Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 5.748
Filtrar
1.
BMC Genomics ; 22(1): 596, 2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34353280

RESUMO

BACKGROUND: The eating and cooking qualities (ECQs) of rice (Oryza sativa L.) are key characteristics affecting variety adoption and market value. Starch viscosity profiles tested by a rapid visco analyzer (RVA) offer a direct measure of ECQs and represent the changes in viscosity associated with starch gelatinization. RVA profiles of rice are controlled by a complex genetic system and are also affected by the environment. Although Waxy (Wx) is the major gene controlling amylose content (AC) and ECQs, there are still other unknown genetic factors that affect ECQs. RESULTS: Quantitative trait loci (QTLs) for starch paste viscosity in rice were analyzed using chromosome segment substitution lines (CSSLs) developed from the two cultivars 9311 and Nipponbare, which have same Wx-b allele. Thus, the effect of the major locus Wx was eliminated and the other locus associated with the RVA profile could be identified. QTLs for seven parameters of the starch RVA profile were tested over four years in Nanjing, China. A total of 310 QTLs were identified (from 1 to 55 QTLs per trait) and 136 QTLs were identified in more than one year. Among them, 6 QTLs were stalely detected in four years and 26 QTLs were detected in at least three years including 13 pleiotropic loci, controlling 2 to 6 RVA properties simultaneously. These stable QTL hotspots were co-located with several known starch synthesis-related genes (SSRGs). Sequence alignments showed that nucleotide and amino acid sequences of most SSRGs were different between the two parents. Finally, we detected stable QTLs associated with multiple starch viscosity traits near Wx itself, supporting the notion that additional QTLs near Wx control multiple characteristic values of starch viscosity. CONCLUSIONS: By eliminating the contribution from the major locus Wx, multiple QTLs associated with the RVA profile of rice were identified, several of which were stably detected over four years. The complexity of the genetic basis of rice starch viscosity traits might be due to their pleiotropic effects and the multiple QTL hot spots. Minor QTLs controlling starch viscosity traits were identified by using the chromosome segment substitution strategy. Allele polymorphism might be the reason that QTLs controlling RVA profile characteristics were detected in some known SSRG regions.


Assuntos
Oryza , Amido/química , Alelos , Cromossomos , Oryza/genética , Locos de Características Quantitativas , Viscosidade
2.
J Photochem Photobiol B ; 222: 112264, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34320457

RESUMO

Most modern sunscreens contain physical filters, which scatter the sunlight, increasing the photons' pathway in the upper stratum corneum. This effect can lead to a better efficacy of the UV filters and improve the diffuse reflection. However, the addition of nanosized inorganic UV filters reduces the antioxidant capacity of sunscreen formulations. Two cream formulations (F1, F2) which differ in the ingredient PEG75 Lanolin (F2), have been characterized for their radical protection factor (RPF) and their optical properties in vitro using electron paramagnetic resonance (EPR) spectroscopy and UV/VIS spectrometry. The RPF for PEG-75 Lanolin was also determined. Furthermore, their radical protection properties were analyzed on porcine skin ex vivo after visible light irradiation by EPR. The structure of each formulation in the skin surface was determined by reflectance confocal microscopy in vivo. The addition of lanolin increased the reflectance and reduced the transmittance for visible light, improving the scattering drastically. Besides, the antioxidant capacity was also increased for F2, something unpublished until now. F1 presented a lower scattering provided by starches. The sunscreens showed high scattering properties and antioxidant capacity, especially for F2, which presented the lowest radical formation in the skin model. These results are consistent with the RPF measurements where F2 has a higher RPF value (193 ± 3 × 1014 radicals/mg) than F1 (155 ± 4 × 1014 radicals/mg) and for PEG-75 Lanolin (37 ± 1 × 1014 radicals/mg). The combination of starches and PEG-75 Lanolin is the first solution to provide both, light scattering and antioxidant capacity, in sunscreens.


