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Zein encapsulation of amphiphilic compounds
No full textFunctional compounds including flavors, essential oils, antioxidants or nutraceuticals are widely added into food system to enhance sensory properties or for health purposes. However, these compounds might not be stable in food systems during processing, storage and food preparation. Encapsulation has been proposed as a practical approach to stabilize these compounds and control their release. Zein is an amphiphilic protein originally obtained from corn. Its film-forming and coating ability make it potentially useful as a wall material for encapsulation. Amphiphilic compounds have been recognized to form well defined microspheres by evaporation induced self-assembly (EISA) in binary solvents, which is useful in encapsulation. The goals of this research were to improve our understanding of the development of zein encapsulation structures. The main objective was to investigate the effect of the hydrophobicity of core materials as measured by contact angle on the formation and structure of zein encapsulates obtained by evaporation induced self-assembly of ethanol-water systems. A second objective was to apply the knowledge learned in the above objective to propose a strategy to capture and encapsulate flavors generated in frying oils. Results showed that citral was effectively encapsulated with zein. Zein encapsulation morphology was related to the droplet formation ability of core materials in ethanol-water systems. Amphiphilic compounds were believed to form stable droplets in ethanol-water, which favored zein encapsulation. Hydrophobic compounds showed phase separation in ethanol-water which led to the formation of films rather than closed structures. A model system consisting of mixtures of a flavor and a hydrophobic carrier was used to study the effect of carriers on encapsulation ability of zein by the self-assembly process. The presence of the carrier negatively affected encapsulation effectiveness. Citral was recovered from the flavor-carrier mixture by extraction and phase separation at sub-freezing temperatures. Recovered citral was effectively encapsulated by zein. Fried chips flavors were also recovered from frying oil and encapsulated in zein by ethanol extraction and phase separation at low temperatures. Sensory ranking test was used to confirm the presence of recovered flavors after zein encapsulation.Item withdrawn by Mark Zulauf ([email protected]) on 2012-06-19T21:58:37Z
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Frauen und Revolution: Wege geschlechtlicher Emanzipation
No full textDr. Huda Zein (Marburg) sprach im Rahmen der Studium Generale Reihe "Facetten des Vorderen Orients. Eine sich wandelnde Region im Fokus." Ihr Vortrag beschäftigte sich mit der Rolle der Frauen in der arabischen Welt, die gerade starke Umbrüche erlebt
Nanopartículas de zeína: preparação, caracterização e desenvolvimento de um sistema de liberação controlada de terpinen-4-ol
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas, Programa de Pós-Graduação em Química, Florianópolis, 2014.Este trabalho descreve o desenvolvimento de nanopartículas (NPs) biodegradáveis, incluindo NPs revestidas com quitosana (CS) e a utilização de promotores de permeação (SPEs), visando a liberação transdémica do terpinen-4-ol (T4OL). Três diferentes sistemas de NPs foram desenvolvidos: NPs de zeína, NPs de zeína na presença de SPEs e NPs de zeína revestidas com CS. As NPs foram preparadas pela adaptação de um processo de precipitação em antisolvente. Todos os sistemas investigados apresentaram forma esférica e mostraram tamanhos em torno de 200 nm, com uma estreita faixa de distribuição de tamanho. As NPs também foram caracterizadas por microscopia eletrônica de transmissão (TEM), tendo sido obtidos dados que confirmaram os valores do tamanho obtidos por espalhamento de luz dinâmico (DLS). As suspensões de NPs contendo T4OL apresentaram valores de eficiência de encapsulação (EE) próximos a 90%. O revestimento das NPs com CS foi confirmado através das medidas de tamanho das partículas e de potencial zeta (?). Foi avaliada a estabilidade das suspensões de NPs de zeína contendo T4OL em função do tempo. As NPs na presença ou ausência de SPEs foram estáveis por até 20 dias, enquanto para as NPs na presença ou ausência de CS a estabilidade foi até o 30o dia. As NPs de zeína também foram avaliadas quanto à liberação, permeação e retenção de T4OL através da pele de orelha suína, em um modelo da câmara de difusão de Franz. Foi estudado ainda o efeito dos SPEs sobre a permeação cutânea do T4OL contido nas NPs, tendo sido observada uma melhora na permeação do T4OL e que sua liberação ocorre de maneira mais controlada. Os resultados mostram que as NPs de zeína estudadas são sistemas nanoestruturados promissores para a entrega prolongada T4OL, exibindo potencial para ser utilizado em terapia anti - melanoma.Abstract : This study describes the development of biodegradable nanoparticles (NPs), including NPs recovered with chitosan (CS) and the