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BACKGROUND: Phyllanthus emblica Linn. (PE) is rich in polyphenols, which can be categorized into free and bound phenolics (PEFP and PEBP). This study evaluated the inhibitory effect of PEFB and PEBP on α-amylase for the first time. The mechanism of the inhibition effect of PEFP and PEBP on α-amylase was investigated by enzyme inhibition kinetics, multispectral analysis, thermodynamics, and molecular docking. RESULTS: Free and bound phenolics inhibited α-amylase activity effectively in a mixed type of inhibition. Fluorescence quenching and thermodynamic analyses showed that the binding of PEFP and PEBP to α-amylase occurred through a static quenching process (Kq = 6.94 × 10¹² and 5.74 × 10¹² L mol-1 s-1), which was accompanied by a redshift (λem from 343 to 347 nm), leading to a change in the microenvironment. This process was found to be a spontaneous exothermic reaction (ΔG < 0). Circular dichroism (CD) analysis confirms that the secondary structure of α-amylase was altered, in particular a decrease in α-helixes and an increase in random coils. Molecular docking studies showed that PEFP and PEBP interacted with α-amylase through hydrogen bonding and hydrophobic interactions. CONCLUSION: The present study provides valuable insights into the mechanism of action of PEFP and PEBP on α-amylase, which will provide a theoretical basis for their possible use as novel natural α-amylase inhibitors. © 2024 Society of Chemical Industry.
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BACKGROUND: Recently, frozen dough has become more popular because of its ability to be quickly transformed into freshly baked foods. During the storage and transport process, frozen dough can suffer some degree of damage caused by ice crystallization and recrystallization. Adding polysaccharides to frozen dough is a good way to solve this problem. Tamarind seed polysaccharide (TSP) has excellent ice crystal steady ability and has also been widely used in frozen foods. However, there is no study on the use of TSP in frozen dough. RESULTS: TSP can stabilize the bound water content, inhibit the freezable water content, and increase elasticity. However, the dough with different structures of TSP added was less firm after 30 days of freezing compared to the dough without TSP, and the porosity and stomatal density of the prepared steamed bread gradually decreased. The addition of TSP reduced gluten deterioration during the freezing process, thus decreasing the collapse and uneven porosity of the steamed bread. CONCLUSIONS: The results could provide new insights into the structure of TSP and its effect on the quality characteristics of frozen dough. © 2023 Society of Chemical Industry.
Assuntos
Tamarindus , Congelamento , Gelo , Água/química , Vapor , Polissacarídeos , Pão/análise , Sementes , Relação Estrutura-AtividadeRESUMO
A polysaccharide was extracted in high yield from tamarind (Tamarindus indica L.) seed (TSP) by acidic hot water extraction and ethanol precipitation. It was composed of 86.2% neutral polysaccharide, 5.4% uronic acid and 1.3% protein. The molecular weight of TSP was estimated to be about 1735 kDa, with glucose, xylose, and galactose in a molar ratio of 2.9:1.8:1.0 as the major monosaccharides. The steady shear and viscoelastic properties of TSP aqueous solutions were investigated by dynamic rheometry. Results revealed that TSP aqueous solution at a concentration above 0.5% (w/v) exhibited non-Newtonian shear-thinning behavior. Dynamic oscillatory analysis revealed that 10% (w/v) TSP showed as a "weak gel" structure. Apparent viscosities and viscoelastic parameters of TSP solutions decreased drastically in an alkaline solution of pH > 10, but slightly influenced by acidic solution, high temperature and the presence of salt ions and sucrose. These results indicated that TSP possessed excellent pH-resistance and thermo-stability, which might be suitable for applications in acidic beverages and high-temperature processed foodstuffs.
