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1.
J Appl Oral Sci ; 28: e20190501, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32236356

RESUMO

INTRODUCTION: The acquired pellicle formation is the first step in dental biofilm formation. It distinguishes dental biofilms from other biofilm types. OBJECTIVE: To explore the influence of salivary pellicle formation before biofilm formation on enamel demineralization. METHODOLOGY: Saliva collection was approved by Indiana University IRB. Three donors provided wax-stimulated saliva as the microcosm bacterial inoculum source. Acquired pellicle was formed on bovine enamel samples. Two groups (0.5% and 1% sucrose-supplemented growth media) with three subgroups (surface conditioning using filtered/pasteurized saliva; filtered saliva; and deionized water (DIW)) were included (n=9/subgroup). Biofilm was then allowed to grow for 48 h using Brain Heart Infusion media supplemented with 5 g/l yeast extract, 1 mM CaCl2.2H2O, 5% vitamin K and hemin (v/v), and sucrose. Enamel samples were analyzed for Vickers surface microhardness change (VHNchange), and transverse microradiography measuring lesion depth (L) and mineral loss (∆Z). Data were analyzed using two-way ANOVA. RESULTS: The two-way interaction of sucrose concentration × surface conditioning was not significant for VHNchange (p=0.872), ∆Z (p=0.662) or L (p=0.436). Surface conditioning affected VHNchange (p=0.0079), while sucrose concentration impacted ∆Z (p<0.0001) and L (p<0.0001). Surface conditioning with filtered/pasteurized saliva resulted in the lowest VHNchange values for both sucrose concentrations. The differences between filtered/pasteurized subgroups and the two other surface conditionings were significant (filtered saliva p=0.006; DIW p=0.0075). Growing the biofilm in 1% sucrose resulted in lesions with higher ∆Z and L values when compared with 0.5% sucrose. The differences in ∆Z and L between sucrose concentration subgroups was significant, regardless of surface conditioning (both p<0.0001). CONCLUSION: Within the study limitations, surface conditioning using human saliva does not influence biofilm-mediated enamel caries lesion formation as measured by transverse microradiography, while differences were observed using surface microhardness, indicating a complex interaction between pellicle proteins and biofilm-mediated demineralization of the enamel surface.


Assuntos
Biofilmes/crescimento & desenvolvimento , Esmalte Dentário/microbiologia , Saliva/química , Sacarose/química , Desmineralização do Dente/microbiologia , Animais , Bovinos , Esmalte Dentário/química , Película Dentária/microbiologia , Dureza , Microrradiografia/métodos , Pasteurização , Valores de Referência , Saliva/microbiologia , Sacarose/análise , Propriedades de Superfície
2.
Life Sci ; 250: 117545, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32173313

RESUMO

AIMS: Chronic stress leads to the development of male sexual problems such as ejaculatory dysfunctions. The rhythmic contractions of vas deferens (VD) play an important role on the ejaculatory process. In the current study, we investigated whether infliximab (IFX) treatment has any beneficial effects on possible alterations in contractility of VD obtained from rats exposed to unpredictable chronic mild stress (UCMS). MATERIALS AND METHODS: The rats were randomly divided into four groups: control, control+IFX, UCMS and UCMS+IFX. IFX (5 mg/kg/week, i.p.) was administrated for 5 weeks during UCMS period. Depressive like-behaviors were evaluated using locomotor activity, forced swimming and sucrose consumption and preference tests. The blood was collected for serum biochemical determinations. VD tissues were harvested for functional studies and, measurements of oxidative stress, inflammatory and apoptotic biomarkers. KEY FINDINGS: We observed increased serum concentration of corticosterone and depressive-like behaviors in rats exposed to UCMS. In VD tissues of UCMS-exposed rats, noradrenaline- and adenosine triphosphate (ATP)-induced contractile responses significantly enhanced and electrical field stimulation (EFS)-induced contractile responses markedly decreased. UCMS exposure induced inflammation, oxidative stress and apoptosis in VD. However, IFX treatment significantly improved all the aforementioned parameters. SIGNIFICANCE: The results of the present study revealed that chronic stress-induced depression caused VD dysfunction by promoting inflammation and oxidative stress in VD. IFX protected against VD dysfunction through its anti-inflammatory and antioxidant effects.


