Search Results (35)

Leccinum is an ecologically significant and taxonomically complex genus of ectomycorrhizal fungi widely distributed across boreal, temperate, Mediterranean, and selected tropical regions. Despite its ecological, nutritional, and applied importance, no comprehensive review has previously synthesized global knowledge on this genus. This work provides the first integrative assessment of Leccinum research, combining a bibliometric analysis of 293 peer-reviewed publications with an in-depth qualitative synthesis of ecological, biochemical, and environmental findings. Bibliometric results show increasing scientific attention since the mid-20th century, with major contributions from Europe, Asia, and North America, and dominant research themes spanning taxonomy, ecology, chemistry, and environmental sciences. The literature review highlights substantial advances in phylogenetic understanding, species diversity, and host specificity. Leccinum forms ectomycorrhizal associations with over 60 woody host genera, underscoring its functional importance in forest ecosystems. Nutritionally, Leccinum species are rich in proteins, carbohydrates, minerals, bioactive polysaccharides, phenolic compounds, and umami-related peptides, with demonstrated antioxidant, immunomodulatory, and antitumor activities. At the same time, the genus exhibits notable bioaccumulation capacity for heavy metals (particularly Hg, Cd, and Pb) and radionuclides, making it both a valuable food source and a sensitive environmental bioindicator. Applications in biotechnology, environmental remediation, forest restoration, and functional food development are emerging but remain insufficiently explored. Identified research gaps include the need for global-scale phylogenomic frameworks, expanded geographic sampling, standardized biochemical analyses, and deeper investigation into physiological mechanisms and applied uses. This review provides the first holistic synthesis of Leccinum, offering an integrated perspective on its taxonomy, ecology, nutritional composition, environmental significance, and practical applications. The findings serve as a foundation for future mycological, ecological, and biotechnological research on this diverse and understudied fungal genus. Full article

Umami peptides were screened and identified from yak bone collagen for the first time by in silico analysis, molecular docking, and electronic tongue. Twenty proteases with known cleavage sites were used for the simulated proteolysis, and results indicated that “pepsin + papain” was the optimal enzymatic strategy for yak bone collagen to generate peptides with potential umami taste. Moreover, 82 novel unreported peptides with umami taste were found from the simulated hydrolysate, among which 9 peptides exhibited high binding affinity with the T1R1/T1R3 receptor (both -CDOCKER energy and CDOCKER interaction energy > 40 kcal/mol) via molecular docking. Subsequently, six novel umami peptides were identified through sensory evaluation and electronic tongue analysis, including VY, VM, SL, SN, VN, and IS (umami sensory score > 5). These peptides were also in silico characterized with high hydrophobicity, good water solubility, non-toxicity, non-allergenicity, good intestinal absorption, and good oral bioavailability. Furthermore, the identified peptides could bind with the key residues (such as HIS281 and LEU304) within the Venus flytrap domain of the T1R3 subunit of receptor T1R1/T1R3 through hydrogen bonds and electrostatic attractions to generate umami perception. This study revealed the mechanism of umami peptides identified from yak bone collagen and provides a novel approach for the development of umami peptides from animal sources. Full article

Marine-derived proteins are important sources in the preparation of umami peptides due to their delicious and unique taste. The research endeavored to elucidate the established umami peptide library derived from Skipjack tuna protein through a combined approach of computational and experimental proteolysis. A total of five potential shared umami peptides (GVGGHGAGG, GVTGVG, GGVAGCQGK, MANR, and SPAAK) were identified through database and molecular docking, which revealed that hydrogen bonds and electrostatic forces critically influence the interaction between peptides and T1R1/T1R3. The specific amino acids within the T1R1/T1R3 corresponding to glutamic acid, serine, arginine, aspartic acid, and histidine significantly influenced the affinity for umami peptides. It was verified through sensory and electronic tongue analysis that all these peptides exhibit umami performance and flavor-enhancing effects. Furthermore, bioinformatic predictions and computer simulations exploring the biological activity of umami peptides revealed that GVGGHGAGG, GVTGVG, and GGVAGCQGK, combined with Keap1, presented potential antioxidant activity. These observations offered new insights for identifying bioactive umami peptides from aquatic products and a theoretical foundation for developing novel seasonings. Full article

