Search Results (829)

Coffee fermentation is a critical yet under-optimized stage of the coffee value chain, with significant implications for beverage quality, process consistency, and smallholder livelihoods. Pichia species, together with several non-Saccharomyces yeasts historically associated with the genus, are frequently detected in natural and semi-dry coffee fermentation; however, their functional roles remain insufficiently characterized, constraining evidence-based starter-culture design. Direct coffee evidence implicates P. kudriavzevii, P. kluyveri, and Meyerozyma guilliermondii (formerly Pichia guilliermondii) in substrate transformation, fermentation dynamics, and sensory quality development. However, these findings are derived exclusively from studies conducted on single farms during single harvest seasons, without independent validation across multiple farms, harvest seasons, origins, or production environments, limiting their broader applicability. In contrast, ecologically prevalent species, including P. fermentans, Wickerhamomyces anomalus (formerly Pichia anomala), and Debaryomyces hansenii (formerly Pichia hansenii), remain largely unexplored in the context of coffee fermentation. To contextualize the current knowledge and identify promising avenues for future research, this review synthesizes evidence from cocoa, Baijiu, bakery, vinegar, dairy, and other solid-state fermentation systems. Across these diverse matrices, Pichia and related non-Saccharomyces yeasts frequently exert a disproportionate influence on flavor development, microbial succession, and process stability relative to their population abundance. The reported mechanisms include ester and higher-alcohol production, modulation of bacterial community dynamics, extracellular enzymatic activity, and bioprotective effects. Notably, functional impact often occurs without numerical dominance; ester production can increase alongside declining ethanol yield, and ecological persistence may increase despite declining absolute abundance, implicating community-level interactions in addition to direct metabolic activity. However, both the mechanisms and the magnitudes of these effects vary across fermentation systems, underscoring that functions demonstrated in one matrix cannot be assumed to translate directly to coffee without experimental validation. Future progress will require strain-level characterization, mechanistic studies, deliberate multi-species consortium design, process optimization, and field-scale validation in diverse coffee-producing environments. Such efforts will provide a scientific foundation for evidence-based starter-culture development capable of improving coffee quality, consistency, and producer value. Full article

The gut microbiota is a metabolically active ecosystem that influences host physiology through bioactive metabolites and interactions with host signaling pathways. Recent research has established a bidirectional gut–muscle axis in which microbial metabolites and muscle-derived factors (myokines) regulate muscle protein synthesis, degradation, regeneration, fiber-type specification, and overall muscle performance. Studies using germ-free, antibiotic-treated, probiotic-supplemented, and fecal microbiota transplantation models demonstrate that the gut microbiota is a critical determinant of skeletal muscle mass and function. Key mediators include short-chain fatty acids, bile acids, aromatic amino acid metabolites, microbial-associated molecular patterns, and methylamine metabolites. This review summarizes current mechanistic knowledge of gut–muscle communication and its relevance to livestock production. In monogastric livestock, particularly pigs and poultry, microbiota transplantation experiments and targeted probiotic interventions provide causal evidence that gut microbial communities influence muscle growth, muscle fiber composition, intramuscular fat deposition, carcass traits, and meat quality, including tenderness, marbling, water-holding capacity, and flavor. Several studies have also identified specific microbial taxa and metabolites capable of transferring desirable production phenotypes. In contrast, evidence in ruminants remains largely associative and originates mainly from multi-omics and dietary intervention studies. Future research should validate causal mechanisms, identify robust microbial biomarkers, and develop species-specific microbiome-based strategies for precision livestock production. Full article