Assuntos
Infliximab/farmacologia , Estresse Oxidativo , Estresse Fisiológico , Ducto Deferente/efeitos dos fármacos , Animais , Anti-Inflamatórios/farmacologia , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Corticosterona/sangue , Depressão/tratamento farmacológico , Relação Dose-Resposta a Droga , Ejaculação/efeitos dos fármacos , Campos Eletromagnéticos , Glutationa/metabolismo , Inflamação/sangue , Peroxidação de Lipídeos , Masculino , Norepinefrina/metabolismo , Ratos , Ratos Wistar , Sacarose/química , Superóxido Dismutase/metabolismo
3.
Food Chem ; 318: 126467, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32145542

RESUMO

This study aims to investigate in depth the mechanism of acrylamide formation in coffee during roasting. For this purpose, a comprehensive kinetic model including the elementary steps for acrylamide formation was proposed. The changes in sucrose, reducing sugars, free amino acids, asparagine, acrylamide, 3-deoxyglucosone, methylglyoxal, glyoxal, and 5-hydroxymethylfurfural were monitored in coffee during roasting at 200, 220 and 240 °C. Dominant pathways of complex reactions leading to acrylamide were unravelled by means of multiresponse kinetic modelling approach. The results of the model indicated that sucrose degrades into glucose and a reactive fructofuranosyl cation. Interestingly, glucose takes part mostly in the formation of intermediates, glyoxal and especially 3-deoxyglucosone rather than acrylamide formation. On the other hand, fructofuranosyl cation contributed mostly to the formation of 5-hydroxymethylfurfural which was found to be the most important intermediate precursor of acrylamide formed in coffee during roasting.


Assuntos
Acrilamida/química , Café/química , Furaldeído/análogos & derivados , Aminoácidos/química , Desoxiglucose/análogos & derivados , Desoxiglucose/química , Indústria de Processamento de Alimentos/métodos , Furaldeído/química , Glucose/química , Glioxal/química , Temperatura Alta , Cinética , Aldeído Pirúvico/química , Sacarose/química
4.
Enzyme Microb Technol ; 132: 109412, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31731958

RESUMO

Transglycosylation is one of enzymatic methods to improve the physical and biochemical properties of various functional compounds. In this study, stevioside glucosides were synthesized using sucrose as a substrate, stevioside (Ste) as an acceptor, and dextransucrase from Leuconostoc mesenteroides B-512 F/KM. The highest Ste conversion yield of 98% was obtained with 50 mg/mL Ste, 800 mM sucrose, and dextransucrase 4 U/mL at 28 °C for 6 h. The concentration of Ste was unchanged while of Ste-G1 was increased from 7.7 mM to 9.1 mM as the Ste acceptor reaction digest was treated with dextranase from Lipomyces starkeyi. Ste-G1 (13-O-ß-sophorosyl-19-O-ß-isomaltosyl-steviol), Ste-G2 (13-O-(ß-(1→6) glucosyl)-ß-glucosylsophorosyl-19-O-ß-isomaltosyl-steviol), and Ste-G2' (13-O-ß-sophorosyl-19-O-ß-isomaltotriosyl-steviol) were determined by NMR. These glucosylated Ste showed increased stabilities at pH 2, 60 °C for 48 h as compared to Ste. Ste-G1, Ste-G2, and Ste-G2' inhibited the insoluble glucan synthesis from sucrose by mutansucrase from Streptococcus muntans by the transfer of the glucosyl group of sucrose to Ste-G1, Ste-G2, and Ste-G2'. The relative water solubility of curcumin, pterostilbene or idebenone was increased by Ste or Ste glucosides treatment. Ste and Ste-G1 restored cell viability in RAW264.7 cells at concentrations up to 8 mg/mL and inhibited nitric oxide production in LPS-induced RAW264.7 cells with IC50 of 3.29 and 1.87 mg/mL.


