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1.
Food Chem ; 310: 125983, 2020 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-31835225

RESUMO

In this study, the effects of the addition of various polysaccharides (konjac gum, gellan gum, and curdlan gum) on the rheological and textural properties of calcium sulfate-induced soy protein isolate gels were investigated. The incorporation of konjac gum and curdlan gum at 0.3 and 0.5% (w/v) concentrations and gellan gum at 0.5% concentration significantly enhanced (P < 0.05) the hardness and water-holding capacity of the resultant gels. The increased elastic moduli during and after gelation, reinforced fracture stress, and lowered onset gelling temperature indicated that the addition of the abovementioned polysaccharides strengthened gel structures and accelerated gelation. Confocal laser scanning microscopy analysis revealed that the polysaccharides also improved gel microstructures, with the gels containing konjac gum displaying the highest homogeneity. The findings of this study may provide important information for the development of innovative soy protein isolate-based gel products with improved texture.

2.
Food Chem ; 308: 125596, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-31648097

RESUMO

The protective mechanism of glycerol on ß-lactoglobulin were studied in 0-60% glycerol solutions by experimental and molecular simulation approaches. Results showed that the stability of ß-lactoglobulin increased with glycerol concentration, with little secondary structure changes induced by glycerol. The tertiary structure altered slightly with glycerol concentration, resulting in a stronger near UV circular dichroism signal and intrinsic tryptophan fluorescence quenching, indicating aromatic side chains closer to hydrophobic microenvironment. The Rg of ß-lactoglobulin increased with glycerol concentration without dimer dissociation, due to expansion of the quaternary structures. Moreover, the flexibility (RMSF) of ß-lactoglobulin decreased by glycerol. Distance between areas enclosing Asp33 and Arg40 from separate chains did not increase, suggesting possibly reinforced electrostatic attractions. In conclusion, the stabilization of ß-lactoglobulin in glycerol solution is probably the comprehensive results of the decreased molecular flexibility, the strengthened hydrophobic interaction in individual chain, and the possibly reinforced electrostatic attractions between two chains of ß-lactoglobulin.


Assuntos
Glicerol/química , Lactoglobulinas/química , Dicroísmo Circular , Interações Hidrofóbicas e Hidrofílicas , Modelos Moleculares , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína
3.
Langmuir ; 35(37): 12017-12027, 2019 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-31411485

RESUMO

Droplet-stabilized emulsions (DSEs) were made from oil droplets coated with whey protein microgel (WPM) particles. The WPM particles with z-average hydrodynamic diameters of 270.9 ± 4.7 and 293.8 ± 6.7 nm were obtained by heating whey proteins with 10 mM phosphate buffer, pH 5.9 (-PB) and no buffer (-NPB), respectively. The primary emulsions coated by WPM-NPB and WPM-PB particles had mass fractal dimensions of ∼2.75, as determined by small- and ultra-small-angle neutron scattering (SANS and USANS). The size of the subsequently formed DSEs (D32 ≈ 7-23 µm), which were stabilized by the primary emulsion droplets, made with either WPM-NPB (termed DSE-NPB) or WPM-PB (termed DSE-PB) was dependent on the concentration of the primary emulsion (10-60 wt %) in the aqueous phase. At the DSE-NPB interface, the adsorbed primary emulsion droplets formed a fractal network with a surface fractal dimension of about 3, indicating a rough interfacial layer. Combined SANS and USANS allowed a comprehensive understanding of the multilength scale structures from WPM particles to DSEs.

4.
Int J Biol Macromol ; 140: 377-383, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31445144

RESUMO

Protein conjugated with dyes is a method which can be used for analyzing food components. For example ß-lactoglobulin (ßlg) can be conjugated with amine-reactive dyes to form ßlg-dye conjugates. In this study, the effect of pH on the conjugation of ßlg with fluorescein isothiocyanate (FITC) was investigated using MALDI-TOF MS, LC-MS, dynamic light scattering (DLS) and fourier transform infrared spectroscopy (FTIR). The results showed that the binding numbers increased with the increase in pH, which leading to a greater change in the zeta-potential and the secondary structure of ßlg after dye conjugation. In particular, the degree of labelling (DOL) was 94.9 ±â€¯7.9%, and the conjugation was mono-labelled at pH 8, indicating no significant changes in the physicochemical properties of ßlg. Furthermore, LC-MS revealed that the most probable conjugated lysine is located at position 100, 47 and 77 of ßlg.