Assuntos
Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Reologia , Sementes/química , Tamarindus/química , Elasticidade , Concentração de Íons de Hidrogênio , Peso Molecular , Sais/farmacologia , Soluções , Espectroscopia de Infravermelho com Transformada de Fourier , Sacarose/farmacologia , Temperatura , ViscosidadeRESUMO
High pressure processing (HPP) juice often experiences cloud loss during storage, caused by the activity of pectin methylesterase (PME). The combination of HPP with natural pectin methylesterase inhibitor (PMEI) could improve juice stability. However, extracting natural PMEI is challenging. Gene recombination technology offers a solution by efficiently expressing recombinant PMEI from Escherichia coli and Pichia pastoris. Experimental and molecular dynamics simulation were conducted to investigate changes in activity, structure, and interaction of PME and recombinant PMEI during HPP. The results showed PME retained high residual activity, while PMEI demonstrated superior pressure resistance. Under HPP, PMEI's structure remained stable, while the N-terminus of PME's α-helix became unstable. Additionally, the helix at the junction with the PME/PMEI complex changed, thereby affecting its binding. Furthermore, PMEI competed with pectin for active sites on PME, elucidating. The potential mechanism of PME inactivation through the synergistic effects of HPP and PMEI.
Assuntos
Hidrolases de Éster Carboxílico , Proteínas de Plantas , Proteínas de Plantas/metabolismo , Hidrolases de Éster Carboxílico/metabolismo , Domínio Catalítico , AlimentosRESUMO
In this work, a zein-tamarind seed polysaccharide (TSP) co-delivery system was fabricated using an anti-solvent precipitation method. The formation mechanism, characterization, and effect on alleviating colitis and gut microbiota dysbiosis in mice of zein-TSP-curcumin (Z/T-Cur) nanocomplexes were investigated. Hydrogen bonding and the hydrophobic effect played a key role in the formation of Z/T-Cur nanocomplexes, and the interactions were spontaneous and driven by enthalpy. The encapsulation efficiency, loading capacity, and bioavailability increased from 60.8% (Zein-Cur) to 91.7% (Z/T-Cur1:1), from 6.1% (Zein-Cur) to 18.3% (Z/T-Cur1:1), and from 4.7% (Zein-Cur) to 20.0% (Z/T-Cur1:1), respectively. The Z/T-Cur significantly alleviated colitis symptoms in DSS-treated mice. Additionally, the prepared nanocomplexes rebalanced the gut microbiota composition of colitis mice by increasing the abundance of Akkermansia. Odoribacter and Monoglobus were rich in the Z-T-Cur treatment group, and Turicibacter and Bifidobacterium were rich in the zein-TSP treatment group. This study demonstrated that the TSP could be helpful in the targeted drug delivery system.
Assuntos
Colite , Curcumina , Microbioma Gastrointestinal , Nanopartículas , Tamarindus , Zeína , Animais , Camundongos , Curcumina/química , Zeína/química , Nanopartículas/química , Disbiose/tratamento farmacológico , Polissacarídeos , Colite/induzido quimicamente , Colite/tratamento farmacológico , Tamanho da PartículaRESUMO
The complex sample matrix poses significant challenges in accurately detecting heavy metals. In view of its superior performance for the biological adsorption of heavy metals, probiotic bacteria can be explored for functional unit to eliminate matrix interference. Herein, Lactobacillus rhamnosus (LGG) demonstrates a remarkable tolerance and can adsorb up to 300 µM of Hg2+, following the Freundlich isotherm model with the correlation coefficient (R2) value of 0.9881. Subsequently, by integrating the CRISPR/Cas12a system, a sensitive and specific fluorescent biosensor, "Cas12a-MB," has been developed for Hg2+ detection. Specifically, Hg2+ adsorbed onto LGG can specifically bind to the nucleic acid probe, thereby inhibiting the binding of the probe to LGG and the subsequent activation of the CRISPR/Cas12a system. Under optimal experimental conditions, with the detection time of 90 min and the detection limit of 0.44 nM, the "Cas12a-MB" biosensor offers a novel, eco-friendly approach for Hg2+ detection, showcasing the innovative application of probiotics in biosensor.