Collagen peptides derived from fish skin may be limited in food applications due to undesirable flavors. To investigate the effects of Maillard reaction modification on their physicochemical and flavor properties, collagen peptides from tilapia skin were prepared via enzymatic hydrolysis, followed by the Maillard reaction with four reducing sugars (xylose, ribose, glucose and glucosamine) through a combined procedure involving simultaneous enzyme inactivation and Maillard reaction at 100 °C. The resultant Maillard reaction products (MRPs) were characterized by analyzing free amino groups, peptide size distribution and color difference, while the reaction progression was monitored using UV absorption and fluorescence spectroscopy. The flavor profile of MRPs was analyzed through quantitative descriptive sensory evaluation and GC-MS coupled with principal component analysis. Among the four reducing sugars tested, glucosamine-induced Maillard reaction products exhibited the most pronounced physicochemical and sensory improvements. Specifically, glucosamine-MRPs showed the greatest reduction in free amino groups (0.69 μmol/L) and a notable decrease in high-molecular-weight peptides (3.31%), accompanied by an increase in low-molecular-weight fractions. Colorimetric analysis revealed a marked color change (ΔE = 31.78), and spectral analysis further confirmed intensified UV absorbance and fluorescence intensity in the glucosamine group, indicating advanced reaction progression. Sensory evaluation demonstrated a significant reduction in bitterness and enhancement of umami and saltiness. Moreover, GC-MS analysis revealed that the glucosamine-treated group exhibited the most favorable volatile profile, characterized by an increase in aromatic compounds and a substantial decrease in undesirable odorants. This study provides a theoretical basis for controlling the undesirable flavor of collagen peptides through low-extent Maillard reactions by different reducing sugars. Full article

The revalorization of porcine meat by-products is necessary to reduce their environmental and economic impact. Porcine lungs are usually discarded or used for low-value purposes despite their richness in collagen, elastin, or phospholipids. Enzymatic hydrolysis, in combination with ultrasound pretreatment, improves the generation of hydrolyzates with biological and taste-enhancing properties. The main objective of this study was to evaluate the impact of ultrasound pretreatment and enzyme concentration in the development of functional and taste-rich porcine lung hydrolyzates. Ultrasound pretreatments significantly increased the degree of hydrolysis and the antioxidant activity in 1:100 Enzyme: Substrate (E/S) ratio hydrolyzates. On the other hand, the combination of 1:20 E/S concentration with ultrasound pretreatment significantly increased the umami free amino acids content and Equivalent Umami Concentration (EUC), being the last one comparable with other umami-rich foods and ingredients. In silico predictions showed that the use of ultrasound pretreatment enhances the percentage of potential bioactive peptides according to PeptideRanker, whereas the bioinformatics tools UMPred-FRL and BERT4Bitter showed more umami peptides than bitter in all the hydrolyzates. These results suggest the combination of ultrasound pretreatment with 1:20 E/S can be a good strategy to revalorize porcine lung by producing hydrolyzates that could be used as a functional ingredient. Full article

This study was designed to systematically identify novel umami peptides in lager beer, clarify their molecular interactions with the T1R1/T1R3 receptor, and determine their specific effects on multidimensional sensory attributes. The peptides were characterized by LC-MS/MS combined with de novo sequencing, and 906 valid sequences were obtained. Machine-learning models (UMPred-FRL, Tastepeptides-Meta, and Umami-MRNN) predicted 76 potential umami peptides. These candidates were docked to T1R1/T1R3 with the CDOCKER protocol, producing 57 successful complexes. Six representative peptides—KSTEL, DELIK, DIGISSK, IEKYSGA, DEVR, and PVPL—were selected for 100 ns molecular-dynamics simulations and MM/GBSA binding-energy calculations. All six peptides stably occupied the narrow cleft at the T1R1/T1R3 interface. Their binding free energies ranked as DEVR (−44.09 ± 5.47 kcal mol⁻¹) < KSTEL (−43.21 ± 3.45) < IEKYSGA (−39.60 ± 4.37) ≈ PVPL (−39.53 ± 2.52) < DELIK (−36.14 ± 3.11) < DIGISSK (−26.45 ± 4.52). Corresponding taste thresholds were 0.121, 0.217, 0.326, 0.406, 0.589, and 0.696 mmol L⁻¹ (DEVR < KSTEL < IEKYSGA < DELIK < PVPL < DIGISSK). TDA-based sensory validation with single-factor additions showed that KSTEL, DELIK, DEVR, and PVPL increased umami scores by ≈21%, ≈22%, ≈17%, and ≈11%, respectively, while DIGISSK and IEKYSGA produced marginal changes (≤2%). The short-chain peptides thus bound with high affinity to T1R1/T1R3 and improved core taste and mouthfeel but tended to amplify certain off-flavors, and the long-chain peptides caused detrimental impacts. Future formulation optimization should balance flavor enhancement and off-flavor suppression, providing a theoretical basis for targeted brewing of umami-oriented lager beer. Full article

