formation at an IC₅₀ of 7–10 µM. Moreover, the effects of compounds 3-9 on non-cancerous H9c2 cardiomyocytes, HaCaT keratinocytes, MCF-10A breast epithelial cells, and breast cancer MCF-7 and MDA-MB-231 cells were also investigated. Compound 8 (10 µM) significantly decreased the viability of MCF-7 cells, inhibited colony formation, and arrested cell cycle progression and proliferation in monolayer culture. Moreover, 8 significantly decreased the area of MCF-7 3D spheroids by approximately 30%. A competitive test with 4-hydroxytamoxyfen and molecular docking showed that estrogen receptors (ERβ more than ERα) were involved in the anticancer effect of petromurin C (8). Full article

Background: Understanding how aroma compounds enhance monosodium glutamate (MSG) umami perception remains a critical challenge in flavor science. Methods: The umami-enhancing effects of meaty flavorings were investigated using nasal clip sensory evaluation (orthonasal blockage). Active aroma compounds were subsequently identified using gas chromatography-mass spectrometry (GC-MS). The three-dimensional structure of the umami receptor T1R1/T1R3 was constructed by homology modeling. The interaction mechanism was deciphered using molecular dynamics (MD) simulations. Results: Seafood essence S demonstrated the most potent umami enhancement. Five key compounds significantly intensified the MSG umami intensity: methional, dimethyl sulfide (DMS), D-limonene (DLE), 2,3-dimethylpyrazine, and dimethyl trisulfide. Notably, this enhancement persisted even under nasal clip conditions, revealing a novel mechanism independent of cross-modal interactions. Sulfur-containing compounds consistently demonstrated umami-enhancing effects across the evaluation conditions. MD simulations showed that aroma compounds induced allosteric remodeling of T1R1/T1R3, strengthening MSG-receptor hydrogen bonding (1.8–2.6-fold increase), reducing receptor flexibility, and stabilizing the ternary complex. Binding affinity was highest for DMS, followed by DLE and methional. Conclusion: This study provides the first receptor-level evidence that aroma compounds directly modulate MSG-taste receptor interactions through allosteric regulation, offering a novel theoretical framework for odor–taste interactions with significant implications for umami enhancer design and flavor research. Full article

This study aimed at defining the infrared spectral signatures of volatile organic compounds (VOCs) of relevant interest for coffee bean authentication and quality control. Fourier Transform Infrared Spectroscopy was employed to acquire the mid-infrared absorption spectra of some representative coffee markers, namely Pyridine, 2-Methylpyrazine, 2,5-Dimethylpyrazine, Furfural, 5-Methylfurfural and Furfuryl Alcohol, with high resolution of 0.1 cm⁻¹. Mixtures of these VOCs simulating their amount in coffee seeds were analyzed using multilinear regression. The achieved results demonstrate the potentiality of coffee fingerprinting by VOC’s signature in the absorption spectra for discriminating coffee origin. Full article

Understanding how leaf maturity affects the flavor attributes of green tea is crucial for optimizing harvest timing and processing strategies. This study comprehensively characterized the flavor profiles of Fudingdabai green teas at three distinct leaf maturity stages—single bud (FDQSG), one bud + one leaf (FDMJ1G), and one bud + two leaves (FDTC2G)—using a multimodal approach integrating electronic nose, electronic tongue, HS-GC-IMS, relative odor activity value (rOAV) evaluation, and machine learning algorithms. A total of 85 volatile compounds (VOCs) were identified, of which 41 had rOAV > 1. Notably, 2-methylbutanal, 2-ethyl-3,5-dimethylpyrazine, and linalool exhibited extremely high rOAVs (>1000). FDQSG was enriched with LOX (lipoxygenase)-derived fresh, grassy volatiles such as (Z)-3-hexen-1-ol and nonanal. FDMJ1G showed a pronounced accumulation of floral and fruity compounds, especially linalool (rOAV: 7400), while FDTC2G featured Maillard- and phenylalanine-derived volatiles like benzene acetaldehyde and 2,5-dimethylfuran, contributing to roasted and cocoa-like aromas. KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis revealed significant enrichment in butanoate metabolism and monoterpenoid biosynthesis. Random forest–SHAP analysis identified 20 key flavor markers, mostly VOCs, that effectively discriminated samples by tenderness grade. ROC–AUC validation further confirmed their diagnostic performance (accuracy ≥ 0.8). These findings provide a scientific basis for flavor-driven harvest management and the quality-oriented grading of Fudingdaibai green tea. Full article