Assuntos
Dextranase/metabolismo , Diterpenos de Caurano/química , Glucosídeos/química , Glucosiltransferases/metabolismo , Sacarose/química , Edulcorantes/química , Leuconostoc mesenteroides/enzimologia , Espectroscopia de Ressonância Magnética , Polimerização , Solubilidade
5.
Biosci Biotechnol Biochem ; 84(1): 17-24, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31566084

RESUMO

Human milk oligosaccharides (HMOs) have drawn attention for their contribution to the explosive bifidobacterial growth in the intestines of neonates. We found that bifidobacteria can efficiently metabolize lacto-N-biose I (LNB), the major building blocks of HMOs, and we have developed a method to synthesize LNB by applying this system. We produced LNB on a kilogram scale by the method. This proved that, among the enterobacteria, only bifidobacteria can assimilate LNB, and provided the data that supported the explosive growth of bifidobacteria in neonates. Furthermore, we were also able to reveal the structure of LNB crystal and the low stability for heating at neutral pH, which has not been clarified so far. In this paper, using bifidobacteria and LNB as examples, I describe the research on oligosaccharide synthesis that was conducted by utilizing a sugar metabolism.Abbreviations: LNB: lacto-N-biose I; GNB: galacto-N-biose; HMOs: human milk oligosaccharides; GLNBP: GNB/LNB phosphorylase; NahK: N-acetylhexosamine 1-kinase; GalT: UDP-glucose-hexose-1-phosphate uridylyltransferase; GalE: UDP-glucose 4-epimerase; SP: sucrose phosphorylase.


Assuntos
Acetilglucosamina/análogos & derivados , Bifidobacterium/metabolismo , Glucosiltransferases/química , Leite Humano/química , Oligossacarídeos/metabolismo , Sacarose/química , Acetilglucosamina/síntese química , Acetilglucosamina/química , Acetilglucosamina/metabolismo , Resinas de Troca de Ânions/química , Bifidobacterium/crescimento & desenvolvimento , Cristalização , Dissacaridases/metabolismo , Microbioma Gastrointestinal/fisiologia , Temperatura Alta , Humanos , Concentração de Íons de Hidrogênio , Recém-Nascido
6.
Colloids Surf B Biointerfaces ; 185: 110600, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31704608

RESUMO

In this communication, fenugreek ß-amylase was immobilized onto functionalized tungsten disulfide nanoparticles through cross-linker glutaraldehyde and successful immobilization was confirmed by SEM, AFM and FTIR spectroscopy. To make the process economical and efficient, optimization of independent variables was carried out using Box-Behnken design of response surface methodology. Approximately similar predicted (85.6%) and experimental (84.2%) immobilization efficiency revealed that the model is suitable for design of space. Optimum temperature was calculated to be 60 °C. After immobilization, an increased Km (2.12 times) and a decreased Vmax (0.58 times), indicated inaccessibility of active site residues to the substrate. The immobilized enzyme retained 77% relative activity after 10 uses whereas 40% residual activity was obtained after 120 days. An increased half-life with concomitantly decreased kinetic rate constant revealed that the immobilized enzyme is more stable at a higher temperature and the process followed first-order kinetics (R2 > 0.93). The limit of detection for maltose and sucrose fluorescence biosensor was found to be 0.052 and 0.096 mM, respectively. Thermodynamic parameters such as changes in Gibbs free energy (ΔG < 0), enthalpy (ΔH > 0) and entropy (ΔS >0) revealed that the process is spontaneous and endothermic, driven by hydrophobic interactions. Thermo-stability data at higher temperature for the immobilized enzyme makes it a suitable candidate for industrial applications in the production of maltose in food and pharmaceutical industries. Furthermore, fluorescence biosensor could be used to detect and quantify maltose and sucrose to maintain the quality of industrial products.


