Search Results (107)

Hawk tea (Litsea coreana Levl. var. lanuginosa), a naturally caffeine-free herbal beverage widely consumed in Southwest China, is characterized by a pronounced camphoraceous note that often deters first-time consumers. In this study, hawk tea leaves were subjected to solid-state fermentation with four microbial strains—Monascus purpureus, Aspergillus cristatus, Bacillus subtilis, and Blastobotrys adeninivorans. The volatile compounds of unfermented and fermented hawk teas were identified by ultra-fast gas chromatography electronic nose (ultra-fast GC e-nose), gas chromatography–mass spectrometry (GC-MS) and gas chromatography–ion mobility spectrometry (GC-IMS) analyses, respectively. Furthermore, the calculation of odor activity values (OAVs) and relative odor activity value (ROAV) revealed that 6 and 25 volatile chemicals, including perillaldehyde (OAV 3.692) and linalool (ROAV 100), were the main contributors to the floral, fruity, and woody aroma of fermented hawk tea. Sensory evaluation confirmed that fermentation generally enhanced woody notes while significantly reducing the characteristic camphoraceous and oil oxidation odors. Notably, the Blastobotrys adeninivorans-fermented sample exhibited the most pronounced floral and fruity nuances, accompanied by significantly elevated aroma complexity and acceptability. Consequently, Blastobotrys adeninivorans represents a promising starter culture for the improvement of hawk tea flavor. Full article

Geographical relocation can alter flavor quality in marine crops. Here, the same cultivar of Pyropia haitanensis (“ZHEDONG 1”) was cultivated at six sites spanning northern to southern China, and taste- and odor-active compounds were characterized by LC–MS and GC×GC–TOFMS together with environmental measurements. Inosine monophosphate was identified as the major contributor to umami intensity and showed a strong positive association with nitrate levels. A conserved core aroma profile dominated by heptanal, 2-pentylfuran, nonanal, and 2-ethyl-1-hexanol was consistent across regions, whereas differences in their relative abundances led to distinct regional sensory nuances. Correlation analyses further indicated that phosphate, temperature, and pH shaped volatile composition. These results demonstrate that while P. haitanensis retains a genetically determined intrinsic flavor, environmental conditions modulate flavor intensity and aromatic complexity during cross-regional cultivation. Full article

Sunflower (Helianthus annuus L.) seeds exhibit variation in flavor and nutritional quality. In this study, we combined metabolomics (UPLC–MS/MS and GC–MS) with nutritional analysis and a database-driven flavoromics approach to elucidate the biochemical basis of quality differences between sunflower varieties SH361 and SH363. A total of 1448 seed metabolites were identified, with 242 varying between varieties (predominantly flavonoids and terpenoids). Based on the known aroma descriptors of identified metabolites, we inferred that SH363 would have a more intense nutty-aromatic flavor, whereas SH361 would be characterized by a predominantly sweet taste. SH363 seeds also contained ~50% oil (versus ~24% in SH361) and lower sugar content, indicating an inverse oil–sugar balance that is associated with more complex flavor notes. Lipids and aromatic terpenoids were identified as likely key contributors to SH363’s richer flavor profile. Overall, although limited to two genotypes, this work provides new insights into the metabolic basis of sunflower seed flavor differences and supports a conceptual model of lipid-associated flavor enhancement. These findings offer valuable guidance for breeding programs aimed at improving sunflower seed flavor and nutritional quality. Full article