Assuntos
Técnicas Biossensoriais , Sistemas CRISPR-Cas , Lacticaseibacillus rhamnosus , Mercúrio , Probióticos , Mercúrio/análise , Mercúrio/química , Técnicas Biossensoriais/métodos , Probióticos/química , Lacticaseibacillus rhamnosus/isolamento & purificação , Lacticaseibacillus rhamnosus/genética , Adsorção , Limite de DetecçãoRESUMO
Phyllanthus emblica Linn. (PE) fresh fruits contain high concentrations of polyphenolics, of which free and bound phenolics are rich in biological activities. In this study, the inhibitory activity and mechanism of PEFP and PEBP on α-glucosidase (α-GLU) were investigated using spectroscopic techniques, kinetic analysis, and molecular docking. The results showed that 13 PEFP and 12 PEBP were identified by UPLC-MS/MS analysis, and Bis-HHDP-hexose and castalagin (vesgalagin) were found for the first time in PE fresh fruits. Kinetic analysis of enzyme inhibition showed that a mixture of free and bound phenolics inhibited α-GLU, and the effect of the conformational relationship of PEFP and PEBP with α-GLU on hypoglycemia was further explored by fluorescence quenching, circular dichroism (CD) spectroscopy, and molecular docking analysis. The findings demonstrated the inhibitory activity and mechanism of free and bound phenolics on α-GLU and provided a theoretical basis for PE polyphenolics as α-GLU inhibitors for hypoglycemia.
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Frutas , Inibidores de Glicosídeo Hidrolases , Fenóis , Phyllanthus emblica , Extratos Vegetais , alfa-Glucosidases , alfa-Glucosidases/química , alfa-Glucosidases/metabolismo , Dicroísmo Circular , Frutas/química , Inibidores de Glicosídeo Hidrolases/química , Inibidores de Glicosídeo Hidrolases/farmacologia , Cinética , Simulação de Acoplamento Molecular , Fenóis/química , Fenóis/farmacologia , Phyllanthus emblica/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Polifenóis/química , Polifenóis/farmacologia , Espectrometria de Massas em TandemRESUMO
Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma, and the role of SYK in its pathogenesis is not completely understood. Using tissue microarray, we demonstrated for the first time that SYK protein is activated in 27 of 61 (44%) primary human DLBCL tissues. Among DLBCL cell lines, 7 were sensitive and 3 were resistant to a highly specific SYK inhibitor, PRT060318. In sensitive DLBCL cells, SYK inhibition blocked the G(1)-S transition and caused cell-cycle arrest. This effect was reproduced by genetic reduction of SYK using siRNA. A detailed analysis of the BCR signaling pathways revealed that the consequence of SYK inhibition on PLCγ2 and AKT, as opposed to ERK1/2, was responsible for cell-cycle arrest. Genetic knock-down of these key molecules decelerated the proliferation of lymphoma cells. In addition, BCR signaling can be blocked by PRT060318 in primary lymphoma cells. Together, these findings provide insights into cellular pathways required for lymphoma cell growth and support the rationale for considering SYK inhibition as a potentially useful therapy for DLBCL. The results further suggest the possibility of using PLCγ2 and AKT as biomarkers to predict therapeutic response in prospective clinical trials of specific SYK inhibitors.