The flavor variation among different tea plant cultivars significantly influences their economic value. ‘Huangjinya’ (HJY), a typical light-sensitive etiolated tea cultivar, is prized for its fresh and mellow taste with low bitterness and astringency, and commands a high market value, serving as excellent germplasm for breeding superior-flavor tea varieties. Previous studies have largely focused on the mechanisms underlying fresh and umami tastes, whereas the regulatory mechanisms underlying bitterness and astringency remain poorly understood. In this study, two tea plant (Camellia sinensis (L.) O. Kuntze) cultivars with distinct bitterness and astringency phenotypes, namely ‘Fuxuan 9’ (FX) and HJY, were used to investigate the formation mechanism of reduced bitterness and astringency through integrated metabolomic and transcriptomic analyses. Metabolomic profiling identified 601 differentially accumulated metabolites between the two cultivars, which were significantly enriched in the flavonoid biosynthesis pathway. Notably, although the total flavonoid content was higher in HJY, the accumulation of non-esterified catechins (C, EC, EGC), which are key contributors to bitterness, was significantly lower than in FX. By contrast, the levels of esterified catechins (EGCG, GCG) showed no marked differences between cultivars. This distinct accumulation pattern provides a metabolic basis potentially associated with the reduced bitterness and astringency in HJY. Transcriptomic analysis revealed that the catechin biosynthetic gene CsLAR was significantly down-regulated in HJY, consistent with the reduced accumulation of non-esterified catechins. Promoter cloning and functional validation confirmed that the CsLAR promoters in both cultivars were active, which differed by only one regulatory element. Under shading treatment, CsLAR expression in HJY was more sensitive to light and decreased more markedly, suggesting that the expression of CsLAR may be regulated by transcription factors. Furthermore, 385 differentially expressed transcription factors were identified, with predicted binding sites in the CsLAR promoter region, implying their potential involvement in modulating catechin accumulation through modulation of CsLAR expression. Together, these multi-omics findings reveal molecular features potentially contributing to the low bitterness and astringency of HJY, providing a theoretical basis and candidate regulators for breeding tea cultivars with improved flavor profiles. Full article

This study aimed to evaluate the impact of four strains, Bifidobacterium longum BL11, Streptococcus thermophilus LB42, Lacticaseibacillus casei LC15, and Lactiplantibacillus plantarum XJ25, on the antioxidant activity, flavor components and metabolic characteristics of fermented coffee pulp beverage (CPB). Results indicated that the antioxidant activities were remarkably enhanced in the fermented CPB samples (p < 0.05). A total of 103 volatile compounds (VOCs) were detected by HS-SPME-GC-MS and GC-IMS, with 37 types of VOCs newly generated after fermentation, including esters, alcohols and ketones, thereby enhancing the flavor quality of CPB. In addition, a total of 334 differential non-volatile metabolites covering 20 subclasses were obtained in all CPB samples, such as D-tagatose, glyceraldehyde, isorhynchophylline and pyruvic acid, which showed remarkably increased levels after fermentation (p < 0.05). Organic acids, amino acids and derivatives were the two major classes of differential metabolites. The CPB samples had a different flavor profile after fermentation, while the group of Lactiplantibacillus plantarum showed the highest overall acceptability. These findings provide a systematic comparison of single-strain fermentation effects on VOCs and non-volatile metabolites in CPB samples, promoting its high-value utilization in innovative food applications. Full article

Drying is widely used to stabilize foods, but long processing times and thermal exposure increase energy demand and can impair color, texture, nutrients, and flavor. Cold plasma (CP) pretreatment has attracted interest as a nonthermal strategy for accelerating moisture removal while maintaining product quality. This critical review examines CP pretreatment-assisted drying across food materials by linking structural remodeling with redox regulation and metabolic responses. Current evidence shows that changes in surface wettability, cuticular barriers, cell-wall and membrane integrity, and pore connectivity can facilitate water migration and shorten drying. CP-associated modulation of browning enzymes, oxidative status, and bioactive or flavor-related metabolites may also influence color, antioxidant capacity, nutrient retention, and flavor. However, these effects vary with discharge mode, treatment intensity, gas composition, pressure, temperature, and food-matrix properties. Excessive exposure can instead aggravate oxidation and diminish product quality. Current mechanistic evidence is strongest for plant foods and edible fungi and remains limited for animal-source foods. Together, these findings link plasma-generated chemical and physical agents to structural, biochemical, and drying responses. They provide a basis for defining material-specific operating windows and developing reproducible, safe, and scalable CP pretreatment-assisted drying of foods. Full article