Assuntos
Dissulfetos/química , Enzimas Imobilizadas/metabolismo , Maltose/metabolismo , Nanopartículas/química , Sacarose/metabolismo , Trigonella/enzimologia , Compostos de Tungstênio/química , beta-Amilase/metabolismo , Estabilidade Enzimática , Enzimas Imobilizadas/química , Concentração de Íons de Hidrogênio , Cinética , Maltose/química , Sacarose/química , Temperatura , Termodinâmica , beta-Amilase/química
7.
J Dairy Res ; 86(4): 477-482, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31823833

RESUMO

The work described in this Research Communication concerns the production of Dulce de leche (DL), that is a traditional product from South America obtained by concentration. Maillard reaction (MR) products are mainly responsible for the formation of color and flavor in this product. Lactose-hydrolyzed products have been developed to supply consumer demand, but this hydrolysis may affect the flavor, color, taste, texture and even some nutritional aspects of the product. We studied the influence of different levels of lactose-hydrolysis, sucrose addition and initial pH on the development of MR, appraised by the determination of 5-hydroxymethylfurfural (HMF). A process simulator with multi-monitoring system was used to produce 15 DL. Box-Behnken 33 experimental design was applied for the three factors: pH, lactose-hydrolysis level and sucrose concentration. Lipids, protein, ashes, carbohydrates, water activity, dissolved solids, colorimetric analysis and HMF (free and total) are among the physicochemical attributes and MR indicators analyzed in this work. The products showed significant differences in composition but all the values were in agreement with the literature. Moreover, higher levels of lactose hydrolysis and higher pH presented a direct relation with the development of MR, observed by an increase in coloration (lower luminosity) and more formation of HMF, both free and total. The present study expands the knowledge about DL spread made of lactose-hydrolyzed milk, allowing the food industries to produce a lactose free DL with nutritional and sensory characteristics closer to the traditional product.


Assuntos
Furaldeído/análogos & derivados , Lactose/química , Leite/química , Animais , Fenômenos Químicos , Cor , Manipulação de Alimentos/métodos , Furaldeído/química , Concentração de Íons de Hidrogênio , Hidrólise , Reação de Maillard , América do Sul , Sacarose/análise , Sacarose/química , Paladar
8.
Pharm Res ; 37(1): 14, 2019 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-31873808

RESUMO

PURPOSE: The aim of this study is to determine the effects of saccharide-containing excipients on the surface composition of spray-dried protein formulations and their matrix heterogeneity. METHODS: Spray-dried formulations of myoglobin or bovine serum albumin (BSA) were prepared without excipient or with sucrose, trehalose, or dextrans. Samples were characterized by solid-state Fourier-transform infrared spectroscopy (ssFTIR), differential scanning calorimetry (DSC), size exclusion chromatography (SEC) and scanning electron microscopy (SEM). Protein surface coverage was determined by X-ray photoelectron spectroscopy (XPS), while conformational differences were determined by solid-state hydrogen/deuterium exchange with mass spectrometry (ssHDX-MS). RESULTS: Structural differences were exhibited with the inclusion of different excipients, with dextran formulations indicating perturbation of secondary structure. XPS indicated sucrose and trehalose reduced protein surface concentration better than dextran-containing formulations. Using ssHDX-MS, the amount of deuterium incorporation and populations present were the largest in the samples processed with dextrans. Linear correlation was found between protein surface coverage and ssHDX-MS peak area (R2 = 0.853) for all formulations with saccharide-containing excipients. CONCLUSIONS: Lower molecular weight species of saccharides tend to enrich the particle surface and reduce protein concentration at the air-liquid interface, resulting in reduced population heterogeneity and improved physical stability, as identified by ssHDX-MS.