Flavor quality fundamentally influences the market value of bivalves, yet the molecular basis of interspecific umami variation remains poorly understood, hindering flavor-directed breeding. This study compared umami compounds and related gene expression across six economically important bivalve species from Southeast China: Crassostrea sikamea, Meretrix meretrix, M. mercenaria, Cyclina sinensis, Ruditapes philippinarum, and Sinonovacula constricta. Using quantitative chemical analysis and qPCR, key taste components and gene expression levels were assessed during the peak flavor season. Results identified glutamic acid, aspartic acid, guanosine monophosphate, and adenosine monophosphate as major umami contributors. Crassostrea sikamea showed the highest umami intensity (Equivalent umami concentration = 449.35 g Monosodium Glutamate/100 g dry weight), followed by Meretrix meretrix (EUC = 329.56 g MSG/100 g dry weight). Expression of glutamate dehydrogenase 1 strongly correlated with glutamic acid content (r = 0.90, p < 0.01), indicating its regulatory role. glutamic-oxaloacetic transaminase 1 and adenylosuccinate synthase also associated positively with aspartic and glutamic acids, respectively, while hypoxanthine phosphoribosyltransferase 1 correlated negatively. Bioinformatics revealed species-specific variations in key enzyme active sites. This study integrates flavor phenotyping with genetic analysis, offering novel insights into umami regulation and providing candidate genes for molecular breeding aimed at flavor enhancement, but subject to further functional validation and heritability analysis. Full article

Sichuan-style black soybean soy sauce is a traditional fermented condiment renowned for its complex and regionally distinctive flavor profile. This study systematically investigated the physicochemical properties, flavor compounds, and microbial succession during six months of natural fermentation to elucidate the mechanisms underlying its unique flavor formation. Results showed that the amino acid nitrogen level increased to a peak of 1.37 g/100 mL before stabilizing at 1.01 g/100 mL, accompanied by a continuous rise in total acidity (0.69–2.75 g/100 mL). A total of 132 volatile compounds were identified, with esters (e.g., hexanoic acid, methyl ester, hexadecanoic acid, and methyl ester), alcohols (e.g., (E)-2-hepten-1-ol and trans-2-undecen-1-ol), and aldehydes (e.g., benzaldehyde and benzeneacetaldehyde) serving as key differentiating components. Nine taste-active (TAV ≥ 1) and 22 odor-active (ROAV ≥ 1) compounds were recognized as major flavor determinants, among which methional (ROAV = 4.77–119.05), 1-octen-3-ol (ROAV = 40.68–149.35), and 4-ethyl-2-methoxyphenol (ROAV = 4.70–36.26) were dominant contributors imparting sauce-like, mushroom-like, and smoky-clove notes, respectively. Microbial succession revealed a transition from Weissella and Aspergillus dominance in the early stage to salt-tolerant Tetragenococcus and aroma-producing yeasts (Kodamaea and Zygosaccharomyces) in later phases. Beyond organic acids and fermentation parameters (e.g., pH and salinity), microbial interactions were identified as critical drivers shaping community assembly and succession. Metabolic pathway analysis revealed a stage-dependent mechanism of flavor formation. During the initial stage (0–2 months), Aspergillus-mediated proteolysis released free amino acids as key taste precursors. In the later stages (3–6 months), Tetragenococcus and aroma-producing yeasts dominated, synthesizing characteristic esters (e.g., benzoic acid and methyl ester, correlated with Tetragenococcus; r = 0.71, p < 0.05), phenolics (e.g., 4-ethyl-2-methoxyphenol, correlated with Wickerhamomyces; r = 0.89, p < 0.05), and sulfur-containing compounds (e.g., methional, correlated with Wickerhamomyces; r = 0.83, p < 0.05). Full article