Cider is a low-alcohol fruit wine produced by partial or complete fermentation of apple juice. In recent years, its consumption has grown significantly, especially in Asia. Its distinctive flavor profile reflects a complex interplay of aroma and non-volatile components. The composition of cider is mainly influenced by three factors: raw materials, starter cultures, and production process. This review begins by outlining the composition of cider, covering both its aromatic compounds and non-volatile components. The primary aroma profile is defined by higher alcohols, esters, fatty acids, and carbonyl compounds, while sugars, organic acids, and polyphenols are the key determinants of its taste. Subsequently, it provides a detailed analysis of how the raw material, the choice of starter cultures, and the applied production processes collectively shape the cider’s flavor. Research shows that apple variety and maturity influence the levels of sugars, organic acids, and polyphenols, shaping the flavor foundation of cider. To enhance flavor diversity, inoculation strategies have shifted from single-strain fermentation with Saccharomyces cerevisiae to mixed fermentations using non-Saccharomyces yeasts and lactic acid bacteria, either simultaneously or sequentially. Currently, screening non-Saccharomyces strains has become a key strategy to increase cider flavor complexity. Precise micro-oxygenation and nutrient supply regulate microbial metabolism, thereby controlling the fermentation process and the production of specific flavor compounds. In the future, given the untapped diversity of non-Saccharomyces yeasts and lactic acid bacteria in winemaking traits, research in this direction may be key to improving cider quality. In addition, selecting apple cultivars tailored to specific cider styles and exploring pre-fermentation treatments such as cold maceration and enzymolysis may also contribute to enhancing the flavor diversity of cider. Full article

Liupao tea (LPT), one of China’s representative fermented dark teas, develops its unique “red, heavy, aged, and mellow” flavor characteristics. This review provides a comprehensive update on LPT aroma, integrating analyses of volatile organic compounds (VOCs), associated microorganisms, odor-active compounds (OACs), and metabolic pathways of key odor-active compounds (KOACs). With over 2000 VOCs documented, predominated by alcohols (368), hydrocarbons (357), and ketones (351), the total for LPT substantially exceeds the approximately 1000 compounds typically reported for other dark teas. By combining sensory evaluation with techniques such as gas chromatography–olfactometry (GC-O) and odor activity value (OAV), KOACs, predominantly comprising alcohols, aldehydes, and methoxybenzene derivatives, were identified as key contributors to the floral, fruity, aged, stale and other notes that define LPT’s characteristic aroma. The formation of the aroma compounds is closely linked to microbial metabolism and the enzymatic activities generated by microorganisms. Fungi, including Aspergillus, Rhodotorula, Geosmithia, Wallemia, Penicillium, Blastobotrys, Fusarium, and Xeromyces, and bacteria, including Burkholderia, Ralstonia, and Achromobacter, serve as the primary functional microorganisms driving fermentation and aging. This review provides a comprehensive framework for understanding the chemical and microbial complexity of LPT aroma. Full article

Sorghum tannins have been suggested to influence microbial ecology and flavor formation in Xiaoqu light-flavor Baijiu (XLB), but their specific contribution is difficult to distinguish from confounding, cultivar-dependent variations in macromolecular components. To address this limitation, a controlled fermentation system was established using a uniform, low-tannin substrate. Based on preliminary gradient trials, a 1.0% tannin supplementation level was selected, and high-throughput sequencing combined with HS-SPME-GC-MS was employed to investigate tannin-related microbial and volatile changes. Compared with the group without tannin supplementation, 1.0% tannin supplementation altered bacterial and fungal community succession during the fermentation, reducing the relative abundances of Saccharomyces and Weissella, and enriching taxa including Cyberlindnera and Pantoea. The tannin-supplemented group exhibited a more complex and stable microbial co-occurrence network. Furthermore, PICRUSt2 predictions suggested enhanced metabolic potentials primarily related to carbohydrate and amino acid pathways. FUNGuild analysis further suggested that tannin supplementation shifted fungal trophic-mode composition, particularly saprotrophic and saprotroph-containing groups. At the end of fermentation, total volatile compounds increased from 4.208 μg/g to 4.983 μg/g, total esters and acids increased by 27.0% and 112.3%, respectively, whereas total alcohols decreased by 13.3%. Spearman correlation analysis revealed that the enriched non-Saccharomyces fungi and acid-producing bacteria in the tannin-supplemented group were positively associated with the accumulation of acids and esters, whereas the control microbiota was mainly linked to an alcohol-oriented profile. These findings may provide process-level evidence for tannin-related microbial and volatile changes during XLB fermentation. Full article