Assuntos
Excipientes/química , Mioglobina/química , Soroalbumina Bovina/química , Química Farmacêutica/métodos , Dessecação/métodos , Deutério/química , Dextranos/química , Espectrometria de Massas/métodos , Sacarose/química , Propriedades de Superfície , Trealose/química
9.
Int J Mol Sci ; 21(1)2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31877648

RESUMO

Given its potential role in the synthesis of novel prebiotics and applications in the pharmaceutical industry, a strong interest has developed in the enzyme levansucrase (LSC, EC 2.4.1.10). LSC catalyzes both the hydrolysis of sucrose (or sucroselike substrates) and the transfructosylation of a wide range of acceptors. LSC from the Gram-negative bacterium Erwinia tasmaniensis (EtLSC) is an interesting biocatalyst due to its high-yield production of fructooligosaccharides (FOSs). In order to learn more about the process of chain elongation, we obtained the crystal structure of EtLSC in complex with levanbiose (LBS). LBS is an FOS intermediate formed during the synthesis of longer-chain FOSs and levan. Analysis of the LBS binding pocket revealed that its structure was conserved in several related species. The binding pocket discovered in this crystal structure is an ideal target for future mutagenesis studies in order to understand its biological relevance and to engineer LSCs into tailored products.


Assuntos
Proteínas de Bactérias/metabolismo , Dissacarídeos/metabolismo , Erwinia/metabolismo , Frutanos/metabolismo , Hexosiltransferases/metabolismo , Proteínas de Bactérias/química , Sítios de Ligação , Cristalização , Cristalografia por Raios X , Erwinia/química , Hexosiltransferases/química , Modelos Moleculares , Oligossacarídeos/metabolismo , Conformação Proteica , Sacarose/química
10.
Carbohydr Res ; 486: 107783, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31669569

RESUMO

For the first time, oxidized sucrose (oxysucrose) was used as a hydrophilic crosslinking reagent instead of conventional anti-crease reagents for cotton fabrics. In this research, the partial oxidization of sucrose with sodium periodate generated multiple aldehydes, which acted as multifunctional cross-linkers and endowed cotton fabrics with anti-crease and hydrophilic function. The results showed that the oxysucrose-treated cotton fabrics obtained the maximum crease recovery angle of 245°, durable press rating of 3.0, and whiteness index of 82.8. Importantly, the oxysucrose-treated samples showed better hydrophilicity that overcomes the hydrophobization deficiency of anti-creased cotton fabrics treated with previously reported dimethylol dihydroxy ethylene urea (DMDHEU), glutaraldehyde (GA), and 1, 2, 3, 4,-butanetetracarboxylic acid (BTCA). The etherification reaction between the aldehyde group of oxysucrose and the hydroxyl group of cellulose was investigated and the possible crosslinking and anti-crease mechanism was proposed.


Assuntos
Aldeídos/química , Fibra de Algodão/análise , Interações Hidrofóbicas e Hidrofílicas , Fenômenos Mecânicos , Sacarose/química , Indicadores e Reagentes/química
11.
Molecules ; 24(21)2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31694205

RESUMO

Leuconostoc lactis CCK940, which exhibits glycosyltransferase activity, produces oligosaccharides using sucrose and maltose as donor and receptor molecules, respectively. The oligosaccharides produced were purified by Bio-gel P2 chromatography and the purified oligosaccharides (CCK-oligosaccharides) consisted of only glucose. 1H-NMR analysis revealed that the CCK-oligosaccharides were composed of 77.6% α-1,6 and 22.4% α-1,4 glycosidic linkages, and the molecular weight of the CCK-oligosaccharides was found to be 9.42 × 102 Da. To determine the prebiotic effect of the CCK-oligosaccharides, various carbon sources were added in modified media. Growth of six probiotic strains, Lactobacillus casei, L. pentosus, L. plantarum, Weissella cibaria, Bifidobacterim animalis, and Saccharomyces cerevisiae, was better when the CCK-oligosaccharides were used as the sole carbon source compared to fructo-oligosaccharides, which are widely used as prebiotics. These results showed that the CCK-oligosaccharides produced from Leu. lactis CCK940 could serve as good candidates for novel prebiotics.