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Antineoplásicos/farmacologia , Resistencia a Medicamentos Antineoplásicos , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Proteínas de Neoplasias/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Proteínas Tirosina Quinases/antagonistas & inibidores , Biomarcadores/metabolismo , Linhagem Celular Tumoral , Fase G1/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Linfonodos/efeitos dos fármacos , Linfonodos/metabolismo , Linfonodos/patologia , Linfoma Difuso de Grandes Células B/metabolismo , Linfoma Difuso de Grandes Células B/patologia , Terapia de Alvo Molecular , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Fosfolipase C gama/antagonistas & inibidores , Fosfolipase C gama/genética , Fosfolipase C gama/metabolismo , Fosforilação/efeitos dos fármacos , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Proteínas Tirosina Quinases/genética , Proteínas Tirosina Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Interferência de RNA , RNA Mensageiro/metabolismo , RNA Interferente Pequeno , Transdução de Sinais/efeitos dos fármacos , Quinase Syk , Células Tumorais CultivadasRESUMO
Two hydrolyzed fractions of tamarind seed polysaccharide (TSP), denoted ETSP1 (176.68 kDa) and ETSP2 (34.34 kDa), were prepared by partial degradation via endo-xyloglucanase, and then characterized and evaluated by simulated gastrointestinal digestion in vitro. The results showed that the hydrolyzed TSPs remained indigestible in gastric and small intestinal media, and were fermented by gut microbiota, similar to the native TSP (Mw = 481.52 kDa). Although the degradation of hydrolyzed TSPs was accelerated during fermentation with a decreasing degree of polymerization, the content of produced total short-chain fatty acids (SCFAs) decreased. After fermentation, the gut microbiota composition was modified, esp. the Firmicutes/Bacteroidetes ratio decreased (1.06 vs. 0.96 vs. 0.80) with a decreasing degree of polymerization, which implied that the potential anti-obesity prebiotic effect was enhanced. At the genus level, hydrolyzed TSPs maintained similar roles as native TSP, including promoting beneficial bacteria (Bifidobacterium, Parabacteroides, and Faecalibacterium) and inhibiting enteropathogenic bacteria (Escherichia-Shigella and Dorea). Moreover, ETSP1 had additional potential due to abundant Bacteroides vulgatus (LDA = 4.68), and ETSP2 might perform better as related to Bacteroides xylanisolvens (LDA = 4.40). All these results indicated the prebiotic potential of hydrolyzed TSP with detailed information about changes in degradation and gut microbiota based on enzyme-hydrolysis.
Assuntos
Microbioma Gastrointestinal , Tamarindus , Digestão , Polissacarídeos/farmacologia , Sementes/metabolismo , Ácidos Graxos Voláteis/metabolismo , Fermentação , PrebióticosRESUMO
This study aimed to investigate the inhibition effects of tamarind seed polysaccharide (TSP) on ice recrystallization and to figure out its possible molecular weight-dependent effects. TSP fractions (2412.38-20.75 kDa) were prepared while preserving the natural structure. Ice recrystallization was effectively inhibited by TSP. Decreasing the molecular weight to a certain range, such as 224.04 kDa and 90.41 kDa, could enhance the activity of TSP due to the reduction of self- and intermolecular aggregation. Adding TSP into water decreased the melting temperature of bulk ice. Raman spectra showed that partial group vibrations or deformations of TSP molecules were restricted upon solution freezing and also revealed a destructuring effect of TSP on the H-bond network of water. These findings suggested the potential of TSP as a novel food cryoprotectant and help produce TSP fractions with enhanced activity, and shed new light on understanding the antifreeze mechanism of natural polysaccharides.
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Tamarindus , Gelo , Peso Molecular , Sementes , Polissacarídeos/farmacologia , Carboidratos da Dieta , Água , CrioprotetoresRESUMO
Octenyl succinic anhydride modified tamarind seed polysaccharides (OTSPs) with various degrees of substitution were first synthesized and characterized in this work. The structural, solid-state, solution and emulsifying properties of the OTSPs and the effect of the degree of substitution (DS) were investigated. The structural characterization confirmed the successful grafting of the OSA moiety into TSP and the chain extension of the OTSPs. The hydrophobicity of the modified polysaccharide molecules increased, the absolute value of the zeta potential increased, and the thermal stability decreased, which were positively or negatively correlated with the changes in DS. In contrast, the hydrolysis of polysaccharides in alkaline aqueous solution led to a decrease in molar mass and the rigidity of the molecules, which were not significantly related to DS. Particle size analysis showed that OTSPs tended to aggregate into relatively small agglomerates, which was confirmed by the results of morphological analysis. Most importantly, the instability indices of emulsions stabilized by TSP, arabic gum and OSA-starch were 0.521, 0.715, and 0.804, respectively, while for OTSPs this parameter was between 0.04 and 0.19 under the same conditions, indicating better physical stability of the OTSP-stabilized emulsions, especially for OTSP-30. Overall, OTSP has great potential as an emulsifier for oil-in-water emulsions, especially for emulsification and stabilization in food processing.
