RESUMEN
Noni fruit has an unpleasant flavour but is highly bioactive. Therefore, it is necessary to clarify the effect of temperature regulation on quality of fermented noni fruit. In the present study, the formation of flavours, amino acid profiles, and iridoid glycosides during noni fruit fermentation at different temperatures were investigated. We initially found that different temperatures affected core microbial communities. The general evolutionary trends of Acetobacter and Gluconobacter were influenced by different temperatures. Furthermore, high temperature helped maintain low octanoic and hexanoic acids. Subsequently, we found that high temperature improved total amino acids and iridoid glycosides. The correlation network analysis revealed that bacterial communities impacted the quality (volatile flavours, amino acid profiles, and iridoid glycosides) of fermented noni fruit. Overall, altering the temperature induced variations in microbial communities and quality during the noni fruit fermentation process. These results are instrumental in the pursuit of quality control in natural fermentation processes.
Asunto(s)
Aminoácidos , Bacterias , Fermentación , Frutas , Glicósidos Iridoides , Microbiota , Morinda , Temperatura , Frutas/química , Frutas/metabolismo , Frutas/microbiología , Aminoácidos/metabolismo , Aminoácidos/análisis , Bacterias/metabolismo , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Morinda/química , Morinda/metabolismo , Glicósidos Iridoides/metabolismo , Glicósidos Iridoides/análisis , Glicósidos Iridoides/química , Compuestos Orgánicos Volátiles/metabolismo , Compuestos Orgánicos Volátiles/química , Aromatizantes/metabolismo , Aromatizantes/químicaRESUMEN
Field pea seeds have long been recognized as valuable feed ingredients for animal diets, due to their high-quality protein and starch digestibility. However, the chemical composition of pea cultivars can vary across different growing locations, consequently impacting their nutrient profiles. This study employs untargeted metabolomics in conjunction with the quantification of fatty acids and amino acids to explore the influence of three different growing locations in Spain (namely Andalusia, Aragon and Asturias), on the nutritional characteristics of seeds of various pea cultivars. Significant interactions between cultivar and environment were observed, with 121 metabolites distinguishing pea profiles. Lipids, lipid-like molecules, phenylpropanoids, polyketides, carbohydrates, and amino acids were the most affected metabolites. Fatty acid profiles varied across locations, with higher C16:0, C18:0, and 18:1 n-9 concentration in Aragón, while C18:2 n-6 predominated in Asturias and C18:3 n-3 in Andalusia. Amino acid content was also location-dependent, with higher levels in Asturias. These findings underscore the impact of environmental factors on pea metabolite profiles and emphasize the importance of selecting pea cultivars based on specific locations and animal requirements. Enhanced collaboration between research and industry is crucial for optimizing pea cultivation for animal feed production.
Asunto(s)
Aminoácidos , Alimentación Animal , Ácidos Grasos , Valor Nutritivo , Pisum sativum , Semillas , Pisum sativum/metabolismo , Pisum sativum/química , Pisum sativum/crecimiento & desarrollo , Alimentación Animal/análisis , Aminoácidos/metabolismo , Aminoácidos/análisis , Semillas/química , Semillas/metabolismo , Semillas/crecimiento & desarrollo , Ácidos Grasos/metabolismo , Ácidos Grasos/análisis , Animales , España , MetabolómicaRESUMEN
This study examined the impact of live bread yeast (Saccharomyces cerevisiae) on the nutritional characteristics of Asian dried noodles. Micronutrient analysis of fermented noodles revealed a 6.9% increase in the overall amino acid content, a 37.1% increase in the vitamin B content and a 63.0% decrease in the phytic acid level. Molecular weight analysis of starch and protein contents revealed moderate decrease in the fermented noodles. The in vitro digestion of fermented noodles showed a slightly faster initial acidification, four-fold decrease in the initial shear viscosity (from 8.85 to 1.94 Pa·s). The initial large food particle count (>2 mm diameter) was 19.5% lower in the fermented noodles. The fermented noodles contained slightly higher free sugar content (73.5 mg g-1 noodle) during the gastric digestion phase. The overall nutrition and digestion results indicate nutritional improvement and digestion-easing attributes in the fermented noodles.