Assuntos
Antioxidantes/química , Lanolina/química , Luz , Amido/química , Protetores Solares/química , Animais , Composição de Medicamentos , Espectroscopia de Ressonância de Spin Eletrônica , Pele/efeitos dos fármacos , Pele/efeitos da radiação , Fator de Proteção Solar , Protetores Solares/farmacologia , Suínos
3.
Molecules ; 26(12)2021 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-34198695

RESUMO

Unripe banana fruit of Musa acuminata (Musa AAA; Hom Khieo) and Musa sapientum L. (Musa ABB; Namwa) growing in Chiang Rai (Thailand) were used for extraction. The yield of the starches was 16.88% for Hom Khieo (HK) and 22.73% for Namwa (NW) based on unripe peeled banana fruit. The amylose contents of HK and NW were 24.99% and 26.23%, respectively. The morphology of starch granules was oval shape with elongated forms for large granules and round shape for small granules. The HK and NW showed B-type crystalline structure and the crystallinities were 23.54% and 26.83%, respectively. The peak temperature of gelatinization was around 77 °C and the enthalpy change (ΔH) was 3.05 and 7.76 J/g, respectively. The HK and NW banana starches showed 1.27 ± 0.12 g/g and 1.53 ± 0.12 g/g water absorption capacity, and 1.22 ± 0.11 g/g and 1.16 ± 0.12 g/g oil absorption capacity, respectively. The swelling power of the banana starches was 17.23 ± 0.94 g/g and 15.90 ± 0.15 g/g, respectively, and the percentage of solubility in water showed 26.43 ± 2.50 g/g and 20.54 ± 0.94 g/g, respectively. The banana starches showed very poor flow character. The HK and NW starches have the potential to be used in powder base preparations with no effect on the sensory texture of the product at 15% w/w maximum.


Assuntos
Amilose/química , Cosméticos/química , Musa/química , Amido/química , Temperatura , Termodinâmica , Difração de Raios X/métodos , Frutas , Solubilidade , Água
4.
Molecules ; 26(13)2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-34202382

RESUMO

Antioxidant polyphenols in black tea residue are an underused source of bioactive compounds. Microencapsulation can turn them into a valuable functional ingredient for different food applications. This study investigated the potential of using spent black tea extract (SBT) as an active ingredient in food packaging. Free or microencapsulated forms of SBT, using a pectin-sodium caseinate mixture as a wall material, were incorporated in a cassava starch matrix and films developed by casting. The effect of incorporating SBT at different polyphenol contents (0.17% and 0.34%) on the structural, physical, and antioxidant properties of the films, the migration of active compounds into different food simulants and their performance at preventing lipid oxidation were evaluated. The results showed that adding free SBT modified the film structure by forming hydrogen bonds with starch, creating a less elastic film with antioxidant activity (173 and 587 µg(GAE)/g film). Incorporating microencapsulated SBT improved the mechanical properties of active films and preserved their antioxidant activity (276 and 627 µg(GAE)/g film). Encapsulates significantly enhanced the release of antioxidant polyphenols into both aqueous and fatty food simulants. Both types of active film exhibited better barrier properties against UV light and water vapour than the control starch film and delayed lipid oxidation up to 35 d. This study revealed that starch film incorporating microencapsulated SBT can be used as a functional food packaging to protect fatty foods from oxidation.


Assuntos
Membranas Artificiais , Extratos Vegetais/química , Amido/química , Chá/química
5.
Molecules ; 26(13)2021 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-34202905

RESUMO

Cereals are subject to contamination by pathogenic fungi, which damage grains and threaten public health with their mycotoxins. Fusarium graminearum and its mycotoxins, trichothecenes B (TCTBs), are especially targeted in this study. Recently, the increased public and political awareness concerning environmental issues tends to limit the use of traditional fungicides against these pathogens in favor of eco-friendlier alternatives. This study focuses on the development of biofungicides based on the encapsulation of a curcumin derivative, tetrahydrocurcumin (THC), in polysaccharide matrices. Starch octenylsuccinate (OSA-starch) and chitosan have been chosen since they are generally recognized as safe. THC has been successfully trapped into particles obtained through a spray-drying or freeze-drying processes. The particles present different properties, as revealed by visual observations and scanning electron microscopy. They are also different in terms of the amount and the release of encapsulated THC. Although freeze-dried OSA-starch has better trapped THC, it seems less able to protect the phenolic compound than spray-dried particles. Chitosan particles, both spray-dried and lyophilized, have shown promising antifungal properties. The IC50 of THC-loaded spray-dried chitosan particles is as low as 0.6 ± 0.3 g/L. These particles have also significantly decreased the accumulation of TCTBs by 39%.