The potential of lactic acid bacteria (LAB) to enhance fruit juice is well known; however, the optimal fermentation strategy for wampee juice (WJ), considering its physicochemical and sensory characteristics and antioxidant activity, remains to be explored. For WJ fermentation, a co-culture of three LAB strains—Pediococcus pentosaceus SL05, Pediococcus acidilactici SL08, and Lactiplantibacillus plantarum JYLP-002—was optimized using a combined approach of simple lattice mixture design and a genetic algorithm (GA). After 48 h of fermentation, the optimal mixed fermentation group demonstrated a comprehensive superiority over both the unfermented and single-strain fermentation groups. It exhibited significantly higher levels of viable bacterial counts, total organic acid content, total phenolic and flavonoid contents, antioxidant capacity, and an enriched profile of volatile flavor compounds. Moreover, comprehensive volatile profiling via HS-SPME-GC-MS and HS-GC-IMS identified 59 and 29 volatile components, respectively; β-phellandrene, α-terpineol, α-pinene, methyl acetate, (E)-3-hexen-1-ol, and 3-methyl-1-butanol, as well as butanal, (E)-3-hexenoic acid, β-pinene, and propyl butanoate, were considered as key aroma contributors in the fermented WJ (FWJ). This study provides a theoretical foundation and practical framework for the enhancement of WJ quality through mixed LAB fermentation. Full article

Background/Objectives: Fungal and bacterial infections are major contributors to oral diseases in older adults. Although chlorhexidine (CHX) is widely recognized for its antimicrobial efficacy, its prolonged use is constrained by adverse effects. Virgin coconut oil (VCO) possesses antimicrobial properties; however, its high viscosity reduces acceptability. This study aimed to develop a flavor-enhanced coconut oil-based mouthwash (FCoMW) and evaluate its clinical safety, antimicrobial efficacy, and user satisfaction. Methods: A 14-day randomized controlled trial was conducted in older adults at the Faculty of Dentistry, Chiang Mai University, Thailand (April–July, 2024). Participants were randomly allocated by simple randomization to FCoMW, CHX, and normal saline solution (NSS). The evaluator was blinded. Assessments included burning sensation, oral mucosal alterations, changes in oral Candida and bacterial counts, and user satisfaction. Results: Among 51 participants (NSS: 17; CHX: 16; FCoMW: 18), FCoMW significantly reduced oral Candida counts by Day 14 (p < 0.0001), with efficacy comparable to CHX. CHX achieved greater bacterial reduction (p < 0.05). No adverse effects occurred with FCoMW. User satisfaction was high for scent, freshness, and overall acceptability. Conclusions: FCoMW is safe, well-accepted, and efficacious against oral Candida, offering a natural alternative to chlorhexidine for long-term use in older adults. Full article

Broad bean paste (BBP), a traditional Chinese fermented condiment, often suffers from inconsistent quality during spontaneous fermentation. In this study, Weissella confusa KUST3424 and Bacillus subtilis KUST4527 were isolated from BBP and evaluated as starter cultures, either individually or in combination. Flavor characteristics were analyzed using an electronic nose, electronic tongue, and GC–MS combined with odor activity value (OAV) calculations. Results showed that 13 key flavor compounds with OAVs greater than 1 were identified as major contributors to the overall aroma of fermented BBP juice (FBPJ). Moreover, inoculated groups exhibited distinct flavor profiles compared with natural fermentation, with the co-culture producing the most pronounced improvements. The mixed fermentation markedly enhanced desirable alcohols and esters, including significant increases in isoamyl alcohol (125.87%), 2-furanmethanol (128.91%), phenethyl alcohol (354.06%), and 4-vinylguaiacol (150.99%). In addition, compounds such as acetoin, guaiacol, ethyl hexanoate, and ethyl benzoate were newly generated in the co-culture group, while the diversity and total content of esters increased significantly from 0.52% to 9.69%. These findings demonstrate that the combined use of W. confusa KUST3424 and B. subtilis KUST4527 as starter cultures can effectively enhance the complexity and overall quality of BBP flavor. This co-culture strategy shows promise for enhancing flavor control and consistency in industrial-scale BBP production. Full article