Asunto(s)
Digestión , Fermentación , Saccharomyces cerevisiae , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/química , Nutrientes/metabolismo , Nutrientes/análisis , Humanos , Aminoácidos/metabolismo , Aminoácidos/análisis , Pan/análisis , Pan/microbiología , Modelos Biológicos , China , Pueblos del Este de AsiaRESUMEN
Yeast assimilable nitrogen (YAN) is one of the important factors affecting yeast growth and metabolism. However, the nitrogen requirement of indigenous commercial S. cerevisiae NX11424 is unclear. In this study, metabolomics was used to analyze the metabolite profiles of the yeast strain NX11424 under high (433 mg/L) and low (55 mg/L) YAN concentrations. It was found that yeast biomass exhibited different trends under different YAN conditions and was generally positively correlated with the initial YAN concentration, while changes of key biomarkers of yeast strain NX11424 at different stages of fermentation showed a similar trend under high and low YAN concentrations. The YAN concentration affected the metabolite levels of the yeast strain NX11424, which resulted in the significant difference in the levels of pyruvic acid, α-oxoglutarate, palmitoleic acid, proline, butane-2,3-diol, citrulline, ornithine, galactinol, citramalic acid, tryptophan, alanine, phosphate and phenylethanol, mainly involving pathways such as central carbon metabolism, amino acid metabolism, fatty acid metabolism, purine metabolism, and energy metabolism. Yeast strain NX11424 could utilize proline to produce protein under a low YAN level. The intracellular level of citrulline and ornithine under high YAN concentration was higher than that under low YAN level. Yeast strain NX11424 is more suitable for fermentation at lower YAN level. The results obtained here will help to rational utilize of YAN by S. cerevisiae NX11424, and is conducive to precise control of the alcohol fermentation and improve wine quality.
Asunto(s)
Fermentación , Metabolómica , Nitrógeno , Saccharomyces cerevisiae , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/crecimiento & desarrollo , Nitrógeno/metabolismo , Vino/análisis , Vino/microbiología , Biomasa , Aminoácidos/metabolismoRESUMEN
Alcoholic fermentation is one of man's most efficient food preservation processes, and innovations in this area are a trend in food science and nutrition. In addition to the classic Saccharomyces yeasts, various other species may have desirable characteristics for obtaining fruit wines. This study investigated the profile of non-Saccharomyces commercial yeasts compared with S. cerevisiae regarding pineapple wine's chemical composition and bioaccessibility. The fermentation profile of the yeasts Lachancea thermotolerans, Brettanomyces bruxellensis, Brettanomyces lambicus, and S. cerevisiae was evaluated for sugar and alcohol content, and the pineapple wines obtained were analyzed for amino acids, phenolics, and organic acids by HPLC and volatile profile by GC/MS. All yeast strains were able to produce ethanol and glycerol at acceptable levels. L. thermotolerans produced higher levels of lactic acid (0.95 g/L) and higher consumption of free amino acids. B. bruxellensis produced higher levels of individual phenolics and ethanol 109 g/L. The alcoholic fermentation process improved the bioaccessibility of phenolics such as catechin (237 %), epigallocatechin gallate (81 %), procyanidin B1 (61 %) and procyanidin B2 (61 %). The yeasts differed in their volatile profiles, with Brettanomyces and Lachancea producing higher levels of compounds associated with pineapple aroma, such as ester ethyl butyrate (260-270 µg/L). These results demonstrate the importance of choosing the yeast strain for the conduction of alcoholic fermentation and that the yeasts Brettanomyces and Lachancea showed technological potential in obtaining pineapple wines. This study contributes to developing processes for obtaining fruit wines by highlighting two non-Saccharomyces yeast species with technological potential for alcoholic fermentations.