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Tamarindus , Emulsões/química , Emulsificantes/química , Amido/química , Esterificação , Tamanho da Partícula , Anidridos Succínicos/químicaRESUMO
Polysaccharides are becoming potential candidates for developing food-grade cryoprotectants due to their extensive accessibility and health-promoting effects. However, unremarkable ice recrystallization inhibition (IRI) activity and high viscosity limit their practical applications in some systems. Our previous study found a galactoxyloglucan polysaccharide from tamarind seed (TSP) showing moderate IRI activity. Herein, the enhancement of the IRI performance of TSP via enzymatic depolymerization and degalactosylation-induced self-assembly was reported. TSP was depolymerized and subsequently removed â¼40 % Gal, which induced the formation of supramolecular rod-like fiber self-assembles and exhibited a severalfold enhancement of IRI. Ice shaping assay did not show obvious faceting of ice crystals, indicating that both depolymerized and self-assembled TSP showed very weak binding to ice. Molecular dynamics simulation confirmed the absence of molecular complementarity with ice. Further, it highlighted that degalactosylation did not cause significant changes in local hydration properties of TSP from the view of a single oligomer. The inconsistency between molecular simulation and macroscopic IRI effect proposed that the formation of unique supramolecular self-assemblies may be a key requirement for enhancing IRI activity. The findings of this study provided a new opportunity to enhance the applied potential of natural polysaccharides in food cryoprotection.
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Gelo , Tamarindus , Gelo/análise , Tamarindus/química , Cristalização , Polissacarídeos/química , Sementes/químicaRESUMO
Acetylation modification was conducted to improve the water-solubility and solution properties of xyloglucan from tamarind seeds (TSX). Three acetylated TSX with different degree of substitution (DS) were successfully prepared, and their structure and molecular parameters were investigated by FT-IR, NMR, and high-performance size exclusion chromatography (HPSEC). Further, the effects of acetylation on the thermal stability, solubility, and rheological properties of TSX were studied. Results showed that acetyl groups were mainly substituted at the O-6 position of terminal galactose with DS of 0.2, 0.47, and 0.36 for AC-2, AC-5, and AC-10, respectively. HPSEC analysis indicated that molecular weight of acetylated derivatives decreased slightly, and the solution conformation became more flexible as the DS increase. By comparing with TSX, the thermal stability, water-solubility, solution transmittance, and ζ-potential of acetylated TSX were significantly improved as the DS increase. In addition, rheological studies demonstrated that acetylation reduced the shear viscosity, but high DS of acetylation could induce the weak gelling property of TSX. In conclusion, acetylation modification could be applied to improve the physicochemical properties of TSX and promote its further application in food and pharmaceutical industries.
Assuntos
Sementes , Água , Espectroscopia de Infravermelho com Transformada de Fourier , Sementes/química , Acetilação , Viscosidade , Água/análiseRESUMO
Many studies have indicated that an entropy model can capture the dynamic characteristics of resting-state functional magnetic resonance imaging (rfMRI) signals. However, there are problems of subjectivity and lack of uniform standards in the selection of model parameters relying on experience when using the entropy model to analyze rfMRI. To address this issue, an optimized multiscale entropy (MSE) model was proposed to confirm the parameters objectively. All healthy elderly volunteers were divided into two groups, namely, excellent and poor, by the scores estimated through traditional scale tests before the rfMRI scan. The parameters of the MSE model were optimized with the help of sensitivity parameters such as receiver operating characteristic (ROC) and area under the ROC curve (AUC) in a comparison study between the two groups. The brain regions with significant differences in entropy values were considered biomarkers. Their entropy values were regarded as feature vectors to use as input for the probabilistic neural network in the classification of cognitive scores. Classification accuracy of 80.05% was obtained using machine learning. These results show that the optimized MSE model can accurately select the brain regions sensitive to cognitive performance and objectively select fixed parameters for MSE. This work was expected to provide the basis for entropy to test the cognitive scores of the healthy elderly.