Roasting intensity and cultivar shape the physicochemical composition and sensory characteristics of date seed-based coffee alternatives. This study evaluated quality traits among eight date seed cultivars (Zahidi, Medjool, Deglet nour, Thoory, Halawi, Barhee, Khadrawy, Bau Strami) roasted at three intensities (light: 180 °C; medium: 200 °C; dark: 220 °C) using digital technologies, including near-infrared spectroscopy (NIR), electronic nose (e-nose), and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS), supported by machine learning (ML) modeling. NIR spectra showed distinct chemical fingerprints for date seed powders and beverages, with key absorption bands from 1673–2396 nm and 1720–1927/2238–2396 nm, respectively. E-nose outputs showed higher volatile emissions in dark-roasted samples, particularly for ethanol and NH₃. GC-MS identified 25 volatile compounds, mainly pyrazines and furanic compounds. Pyrazine concentration was greatest in Bau Strami and Medjool cultivars, whereas Halawi and Thoory cultivars had greater content of furfural. Two ML classification models achieved high accuracy in classifying cultivars (NIR inputs: 99%; e-nose inputs: 98%) and roasting levels, while regression models (NIR inputs: R = 0.88; e-nose inputs: R = 0.90) effectively predicted volatile aromatic compounds obtained using GC-MS. Dark roasting resulted in a significant pH reduction and intensified browning, with furfural persisting as a stable aroma contributor. These findings highlight the potential of date seeds as a coffee alternative, with roasting level and cultivar selection influencing flavor profiles. The findings also demonstrate the utility of digital sensing technologies as an efficient, low-cost tool for rapid quality assessment and process optimization in the development of novel beverages. Full article

Background: Dietary supplements and functional foods derived from mushrooms have gained increasing popularity. Among these, Coprinus comatus stands out due to its excellent flavor and high nutritional value. However, its susceptibility to autolysis and short shelf life significantly limits its utilization. Although a few studies have attempted to elucidate the autolysis mechanism of C. comatus, only few research has been conducted on the detailed metabolic changes occurring during its growth cycle. Objectives: By conducting a dynamic metabolic profiling analysis of C. comatus metabolites across different developmental stages and tissue parts, this study aims to elucidate the variations in its metabolic composition. Methods: In this study, fruiting bodies of C. comatus were cultivated and collected at four distinct developmental stages. These samples were further divided into cap and gills (CG) and stipe (ST) tissues. Subsequently, UHPLC-Q-Orbitrap was employed for non-targeted dynamic metabolomics analysis of C. comatus samples. The identification of analytes was performed using Compound Discovery 3.3. Then, differential accumulated metabolites (DAMs) between CG and ST at the same stage and CG or ST between adjacent stages were identified. Furthermore, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was conducted to identify potential contributors to the observed metabolic changes. In addition, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity of samples was determined. Results: A total of 490 metabolites were annotated, and the most abundant metabolite groups were lipids, alkaloids, amino acids and their derivatives. It revealed that the metabolites of the ST remained relatively stable across the four growth stages, whereas autolysis induced significant alterations in the metabolites of the CG. KEGG pathway analysis indicated that these changes were primarily linked to lipid and amino acid biosynthesis and metabolic pathways. Furthermore, DPPH assays demonstrated a significant increase in the free radical scavenging activity of CG following autolysis. Conclusions: The metabolites of C. comatus exhibit dynamic variations across different growth stages and tissue locations. The significant morphological changes in CG induced by autolysis are mirrored by corresponding alterations in its metabolic profile. The enhanced DPPH free radical scavenging activity observed in the autolyzed samples, along with the distribution patterns of bioactive components, provides valuable insights for the efficient utilization of C. comatus. Full article