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Ananas , Etanol , Fermentación , Saccharomyces cerevisiae , Vino , Vino/análisis , Ananas/química , Saccharomyces cerevisiae/metabolismo , Etanol/metabolismo , Etanol/análisis , Fenoles/análisis , Fenoles/metabolismo , Aminoácidos/análisis , Aminoácidos/metabolismo , Brettanomyces/metabolismo , Saccharomycetales/metabolismo , Compuestos Orgánicos Volátiles/análisis , Cromatografía de Gases y Espectrometría de Masas , Frutas/químicaRESUMEN
Binding-activated optical sensors are powerful tools for imaging, diagnostics, and biomolecular sensing. However, biosensor discovery is slow and requires tedious steps in rational design, screening, and characterization. Here we report on a platform that streamlines biosensor discovery and unlocks directed nanosensor evolution through genetically encodable fluorogenic amino acids (FgAAs). Building on the classical knowledge-based semisynthetic approach, we engineer ~15 kDa nanosensors that recognize specific proteins, peptides, and small molecules with up to 100-fold fluorescence increases and subsecond kinetics, allowing real-time and wash-free target sensing and live-cell bioimaging. An optimized genetic code expansion chemistry with FgAAs further enables rapid (~3 h) ribosomal nanosensor discovery via the cell-free translation of hundreds of candidates in parallel and directed nanosensor evolution with improved variant-specific sensitivities (up to ~250-fold) for SARS-CoV-2 antigens. Altogether, this platform could accelerate the discovery of fluorogenic nanosensors and pave the way to modify proteins with other non-standard functionalities for diverse applications.
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Aminoácidos , Técnicas Biosensibles , Colorantes Fluorescentes , SARS-CoV-2 , Técnicas Biosensibles/métodos , Colorantes Fluorescentes/química , Humanos , SARS-CoV-2/genética , COVID-19/virología , Nanotecnología/métodos , Péptidos/metabolismo , Péptidos/química , Péptidos/genéticaRESUMEN
Gliomas are highly complex and metabolically active brain tumors associated with poor prognosis. Recent reports have found altered levels of blood metabolites during early tumor development, suggesting that tumor development could be detected several years before clinical manifestation. In this study, we performed metabolite analyses of blood samples collected from healthy controls and future glioma patients, up to eight years before glioma diagnosis, and on the day of glioma surgery. We discovered that metabolites related to early glioma development were associated with an increased energy turnover, as highlighted by elevated levels of TCA-related metabolites such as fumarate, malate, lactate and pyruvate in pre-diagnostic cases. We also found that metabolites related to glioma progression at surgery were primarily high levels of amino acids and metabolites of amino acid catabolism, with elevated levels of 11 amino acids and two branched-chain alpha-ketoacids, ketoleucine and ketoisoleucine. High amino acid turnover in glioma tumor tissue is currently utilized for PET imaging, diagnosis and delineation of tumor margins. By examining blood-based metabolic progression patterns towards disease onset, we demonstrate that this high amino acid turnover is also detectable in a simple blood sample. These findings provide additional insight of metabolic alterations during glioma development and progression.
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Biomarcadores de Tumor , Neoplasias Encefálicas , Glioma , Humanos , Glioma/sangre , Glioma/cirugía , Glioma/diagnóstico , Glioma/patología , Neoplasias Encefálicas/sangre , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/cirugía , Neoplasias Encefálicas/metabolismo , Masculino , Femenino , Biomarcadores de Tumor/sangre , Persona de Mediana Edad , Adulto , Progresión de la Enfermedad , Aminoácidos/sangre , Aminoácidos/metabolismoRESUMEN
Thiol dioxygenases (TDOs) are nonheme Fe(II)dependent enzymes that catalyze the O2-dependent oxidation of thiol substrates to their corresponding sulfinic acids. Six classes of TDOs have thus far been identified and two, cysteine dioxygenase (CDO) and cysteamine dioxygenase (ADO), are found in eukaryotes. All TDOs belong to the cupin superfamily of enzymes, which share a common ßbarrel fold and two cupin motifs: G(X)5HXH(X)3-6E(X)6G and G(X)5-7PXG(X)2H(X)3N. Crystal structures of TDOs revealed that these enzymes contain a relatively rare, neutral 3His ironbinding facial triad. Despite this shared metal-binding site, TDOs vary greatly in their secondary coordination spheres. Sitedirected mutagenesis has been used extensively to explore the impact of changes in secondary sphere residues on substrate specificity and enzymatic efficiency. This chapter summarizes site-directed mutagenesis studies of eukaryotic TDOs, focusing on the tools and practicality of nonstandard amino acid incorporation.