Assuntos
Antifúngicos , Agentes de Controle Biológico , Quitosana , Fusarium/crescimento & desenvolvimento , Amido/análogos & derivados , Antifúngicos/química , Antifúngicos/farmacologia , Agentes de Controle Biológico/química , Agentes de Controle Biológico/farmacologia , Quitosana/química , Quitosana/farmacologia , Curcumina/análogos & derivados , Curcumina/química , Curcumina/farmacologia , Amido/química , Amido/farmacologia
6.
Int J Biol Macromol ; 185: 1005-1014, 2021 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-34217745

RESUMO

The effects of various physical state lipids (rapeseed oil (RO), shortening (ST), beeswax (BW)), on the physicochemical properties of starch (S) (hydroxypropyl distarch phosphate (HP), oxidized hydroxypropyl starch (OS))/gelatin (G) blown films were studied. S/G-lipid blends showed decreased storage modulus and complex viscosity. The formation of hydrogen bonds was inhibited by the ST and BW, but facilitated by the RO. Compared with BW and ST, RO was more effective to promote the melted and fractured of starch. Lipids addition promoted the compatibility of starch and gelatin. The presence of the lipids significantly improved the surface hydrophobicity, mechanical, water vapor barrier and water resistance properties of S/G films. S/G-RO films exhibited the strongest surface hydrophobicity and tensile strength, while HP/G-BW film showed the strongest water resistance and water vapor barrier properties. These results revealed that the appropriate lipids could be used to produce S/G-lipid films with desirable physicochemical properties.


Assuntos
Gelatina/química , Lipídeos/química , Amido/química , Filmes Comestíveis , Módulo de Elasticidade , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Permeabilidade , Resistência à Tração , Viscosidade
7.
Int J Biol Macromol ; 185: 725-738, 2021 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-34224757

RESUMO

Highland barley (HB) is mainly composed of starch, which may account for up to 65% of the dry weight to the kernel. HB possesses unique physical and chemical properties and has good industrial application potential. It has also been identified as a minor grain crop with excellent nutritional and health functions. Highland barley starch (HBS) features a number of structural and functional properties that render it a useful material for numerous food and non-food applications. This review summarizes the current status of research on the extraction processes, chemical composition, molecular fine structures, granular morphology, physicochemical properties, digestibility, chemical and physical modifications, and potential uses of HBS. The findings provide a comprehensive reference for further research on HBS and its applications in various food and non-food industries.


Assuntos
Hordeum/química , Amido/química , Tecnologia de Alimentos , Estrutura Molecular
8.
Int J Biol Macromol ; 185: 849-860, 2021 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-34237362

RESUMO

Plastic-based food packaging is generating a serious environmental problem by accumulating large amounts of plastic in the surroundings. Ecological and health concerns are driving research efforts for developing biodegradable films. There are few alternatives that could reduce the environmental impact; one of them is to substitute petroleum-based plastic with starch-based film. Starch has remarkable properties, including biodegradability, sustainability, abundancy, and capable of being modified or blended with other polymers. However, low mechanical strength and low water resistance restrict its application in food packaging. Nanocellulose isolated from lignocellulosic fibers has attracted tremendous interest in the field of science due to high crystallinity and mechanical strength, unique morphology along with abundancy, renewability, and biodegradability. Therefore, nano cellulose as a reinforcer proved to be a good option for fabricating biocomposites for food packaging. The current review will give a critical snapshot of the potential application of nanocellulose in food packaging and discuss new challenges and opportunities for starch biocomposites enriched with nano cellulose.


Assuntos
Celulose/química , Amido/química , Embalagem de Alimentos , Estrutura Molecular , Nanocompostos , Permeabilidade , Resistência ao Cisalhamento , Temperatura
9.
Int J Biol Macromol ; 185: 451-461, 2021 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-34216655

RESUMO

An active antioxidant film was fabricated by using polyvinyl alcohol (PVA) and corn starch (ST) and incorporated with and 3, 5, 10, and 20% (v/v) coconut shell extract (CSE) and sepiolite clay (SP) for the first time. The microstructure and physical properties of prepared films were characterized and examined. The addition of sepiolite clay to PVA improved the elongation break 15.57 to 69.24%, and water vapor permeability increased with the addition of CSE. In addition to CSE to films, the antioxidant activity properties of the films were enhanced up to 80%. Further, increasing the amount of CSE slightly affected the color of the active films. The thermal properties of films were enhanced with the addition of CSE and SP. The dispersion of SP in the PVA matrix was affected by an increase in CSE concentration in the PVA matrix. Remarkably, PVA-ST film-based sachets successfully improved the oxidative stability of packaged soybean oil. Our results suggest PVA-ST film containing CSE and sepiolite clay can be utilized as a novel antioxidant packaging material in the food processing industry.