Fermentation plays a pivotal role in shaping the flavor and overall quality of Pu-erh tea, a microbially fermented dark tea. Here, we monitored physicochemical properties, chemical constituents, and microbial succession at 15 fermentation time points. Amplicon sequencing identified Staphylococcus, Bacillus, Kocuria, Aspergillus, Blastobotrys, Thermomyces, and Rasamsonia as dominant genera, with prokaryotic communities showing greater richness and diversity than eukaryotic ones. Beta diversity and clustering analyses revealed stable microbial structures during late fermentation stages. Non-targeted metabolomics detected 347 metabolites, including 56 significantly differential compounds enriched in caffeine metabolism and unsaturated fatty acid biosynthesis. Fermentation phases exhibited distinct metabolic patterns, with volatile aroma compounds (2-acetyl-1-pyrroline, 2,5-dimethylpyrazine) and health-beneficial fatty acids (linoleic acid, arachidonic acid) accumulating in later stages. OPLS-DA and KEGG PATHWAY analyses confirmed significant shifts in metabolite profiles relevant to flavor and biofunctionality. RDA revealed strong correlations between microbial taxa, environmental parameters, and representative metabolites. To functionally verify microbial contributions, 17 bacterial and 10 fungal strains were isolated. Six representative strains, mainly Bacillus and Aspergillus, exhibited high enzymatic activity on macromolecules, confirming their roles in polysaccharide and protein degradation. This integrative multi-omics investigation provides mechanistic insights into Pu-erh tea fermentation and offers a scientific basis for microbial community optimization in tea processing. Full article

Postharvest fungal diseases are a major cause of fruit spoilage and economic losses, particularly in perishable commodities like strawberries. In this study, a plant-derived Weissella paramesenteroides strain R2 was isolated from the mango fruit surface and evaluated for its antifungal potential. Dual-culture assays revealed the strong inhibitory activity of strain R2 against key postharvest pathogens, including Botrytis cinerea, Colletotrichum gloeosporioides, and Fusarium oxysporum. Notably, cell-free fermentation broth exhibited no antifungal activity, whereas the volatile organic compounds (VOCs) produced by R2 significantly suppressed fungal growth in sealed plate assays. GC-MS analysis identified 84 VOCs, with pyrazines as the dominant group. Three major compounds, 2,5-dimethylpyrazine, 2,4-di-tert-butylphenol, and 2-furanmethanol, were validated for their antifungal activity. The application of R2 VOCs in strawberry preservation significantly reduced disease incidence and severity during storage. These findings highlight W. paramesenteroides R2 as a promising, food-safe biocontrol agent for postharvest disease management via VOC-mediated mechanisms. Full article

Investigating the volatiles isolated from a commercial spirulina (Arthrospira platensis) dietary supplement by gas chromatography–olfactometry (GC–O) in combination with an aroma extract dilution analysis (AEDA) resulted in 29 odor events with flavor dilution (FD) factors between 8 and 2048. Identification experiments, including various offline and online fractionation approaches, led to the structure assignment of 30 odorants, among which the most potent were sweaty 2- and 3-methylbutanoic acid (FD 2048), roasty, earthy, shrimp-like 2-ethyl-3,5-dimethylpyrazine (FD 2048), vinegar-like acetic acid (FD 1024), and floral, violet-like β-ionone (FD 1024). Static headspace dilution analysis revealed sulfuric, cabbage-like methanethiol (FD factor ≥ 32) as an additional potent odorant. In summary, 31 important spirulina odorants were identified in this study, and 14 were reported for the first time as spirulina constituents. Our data will provide a basis for future odor optimization of spirulina-based food products. Full article