Asunto(s)
Aminoácidos , Dioxigenasas , Mutagénesis Sitio-Dirigida , Dioxigenasas/química , Dioxigenasas/metabolismo , Dioxigenasas/genética , Aminoácidos/metabolismo , Aminoácidos/química , Especificidad por Sustrato , Cisteína-Dioxigenasa/química , Cisteína-Dioxigenasa/metabolismo , Cisteína-Dioxigenasa/genética , Compuestos de Sulfhidrilo/metabolismo , Compuestos de Sulfhidrilo/química , Humanos , Animales , Modelos MolecularesRESUMEN
It is a consensus in the international manned space field that factors such as microgravity during the space flight can cause anxiety, depression and other important brain function abnormalities in astronauts. However, the neural mechanism at the molecular level is still unclear. Due to the limitations of research conditions, studies of biological changes in the primate brain have been comparatively few. We took advantage of -6° head-down bed rest (HDBR), one of the most implemented space analogues on the ground, to investigate the effects of simulated weightlessness on non-human primate brain metabolites. The Rhesus Macaque monkeys in the experiment were divided into three groups: the control group, the 42-day simulated weightlessness group with HDBR, and the recovery group, which had 28 days of free activity in the home cage after the HDBR. Liquid chromatography-mass spectrometry (LC-MS) was used to perform metabolomics analysis on specific brain areas of the monkeys under three experimental conditions. Our results show that simulated weightlessness can cause neurotransmitter imbalances, the amino acid and energy metabolism disorders, and hormone disturbances. But these metabolomics changes are reversible after recovery. Our study suggests that long-term brain damage in space flight might be reversible at the metabolic level. This lays a technical foundation for ensuring brain health and enhancing the brain function in future space studies.
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Reposo en Cama , Encéfalo , Inclinación de Cabeza , Macaca mulatta , Simulación de Ingravidez , Animales , Encéfalo/metabolismo , Masculino , Metabolómica , Ingravidez/efectos adversos , Neurotransmisores/metabolismo , Aminoácidos/metabolismo , Hormonas/metabolismoRESUMEN
The current standard method for amino acid signal identification in protein NMR spectra is sequential assignment using triple-resonance experiments. Good software and elaborate heuristics exist, but the process remains laboriously manual. Machine learning does help, but its training databases need millions of samples that cover all relevant physics and every kind of instrumental artifact. In this communication, we offer a solution to this problem. We propose polyadic decompositions to store millions of simulated three-dimensional NMR spectra, on-the-fly generation of artifacts during training, a probabilistic way to incorporate prior and posterior information, and integration with the industry standard CcpNmr software framework. The resulting neural nets take [1H,13C] slices of mixed pyruvate-labeled HNCA spectra (different CA signal shapes for different residue types) and return an amino acid probability table. In combination with primary sequence information, backbones of common proteins (GB1, MBP, and INMT) are rapidly assigned from just the HNCA spectrum.
Asunto(s)
Proteínas , Proteínas/química , Resonancia Magnética Nuclear Biomolecular/métodos , Programas Informáticos , Aminoácidos/química , Algoritmos , Isótopos/química , Aprendizaje AutomáticoRESUMEN
The epidemic and outbreaks of influenza B Victoria lineage (Bv) during 2019-2022 led to an analysis of genetic, epitopes, charged amino acids and Bv outbreaks. Based on the National Influenza Surveillance Network (NISN), the Bv 72 strains isolated during 2019-2022 were selected by spatio-temporal sampling, then were sequenced. Using the Compare Means, Correlate and Cluster, the outbreak data were analyzed, including the single nucleotide variant (SNV), amino acid (AA), epitope, evolutionary rate (ER), Shannon entropy value (SV), charged amino acid and outbreak. With the emergence of COVID-19, the non-pharmaceutical interventions (NPIs) made Less distant transmission and only Bv outbreak. The 2021-2022 strains in the HA genes were located in the same subset, but were distinct from the 2019-2020 strains (P < 0.001). The codon G â A transition in nucleotide was in the highest ratio but the transversion of C â A and T â A made the most significant contribution to the outbreaks, while the increase in amino acid mutations characterized by polar, acidic and basic signatures played a key role in the Bv epidemic in 2021-2022. Both ER and SV were positively correlated in HA genes (R = 0.690) and NA genes (R = 0.711), respectively, however, the number of mutations in the HA genes was 1.59 times higher than that of the NA gene (2.15/1.36) from the beginning of 2020 to 2022. The positively selective sites 174, 199, 214 and 563 in HA genes and the sites 73 and 384 in NA genes were evolutionarily selected in the 2021-2022 influenza outbreaks. Overall, the prevalent factors related to 2021-2022 influenza outbreaks included epidemic timing, Tv, Ts, Tv/Ts, P137 (B â P), P148 (B â P), P199 (P â A), P212 (P â A), P214 (H â P) and P563 (B â P). The preference of amino acid mutations for charge/pH could influence the epidemic/outbreak trends of infectious diseases. Here was a good model of the evolution of infectious disease pathogens. This study, on account of further exploration of virology, genetics, bioinformatics and outbreak information, might facilitate further understanding of their deep interaction mechanisms in the spread of infectious diseases.