Assuntos
Antioxidantes/química , Argila/química , Cocos/química , Silicatos de Magnésio/química , Álcool de Polivinil/química , Amido/química , Embalagem de Alimentos , Microscopia Eletrônica de Varredura , Permeabilidade , Extratos Vegetais/química , Espectroscopia de Infravermelho com Transformada de Fourier , Vapor , Resistência à Tração , Difração de Raios X
10.
Int J Mol Sci ; 22(14)2021 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-34298901

RESUMO

The aim of the study was to determine how the molecular structure of porcine fat-in-water type emulsions stabilised with potato starch affected their rheomechanical properties. Dynamic mechanical analysis (DMA) and instrumental analysis of the texture were the method used in experiments. Starch gels with concentrations corresponding to the water starch concentration of the examined emulsions were used as control systems. The analysis of the starch and starch-fat systems showed that the values characterising their rheomechanical and textural properties reflected the spatial reaction of the amylose matrix to dynamic mechanical interactions. Changes in their values resulted from conformational changes in the structure of segments and nodes of the lattice, conditioned by the concentration of starch and the presence of fat. As a result of these changes, starch-fat emulsions are distinguished by greater densities of network segments and nearly two times greater functionalities of nodes than starch gels. The instrumental analysis of the texture showed that the values of the texture parameters in the starch gels were greater than in the starch-fat emulsions. The high values of the correlation coefficients (R~0.9) between the texture determinants and the rheological parameters proved that there was a strong correlation between the textural properties of the tested systems and their rheomechanical properties.


Assuntos
Emulsões/química , Gorduras/química , Solanum tuberosum/química , Amido/química , Água/química , Amilose/química , Animais , Géis/química , Estrutura Molecular , Reologia/métodos , Suínos
11.
Int J Biol Macromol ; 184: 476-482, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34171253

RESUMO

Water chestnut (Trapa bispniosa), rice and corn starch were modified with sodium alginate and subjected to dry heating for 0,2 and 4 h for at 130 °C. The physicochemical, thermal and morphological properties of native as well as modified starches were determined. Thermal and morphological properties were studied using Differential Scanning Calorimeter (DSC) and Scanning Electron Microscopy (SEM). It was observed that the dry heating of starches with and without sodium alginate significantly reduce the swelling power, solubility, paste clarity whereas, water absorption and syneresis increased. The swelling power was higher for corn starch as compared to other starches while rice starch has higher syneresis. In the presence of sodium alginate the water absorption was increased in all starch samples upon heating. The onset temperature was found to be increased after dry heating of all starches. The maximum increased was noticed for rice starch. Morphological studies showed the damaging of granule surface with the accumulation of leached amylose and gum but total degradation was not observed. Peak viscosity, final viscosity, breakdown, and setback of RS- sodium alginate mixture were reduced on dry heating. Although pasting temperature of rice starch was not significantly changed.


Assuntos
Alginatos/química , Eleocharis/química , Oryza/química , Amido/química , Zea mays/química , Varredura Diferencial de Calorimetria , Calefação , Microscopia de Força Atômica , Solubilidade , Viscosidade , Água/química
12.
Int J Biol Macromol ; 184: 509-521, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34171254