Mianning ham is a traditional dry-cured ham from southwestern China, but the coordinated relationships among quality changes, microbial succession, and nonvolatile metabolite remodeling during long-term ripening remain poorly understood. Therefore, samples of Mianning ham aged for one, two, three, and four years were comparatively analyzed. High-throughput sequencing was used to characterize microbial community composition, and untargeted metabolomics was applied to analyze differential metabolite changes and their associations with dominant microorganisms. The results showed that the physicochemical and sensory characteristics of Mianning ham exhibited stage-dependent changes during ripening, with moisture content and pH generally decreasing, while color, texture, and mature flavor characteristics gradually developed. Multivariate statistical analysis identified 99 differential metabolites, which were mainly involved in peptide accumulation, amino acid metabolism, and nitrogen-containing compound transformation. The bacterial communities were mainly composed of Bacillota and Pseudomonadota, while Ascomycota was the predominant fungal phylum. Distinct successional patterns of dominant microbial taxa were observed at different ripening stages. Furthermore, microorganism–metabolite correlation analysis revealed distinct association patterns between internal and surface samples of the ham. Internal microbial communities were mainly associated with nucleotide-related metabolism- and umami-related characteristics, whereas surface microbial communities were more closely associated with the transformation of protein-derived nitrogen-containing compounds and the accumulation of flavor precursors. This study provides insights into the quality formation patterns of Mianning ham during ripening and offers a theoretical basis for ripening-stage evaluation and quality regulation. Full article

Pepper fruits contain diverse primary and secondary metabolites, including ascorbic acid, carotenoids, phenolics, and flavonoids, which contribute to nutritional quality, antioxidant capacity, coloration, and consumer acceptance. Chilaca chili pepper (Capsicum annuum L.) is a Mexican cultivar valued for its distinctive flavor and pungency, representing a valuable resource for studying fruit quality and sustainable crop improvement. This study evaluated the individual and combined effects of arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) on growth, physiological responses, antioxidant activity, and fruit quality traits. Twelve treatments in a 3 × 2 × 2 factorial designs were evaluated for chlorophyll, soluble solids, biomass, APX and LOX activities, and vitamin C and capsaicin contents at three ripening stages (green, mid-red, and red). Enzyme activities were determined spectrophotometrically, and bioactive compounds were quantified from methanolic fruit extracts. Microbial inoculation primarily improved fruit physiological quality rather than vegetative growth. Biomass and growth traits showed no significant differences among treatments (p > 0.05), whereas biochemical responses exhibited distinct ripening-dependent patterns. APX activity, vitamin C, and capsaicin increased from green to mid-red stages and declined at full ripeness. Bacillus sp.-based treatments (T1 and T2) produced a significant transient increase in LOX activity during mid-ripening, while T7 showed a similar but weaker response. AMF progressively enhanced LOX activity and capsaicin accumulation in green fruits. PGPR effects were strain-dependent, with Bacillus sp. promoting early capsaicin accumulation and A. deleyi favoring higher levels during advanced ripening. Overall, AMF and PGPR differentially regulate antioxidant metabolism, vitamin C accumulation, and capsaicinoid biosynthesis while interacting with mineral fertilization to improve fruit quality. These findings support beneficial microorganisms as sustainable tools for enhancing nutrient-use efficiency and fruit nutritional and functional value without replacing mineral fertilization. Full article