5.
J Agric Food Chem ; 67(23): 6614-6624, 2019 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-31117487

RESUMO

Self-assembled micelles based on octenyl succinic anhydride (OSA)-modified starch were prepared to enhance the solubility of ß-carotene. The critical micelle concentration (CMC) was lower for OSA-modified starch with a lower molecular weight (Mw) or higher degree of substitution (DS). Above the CMC, OSA-modified starch assembled into spherical micelles with an average hydrodynamic diameter of <20 nm, as determined by dynamic light scattering (DLS). All the radii of gyration ( Rg), obtained from Guinier fitting of small-angle X-ray scattering (SAXS) data, were between 3 and 9 nm, and they were positively correlated with the Mw but negatively correlated with both the DS and the starch concentration. ß-Carotene was encapsulated effectively into the starch micelles, and the concentration of ß-carotene in the micelles was positively correlated with the concentration, Mw, and DS of the starch, with a maximum value of 53.14 µg/mL. The incorporation of ß-carotene enlarged the hydrophobic core and induced a significant increase in the Rg of the micelles determined by SAXS, and it may have also promoted the aggregation of the micelles resulting in a marked increase in the Dh determined by DLS.


Assuntos
Amido/análogos & derivados , beta Caroteno/química , Composição de Medicamentos , Interações Hidrofóbicas e Hidrofílicas , Micelas , Peso Molecular , Espalhamento a Baixo Ângulo , Solubilidade , Amido/química , Difração de Raios X
6.
Biomacromolecules ; 20(7): 2515-2529, 2019 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-31145611

RESUMO

Peptides can serve as versatile therapeutics with a highly modular structure and tunable biophysical properties. In particular, the efficacy of peptide antibiotics against drug-resistant pathogens is of great promise, as few new classes of antibiotics are being developed to overcome the ever-increasing bacterial resistance to contemporary drugs. This work reports biophysical and antimicrobial studies of a designed library of ultrashort peptides that self-assemble into hydrogels at concentrations as low as 0.5% w/v in buffered saline, as confirmed by rheology. The hydrogels are constituted by ß-sheet-rich nanofibril networks, as determined by biophysical techniques including spectroscopy (attenuated total reflectance Fourier transform infrared spectroscopy and Congo red binding assay), short- and wide-angle X-ray scattering, and electron microscopy. Both peptide solutions and self-assembled hydrogels show potent antimicrobial activity against S. aureus and Pseudomonas aeruginosa by membrane lysis. These peptides also displayed selectivity toward bacterial cells over human dermal fibroblasts in vitro, as determined from Live/Dead, scanning electron microscopy, and coculture assays. This work reports an antimicrobial self-assembling motif of only three residues comprising an aromatically acylated cationic d-Dab/Lys amino acid, a second cationic residue, and naphthylalanine that heavily influences the self-assembly of these peptides into hydrogels. The variations in the antimicrobial activity and self-assembly properties between analogues may have implications in future studies on the correlation between self-assembly and biological activity in ultrashort peptides.

7.
Carbohydr Polym ; 212: 40-50, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30832873

RESUMO

The effects of amyloglucosidase digestion on the multi-scale supramolecular structural changes of native corn starch were examined by ultra-small angle neutron scattering (USANS), small angle X-ray scattering (SAXS), particle sizing, and scanning electron microscopy (SEM). Well-defined and spherical pores were formed upon amyloglucosidase digestion as revealed by SEM. The pore polydispersity was determined using USANS by assuming spherical pore morphology with log-normal distribution. Both USANS and SEM measurements demonstrated that the pores become larger and more polydisperse as the digestion time increased. Moreover, SAXS revealed that the lamellar peak area decreased gradually for both thermally and enzymatically treated starches, indicating partial loss of lamellar organisation. Overall, the results demonstrate structural changes occur on multiple length scales upon enzymatic digestion from granular to lamellar with small-angle scattering demonstrated to provide detailed characterization of the resultant microporous structures.