RESUMO

In this study, carboxymethyl cassava starch (CMCS)-functionalized magnetic nanoparticles (CMCS@Fe3O4) were synthesized via a simple one-pot co-precipitation method using CMCS materials with varying degrees of substitution, and used for the adsorption/removal of doxorubicin hydrochloride (Dox; a clinically available anti-cancer drug) from aqueous solution. The adsorption of Dox was studied using experimental conditions with varied pH, temperature, initial Dox concentration, and CMCS@Fe3O4 dosage. The CMCS@Fe3O4 adsorbents were characterized by scanning electron microscopy, transmission electron microscopy, infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and vibrating sample magnetometry. Each CMCS@Fe3O4 adsorbent exhibited a cubic inverse spinel iron oxide phase, small particle size, favorable magnetic properties, and good thermal stability. Batch adsorption experiments showed that the Dox adsorption efficiency reached 85.46% at a CMCS@Fe3O4 concentration of 20 mg mL-1 at 303 K in pH 7.0. The adsorption experimental results indicated that the adsorption kinetics followed a pseudo-second-order model and the Langmuir equation. Considering the environmentally nontoxic nature of Fe3O4 and starch, the CMCS@Fe3O4 material demonstrated significant potential for removing Dox from aqueous solution and in magnetic targeted drug delivery systems for synergistic tumor treatments.


Assuntos
Antineoplásicos/análise , Doxorrubicina/análise , Manihot/química , Amido/análogos & derivados , Poluentes Químicos da Água/análise , Concentração de Íons de Hidrogênio , Fenômenos Magnéticos , Nanopartículas de Magnetita , Nanocompostos , Tamanho da Partícula , Amido/química , Temperatura , Difração de Raios X
13.
Int J Biol Macromol ; 184: 551-557, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34171255

RESUMO

Modified potato starch with slower digestion may aid the development of new starch derivatives with improved nutritional values, and strategies to increase nutritional fractions such as resistant starch (RS) are desired. In this study, a correspondence between starch structure and enzymatic resistance was provided based on the efficient branching enzyme AqGBE, and modified starches with different amylose content (Control, 100%; PS1, 90%; PS2, 72%; PS3, 32%; PS4, 18%) were prepared. Through SEM observation, NMR and X-ray diffraction analyses, we identified that an increased proportion of α-1,6-linked branches in potato starch changes its state of granule into large pieces with crystallinity. Molecular weight and chain-length distribution analysis showed a decrease of molecular weight (from 1.1 × 106 to 1.1 × 105 g/mol) without an obvious change of chain-length distribution in PS1, while PS2-4 exhibited an increased proportion of DP 6-12 with a stable molecular weight distribution, indicating a distinct model of structural modification by AqGBE. The enhancement of peak viscosity was related to increased hydrophobic interactions and pieces state of PS1, while the contents of SDS and RS in PS1 increased by 37.7 and 49.4%, respectively. Our result provides an alternative way to increase the RS content of potato starch by branching modification.


Assuntos
Enzima Ramificadora de 1,4-alfa-Glucana/metabolismo , Burkholderiales/enzimologia , Solanum tuberosum/química , Amido/química , Amilose/química , Proteínas de Bactérias/metabolismo , Cristalografia por Raios X , Estrutura Molecular , Peso Molecular , Viscosidade , Difração de Raios X
14.
Int J Biol Macromol ; 184: 566-573, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34174300

RESUMO

This study aimed to develop potato starch nanocomposite films containing mesoporous nano-silica (SBA-15, SBA-16 and MCM-41) incorporated with Thyme essential oil (TEO). TEO-SBA-15/potato starch films, TEO-SBA-16/potato starch films and TEO-MCM-41/potato starch films were prepared based on potato starch. The physical and mechanical properties of the nanocomposite films were also investigated. The results showed that the addition of mesoporous nano-silica incorporated with TEO improved the properties of potato starch nanocomposite films. Especially, the addition of TEO-MCM-41 markedly enhanced the tensile strength (4.33 MPa), and reduced the water vapor permeability (1.80 g·m-1·h-1·KPa-1) and moisture absorption (37.67%) of potato starch nanocomposite films. The results of scanning electron microscopy (SEM) analysis showed that TEO-MCM-41 hardly agglomerated in the potato starch nanocomposite films. Additionally, Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) confirmed that strong hydrogen bonds were formed between TEO-MCM-41 and potato starch. The release kinetics of TEO proved that incorporating TEO into the pores of mesoporous nano-silica could delay its release rate, and the Peleg model (t/(Mt - M0) = K1 + K2t) was suitable for describing the release behavior. The findings of this study suggested that TEO-MCM-41/potato starch films had a good application prospect in the field of slow-releasing and antimicrobial packaging materials.