Assuntos
Leuconostoc/metabolismo , Oligossacarídeos/química , Bifidobacterium/metabolismo , Fermentação/fisiologia , Lactobacillus/metabolismo , Maltose/química , Prebióticos , Probióticos/química , Sacarose/química
12.
Int J Pharm ; 572: 118807, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31678526

RESUMO

During lyophilisation cycle design, primary drying parameters (chamber pressure and shelf temperature) are adjusted to maximize the sublimation rate and prevent cake collapse, by maintaining the product continuously below its critical temperatures. The objective of this study was to employ mixture design of experiments to generate empirical models capable of predicting glass transition of the maximally freeze concentrated solution (Tg') and collapse temperature (Tc) of amorphous protein (BSA and IgG1) formulations. Additionally, the models developed aid the design of high concentration protein formulations with maximised critical temperatures to obtain shorter and more cost-effective lyophilisation cycles. Formulations contain sucrose as cryo/lyo-protectant and arginine/arginine-HCl as multifunctional excipient (e.g. solubility enhancer, viscosity and aggregation suppressor). The impact of formulation components at varied ratios on critical temperatures was evaluated; the amorphous excipients decrease critical temperatures, on the contrary, the protein increases critical temperatures. The robustness of the empirical models generated with BSA formulations was verified with BSA and IgG1 formulations. The models showed greater accuracy in predicting Tg' than the Fox-Flory equation. For the first time, empirical models are reported to predict both critical temperatures. Finally, unconventional collapse events observed for formulations with and without arginine/arginine-HCl at different protein concentrations are also discussed.


Assuntos
Liofilização , Imunoglobulina G/química , Soroalbumina Bovina/química , Tecnologia Farmacêutica/métodos , Temperatura , Arginina/química , Crioprotetores/química , Composição de Medicamentos , Excipientes/química , Pressão , Agregados Proteicos , Solubilidade , Sacarose/química , Viscosidade , Vitrificação
13.
Carbohydr Res ; 486: 107825, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31580967

RESUMO

The first synthesis of sucrose-based macrocycles containing two sulfur atoms in the ring was presented. The synthesis was initiated from known 6,6'-dideoxy-6,6'-di-chloro-1',2,3,3',4,4'-hexa-O-benzyl-sucrose in which both terminal positions (C6 and C6') were elongated by the -S-CH2-CH2-OH unit. The resulting diol was converted into dichloride and reacted further with a series of diamines which afforded the corresponding macrocyclic derivatives in high yields.


Assuntos
Compostos Macrocíclicos/química , Compostos Macrocíclicos/síntese química , Sacarose/química , Enxofre/química , Técnicas de Química Sintética
14.
Appl Microbiol Biotechnol ; 103(21-22): 8677-8687, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31587089

RESUMO

In the daily diet, sweeteners play an indispensable role. Among them, sucrose, a widely occurring disaccharide in nature, is a commonly used sweetener. However, the intake of sucrose can cause a rapid increase in blood glucose, which leads to a number of health problems. Therefore, there is an urgent need for possible alternatives to sucrose. Currently, four naturally occurring sucrose isomers, trehalulose, turanose, leucrose, and isomaltulose are considered to be possible alternatives to sucrose due to their suitable sweetness, potential physiological benefits, and feasible production processes. This review covers the properties of these alternative sweeteners, including their structure, sweetness, hydrolysis rate, toxicology, and cariogenicity, and exhibits their potential applications in chronic diseases management, anti-inflammatory supplement, prebiotic dietary supplement, and stabilizing agent. The biosynthesis of these sucrose isomers using carbohydrate-active enzymes and their industrial production processes are also systematically summarized.


Assuntos
Dissacarídeos/química , Isomaltose/análogos & derivados , Sacarose/análogos & derivados , Edulcorantes/química , Dieta , Alimentos , Humanos , Isomaltose/química , Isomerismo , Sacarose/química , Paladar
15.
J Colloid Interface Sci ; 557: 336-348, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31526930

RESUMO

Sucrose and phytic acid as abundant biomass resources have been combined for the fabrication of highly porous carbons with surface areas up to 1897 m2/g through hydrothermal carbonization and phytic acid-induced in-situ activation in the absence of additional activation agents. The carbons were employed as efficient adsorbents for the adsorptive removal of sulfamethoxazole (SMX) from water and the adsorption of dibenzothiophene (DBT) from model fuels. Kinetic and isotherm studies were performed for both processes. The effect of pH and ionic strength on SMX adsorption as well as the effect of arene on DBT adsorption was also investigated. By comparing the two adsorption processes, it was found that heteroatom doping could promote DBT adsorption obviously, but its effect on SMX adsorption was less straightforward. This was mainly attributed to the divergent solution media and thus the different adsorption mechanisms between aqueous and non-aqueous adsorption processes.