Assuntos
Glucana 1,4-alfa-Glucosidase/química , Difração de Nêutrons/métodos , Espalhamento a Baixo Ângulo , Amido/química , Glucana 1,4-alfa-Glucosidase/metabolismo , Hidrólise , Estrutura Molecular , Tamanho da Partícula , Amido/metabolismo
8.
Soft Matter ; 15(7): 1551-1561, 2019 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-30663758

RESUMO

A predicted three-dimensional structure of bovine ß-casein was constructed using homology modeling with the aid of MODELLER and I-TASSER programs, with the validity and reliability of the models evaluated according to stereochemical qualities and small angle X-ray scattering. By comparing the results obtained from the two models using the CRYSOL program, an optimal model of the ß-casein structure derived from I-TASSER was selected and used in subsequent molecular dynamics (MD) analysis. 300 ns MD simulations of ß-casein in water and in the presence of different SDS concentrations at 300 K were performed. The results of the MD simulations indicated that SDS molecules played a dual role in modifying the conformation of ß-casein at 300 K. Concentrations of SDS below its CMC (1 mM), at which only the monomer form of SDS was present, induced ß-casein to lose its secondary structure by converting helices into random coils; however the conformation of the complex was still comparable with that of native ß-casein. In the presence of 10 mM SDS (above its CMC), the helical content of ß-casein was increased along with reduced random coils, and the structural rearrangement led to a more compact conformation. The latter change is likely related to the hydrophobic interactions that dominate the binding of the C-terminal region, along with the anchoring of sulfate groups of SDS on the positively charged N-terminal portion via electrostatic attraction. Hydrogen bonding supplemented the SDS-induced stabilization of ß-casein. A correlated "necklace and bead" model, in which the micelles nucleate on the protein hydrophobic sites, was proposed for the structure of ß-casein-SDS complexes.


Assuntos
Caseínas/química , Simulação de Dinâmica Molecular , Dodecilsulfato de Sódio/química , Conformação Proteica
9.
Food Chem ; 272: 539-548, 2019 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-30309579

RESUMO

This study investigates the effects of pre-acidification (pH 6.7-5.4) of skim milk, followed by pH-restoration of the retentates, on spray-drying performance, physico-chemical properties and functionality of the resulting milk protein concentrate (MPC). Powder recovery decreased with decreasing pH of pre-acidification but improved with pH-restoration. Colloidal calcium was gradually solubilized with decreasing pH of pre-acidification but was slightly recovered by pH-restoration. Dissociation of micellar caseins increased with decreasing pH of pre-acidification of skim milk and was further increased by pH-restoration. Casein micelles maintained their overall structures at pre-acidification pH of 6.7-6.0, and partially disintegrated into loosely entangled aggregates at pH 5.7-5.4; while after pH-restoration, micelles generally maintained their overall structures at pre-acidification pH of 6.0, and completely disintegrated at pH 5.7-5.4. Solubility and emulsifying properties of MPC improved with decreasing pH of pre-acidification and with pH-restoration. Heat stability of MPC declined with decreasing pH of pre-acidification but improved with pH-restoration.


Assuntos
Proteínas do Leite/química , Leite/metabolismo , Animais , Cálcio/química , Dessecação , Difusão Dinâmica da Luz , Concentração de Íons de Hidrogênio , Micelas , Microscopia Eletrônica de Transmissão , Leite/química , Pós/química , Espalhamento a Baixo Ângulo , Solubilidade , Temperatura Ambiente , Difração de Raios X
10.
Ultrason Sonochem ; 51: 325-331, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30322767

RESUMO

The vegetative cells and spores of Geobacillus spp. and Anoxybacillus flavithermus were subjected to 20 kHz ultrasound with a power ∼8 W. Ultrasonication had considerable effect on vegetative cells (5-log reduction in Geobacillus spp. and 1.6-log reduction in A.flavithermus). TEM imaging of the ultrasonicated vegetative cells showed an extensive damage both internally and externally. However, spores showed high resistance towards ultrasound treatment in the absence of NaOH and H2O2, although the outer layers such as the exosporium and the outer coat layer were disrupted, resulting in the reduced resistance of spores towards sonication. The combination of 0.12 M NaOH and 10 min ultrasonication inactivated 6 log spores of Geobacillus spp. A 7 log spore reduction of A.flavithermus was achieved by combining 0.17 M NaOH with 10 min ultrasonication. Ultrasonication combined with 1% H2O2 inactivated ∼7 log Geobacillus spp. spores in 6 min and ∼7 log A.flavithermus spores in 3 min. These ultrasound treatments in the presence of NaOH and H2O2 are synergistic as they showed a greater spore reduction when compared to NaOH combined with high temperature (85 °C), where only 1 and 3 log reduction was achieved in Geobacillus spp. and A.flavithermus spores, respectively.