Proteomics combined with peptidomics approaches were used to analyze the protein degradation and the release pattern of umami peptides in stewed chicken. The results showed that a total of 422 proteins were identified, of which 273 proteins consistently existed in samples stewed for 0–5 h. Myosin heavy chain exhibited the highest abundance (26.29–30.26%) throughout the stewing process. The proportion of proteins under 20 kDa increased progressively with the duration of stewing and reached 61% at 4–5 h of stewing. A total of 8018 peptides were detected in the soup samples, and 2323 umami peptides were identified using the prediction platforms iUmami-SCM, UMPred-FRL, Umami_YYDS, and TastePertides-DM. Umami peptides derived from titin (accession number A0A8V0ZZ81) were determined to be the most abundant, accounting for 24% of the total umami peptides, and Val534 and Lys33639 were the key N-terminal and C-terminal amino acids of these umami peptides. Abundance analysis showed that the umami peptides KK16 and SK18 ranked among the top 5 in the samples stewed for 0–5 h, and they were most abundant in the 3 h stewed samples. The results obtained will provide data support for promoting the industrialization of high-quality chicken soup products. Full article

Deep learning has great potential in the field of functional peptide prediction. This study combines metagenomics and deep learning to efficiently discover potential umami peptides in fermented sausages. A candidate peptide library was generated using metagenomic data from fermented sausages, an integrated deep learning model was constructed for prediction, and SHAP (SHapley Additive exPlanations) interpretability analysis was performed to elucidate the key amino acid features and contributions of the model in predicting umami peptides, screening the top ten peptides with the highest predicted probability. Subsequently, molecular docking was performed to assess the binding stability of these peptides with the umami receptor T1R1/T1R3, selecting the three peptides DDSMAATGL, DGEEDASM, and DEEEVDI with the most stable binding for further study. Docking analysis revealed the important roles of the key receptor residues Glu301, Arg277, Lys328, and His71 in hydrogen bond formation. Molecular dynamics simulations validated the robust integrity of the peptide–receptor associations. Finally, sensory evaluation demonstrated that these three peptides possessed significant umami characteristics, with low umami thresholds (0.11, 0.37, and 0.44 mg/mL, respectively). This study, based on metagenomics and deep learning, provides a high-throughput strategy for the discovery and validation of functional peptides. Full article

Umami taste compounds are perceived in broilers through taste buds that detect peptides and amino acids, which can positively or negatively affect their feeding behavior. In this study, we evaluated the intake behavior for four essential amino acids (Lysine, Methionine, Threonine, and Tryptophan) in chickens. Sixty-four one-day-old male birds (Ross 308) were used. For 16 days during the early stage of the birds, two-choice preference tests were performed, in which 16 combinations composed of four amino acids in four concentrations (0.1 to 1.5%) diluted in water were evaluated, which were supplied in contrast to the delivery of water (a neutral compound) to a pair of birds in a pen for 4 h of administration after a prior 1 h fast. Amino acid solutions such as Threonine and Tryptophan tended to show less preference at the highest exposed concentrations (1.5%) concerning drinking water, which was confirmed in the case of Threonine when performing a sensory-motivated intake analysis (SMI). The opposite occurred with Lysine (1.5%), which numerically showed a higher preference ratified by SMI and acceptability analysis concerning water and other concentrations of the same amino acid, respectively. When palatability was measured with pecking cluster size, no significant differences across amino acid concentrations were observed, which is probably attributed to short recording periods and differences in solution intake behavior between chickens and previous experimental models such as rats. The results reinforce the notion that it is necessary to standardize feeding behavior tests in birds according to their feeding patterns and nutritional needs. Full article