Summer–autumn green tea (SAGT) is a high-yield green tea often compromised by pronounced bitterness, astringency and a weak aroma, which severely limit its consumer acceptability and economic value. To enhance its quality, this study employed solid-state fermentation with Eurotium cristatum, the core probiotic fungus in Fu brick tea (FBT), to investigate its effects on the physicochemical, sensory, and volatile profiles of SAGT. The findings showed that after fermentation, the tea leaves developed a golden-yellow color, and the tea infusion turned brown. Moreover, the contents of flavonoids, tea polyphenols, soluble sugars, catechins, and free amino acids showed decreases of 3%, 33%, 38%, 41%, and 48%, respectively, when compared to SAGT. At the same time, the astringency and bitterness levels of the infusions significantly diminished (p < 0.05) post-fermentation, and the 8-day fermented tea sample was the most preferred by the sensory panel. During fermentation, E-nose, GC-MS, and GC-IMS analyses revealed a substantial transformation of the volatile profile, with a total of 104 and 129 volatile organic compounds (VOCs) were identified using GC-MS and GC-IMS techniques, respectively. The ROAV analysis highlighted 22 aroma-active compounds, particularly linalool and methyl salicylate, whose values increased significantly (p < 0.05), reaching values of 19,561.95 and 109.56, respectively, making them key contributors to the prominent floral and minty fragrance in the fermented tea. Additionally, PLS-DA analysis revealed 22 and 33 differential VOCs in the GC-MS and GC-IMS methods, respectively, with the majority stemming from the PAL and MEP metabolic pathways. This study provides theoretical insights aimed at enhancing the flavor quality of SAGT. Full article

The traditional use of iced trash fish (IF) in Chinese mitten crab (Eriocheir sinensis) aquaculture raises sustainability concerns, but the shift to formulated feeds (FF—a commercial compound feed specifically designed to meet nutritional requirements by blending multiple ingredients and containing a balance of nutrients) is often hindered by fears of compromising its prized flavor. This study aimed to comprehensively evaluate whether a commercial formulated feed could effectively replace IF without diminishing flavor quality, hypothesizing that FF would alter the intestinal volatile profile, thereby influencing muscle flavor. Male crabs were fed either IF or FF for eight weeks. Muscle flavor was assessed using sensory evaluation, electronic nose (E-nose), and gas chromatography–ion mobility spectrometry (GC–IMS). Volatile compounds in intestinal chyme were also analyzed by GC–IMS to explore potential transfer mechanisms. The results indicated that crabs fed with FF showed higher sensory scores for sweetness. Additionally, the E-nose analysis revealed a clear separation trend between dietary groups and showed markedly higher sensor response values for aromatic compounds, biogenically derived compounds and Maillard reaction products, sulfur-containing organic compounds, aliphatic hydrocarbons, total volatile organic compounds, alcohols and organic solvents, and alkenes in the FF group compared to the IF group. Thirty-four volatiles were discovered in the muscle. Statistical analysis (independent samples t-test) showed that the FF group exhibited significantly elevated levels of 3-methylbutanal-M, propanal, (E)-2-pentenal, 2,3-pentanedione, and pentan-1-ol-M, whereas the IF group exhibited significantly elevated levels of 2-hexanone, dihydro-2(3H)-furanone, butyl acetate, ethyl 2-methylpropanoate, and phenol (p < 0.05). Fourty-eight volatiles were identified in the intestinal chyme. Propanal and ethyl 2-methylpropanoate were the dominant odor contributors based on correlation network analysis. Strong correlations were identified between the flavor profiles of intestinal chyme and muscle, suggesting a potential transfer or transformation of volatiles. This work provides a scientific basis for optimizing aquafeed formulations to ensure sustainable crab production without sacrificing end-flavor quality. Full article