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Encéfalo , Imageamento por Ressonância Magnética , Idoso , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico/métodos , Cognição , Entropia , Humanos , Imageamento por Ressonância Magnética/métodosRESUMO
The role of molecular aggregation was investigated on physicochemical and macromolecular properties of tamarind kernel polysaccharides via partial degalactosylation (TKPs vs. CTKPs). From the results, their main structural characteristics remained when partially degalactosylated, while primary aggregates as fundamental solution behavior were dynamically converted into higher aggregated forms. Micromorphologically, their conformational changes in different forms of crimping and aggregation could be further promoted by partial Gal removal to assemble on larger scales via hydrophobic interactions. Obviously, the aggregation role was unignorable, especially after partial degalactosylation, which affected TKPs and CTKPs differently concerning viscous behaviors, macromolecular characteristics, amorphous-crystalline transition and thermal stability, probably related to distinctiveness in polymerization degree, chemical structure, conformational entropy, solvent-solute interactions, specific intermolecular associations, etc. Therefore, molecular aggregation in tamarind kernel polysaccharides via specific Gal tailoring could be potential in applicable fields, such as postsurgical adhesion, packaging material design and plasma lipid metabolism.
RESUMO
A polysaccharide from tamarind seeds (TSP) was characterized in terms of backbone and side chain structural features, as well as conformational property using methylation and GC-MS analysis, 2D NMR, MALDI-TOF MS, and high performance size exclusion chromatography (HPSEC). Results showed that TSP was a galactoxyloglucan (GXG) consisting of glucose, xylose, and galactose in a molar ratio of 3.1: 1.7: 1.0. The Mw was determined to be 524.0 kDa with radius of gyration (Rg) of 55.6 nm. The chemical structure was confirmed as a classical ß-(1 â 4)-glucan with short side chains of T-ß-Galp-(1 â 2)-α-Xylp-(1 â and T-α-Xylp-(1 â attached to O-6 position of glucose. MALDI-TOF MS analysis indicated that TSP mainly composed of nonasaccharide (XLLG) and octasaccharide (XLXG or XXLG) blocks in periodic or interrupted sequence in a ratio of 3: 2, occasionally interrupted by heptasaccharide (XXXG), hexasaccharide (XLG or XXGG), or even hendesaccharide blocks. Conformational study indicated that TSP was in a random-coil shape with relative extended stiff chain in aqueous solution. This study provided more evidences to make an amendment to the fine structure of tamarind GXG.
Assuntos
Galactose/química , Glucanos/química , Sementes/química , Tamarindus/química , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Galactose/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Glucanos/metabolismo , Glicosídeo Hidrolases/metabolismo , Hidrólise , Metilação , Conformação Molecular , Peso Molecular , Monossacarídeos/análise , Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Espectroscopia de Prótons por Ressonância Magnética , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
A polysaccharide (PFPP) from purple passion fruit peel was optimally extracted, with the highest yield (10.05%, w/w) obtained under 35⯰C extraction temperature, 240â¯W ultrasonic power, 65:1â¯mL/g liquid-to-solid ratio, 0.6% (w/v) ammonium oxalate, 30â¯min extraction time and pH 2.0. According to composition analyses, pectic PFPP and its fractions (PFPP-10, -15 and -20) were revealed as linear homogalacturonans interrupted by rhamnogalacturonan I in different lengths and extensities, where low esterification degrees (35.35-39.66%) were indicated via FT-IR. Furthermore, based on macromolecular models, comprehensive analyses on macromolecular and conformational characterizations of PFPP fractions were conducted quantitatively through, e.g., shape factor (1.42-1.79), Mark-Houwink-Sakurada exponent (0.55-0.74), conformational power-law exponent (0.52-0.58), fractal dimension (1.72-1.94) and persistence length (6.73-13.47â¯nm). Therefore, different semi-flexible coil conformations were proposed schematically, where lower molecular-weight PFPP fractions were less flexible. This could provide a molecular basis for precise re-utilizations of PFPP in food and pharmaceutical industries.