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Brotes de Enfermedades , Evolución Molecular , Gripe Humana , Mutación , Polimorfismo de Nucleótido Simple , Humanos , Gripe Humana/epidemiología , Gripe Humana/virología , Gripe Humana/genética , Virus de la Influenza B/genética , Aminoácidos/genética , Epítopos/genética , Filogenia , Sustitución de Aminoácidos , Glicoproteínas Hemaglutininas del Virus de la Influenza/genéticaRESUMEN
Electrospray ionization is widely used to generate vapor phase ions for analysis by mass spectrometry in proteomics research. However, only a small fraction of the analyte enters the mass spectrometer due to losses that are fundamentally linked to the use of a background gas to stimulate the generation of ions from electrosprayed droplets. Here we report a nanopore ion source that delivers ions directly into high vacuum from aqueous solutions. The ion source comprises a pulled quartz pipette with a sub-100 nm opening. Ions escape an electrified meniscus by ion evaporation and travel along collisionless trajectories to the ion detector. We measure mass spectra of 16 different amino acid ions, post-translationally modified variants of glutathione, and the peptide angiotensin II, showing that these analytes can be emitted as desolvated ions. The emitted current is composed of ions rather than charged droplets, and more than 90% of the current can be recovered in a distant collector.
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Aminoácidos , Iones , Nanoporos , Péptidos , Espectrometría de Masa por Ionización de Electrospray , Vacio , Aminoácidos/química , Péptidos/química , Espectrometría de Masa por Ionización de Electrospray/métodos , Proteómica/métodos , Angiotensina II/químicaRESUMEN
Amino acids serve as the primary means of transport and organic nitrogen carrier in plants, playing an essential role in plant growth and development. Amino acid transporters (AATs) facilitate the movement of amino acids within plants and have been identified and characterised in a number of species. It has been demonstrated that these amino acid transporters exert an influence on the quality attributes of plants, in addition to their primary function of transporting amino acid transport. This paper presents a summary of the role of AATs in plant quality improvement. This encompasses the enhancement of nitrogen utilization efficiency, root development, tiller number and fruit yield. Concurrently, AATs can bolster the resilience of plants to pests, diseases and abiotic stresses, thereby further enhancing the yield and quality of fruit. AATs exhibit a wide range of substrate specificity, which greatly optimizes the use of pesticides and significantly reduces pesticide residues, and reduces the risk of environmental pollution while increasing the safety of fruit. The discovery of AATs function provides new ideas and ways to cultivate high-quality crop and promote changes in agricultural development, and has great potential in the application of plant quality improvement.
Asunto(s)
Sistemas de Transporte de Aminoácidos , Sistemas de Transporte de Aminoácidos/metabolismo , Proteínas de Plantas/metabolismo , Productos Agrícolas/metabolismo , Aminoácidos/metabolismo , Plantas/metabolismoRESUMEN
Hyperpolarized pyruvate is a widely used marker to track metabolism in vivo and a benchmark molecule for hyperpolarization methods. Here, we show how a combination of improved bullet-DNP instrumentation, an optimized sample preparation and a further sensitivity increase via a 13C-1H polarization transfer after dissolution enable the observation of pyruvate at a concentration of 250 nM immediately after dissolution. At this concentration, the experiment employs a total mass of pyruvate of only 20 ng or 180 pmol. If the concentration is increased to 45 µM, pyruvate may be detected 1 min after dissolution with a signal-to-noise ratio exceeding 50. The procedure can be extended to observe a mixture of amino acids at low micromolar concentrations.