Resveratrol is a plant-derived stilbene polyphenol that has attracted interest as a potential dietary additive for improving edible fish muscle quality. This review summarizes current evidence on pre-harvest dietary resveratrol supplementation and its possible effects on nutritional composition, flavor-related biochemical traits, and physicochemical quality of fish muscle or fillets. We distinguish nutritional quality, including proximate composition, amino-acid profiles, and fatty-acid composition, from flavor-related and sensory-relevant proxies, such as free amino acids, inosine monophosphate, volatile precursors, color, pH, water-holding capacity, and texture. Direct evidence from edible fish muscle remains limited and fragmented, and most available studies rely on biochemical or instrumental endpoints rather than trained-panel sensory evaluation or consumer acceptance testing. Reported effects suggest species- and dose-dependent changes in muscle protein deposition, amino-acid accumulation, fatty-acid composition, pH, cooking or drip loss, and texture-related traits. Putative mechanisms may involve antioxidant protection, muscle fiber remodeling, lipid metabolism, endoplasmic-reticulum stress, and delivery-dependent bioavailability; however, many mechanistic links are still inferred from hepatic tissues, mammalian models, or in vitro systems. Future studies should combine standardized dose–response feeding trials with gas chromatography–mass spectrometry (GC–MS)-based volatile profiling, lipid and protein oxidation indices, instrumental texture analysis, sensory evaluation, and shelf-life testing before resveratrol can be recommended as a robust feed-based strategy for improving edible fish muscle quality. Full article

The industrial use of non-Saccharomyces yeasts offers a robust bioprocess strategy for modulating volatile biochemical profiles and reducing climate-driven ethanol production in fermented beverages. This study explores the metabolic diversity of indigenous non-Saccharomyces, with a particular focus on Starmerella bacillaris MI151, selected for sequential inoculation with Saccharomyces cerevisiae MI118. Pilot-scale bioreactor fermentations (25 L) of two Romanian matrix-specific aromatic grape cultivars, Busuioacă de Bohotin and Tămâioasă Românească, exhibited clear strain-dependent carbon flux changes. The sequential culture actively triggered the glycerol-pyruvic pathway, which consistently reduced the final ethanol concentration to up to 0.94% (v/v) and maintained a balanced profile of volatile compounds. GC-MS-based metabolomic profiling revealed substantial changes in the esterification kinetics and glycosidic precursor cleavage. The sequential fermentation resulted in a synergistic increase in n-hexyl acetate (up to 2310.01 µg/L) and bypassing of the standard enzymatic repression, freeing highly volatile monoterpenes (β-citronellol and β-geraniol) in the analyzed matrices. This targeted microbial system successfully modulated the organic acid–phenolic balance, neutralizing harsh structural finishes, as confirmed by quantitative sensory mapping. Finally, these specific local yeast strains exhibit strong bioprocess scalability, offering a predictable, non-engineered strategy to lower the ethanol yield while driving targeted flavor enhancement in climate-vulnerable viticultural regions. Full article

The growing interest in lactic acid bacteria (LAB) within the baking sector is driven by their ability to improve both the technological performance and nutritional quality of bakery products. The purpose of this study was to provide a comprehensive overview of current knowledge regarding the use of conventional and unconventional LAB in breadmaking, with particular emphasis on their influence on dough properties, shelf life, sensory characteristics, nutritional value, stress tolerance, and sustainability and their interactions with unconventional yeast. The available evidence indicates that LAB contributes significantly to dough development through acidification, proteolytic activity, and exopolysaccharide production, leading to improvements in viscosity, elasticity, extensibility, water absorption, and gluten network formation. Their metabolic activity also promotes the production of organic acids, bacteriocins, and other antimicrobial compounds that help delay microbial spoilage and extend product shelf life. In addition, LAB fermentation enhances flavor and aroma complexity while increasing mineral bioavailability, vitamin content, and the formation of beneficial bioactive compounds. Attention has been given to the capacity of selected LAB strains to tolerate thermal, osmotic, acidic, and oxidative stress conditions, highlighting their suitability for industrial applications. Furthermore, combinations of LAB with unconventional yeast have shown potential for improving nutritional quality, sensory acceptance, texture, and shelf life and reducing the glycemic impact of bakery products. Overall, LAB represents a versatile group of microorganisms capable of supporting the development of innovative, high-quality, and more sustainable bakery products. The synthesis of current research highlights both the opportunities and challenges associated with their application and emphasizes the need for further studies focused on strain selection, fermentation optimization, and large-scale implementation. Full article