Assuntos
Anoxybacillus/fisiologia , Geobacillus/fisiologia , Peróxido de Hidrogênio/farmacologia , Viabilidade Microbiana/efeitos dos fármacos , Hidróxido de Sódio/farmacologia , Ondas Ultrassônicas , Anoxybacillus/efeitos dos fármacos , Geobacillus/efeitos dos fármacos , Esporos Bacterianos/efeitos dos fármacos , Esporos Bacterianos/fisiologia
11.
Chem Asian J ; 14(8): 1117-1127, 2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30125474

RESUMO

Several hundred (396) compounds from New Zealand flora with medicinal properties were analyzed for their physicochemical properties. It was found that approximately 10 % fulfilled all the requirements to be considered to be lead-like, over half of the compounds were deemed to be in the drug-like space and ≈75 % were in the known drug space. These results indicate the presence of a significant proportion of compounds that are of particular interest to pursue as potential lead compounds or therapeutics. Additionally, compound classes were analyzed separately-most carbonyl-containing compounds (aldehydes, ketones, esters and lactones), along with phenols were the most lead-like compounds, which also displayed very good proportions in the drug-like and known drug space. The information presented herein can be harnessed and utilized in future work, through focussing on the compounds and compound classes that exhibit high-levels of lead-likeness for further development.

12.
Ultrason Sonochem ; 63: 104929, 2019 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-31945573

RESUMO

We investigated the effect of ultrasound (US) and high hydrostatic pressure (HHP) on the size of reformed casein micelles (RMCs) obtained by titrating calcium and phosphorous solution into sodium caseinate solutions. Both US and HHP reduced the size of the RMCs. A decrease in size from ~200 nm to ~170 nm when US (20 kHz, 0.46 W/mL) was applied for 30 min; and down to ~85 nm when HHP was applied 500 MPa for 15 min. Electron microscopic analysis showed that the RMCs before and after US are similar to milk native casein micelles, and that HHP extensively disintegrated the RMCs. Small angle X-ray scattering and SDS-PAGE showed that the internal structure of the RMCs as well as the casein molecules are not affected by the US and HHP treatments.

13.
Foods ; 7(9)2018 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-30189590

RESUMO

Increasing interest in flavonoids in kiwifruit is due to the health-promoting properties of these bioactives. Inhibition of the angiotensin-converting enzyme (ACE) is one of the main therapeutic targets in controlling hypertension. The present study investigated the ACE inhibitory activity of flavonoid-rich extracts obtained from different kiwifruit genotypes. The flavonoid-rich extracts were prepared from fruits of Actinidia macrosperma, Actinidia deliciosa cv Hayward (Green kiwifruit), and Actinidia chinensis cv Hort 16A (Gold kiwifruit) by steeping the lyophilized fruit samples in 70% aqueous acetone, followed by partitioning the crude extracts with hexane. The composition of each extract was analyzed using ultrahigh-performance liquid chromatography-mass spectrometry (UPLC-MS/MS). The ACE inhibitory activity of the fruit extracts was performed using a fluorescence-based biochemical assay. The subclass flavonol was the most abundant group of flavonoids detected in all the extracts tested from three different kiwifruit cultivars. Quercetin-3-O-galactoside, quercetin-3-O-glucoside, quercetin-3-O-rhamnoside, quercetin-3-O-rutinoside, quercetin-3-O-arabinoglucoside, catechin, epigallocatechin gallate, epigallocatechin, chlorogenic, ferulic, isoferulic, and caffeic acid were prominent phenolics found in A. macrosperma kiwifruit. Overall, the flavonoid-rich extract from A. macrosperma showed a significantly (p < 0.05) high percentage of inhibition (IC50 = 0.49 mg/mL), and enzyme kinetic studies suggested that it inhibits ACE activity in vitro. The kiwifruit extracts tested were found to be moderately effective as ACE inhibitors in vitro when compared to the other plant extracts reported in the literature. Further studies should be carried out to identify the active compounds from A. macrosperma and to validate the findings using experimental animal models of hypertension.

14.
Food Res Int ; 109: 380-386, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29803463

RESUMO

The characterisation of a serine protease isolated from tamarillo (Solanum betaceum) fruit and its milk casein hydrolysis activity were investigated. Compared with calf rennet, a crude extract from tamarillo exhibited wider caseinolytic activity on sodium caseinate. The purified protease was named "tamarillin" and revealed proteolytic activity toward purified α-, ß- and κ-casein. Similar to calf rennet, tamarillin preferably hydrolysed κ-casein, but, unlike calf rennet, it also displayed high proteolytic activity toward both α- and ß-casein. The major peptide generated from κ-casein by tamarillin was analysed by gel electrophoresis and liquid chromatography mass spectrometry to confirm its molecular mass as 14,290 Da. The cleavage site was confirmed by in-gel tryptic digestion and time-of-flight mass spectrometry analysis to be at Asn123-Thr124. This was in contrast to the Phe105-Met106 cleavage site of rennet hydrolysis.