The evaluation of aroma-active profiles in dry-cured hams is crucial for determining quality, flavor, consumer acceptance, and economic value. This study characterized the volatile compounds in five varieties of dry-cured hams using gas chromatography-mass spectrometry-olfactometry (GC-MS-O) and an electronic nose (E-Nose). In total, 78 volatile compounds were identified across five varieties of dry-cured hams. A total of 29 compounds were recognized as aroma-active compounds. Odor description, intensity, and hedonic assessment were employed to evaluate these compounds. Black Hoof Cured Ham and Special-grade Xuan-Zi Ham contained higher levels of favorable compounds such as nonanal, 5-butyldihydro-2(3H)-furanone, and 2,6-dimethylpyrazine, contributing to sweet and popcorn-like notes. In contrast, Fei-Zhong-Wang Ham and Liang-Tou-Wu Ham exhibited higher proportions of off-odor compounds with lower hedonic scores. A principal component analysis clearly separated the five hams based on their aroma-active profiles, and a correlation analysis between E-Nose sensor responses and GC-MS-O data demonstrated a strong discriminatory ability for specific samples. These findings offer valuable insights into the chemical and sensory differentiation of dry-cured hams and provide a scientific basis for quality control, product development, and future improvements in E-Nose sensor design and intelligent aroma assessment. Full article

The objective of this study was to obtain and evaluate a coffee aroma extract/oil with sensorial attributes close to the original brew of Greek coffee for use in an instant Greek coffee powder. The oil was obtained directly from commercial Greek coffee by solid-liquid extraction using hexane as a solvent and treated with a series of hexane-ethanol mixtures (0:10, 1:4, 1:9) to remove the intense roasted flavor of the crude coffee oil obtained by hexane; the de-oiled coffee was used for the recovery of water-soluble compounds, and the produced water extract was freeze-dried. The aromatic volatiles of the coffee oil samples were analyzed by using a purge-and-trap device coupled to GC-MS, as well as sensory analysis. The instant Greek coffee powder was produced by mixing the freeze-dried base (74.4%) with the extract derived after treatment of the crude oil with hexane-ethanol mixture 1:4 (18.2%) and foaming agent (7.4%). Two different materials were studied as bases: instant coffee (F3_Gr-D) and ground Greek coffee (reference sample, C_Gr). The shelf-life stability of the produced powders was examined at three storage temperatures (25, 45, 60 °C). Instrumental analysis (purge-and-trap GC-MS) of aroma and sensory analysis (aroma, taste, staling, total sensory quality on a 1–9 hedonic scale) was conducted. Aroma loss (furfuryl alcohol, furfural, dimethyl pyrazines, ethyl methyl pyrazines) and scores for sensory attributes during storage were modeled using 1st and 0-order reaction kinetics, respectively. The storage temperature effect was expressed by the Arrhenius model (activation energy E_a). According to the results, the developed instant coffee powder presented satisfactorily the aroma characteristics of regular Greek coffee. The shelf life for the instant Greek coffee powder was estimated as 80 days (air packed) (based on 20% retention of furfuryl alcohol that was the most abundant aromatic volatile of Greek coffee aroma, ground as well as extract oil). Full article

Novel methods of coffee processing, including animal-assisted fermentation, are gaining popularity—among them, elephant dung coffee stands out for its rarity and high price, making it a likely target for adulteration. This study aims to discover candidate biomarkers for elephant coffee by comparing the chemical composition, antioxidant activity, and volatile profiles of Arabica coffee processed by three methods: conventional, civet-derived, and elephant-derived (all originated from Southeast Asia, medium roast). Analytical methods included HPLC-UV and GC-SPME-MS, along with in vitro antioxidant assays (DPPH, ORAC, ABTS, total phenolics, and total flavonoids). Principal Component Analysis (PCA) was used to evaluate differences between the samples. While elephant coffee showed lower caffeine (0.93%) and antioxidant capacity across all assays, it was richer in selected volatile compounds, such as pyrazines (e.g., 3-ethyl-2,5-dimethylpyrazine; 3.73% RPA), 2- and 3-methybutanal (1.18 and 0.19% RPA), and furfuryl acetate (18.00% RPA; p < 0.05). These changes are likely to be due to fermentation in the gastrointestinal tract. Despite differences, no definitive biomarker of elephant coffee was found, suggesting that discrimination from other coffee samples may not be as simple as previous studies indicated. More studies with a higher number of samples that employ an extensive analytical approach (e.g., omics or NMR) to thoroughly analyze the phytochemical profile of coffee beans before and after digestion by the elephant are needed. Full article