utilization of skin penetration enhancers (SPEs), aiming the T4OL deliveryin the skin. Three different NP systems were developed: zein NPs, zein NPs in the presence of SPEs and zein NPs recovered with CS. Zein NPs were prepared using a modified antisolvent precipitation process (desolvation). All investigated systems presented spherical format and showed sizes at ca. 200 nm, with a narrow range of size distribution. The NPs were also characterized through transmission electronic microscopy analysis, being obtained data that confirmed the obtained size values by dynamic light scattering (DLS). The suspensions of NPs containing T4OL presented EE values of ca. 90%. Recovering of NPs with CS was confirmed by means of measurements of size particles and zeta potential (?). The stability of zein NPs suspensions were evaluated as a function of the time.The NPs in the absence and in the presence of SPEs were stable until the period of 20th day, while for the NPs in the presence and in the absence of CS the stability occurred until the 30th day. The delivey, permeation and retention of zein NPs T4OL through pig ear skin were also evaluated, using a Franz diffusion cell apparatus. The influence of the SPEs on the cutaneous permeation of T4OL contained in the NPs was also studied, being reported an improved T4OL permeation and that its release occurs in a more controlled fashion.The results show that the zein NPs studied here are promising nanostructured systems for the prolonged T4OL delivery, exhibiting a potential to be used in anti-melanoma therapy
Zein-Induced Polyelectrolyte Complexes for Encapsulating Triterpenoid Phytochemicals
No full textThe hydrophobicity and aggregation of zein, a biopolymer,
limit
its application as an effective drug delivery carrier. Here, we developed
a zein-induced polyelectrolyte (ZiP) complex and investigated its
efficiency in delivering 1% hydrolyzed ginseng saponin, a compound
K-rich fraction derived from the root of Panax ginseng. The ZiP complex was formulated by incorporating the self-assembled
amphiphilic prolamin zein into the aqueous phase. The physical properties,
encapsulation efficiency, and stability of the encapsulation system
at room temperature (25 °C) and 45 °C were assessed. The
effects of different ratios of zein, pullulan, and pectin on the formation
of the ZiP complex, the encapsulation stability, and the cellular
efficacy of ZiP complexes were also assessed. The ZiP complex was surface-modified
with hydrophilic pullulan and pectin polysaccharides in a mass ratio
of 1:2:0.2 through electrostatic interactions. The primary hydrophilic
modification of the ZiP complex was formed by the adsorption of pullulan,
which enhanced the encapsulation stability. The outermost hydrophilic
layer comprised the gelling polysaccharide pectin, which further improved
the stability of the macro-sized oil-encapsulated complex, reaching
sizes over 50 μm. The size of the ZiP complex increased when
the concentration of pectin or the total content of the ZiP complex
increased to 2:4:0.2. Compound K was successfully encapsulated with
a particle size of 294.8 nm and an encapsulation efficiency of 99.6%.
The ZiP complex demonstrated stability at high temperatures and long-term
stability of the encapsulated saponin over 24 weeks. These results
revealed the potency of ZiP complexes that enhance the in
vivo absorption of phytochemicals as effective drug delivery
carriers that can overcome the limitations in industrial formulation
development as a delivery system
Fabrication and Characterization of Zein/Viscose Textibe Fibers
No full textAzlons are increasingly concerned for their excellent performance properties and biodegradation. A kind of novel azlon, zein/viscose textibe fibers, were fabricated by wet-spinning of zein and cellulose sulfonate blended solution. Some parameters that determine the fabrication process were optimized. The structure and properties of zein/viscose fibers were characterized, and compared with those of common viscose fibers. Dry breaking tenacity of zein/viscose fibers was 2.02 CN/dtex, whereas dry breaking elongation was 16.6%. Mechanical properties of zein/viscose fibers were a little better than common viscose fibers. The moisture regain rate of zein/viscose fibers was 14.1%, similar to that of viscose fibers. From the microstructure of zein/viscose fiber, viscose acted as framework and zein was accreted to viscose. The content of protein was 14.48% in zein/viscose fibers. The basic chains of zein and viscose were not changed by blended spinning, so the fibers had advantages of both zein and viscose. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 3364-3370, 201
Zein-Based Nanomedicines for Synergistic Chemodynamic/Photodynamic Therapy
No full textCurrent cancer treatment is not only limited to monotherapy
but
is also influenced by limited drug delivery options. Combined chemokinetic-photokinetic
therapy has great promise in enhancing anticancer effects. Meanwhile,
zein has superior self-assembly properties and can be loaded with
photosensitizers. Herein, the targeted multifunctional nanoparticles