Assuntos
Caseínas/metabolismo , Análise de Alimentos/métodos , Manipulação de Alimentos/métodos , Frutas/enzimologia , Extratos Vegetais/metabolismo , Proteínas de Plantas/metabolismo , Serina Proteases/metabolismo , Solanum/enzimologia , Cromatografia de Fase Reversa , Quimosina/metabolismo , Eletroforese em Gel de Poliacrilamida , Hidrólise , Peso Molecular , Fragmentos de Peptídeos/metabolismo , Extratos Vegetais/isolamento & purificação , Proteínas de Plantas/isolamento & purificação , Serina Proteases/isolamento & purificação , Espectrometria de Massas por Ionização por Electrospray , Especificidade por Substrato
15.
Food Chem ; 256: 228-234, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-29606442

RESUMO

A protease from tamarillo fruit (Cyphomandra betacea Cav.) was purified by ammonium sulphate precipitation and diethylaminoethyl-Sepharose chromatography. Protease activity was determined on selected peak fractions using a casein substrate. Sodium dodecyl sulphate polyacrylamide gel electrophoresis analysis showed that the peak with the highest protease activity consisted of one protein of molecular mass ca. 70 kDa. The protease showed optimal activity at pH 11 and 60 °C. It was sensitive to phenylmethylsulphonyl fluoride while ethylenediaminetetraacetic acid and p-chloromercuribenzoic acid had little effect on its activity, indicating that this enzyme was a serine protease. Hg2+ strongly inhibited enzyme activity, possibly due to formation of mercaptide bonds with the thiol groups of the protease, suggesting that some cysteine residues may be located close to the active site. De novo sequencing strongly indicated that the protease was a subtilisin-like alkaline serine protease. The protease from tamarillo has been named 'tamarillin'.


Assuntos
Frutas/enzimologia , Serina Proteases/isolamento & purificação , Solanum/enzimologia , Eletroforese em Gel de Poliacrilamida , Estabilidade Enzimática , Frutas/genética , Concentração de Íons de Hidrogênio , Peso Molecular , Proteólise , Análise de Sequência de Proteína , Serina Proteases/genética , Serina Proteases/metabolismo , Solanum/genética , Subtilisina , Temperatura Ambiente
16.
J Texture Stud ; 49(1): 47-55, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28581065

RESUMO

Physical and sensory properties of gelatin from skin and swim bladder of seabass (SK and SW, respectively) as affected by agar or κ-carrageenan at 10 and 20% substitution were investigated. Hardness of both SK and SW gels containing agar increased with increasing level of agar. However, the addition of κ-carrageenan lowered hardness of mixed gels. Springiness and cohesiveness of either SK or SW gels decreased as the level of both agar or κ-carrageenan increased. Gelling and melting temperatures generally increased when the level of hydrocolloids was increased. The highest gelling (∼36C) and melting temperatures (∼43C) were obtained for SK added with 20% agar and 20% κ-carrageenan, respectively. However, the addition of both hydrocolloids at 10% affected gel microstructure differently. Furthermore, the addition of agar at 10% could increase the likeness score of sensory properties of gelatin gel. Therefore, the addition of hydrocolloids with appropriate level could improve the texture and sensory properties of gelatin from seabass. PRACTICAL APPLICATIONS: Due to the poor gelling property of fish gelatin, compared to its mammalian counterpart, improvement of this property using the selected hydrocolloids can be a promising means. In this work, it was found that agar or κ-carrageenan can be incorporated to fish gelatin to improve gelling, textural and sensory properties of gelatin from skin of seabass (Lates calcarifer). Both agar and κ-carrageenan could increase gelling and melting temperatures of seabass gelatin. The incorporation of hydrocolloids (agar and κ-carrageenan) could also improve the quality of fish gelatin gel, which in turn can widen the applications of fish gelatin in the food and other industries.