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Tamarind (Tamarindus indica L.) seed polysaccharide (TSP) is widely used due to its excellent physico-chemical and biological properties. In this study, therefore, the dynamic digestion and fermentation of TSP in vitro were evaluated with the effect on gut microbiota composition estimated by high-throughput sequencing. The results of gastric and small intestinal digestions showed the molecular weight of TSP kept stable with only small production of reducing sugar. During the fermentation, however, the total carbohydrate kept decreasing and short-chain fatty acids (SCFAs) maintained growing. Compared to the control (distilled water), the contents of total and non-branched SCFAs were higher after fermentation, esp. propionic and butyric acids, and the gut microbiota composition was also modified with inhibited enteropathogenic (genera Escherichia-Shigell and Dorea) and promoted beneficial (genera Lactobacillus, Parabacteroides, Prevotella and Faecalibacterium) bacteria, suggesting TSP has potential prebiotic functions including anti-obesity and anti-inflammation, as well as maintaining intestinal epithelial barrier.
Assuntos
Microbioma Gastrointestinal/fisiologia , Trato Gastrointestinal/metabolismo , Trato Gastrointestinal/microbiologia , Polissacarídeos/metabolismo , Sementes/química , Sementes/metabolismo , Tamarindus/química , Microbioma Gastrointestinal/efeitos dos fármacos , Trato Gastrointestinal/efeitos dos fármacos , Intestino Delgado/efeitos dos fármacos , Intestino Delgado/metabolismo , Intestino Delgado/microbiologia , Polissacarídeos/química , Polissacarídeos/farmacologiaRESUMO
In this study, an ultrasonic-extracted polysaccharide (nCPTP-55) was obtained with the highest yield (61.08%, w/w) from tamarind pulp, which consisted chiefly of total sugar (85.98%, w/w) with few protein (2.10%, w/w). Monosaccharide analysis showed nCPTP-55 was mainly composed of arabinose (39.19 mol%) and glucose (50.48 mol%) with negligible GlcA (2.05 mol%), indicating the neutral nature of nCPTP-55, which was further elucidated structurally via GC-MS and NMR, i.e., an arabinoglucan composed of â3)-ß-D-Glcp-(1â backbone with only T-α-L-Araf-(1â branched at O-4 (27.82%) and O-6 (39.99%), resulting in relatively high A/G ratio (0.68-0.70). Based on MM2 minimized energy, the 3D schematic structures of nCPTP-55 could be considered as structural basis for its conformational behavior, which was preliminarily estimated via HPSEC-MALLS as between compact sphere and loosely hyper-branched chain (ρ = 0.84). Therefore, the relationship between molecular structure and conformational behavior was basically established for nCPTP-55, which was in a bid to have a better knowledge of its structure-property and structure-bioactivity relationships potentially required for more applications in food, cosmetic and pharmaceutical fields.
Assuntos
Mucoproteínas/química , Polissacarídeos/química , Relação Estrutura-Atividade , Tamarindus/química , Arabinose/química , Estrutura Molecular , Monossacarídeos/química , Mucoproteínas/isolamento & purificação , Mucoproteínas/ultraestrutura , Proteínas de Plantas/química , Proteínas de Plantas/isolamento & purificação , Proteínas de Plantas/ultraestrutura , Polissacarídeos/isolamento & purificação , Polissacarídeos/ultraestrutura , Açúcares/química , Tamarindus/efeitos da radiação , UltrassomRESUMO
A ß-glucan was extracted from hull-less barley (HBBG) and its effects on the solution properties and in vitro digestion of corn starch (CS) were studied. Rheological results showed that HBBG diminished the gelling ability and increased the apparent viscosity of CS solution. The critical concentration was lowered from 1.10% (CS) to 0.48% (CS/HBBG mixture), and the slow relaxation component T22 decreased from 1417.47 to 464.16â¯ms after the incorporation of HBBG to CS solution. In vitro digestion study indicated that HBBG significantly increased the apparent viscosity of digesta and inhibited the starch hydrolysis and glucose diffusion. The entanglement and overlap formed by HBBG and CS interaction and aggregates of HBBG itself were considered to enhance the viscosity, thus limiting the water mobility of the system, reducing the contact of digestive enzyme with starch and diffusion of glucose to the small intestinal microvilli. This study suggests that HBBG can be recognized as an important ingredient in starch food to reduce postprandial glycemic responses.