Rhodotorula mucilaginosa plays a key role in developing the taste of dry-cured ham, while the mechanism of Rhodotorula mucilaginosa proteases on myofibrillar protein (MP) hydrolysis and the evolution of taste substances has not been studied. The enzymatic characteristics, hydrolysis capacities for MPs, free amino acid contents, metabolite compositions, and taste attributes were investigated during the interactions of MPs and proteases. The proteases of R. mucilaginosa EIODSF019 (RE) and R. mucilaginosa XZY63-3 (RX) showed high hydrolytic activities at the conditions of pH 5.0~7.0 and 30~40 °C. Compared with RX, RE showed a lower Michaelis constant (Km) value and a better affinity for protein substrates. RE showed a higher capability to degrade myosin and actin compared with RX and P. kudriavzevii XS-5 proteases (PK). The microtopography of enzyme-treated MPs in RE presented a smoother surface and lower root mean square roughness than that in RX and PK. The total content of free amino acids significantly increased from 0.34 mg/100 mL of CK to 17.10 mg/100 mL of RE after 4 h of hydrolysis of MPs. Sixty-two metabolites were identified by LC-MS/MS, and γ-glutamyl peptides were the main components of MP hydrolysates. Sensory scores of umami, richness, and aftertaste showed the largest values in RE among these groups. Partial least squares discriminant analysis and correlation network demonstrated that γ-Glu-Lys, γ-Glu-Tyr, γ-Glu-Glu, γ-Glu-His, γ-Glu-Leu, γ-Glu-Cys, γ-Glu-Ala, and γ-Glu-Gln were positively correlated with the improvements of umami, richness, and aftertaste in RE. Full article

Kelp (Laminaria japonica) is renowned for its rich content of flavor-enhancing amino acids and nucleotides; however, approximately 40% of kelp, including the thin edges and root areas, is discarded during its processing due to its inferior taste. To recycle these kelp byproducts, we have cultivated a functional microbial consortium through continuous enrichment. Analysis via 16S rRNA sequencing has shown that during the three fed-batch fermentation stages of kelp waste, the microbial community was predominantly and consistently composed of three phyla: Halanaerobiaeota, Bacteroidota, and Proteobacteria. At the genus level, Halanaerobium emerged as the dominant player, exhibiting a trend of initial increase followed by a decline throughout the fermentation process. Enzymes such as alginate lyases and both acidic and neutral proteases were found to play crucial roles in the degradation of kelp residues into sauces. Notably, electronic tongue analysis revealed that the fermented kelp sauce demonstrated strong umami characteristics. Furthermore, four novel umami peptides, EIL, STEV, GEEE, and SMEAVEA, from kelp were identified for the first time, with their umami effect largely attributed to strong hydrogen bond interactions with the T1R1–T1R3 umami receptors. In conclusion, this study proposed a sustainable method for kelp by-product utilization, with implications for other seaweed processing. Full article

Hongqujiu, one of the three principal varieties of yellow wine, is a traditional fermented beverage originating from China that employs Hongqu as the fermentation agent. In this study, an untargeted metabolomics approach based on gas chromatography–mass spectrometry (GC-MS) and liquid chromatography–mass spectrometry (LC-MS) was applied to systematically analyze the volatile compounds (VOCs) and non-volatile compounds (NVCs) in Hongqujiu across different aging years for the first time. The analysis identified a total of 262 VOCs and 2564 NVCs in samples of Hongqujiu aged for six distinct years. Based on metabolic differences, the samples were categorized into two groups: the low-year group (5-year, 6-year) and the high-year group (8-year, 10-year, 15-year, 20-year). Nineteen VOCs (e.g., 4-amino-butyric acid and diethanolamine) and thirty NVCs (e.g., palmitoylethanolamide and erinacine D) were identified as key differential metabolites distinguishing the low-year group from the high-year group. The higher-year group is enriched with a variety of substances with different flavors or biological activities, such as sugar derivatives, amino acids and their complexes, organic acids and their intermediate metabolites, steroids and terpenoid compounds, lipids and their derivatives, nitrogen-containing heterocycles, and aromatic compounds. The accumulation of these substances not only shapes the unique and rich flavor characteristics of aged red rice wine (such as the caramel aroma and umami peptide flavor), but also endows red rice wine with potential health benefits due to the physiological regulatory functions of some active ingredients. This study contributes to a deeper understanding of the composition and dynamic variations in metabolites in Hongqujiu, offering a scientific foundation for identifying aged Hongqujiu and conducting further research to enhance its quality. Full article