Assuntos
Ágar/química , Bass , Carragenina/química , Fenômenos Químicos , Gelatina/química , Alimentos Marinhos/análise , Paladar , Adulto , Animais , Coloides , Cor , Manipulação de Alimentos , Congelamento , Géis/química , Dureza , Humanos , Odorantes , Reologia , Temperatura Ambiente , Viscosidade
17.
Biomater Sci ; 5(10): 1993-1997, 2017 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-28853745

RESUMO

We report the design and characterization of a peptide that assembles as ß-hairpins and forms hydrogels under physiological conditions. These hydrogels formed both in the absence and presence of several metal ions and displayed characteristic sheer-thinning properties. In particular, in the presence of Zn2+, we observed a novel hydrogel that proceeded via an intermolecular metal-coordination mechanism - intermolecular assembly that was previously reported instead to promote amyloid type aggregates.


Assuntos
Hidrogel de Polietilenoglicol-Dimetacrilato/química , Peptídeos/química , Zinco/química , Sequência de Aminoácidos , Modelos Moleculares , Conformação Proteica em Folha beta
18.
Ultrason Sonochem ; 35(Pt B): 547-555, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27264042

RESUMO

In this paper, the pitting of potato starch granules in aqueous suspensions (1%) by high-frequency high-power ultrasound (850kHz at a power of 0.2W, 2W or 3.7W; and also 500kHz and 1MHz at a power of 2W) is reported. The number of pits per starch granules was found to be independent of the amylose content of starches, and the surface properties of starch granules as modified through SDS and ethanol washing. At 850kHz, the maximum number of pits per starch granule, for both normal and waxy starches, did not exceed 11. However, a close inspection of fractionated starch granules based on their sizes showed that there is an optimum granule size for which a maximum pit number is obtained. For example, starch granules with diameter size range of ∼15 to ∼30µm had a maximum pit number (between 10 and 20 pits per granule) when sonicated (2W, 850kHz and 30min); while sonication of small (<10µm) and very large (>45µm) granules resulted in a smaller number of pits per granule (∼5). Further, the maximum number of pits per granules is also found to be proportional to the ultrasound frequency, with values of approximately 7, 10 and 11 at 0.50, 0.85, and 1MHz, respectively. FTIR measurements did not show any breakup of starch molecules.


Assuntos
Solanum tuberosum/química , Sonicação , Amido/química , Amilose/análise , Tamanho da Partícula , Propriedades de Superfície , Água/química
19.
Acta Biomater ; 47: 40-49, 2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-27744067

RESUMO

We report the synthesis and characterization of multifunctional peptides comprised of a hydrogel forming ß-sheet peptide segment and a matrix metalloproteinase 2 substrate containing a propargylglycinyl linker that is further derivatized with an RGD peptide sequence via "click" chemistry. In contrast to currently known systems, these multifunctional peptides formed gels that are stiffer than those formed by their respective precursors. All the peptides showed reversible thermoresponsive properties, which render them as suitable lead systems for a variety of possible biomedical applications. STATEMENT OF SIGNIFICANCE: In general, it has been frequently observed that chemical biofunctionalization of peptide hydrogels adversely affects peptide assembly, hydrogel formation or mechanical properties, which severely compromises their application. A functionalization protocol that allows to generate peptide hydrogels that display significantly improved mechanical properties over their unfunctionalized counterparts is reported in this work. These peptides also showed thermoresponsive viscoelastic characteristics, including an example of a peptide hydrogel that displays lower critical solution temperature behaviour.


Assuntos
Hidrogéis/química , Peptídeos/química , Temperatura Ambiente , Cromatografia Líquida de Alta Pressão , Dicroísmo Circular , Metaloproteinase 2 da Matriz/metabolismo , Peptídeos/síntese química , Espalhamento a Baixo Ângulo , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
20.
Chem Soc Rev ; 45(17): 4797-824, 2016 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-27301699

RESUMO

Peptide based hydrogels have received much attention due to their potential biomedical applications. The majority of the gel forming peptides present a ß-sheet motif that is composed of alternating hydrophobic/hydrophilic amino acids. Furthermore, structural characterization of the assembly of these ß-sheet peptides has been refined recently. However, the relationship between peptide residue composition, molecular structure and the mechanical properties of the resulting hydrogel is not entirely understood. In this review, an analysis of the structural features of different ß-sheet peptide hydrogels and their mechanical properties is discussed, in order to provide further insight on the molecular features that are relevant for the design of effective ß-peptide hydrogels.


Assuntos
Hidrogel de Polietilenoglicol-Dimetacrilato/química , Peptídeos/química , Conformação Proteica em Folha beta , Fenômenos Mecânicos , Modelos Moleculares
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