Assuntos
Carbono/química , Ácido Fítico/química , Sacarose/química , Sulfametoxazol/química , Tiofenos/química , Poluentes Químicos da Água/química , Adsorção , Antibacterianos/química , Concentração de Íons de Hidrogênio , Octanos/química , Concentração Osmolar , Porosidade , Água/química , Purificação da Água/métodos
16.
J Agric Food Chem ; 67(37): 10392-10400, 2019 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-31461615

RESUMO

The specificity of fructooligosaccharides as prebiotics depends on their size and structure, which in turn depend on their origin or the synthesis procedure. In this work we describe the application of an inulosucrase (IslA) from Leuconostoc citreum CW28 to produce high molecular weight inulin from sucrose alongside a commercial endoinulinase (Novozym 960) produced by Aspergillus niger for a simultaneous or sequential reaction to synthesize fructooligosaccharides (FOS). The simultaneous reaction resulted in a higher substrate conversion and a wide diversity of FOS when compared to the sequential reaction. A shotgun MS analysis of the commercial endoinulinase preparation surprisingly revealed an additional enzymatic activity: a fructosyltransferase, responsible for the synthesis of FOS from sucrose. Consequentially, the range of FOS obtained in reactions combining inulosucrase from Ln. citreum with the fructosyltransferase and endoinulinase from A. niger with sucrose as substrate may be extended and regulated.


Assuntos
Proteínas de Bactérias/química , Proteínas Fúngicas/química , Glicosídeo Hidrolases/química , Hexosiltransferases/química , Inulina/química , Leuconostoc/enzimologia , Oligossacarídeos/química , Aspergillus niger/enzimologia , Biocatálise , Sacarose/química
17.
Molecules ; 24(16)2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-31426303

RESUMO

The aim of this work was to compare the composition and physicochemical properties (SEM, XRD, solubility, swelling power, paste clarity, retrogradation, freeze-thaw stability, thermal property, and pasting property) of three Chinese yam (Dioscorea opposita Thunb.) starches (CYYS-1, CYYS-2, and CYYS-3) in Yunlong town, Haikou, Hainan Province, China. Our results show that all the CYYS gave a typical C-type X-ray diffraction pattern. The swelling power of CYYS varied from 10.79% to 30.34%, whereas solubility index was in the range of 7.84-4.55%. The freeze-thaw stability of each CYYS showed a contrary tendency with its amylose content. In addition, CYYS-3 showed the highest To (81.1 °C), Tp (84.8 °C), Tc (91.2 °C), and ΔH (14.1 J/g). The pasting temperature of CYYS-1 increased significantly with sucrose addition. NaCl could inhibit the swelling power of CYYS. There were significant decreases in pasting temperature and pasting time of CYYS when pH decreased.


Assuntos
Dioscorea/química , Cloreto de Sódio/química , Amido/química , Sacarose/química , Tecnologia de Alimentos/métodos , Liofilização , Temperatura Alta , Humanos , Microscopia Eletrônica de Varredura , Solubilidade , Amido/isolamento & purificação , Amido/ultraestrutura , Molhabilidade
18.
Int J Pharm ; 570: 118631, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31442499