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Aminoácidos , Ácido Pirúvico , Aminoácidos/análisis , Aminoácidos/química , Ácido Pirúvico/química , Ácido Pirúvico/análisis , Espectroscopía de Resonancia Magnética/métodosRESUMEN
BACKGROUND: Current treatment for chronic kidney disease (CKD) focuses on improving manifestations and delaying progression. Nutritional approaches play a crucial role in CKD management, and various supplements have become available. Ketoanalogues of amino acids (KAs), calcium citrate, and inulin have been proposed as suitable supplements, yet their widespread use has been limited due to insufficient evidence. This study aimed to generate general guidance statements on the appropriateness of these supplements through a RAND/UCLA consensus process. METHODS: A RAND/UCLA consensus panel was convened to evaluate the appropriateness of these supplements in different clinical scenarios. In this study, we present a subgroup analysis focusing on a panel of eleven clinical nephrologists from among the experts. RESULTS: Supplementation of low-protein diets (LPDs) and very low-protein diets (VLPDs) with KA was considered appropriate to reduce manifestations and delay CKD outcomes, supplementation with calcium citrate is considered appropriate to reduce CKD manifestations, and supplementation with inulin is considered appropriate to delay CKD outcomes and manage comorbidities. CONCLUSIONS: Based on a combination of clinical experience and scientific evidence, the panel reached a consensus that KA supplementation of LPD and VLPD, calcium citrate, and inulin are appropriate in patients with CKD across various scenarios.
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Aminoácidos , Citrato de Calcio , Consenso , Dieta con Restricción de Proteínas , Suplementos Dietéticos , Inulina , Insuficiencia Renal Crónica , Insuficiencia Renal Crónica/dietoterapia , Humanos , Inulina/administración & dosificación , Aminoácidos/administración & dosificación , Dieta con Restricción de Proteínas/métodos , Citrato de Calcio/administración & dosificación , Citrato de Calcio/uso terapéuticoRESUMEN
Arabica coffee is one of the most consumed beverages in the world. The chemical components present in raw Arabica coffee beans (RACB) are directly related to the cup quality of the beverage. Environmental and genetic factors influence the content and profile of these components. Then, this work aimed to evaluate different chemical parameters of RACB from 3 varieties planted in 3 different experimental farms located within the "Alta Mogiana" terroir harvested in 2021 and 2022 to identify a better variety for each farm to produce a high cup quality Arabica coffee. The harvest period had a strong influence on most of the studied parameters because atypical weather conditions occurred in the 2021 harvest. The RACB harvested in 2022 yielded better results and supposedly will produce a beverage of high cup quality. Samples harvested in this period presented mainly average moisture levels closer to optimum (11.02 against 8.56 % in 2021); low total titratable acidity (98.00 against 169.75 mL 0.1 M NaOH/100 g in 2021); high amounts of free amino acids (0.96 against 0.93 g GAE/100 g in 2021), low amounts of CGA (4.27 against 4.85 g/100 g in 2021) and caffeine (1.08 against 1.76 g/100 g in 2021) and high amounts of trigonelline (1.12 against 0.96 g/100 g in 2021). The Rome Sudan variety had the best combination of chemical results, mainly when cultivated in Farm 2 in 2022, presenting high amounts of protein content (15.24 %) and free amino acids (0.96 g GAE/100 g), low total titratable acidity (98.3 mL 0.1 M NaOH/100 g), low amounts of CGA (4.55 g/100 g) and caffeine (1.29 g/100 g) and high amounts of trigonelline (1.11 g/100 g). The analysis of chemical compounds could predict the best farm to cultivate each variety studied and was a guide to foresee a higher cup quality of RACB beverages.
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Coffea , Café , Semillas , Coffea/química , Semillas/química , Café/química , Cafeína/análisis , Brasil , Alcaloides/análisis , Aminoácidos/análisisRESUMEN
The taste profile of oolong tea is intricately shaped by origins and roasting. Herein, a comprehensive approach integrating non-targeted metabolomics, quantitative analysis and sensory evaluations was employed to analyze the taste profile of oolong tea. 25 selected representative oolong teas, including Southern Fujian (MN), Northern Fujian (MB), and Taiwan (TW), were meticulously were classified into SX-RG-DD, GS, and TGY based on the chemical taste phenotypes. A total of 314 non-volatile compounds were identified, among which 87 and 77 compounds, including catechin, theaflavins, flavonoids and amino acids were screened as critical taste metabolites responsible for regions and roasting degree, respectively. The reduction of bitter and astringent, coupled with the enhancement of umami, sweet and sweet aftertaste exhibited a correlation with the decrease in (-)-epigallocatechin (EGC), (-)-epicatechin (EC), (-)-epicatechin gallate (ECG) and (-)-epigallocatechin gallate (EGCG), while the increase in catechin (C). These findings provide insights for further research on optimizing tea quality and refining processing techniques.