Fermented cabbage is a globally popular food, whose distinctive flavor is largely determined by microbial metabolism and interspecies interactions. To understand the roles of Lactiplantibacillus plantarum (formerly Lactobacillus plantarum) and Rhodotorula mucilaginosa in regulating microbial community structure and flavor formation during cabbage fermentation, natural fermented cabbage was compared with that inoculated with L. plantarum, R. mucilaginosa and both strains. The results showed that cabbage inoculated with either strain accelerated fermentation, with the fastest acidification observed in the co-inoculated group. Additionally, cabbage inoculated with R. mucilaginosa exhibited a relatively higher total amino acid content (481.50 ± 7.75 g/kg), and the levels of sweet, bitter, and umami amino acids were significantly higher than in the other groups. At the final fermentation stage, 15 differential odor-active compounds (ROAV ≥ 0.1, VIP ≥ 0.5) were identified, contributing mushroom, floral, fruity, malty, buttery, fatty, citrus, soapy, and green notes. Microbial succession analysis revealed that L. plantarum dominated bacterial community restructuring during fermentation and showed antagonistic relationships with the other lactic acid bacteria, including Lactococcus and Weissella. In contrast, R. mucilaginosa mainly influenced fungal community succession and indirectly modulated flavor formation by regulating the abundance of flavor-associated microorganisms, including Lactiplantibacillus, Lactococcus, Staphylococcus, Debaryomyces, and Candida. Correlation analysis further suggested that L. plantarum functioned as a major flavor-driving microorganism; whereas, R. mucilaginosa acted primarily as a microbial community modulator that enhanced flavor complexity through interspecies interactions. These findings highlight the importance of microbial interactions in shaping the flavor characteristics of fermented cabbage and provide insights for improving fermented vegetable flavor through targeted microbial regulation. Full article

Background: Local goat resources have unique meat quality and phenotypic advantages over cultivated breeds. Clarifying breed-specific metabolic differences in meat helps understand meat quality formation and resource utilization. Methods: the study used ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) technology to perform untargeted metabolomic analysis on the longissimus dorsi meat of Beichuan White goats (BCWG) and Tianfu goats (TMG). Results: A total of 452 differential metabolites were identified between the two breeds, including 100 lipids and lipid-like molecules, 74 organic acids and their derivatives, 12 nucleosides, nucleotides, and analogues, 204 organic compounds, and 62 unclassified metabolites. Among them, 132 metabolites exhibited higher abundance in Beichuan White goats and 320 metabolites showed significantly higher abundance in Tianfu goats. Metabolomic profiling revealed that differential metabolites of lipids and amino acids (e.g., valine and glutamate) might be correlated with interbreed disparities in meat sensory quality and flavor, as indicated by metabolomic profiling. BCWG displayed relatively higher abundances of nucleoside and nucleotide metabolites, which might hint at a possible link to variations in disease-resistance capacity. Among the 12 nucleoside and nucleotide differential metabolites, UDP-N-acetylglucosamine, 1-methyllinosine, 1-methylguanosine, 3-methylcytidine, and N-(2-Furanylmethyl) adenosine could serve as candidate molecular indicators for studying immune-related traits in goats. Conclusions: The study clarifies the breed-specific metabolic characteristics of the longissimus dorsi meat in BCWG and TMG at the metabolite level, provides novel molecular markers for chevon quality evaluation and immune trait selection, and lays a theoretical foundation for the rational development and utilization of local goat resources and improvement of cultivated meat goat breeds. Full article