Summer green tea often suffers from an inferior flavor, attributed to its bitterness and astringency. In this study, an integrated shaking and piling process was performed to improve the flavor of summer green tea. The results demonstrated a significant improvement in the sweet and kokumi flavors, accompanied by a reduction in umami, astringency, and bitterness following the treatment. Additionally, the yellowness and color saturation were also enhanced by the treatment. A total of 146 non-volatile metabolites (NVMs) were identified during the study. The elevated levels of sweet-tasting amino acids (L-proline, L-glutamine, and L-threonine), soluble sugars, and peptides (such as gamma-Glu-Gln and glutathione) contributed to the enhanced sweetness and kokumi. Conversely, the decreased levels of ester-catechins, flavonoid glycosides, and procyanidins resulted in a reduction in umami, astringency, and bitterness. Furthermore, the decreased levels of certain NVMs, particularly ascorbic acid and saponarin, played a crucial role in enhancing the yellowness and color saturation of the summer green tea. Our findings offered a novel theoretical framework and practical guidelines for producing high-quality summer green tea. Full article

BIOPEP-UWM, a peptide database, contains 5128 peptides from a myriad of resources. Five listed peptides are Angiotensin-I-converting enzyme (ACE-1; EC3.4.15.1) inhibitory peptides derived from a red alga, while two from Chlorella vulgaris have anti-cancer and antioxidative bioactivities. Herein, we describe a process combining hydrolysis with two enzymes, Alcalase and Viscozyme, and filtration to generate protein-rich, bioactive peptide-containing hydrolysates from mixed species of Chlorella sp. and Scenedesmus sp. The potential of generated algal hydrolysates to act as food ingredients was determined by assessment of their techno-functional (foaming, emulsification, solubility, water holding, and oil holding capacity) properties. Bioactive screening of hydrolysates in vitro combined with mass spectrometry (MS) and in silico predictions identified bioactive and functional hydrolysates and six novel peptides. Peptides derived from Chlorella mix have the sequences YDYIGNNPAKGGLF and YIGNNPAKGGLF with predicted anti-inflammatory (medium confidence) and umami potential. Peptides from Scenedesmus mix have sequences IEWYGPDRPKFL, RSPTGEIIFGGETM, TVQIPGGERVPFLF, and IEWYGPDRPKFLGPF with predicted anti-inflammatory, anti-diabetic, and umami attributes. Such microalgal hydrolysates could provide essential amino acids to consumers as well as tertiary health benefits to improve human global health. Full article

Xiangzao brine is a special flavored food produced by the natural fermentation of Huangjiu lees. To clarify fermentation time on its quality, this study integrated flavoromics analysis, macro-genomics, and polypeptide omics to analyze the volatile flavor components, microbial species, and flavor peptide distributions of four groups of samples (XZ-1Y, XZ-2Y, XZ-3Y, and XZ-4Y) fermented for 1–4 years. The results showed that the samples fermented for 1 year had the highest contents of umami amino acids and umami peptides, and the samples fermented for 4 years had the highest contents of organic acids and fruity components. In addition, 42 volatile flavor components and 532 peptides were identified, including 393 umami taste peptides and only 37 bitter taste peptides. Correlation analysis showed that ethyl lactate and furfural were positively correlated with the abundance of Nocardioides and Stenotrophomonas, respectively. The abundance of Pseudomonas was positively correlated with four previously unreported umami peptides (FATPR, RELER, FNLERP, and RSSFLGQ) screened by molecular docking. This study provides a reference for the flavor metabolism regulation of Xiangzao brine. Full article