Assuntos
Óleos Voláteis/química , Dióxido de Silício/química , Solanum tuberosum/química , Amido/química , Thymus (Planta)/química , Portadores de Fármacos , Cinética , Microscopia Eletrônica de Varredura , Nanocompostos , Óleos Vegetais/química , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Resistência à Tração , Difração de Raios X
15.
Int J Biol Macromol ; 183: 1903-1910, 2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-34097954

RESUMO

Corn starch (CS) and cellulose nanofibrils (CNFs) were incorporated into biodegradable poly (vinyl alcohol) (PVA) to prepare mechanically robust and sustainable composites through melt-processing. Based on the regulation and control of hydrogen bonding network, CS and CNFs can extend the processing window and improve the thermoplasticity of PVA composites. Fourier transform infrared spectroscopy and Raman spectra analysis indicate that the intra- and inter-molecular hydrogen bonds of PVA are broken, accompanied by the formation of new hydrogen bonds among PVA, CS and CNFs during the melt-processing treatment. Thermal analysis shows that the processing window of PVA composite is significantly broadened to 131.46 °C. The tensile strength, modulus and elongation at break of the composites reach to 28.19 MPa, 1572.54 MPa and 10.72% by the incorporation of 10 wt% CS and 10 wt% CNFs. This strategy is not only expected to provide a direction for preparing complex three-dimensional products of PVA by melt-processing, but also provide a method to enhance the mechanical properties of other biodegradable plastics.


Assuntos
Celulose/química , Álcool de Polivinil/química , Amido/química , Temperatura Alta , Ligação de Hidrogênio , Nanocompostos , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Resistência à Tração , Termodinâmica
16.
Int J Biol Macromol ; 183: 2009-2016, 2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-34102234

RESUMO

Cold plasma is an innovative strategy to strengthen the polysaccharide-based films characteristics. This study evaluated the effects of dielectric barrier discharge (DBD) plasma on the hydrophilic character, water vapor permeability (WVP), and tensile properties of corn starch-based films. Starch films were exposed to plasma processing operating at an excitation frequency of 200 Hz for 10, 15, and 20 min. DBD plasma resulted in further enhanced tensile strength and stiffness, and lower hydrophilicity and water solubility; however, it did not present significant effects on the WVP of the resulting films within the ranges studied. Higher hydrophobicity, strength, and stiffness were verified after 20 min. The results presented in this work suggest that the DBD plasma has the potential to make starch-based films a more suitable packaging material.


Assuntos
Gases em Plasma/química , Amido/química , Embalagem de Alimentos , Interações Hidrofóbicas e Hidrofílicas , Solubilidade , Resistência à Tração , Água/química
17.
Int J Mol Sci ; 22(11)2021 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-34073072

RESUMO

Understanding the mechanism of interactions between magnetite nanoparticles and phospholipids that form cellular membranes at the molecular level is of crucial importance for their safe and effective application in medicine (e.g. magnetic resonance imaging, targeted drug delivery, and hyperthermia-based anticancer therapy). In these interactions, their surface coating plays a crucial role because even a small modification to its structure can cause significant changes to the behaviour of the magnetite nanoparticles that come in contact with a biomembrane. In this work, the influence of the magnetite nanoparticles functionalized with native and aminated starch on the thermodynamics, morphology, and dilatational elasticity of the model cell membranes was studied. The model cell membranes constituted the Langmuir monolayers formed at the air-water interface of dipalmitoylphosphatidylcholine (DPPC). The surface of the aminated starch-coated nanoparticles was enriched in highly reactive amino groups, which allowed more effective binding of drugs and biomolecules suitable for specific nano-bio applications. The studies indicated that the presence of these groups also reduced to some extent the disruptive effect of the magnetite nanoparticles on the model membranes and improved their adsorption.