Current marine mackerel (Scomberomorus niphonius) products predominantly involve low-value-added processing, while high-value-added products like fish floss remain underdeveloped. This study utilized mackerel dorsal muscle treated with flavor protease (FP), papain (PP), and neutral protease (NP) (10 U/g, 30 min), followed by steaming and stir-frying. Combined with sensory evaluation, HS-GC-IMS, and automatic amino acid analysis, the characteristic flavor was evaluated by multi-omics. The results showed that FP and NP significantly enhanced odor by reducing fishy compounds (e.g., hexanal) and increasing pyrazines/furans. PP enhanced taste by elevating umami and sweet amino acids (26.68% and 25.98%, respectively). Correlation analysis revealed the following potential pathways: Val and Leu served as precursors for furan, suppressing 2-methyl-3-(methylthio)furan formation, while Asp, Tyr, Phe, Gly, Cys, and Ile promoted 2,5-dimethylpyrazine and 2-methyl-3-(methylthio)furan generation while inhibiting furan. This study demonstrates that minimal protease addition effectively optimizes dried mackerel floss flavor, providing a novel approach for high-quality marine product development. Full article

The volatile profiles of palm sugar, a traditional sweetener used in Southeast Asia, vary according to its geographic and botanical origin. This study investigated the volatile organic components (VOCs) of Indonesian and Malaysian palm sugars derived from Arenga pinnata, Nypa fruticans, and Cocos nucifera using solid-phase microextraction-GC-MS and MS-e-nose analyses. A total of 42 compounds were detected, including 12 Maillard reaction products, 10 esters, 8 alcohols, 5 ketones, 3 carboxylic acids, 3 phenols, and 1 aldehyde. The Indonesian palm (West Java) and nipa (Central Java) sugars contained VOCs of 39.45 and 38.49 µg/100 g palm sugar, respectively, whereas the Balinese palm and Malaysian coconut sugars contained significantly lower volatiles (18.56 and 11.41 µg/100 g, respectively). Hierarchical clustering and principal component analysis (PCA) revealed diverse composition profiles, with palm-derived sugars rich in pyrazines, nipa sugars dominated by carboxylic acids, and coconut sugars characterized by alcohols such as [R,R]-2,3-butanediol. PCA of the MS-e-nose analysis confirmed these variations, with PAR scaling enhancing their differentiation and providing valuable loading plots, including ion masses m/z 43 and 45 (hydrocarbons or carboxylic acids), m/z 60 (acetic acid), and m/z 108 (dimethyl-pyrazines). These findings highlight the influence of geography and plant origin on palm sugar VOCs, which may affect their sensory attributes. Full article

This study aimed to thoroughly investigate the quality differences and influencing factors of Dahongpao tea of different grades. Through sensory evaluation, electronic nose analysis, electronic tongue analysis, biochemical component analysis, and HS-SPME-GC-MS, the taste and aroma characteristics of Dahongpao samples of different grades (superfine, first, and second grades) were comprehensively studied. The results showed that there were significant differences in sensory quality, aroma components, and taste components among Dahongpao of different grades. Superfine Dahongpao has a rich aroma and mellow taste, containing a higher content of esters and aromatic hydrocarbons such as benzaldehyde (2-hydroxy-5-methoxy), hexyl benzoate, and cyclohexanecarboxylic acid 2,3-dichlorophenyl ester, which endow it with fruity, floral, and woody characteristics. In contrast, first- and second-grade Dahongpao contain more alkanes, pyrazines, and furans such as benzene (1-ethyl-1-propenyl), dodecane (2,6,10-trimethyl), and pyrazine (2,6-dimethyl), which impart floral, roasted, and nutty flavors. Moreover, superfine Dahongpao has a more bitter and astringent taste, but the bitterness and astringency dissipate more quickly, while the taste of first- and second-grade Dahongpao is relatively bland. These differences provide a scientific basis for the grade classification of Dahongpao tea and offer references for improving tea quality and standardized production. Full article