RESUMO

The applicability of DCCs in a continuous freeze-drying concept based on spin freezing and infrared heating was evaluated. Maximum applicable filling volume was evaluated. Secondly the mechanistic model for the determination of the optimal dynamic infrared heater temperature during primary drying of regular vials during continuous freeze-drying was adapted and validated for DCCs. Finally, since spin frozen DCCs may be more prone to choked flow due to the small neck opening and the large product surface area, it was evaluated if the choked flow constraints in the model could be increased to improve the efficiency of the drying process. The experiments revealed that the maximum allowable filling volume for spin freezing at the current experimental setup was 0.8 ml which is 80% of the maximum filling volume. Applying the mechanistic model for the determination of the optimal dynamic infrared heater temperature during primary drying of the studied DCCs and experimentally verifying this determined infrared heater temperature trajectory resulted in an elegant freeze-dried product without visual signs of collapse. The experimentally determined primary drying time agreed with the one calculated based on the mechanistic model. Choked flow did not occur during the continuous freeze-drying of DCCs containing 3% sucrose or 3% mannitol.


Assuntos
Preparações Farmacêuticas/química , Composição de Medicamentos/métodos , Liofilização/métodos , Congelamento , Manitol/química , Sacarose/química , Temperatura
19.
Spectrochim Acta A Mol Biomol Spectrosc ; 222: 116861, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31255896

RESUMO

FTIR and NMR spectra were measured in parallel for specific two-components mixtures of various proteins with different sugar molecules, such as arabinose, glucose, and sucrose. In the FTIR spectra of arabinose with some of these proteins, the bands assigned to the vibrational modes of the CH and COH groups disappeared, and new ones, related to an arabinose-protein CN mode, appeared. Similar changes were observed in the FTIR spectra of lyophilized mixtures of arabinose with different amino acids. In additional FTIR spectra, measured for other protein-sugar mixtures, the bands correlated to the ring modes of arabinose, in the range 1150-1000 cm-1, disappeared, and two new very strong narrow bands became dominant, indicating ring opening or some kind of arabinose decomposition. Contrary to the prevailing opinion that complexes between sugars and proteins are formed mainly by hydrogen bonds, the IR and NMR spectra of the sugar-protein mixtures studied here suggest that significant chemical reactions also take place between the interacting sugar and the protein. Two types of sugar-protein chemical reactions can be distinguished on the basis of these IR spectra, leading to the formation of a new CN bond and to the decomposition of sugar skeletal bonds. The new IR bands suggest that the latter reaction results in the formation of new bonds, which are related to new polyether moieties. These results highlight the often ignored non-specific chemical reactions that take place between sugars and proteins, and demonstrate that the simultaneous application of FTIR and NMR spectroscopic analyses can detect and further characterize these types of sugar-protein interactions.


Assuntos
Proteínas/metabolismo , Açúcares/metabolismo , Arabinose/química , Arabinose/metabolismo , Temperatura Baixa , Glucose/química , Glucose/metabolismo , Humanos , Reação de Maillard , Ressonância Magnética Nuclear Biomolecular , Proteínas/química , Espectroscopia de Infravermelho com Transformada de Fourier , Sacarose/química , Sacarose/metabolismo , Açúcares/química , Xilose/química , Xilose/metabolismo
20.
J Agric Food Chem ; 67(34): 9601-9610, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31334648

RESUMO

The influence of sucrose palmitate, Tween 20, and lecithin on the properties of heat-induced aggregates and cold-set gels of ß-lactoglobulin was studied based on an experimental mixture design with a fixed total emulsifier concentration. Emulsifiers were added to the protein solution before heating. Aggregate size and absolute values of ζ potential increased with the addition of emulsifiers, among which lecithin had the most pronounced effect. The water retention of the aggregates correlated positively with the aggregate size. Gels had reduced fracture stress and strains with increasing sucrose palmitate and decreasing Tween 20 contents. The fracture properties correlated with the ζ potentials of the aggregates, and larger aggregates led to gels with higher water-holding capacities. The emulsifiers hence influenced the gel properties indirectly via the aggregate properties. The impact of emulsifiers on food structures should therefore be considered when a food product is designed.


Assuntos
Emulsificantes/química , Lactoglobulinas/química , Lecitinas/química , Polissorbatos/química , Sacarose/análogos & derivados , Emulsões/química , Géis/química , Temperatura Alta , Agregados Proteicos , Sacarose/química , Viscosidade
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