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Biflavonoides , Camellia sinensis , Catequina , Metabolómica , Gusto , Té , Té/química , Metabolómica/métodos , Catequina/análisis , Catequina/análogos & derivados , Humanos , Biflavonoides/análisis , Camellia sinensis/química , Masculino , Flavonoides/análisis , Aromatizantes/análisis , Femenino , Aminoácidos/análisis , Adulto , ChinaRESUMEN
This study aimed to investigate the effect of oxidation on fish gelatin and its emulsifying properties. Fish gelatin was oxidized with varying concentrations of H2O2 (0-30 mM). Increased concentrations of the oxidant led to a decrease in amino acids in the gelatin, including glycine, lysine, and arginine. Additionally, the relative content of ordered secondary structure and triple helix fractions decreased. Zeta potential decreased, while particle size, surface hydrophobicity, and water contact angle increased. Regarding emulsifying behavior, oxidation promoted the adsorption of gelatin to the oil-water interface and reduced interfacial tension. With increased degrees of oxidation, the zeta potential and size of the emulsion droplets decreased. The oxidized gelatin exhibited better emulsifying activity but worse emulsifying stability. Based on these results, a mechanism for how oxidation affects the emulsifying properties of gelatin was proposed: the increase in gelatin's hydrophobicity and the decrease in triple helix structure induced by oxidation reduced the interfacial tension at the oil-water interface. This promoted protein adsorption at the oil-water interface, allowing the formation of smaller oil droplets and enhancing gelatin's emulsifying activity. However, the decrease in electrostatic repulsion between emulsion droplets and the decrease in solution viscosity increased the flocculation and aggregation of oil droplets, ultimately weakening the emulsifying stability of gelatin.
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Emulsiones , Proteínas de Peces , Gelatina , Interacciones Hidrofóbicas e Hidrofílicas , Oxidación-Reducción , Gelatina/química , Emulsiones/química , Animales , Proteínas de Peces/química , Tamaño de la Partícula , Peróxido de Hidrógeno/química , Viscosidad , Aminoácidos/química , Tensión Superficial , Emulsionantes/química , Peces , Adsorción , Estructura Secundaria de ProteínaRESUMEN
Microwaves have been successfully employed in the Lewis acid titanium tetrachloride-assisted synthesis of peptide systems. Dipeptide systems with their amino function differently protected with urethane protecting groups have been synthesized in short periods of time and with high yields. The formation of the peptide bond between the two reacting amino acids was achieved in pyridine by using titanium tetrachloride as a condensing agent and heating the reaction mixture with a microwave reactor. The reaction conditions are compatible with amino acids featuring various side chains and different protecting groups on both the amino function and side chains. Additionally, the substrates retain their chiral integrity after reaction.
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Dipéptidos , Microondas , Titanio , Dipéptidos/química , Dipéptidos/síntesis química , Titanio/química , Aminoácidos/química , SolucionesRESUMEN
Considering that maize (Zea mays L.) is a staple food for a large segment of the population worldwide, many attempts have been made to improve the nutritional value of its grain and at the same time to achieve sustainable cropping systems. The present study aimed to characterize the composition and nutritional value of maize grain as influenced by cropping system, genetic background (variety), and growing year using untargeted NMR metabolomics. The composition of both water- (sugars and polyols, organic acids, and amino acids) and liposoluble metabolites (free and esterified fatty acids, sterols, and lipids) extracted from the maize grain was determined. Multivariate statistical analyses (PCA and ANOVA) pointed to the growing year and the variety as the most important random and fixed factors, respectively, influencing the metabolite profile. The samples were separated along PC1 and PC3 according to the growing year and the variety, respectively. A higher content of citric acid and diunsaturated fatty acids and a lower content of tyrosine, trigonelline, and monounsaturated fatty acids was observed in the organic with respect to the conventional variety. The effect of the cropping system was overwhelmed by the random effect of the growing year. The results provide novel knowledge on the influence of agronomic practices on maize micronutrient contents.