Assuntos
1,2-Dipalmitoilfosfatidilcolina/química , Nanopartículas de Magnetita/química , Membranas Artificiais , Amido/química , Aminação , Propriedades de Superfície , Termodinâmica
18.
Int J Biol Macromol ; 184: 218-234, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34144062

RESUMO

Starch derivatives are versatile compounds that are widely used in the pharmaceutical industry. This article reviews the advances in the research on hydrophilic and hydrophobic starch derivatives used to develop drug delivery systems over the last ten years, specifically microparticles, nanoparticles, nanocrystals, hydrogels, and scaffolds using these materials. The fundamentals of drug delivery systems, regulatory aspects, and chemical modifications are also discussed, along with the synthesis of starch derivatives via oxidation, etherification, acid hydrolysis, esterification, and cross-linking. The chemical modification of starch as a means to overcome the challenges in obtaining solid dosage forms is also reviewed. In particular, dialdehyde starches are potential derivatives for direct drug attachment; carboxymethyl starches are used for drug encapsulation and release, giving rise to pH-sensitive devices through electrostatic interactions; and starch nanocrystals have high potential as hydrogel fillers to improve mechanical properties and control drug release through hydrophilic interactions. Starch esterification with alginate and acidic drugs could be very useful for site-specific, controlled release. Starch cross-linking with other biopolymers such as xanthan gum is promising for obtaining novel polyelectrolyte hydrogels with improved functional properties. Surface modification of starch nanoparticles by cross-linking and esterification reactions is a potential approach to obtain novel, smart solid dosages.


Assuntos
Aprovação de Drogas/organização & administração , Sistemas de Liberação de Medicamentos/métodos , Amido/química , Reagentes para Ligações Cruzadas/química , Esterificação , Legislação de Medicamentos , Estados Unidos , United States Food and Drug Administration
19.
Int J Biol Macromol ; 184: 393-404, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34144064

RESUMO

High hydrostatic pressure-treated corn starch (HPCS) and waxy corn starch (HPWCS) at three concentrations (10%, 15%, and 20%) were applied as novel fat replacers in a model low O/W emulsion at three fat reduction levels (FR, 25%, 50%, and 75%) and some physical, textural and rheological characteristics and stability of the samples were examined and compared with the control. Applying higher concentrations of HPCS and HPWCS increased the zeta potential, hardness and consistency (mainly for HPWCS samples), reversely decreased the Z-average particle size and polydispersity index of the reduced-fat emulsions, but augmenting FR levels caused a reverse inclination. The rheological assay cleared that the emulsions prepared with HPWCS had greater elastic modulus (G') and more gap between G' and viscous modulus (G″) at all concentrations than the HPCS-contained samples. The critical stress (τc) of 25FR samples were significantly higher than the control, showing the well stability of reduced-fat samples. Also, the τc of the HPCS-contained emulsions reduced meaningfully when the FR level increased from 25% to 75%, but for the HPWCS samples, fat reduction didn't change the τc value significantly up to 50% fat reduction. Based on Tangδs(n-LVE), HPWCS contained samples showed more spreadability than the HPCS-contained emulsions.


Assuntos
Emulsões/química , Amido/química , Zea mays/química , Pressão Hidrostática , Tamanho da Partícula , Reologia , Viscosidade
20.
Int J Biol Macromol ; 184: 42-49, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34111483

RESUMO

A cellulose nanocrystal based oxidation system is developed for oxidizing starch in the presence of NaClO, and provides an alternative and green method to improve the oxidizing degree of oxidized starch. The underlying mechanism for the oxidation was studied with confocal laser scanning microscopy. It was found that cellulose nanocrystal would penetrate into the starch microparticles and contribute to oxidation. The function of cellulose nanocrystal on the physicochemical properties of oxidized starch was investigated. With the incorporation of the oxidized starch into starch/polyvinyl alcohol/glyceryl composite films, the mechanical property and transparency of the films improved substantially. The highest oxidation level of starch was attained at 0.5 wt% cellulose nanocrystal dosage and the carboxylate content was 1.10%, the composite film showed the maximum transparency of 0.66 and highest contact angle of 102.0°. Meanwhile, the best film was obtained with oxidized starch containing 1.0 wt% cellulose nanocrystal. Compared to native starch and TEMPO-oxidated starch, the cellulose nanocrystal-based oxidized starch improved the hydrophobicity of film more substanially. In conclusion, cellulose nanocrystal acts as prooxidant and reforcing agent in this starch-based composite film, which makes them promising materials in the preparation of novel composite materials.


Assuntos
Celulose/química , Hipoclorito de Sódio/química , Amido/química , Química Verde , Interações Hidrofóbicas e Hidrofílicas , Microscopia Confocal , Nanopartículas , Oxirredução , Permeabilidade , Álcool de Polivinil/química , Resistência à Tração
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...