Background/Objectives: Kozan Misket orange (Citrus sinensis L.) is a regional Turkish cultivar valued for its unique flavor, yet the mechanisms underlying its aroma development remain unclear. Volatile compounds are key contributors to citrus sensory quality, and β-glucosidase is involved in releasing glycosidically bound aroma precursors. However, no previous study has examined the interaction between enzyme activity and volatile production during maturation in this cultivar. This study aimed to characterize the dynamic changes in volatile composition and β-glucosidase activity across different maturation stages of Kozan Misket orange. Methods: Fruits were harvested at three maturity stages (green, green–yellow, yellow). Physicochemical traits (TSS, TA, TSS/TA), volatile profiles (HS-SPME/GC-MS), and specific β-glucosidase activity were analyzed. Volatile compounds were identified, quantified, and compared across stages. Results: A total of 47 volatile compounds were identified, with monoterpenes dominating at all stages. D-limonene was the most abundant compound, exceeding 86% of total volatiles. Total volatile content increased with maturation, particularly monoterpenes and sesquiterpenes, whereas oxygenated monoterpenes (e.g., linalool, 4-terpineol, α-terpineol) declined at full maturity. Specific β-glucosidase activity decreased markedly from 20.15 to 8.25 U mg⁻¹ protein. This shift suggests that bound precursors contribute more to early-stage aroma release, while later-stage aroma accumulation may rely on metabolic conversions. Conclusions: This study provides the first integrated insight into aroma development in Kozan Misket orange, revealing a dual-phase mechanism linking volatile formation and β-glucosidase activity. These findings clarify cultivar-specific flavor development and offer guidance for harvest optimization and flavor management. Full article

In this study, six club raspberry varieties were examined for their aromatic profiles and sensory qualities, and statistical approaches were used to determine how aroma components affect consumer impressions. Analysis of the aroma’s chemical composition was performed utilizing headspace SPME and GC-MS. MS-DIAL -v5.5.250627 software was used to identify components from commercial libraries, after 10 repetitions for each variety, followed by manual verification. A sensory evaluation of fresh fruits, with 55 volunteers, was statistically analyzed and linked to chemical composition using multivariate analysis and the OPLS-HDA classification method, which was employed for the first time. Tula Magic was scored the highest in the sensory evaluation compared to Adelita, Himbo Top, Glen Dee, San Rafael, and Cascade Harvest. 2-Heptanol (fresh, lemongrass-like, herbal, floral, fruity, green), heptanal (fresh, aldehydic, fatty, green, herbal), and 2-methyl-6-hepten-1-ol (oily-green, herbaceous-citrusy) separated Tula Magic from the other varieties assessed. The same components were recognized in OPLS as positive contributors to the flavor score, while terpenoids like trans-β-ionone, α-ionone, and α,β-dihydro-β-ionone, as well as 2-heptanone, scored slightly lower. This suggests that a fine balance between the individual components is key to the overall aroma sensation. Full article

Fresh burdock (Arctium lappa L.) roots were fermented with probiotic lactic acid bacteria, including Lactobacillus paracasei (L. paracasei), Lactobacillus plantarum (L. plantarum), and Lactobacillus casei (L.casei). The dynamic changes in volatile flavor compounds (VFCs) and microbial community succession were compared during fermentation. Subsequently, correlations between bacteria and characteristic VFCs were analyzed, and potential functions were predicted. The results show that the types of VFCs increased from 25 to 54, and the total content increased from 7.852 ± 1.025 to 48.325 ± 0.624 mg/kg after fermentation for 7 days. Notably, esters and alcohols increased significantly. A total of 42 VFCs were identified as contributors to the overall flavor profile of the fermented burdock root. Among these, ethyl caproate, acetaldehyde, isoamyl acetate, hexaldehyde, phenylacetaldehyde, linalool, and 3-methylbutanol were regarded as the primary characteristic VFCs. Microbial composition analysis revealed three dominant phyla, two dominant genera, and three dominant species. Among them, L. paracasei and L. plantarum were the dominant species during fermentation. L. paracasei was positively correlated with multiple characteristic VFCs and was considered the core functional species in terms of flavor formation. Notably, L. paracasei exhibited a very strong correlation with acetaldehyde (ρ = 0.99). PICRUST2 function prediction further revealed that carbohydrate metabolism and amino acid metabolism were the core pathways of microbial metabolism and important sources of flavor precursors. This study demonstrates that lactic acid bacteria fermentation could markedly improve the flavor quality of burdock roots. Moreover, the formation of VFCs was closely correlated with complex microbial metabolism during fermentation. Full article