based on zein/hyaluronate acid (HA)/tannin (TA)/Cu2+ loaded
with IR780 (ZHTC@IR780) are constructed for synergetic cancer therapy
by chemo-dynamic therapy (CDT) and photodynamic therapy (PDT). There
is experimental proof that ZHTC@IR780 nanoparticles (NPs) can relieve
the tumor hypoxic microenvironment by catalytic decomposition of endogenous
H2O2 to O2 and further react with
O2 to produce toxic 1O2 with 808
nm laser irradiation. The glutathione oxidase-like effects of ZHTC@IR780
NPs can generate Fenton-like Cu+ ions and deplete GSH for
efficient hydroxyl radical (•OH) production. In
addition, CDT combined with PDT enhances the antitumor effect. Photodynamic
therapy can cause immunogenic cell death, increase calreticulin eversion,
release histone with high mobility, and promote apoptosis of tumor
cells
Zein-Bonded Graphene and Biosurfactants Enable the Electrokinetic Clean-Up of Hydrocarbons
No full textNonaqueous phase liquids (NAPL, e.g.,
hydrocarbons and chlorinated
compounds) are common groundwater pollutants. Electrokinetic remediation
of NAPLs uses electric fields to draw them toward electrodes and remove
them from groundwater. The treatment requires NAPL mobility. Emulsification
increases mobility, but at a risk for downstream receptors. We propose
using alkaline aqueous solutions of zein and graphene nanoparticles
(GNP) to form conductive materials, which could also act as barriers
to control NAPL migration. Alkaline zein–GNP solutions can
be injected in the polluted soil and solidified by neutralizing the
pH (e.g., with glacial acetic acid, GAA). Shear rheology experiments
showed that zein–GNP composites were cohesive, and voltammetry
showed that GNP increased electrical conductivity of zein-based materials
by 3.5 times. Gas chromatography–mass spectroscopy (GC–MS)
demonstrated that the electrokinetic treatment of model sandy aquifers
yielded >60% and ∼47% removal of emulsified toluene in freshwater
and in salt solutions, respectively (with 30 min treatment using a
10 V differential voltage between a zein–GNP and an aluminum
electrode. NaCl was used as model salt contaminant. The conductivity
of surfactant solutions was lower in saline water than in freshwater,
explaining differences in toluene removal. Toluene–water emulsions
were stabilized using the natural surfactants lecithin and saponin.
These surfactants acted synergistically in stabilizing emulsions in
either freshwater or salt solutions. Lecithin and saponin likely interacted
at toluene–water interfaces, as indicated by the morphology,
interfacial tension and compressional rigidity of toluene–water
interfaces with both components (relative to interfaces of either
lecithin or saponin alone). The compressional behavior of interfacial
films was well-described by the Marczak model. Electrokinetic treatment
of saturated model sandy aquifers also decreased the turbidity of
emulsions of water and either tricholoroethylene (TCE, by ∼41%)
or diesel (by ∼75%), in the presence of a bacterial biosurfactant.
This decrease was used as semiquantitative indicator of NAPL removal
from water
Obtenção e caracterização de micropartículas de zeína carregadas com extratos antioxidantes de casca de noz-pecã (Carya illinoinensis (wangenh) C. Koch)
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, Programa de Pós-Graduação em Ciência dos Alimentos, Florianópolis, 2014.Este trabalho teve por objetivo produzir e caracterizar micropartículas de zeína carregadas de extratos de casca de noz-pecã [Carya Illinoinensis (Wangenh) C. Koch] obtidas por spray-dryer. Extratos aquosos e hidroalcoólicos de casca de noz-pecã foram obtidos através de extração assistida por ultrassom e a atividade antioxidante dos mesmos foi determinada através das metodologias ABTS e DPPH. Para a microencapsulação dos extratos por spray dryer foi utilizado o biopolímero zeína como material de parede e nas formulações com maior rendimento e eficiência de encapsulação foram avaliados a liberação de compostos fenólicos, a densidade, ângulo de contato, a cor através do sistema CIE Lab, o comportamento térmico por Differencial Scanning Calorimeter (DSC), espectrofotometria no infravermelho (FTIR) e, a morfologia e distribuição de tamanho das partículas por MEV. As micropartículas também foram adicionadas a óleo de palma e girassol e a estabilidade dos mesmos foi avaliada através do Shaal Oven Test. Os teores mais significativos (pAbstract : The aim of this study was to produce and characterize zein microparticles loaded with extracts of pecan nut shell [Carya illinoinensis (Wangenh) C. Koch] obtained by atomization in a spray dryer. The aqueous and hydroalcoholic extracts of pecan nut shell were obtained by ultrasound-assisted extraction (UAE) and their antioxidant activity was determined by the ABTS and DPPH methods. In order to microencapsulate the extract in a spray dryer, zein (a biopolymer) was used as wall material. The following properties were evaluated for the formulations with a higher yield and encapsulation efficiency: release of phenolic compounds, density, contact angle, color (using the CIELAB color system), thermal behavior (using the Differential Scanning Calorimeter [DSC]), infrared spectrophotometry [FTIR], and morphology and distribution of particle size by SEM [scanning electron microscope]). The microparticles were also added to palm and sunflower oils, and their stability was determined by the Schaal Oven Test. The most significant contents (p<0.05) for total phenolics, condensed tannins and antioxidant activity obtained by DPPH and ABTS were observed in the hydroalcoholic extract (275,24mg GAE.g-1; 319,08mg CE.g-1; 1207,62mol TEAC.g-1 and 1191,69 mg TEAC.g- 1respectively). Formulations containing 10g of zein and 0.4g of aqueous extract, and 5g of zein and 0.6g of hydroalcoholic extract, showed a higher yield and encapsulation efficiency. Zein microparticles loaded with aqueous extract (MAE) showed a better release profile of phenolic compounds and a lower density. The contact angle found indicated that the microparticles are hydrophobic despite their hydrophilic core. Thermal analysis revealed that the microparticles exhibit an amorphous behavior up to 200°C, and spectrophotometric analysis of the extracts indicated extract encapsulation, with a predominance of chemical groups present in zein. Microscopic analysis made it possible to observe that the microparticles had a spherical shape, with a smooth, depressed, partly concave surface, without pores, fissures or cracks. Zein particles loaded with aqueous and hydroalcoholic extracts had average sizes of 4,93µm and 4,81µm respectively; their size distribution was unimodal
Size-controlled fabrication of zein nano/microparticles by modified anti-solvent precipitation with/without sodium caseinate
No full textFeng Li,1 Yan Chen,1,2 Shubo Liu,1 Jian Qi,1 Weiying Wang,1 Chenhua Wang,1 Ruiyue Zhong,1 Zhijun Chen,1 Xiaoming Li,1 Yuanzhou Guan,1 Wei Kong,1,2 Yong Zhang1,2 1National Engineering Laboratory for AIDS Vaccine, School of Life Sciences, Jilin University, Changchun, 2Key Laboratory for Molecular Enzymology and Engineering, the Ministry of Education, School of Life Sciences, Jilin University, Changchun, China Abstract: Zein-based nano/microparticles have been demonstrated to be promising carrier systems for both the food industry and biomedical applications. However, the fabrication of size-controlled zein particles has been a challenging issue. In this study, a modified anti-solvent precipitation method was developed, and the effects of various factors, such as mixing method, solvent/anti-solvent ratio, temperature, zein concentrations and the presence of sodium caseinate (SC) on properties of zein particles were investigated. Evidence is presented that, among the previously mentioned factors, the mixing method, especially mixing rate, could be used as an effective parameter to control the size of zein particles without changing other parameters. Moreover, through fine-tuning the mixing rate together with zein concentration, particles with sizes ranging from nanometers to micrometers and low polydispersity index values could be easily obtained. Based on the size-controlled fabrication method, SC-coated zein nanoparticles could also be obtained in a size-controlled manner by incubation of the coating material with the already-formed zein particles. The resultant nanoparticles showed better performance in both drug loading and controlled release, compared with zein/SC hybrid nanoparticles fabricated by adding aqueous ethanol solution to SC solution. The possible mechanisms of the nanoprecipitation process and self-assembly formation of these nanoparticles are discussed. Keywords: zein, phase separation, microparticle, nanoparticle, encapsulation, drug release 
Zein-Alginate-Phosphatidylcholine Nanocomplex Efficiently Delivers Lycopene and Lutein over Dietary-Derived Carotenoid Mixed Micelles in Caco‑2 Cells
No full textThis study evaluated the potency of zein-alginate-phosphatidylcholine
nanoparticles (NPs) on bioaccessibility/intestinal uptake of encapsulated
lycopene (LY) and lutein (LT) versus dietary absorption using simulated
digestion and human intestinal Caco-2 cells. LY-zein-alginate-PC (LYZAP)
and LT-zein-alginate-PC (LTZAP) NPs yield desired properties, which
exhibit sustained release and are suitable for oral administration.
Interestingly, co-treatment of LYZAP + LTZAP showed better release
of carotenoids instead of individual treatment at intestinal pH. Bioaccessibility,
cellular uptake, and basolateral secretion of LY and LT from NPs were
significantly enhanced than micellar carotenoids (dietary mode of
absorption). The increased absorption of carotenoids from NPs correlated
with triglyceride levels. The intestinal cell uptake of carotenoids
by nanoencapsulation may be due to endocytosis, paracellular, and
SRB-1 protein-mediated transport. Overall, LYZAP and LTZAP NPs possess
superior properties to control the release and cellular uptake of
unique or distinct carotenoids. The inclusion of alginate and phosphatidylcholine
in zein-based nanoencapsulation could be a promising strategy to improve
carotenoid bioavailability
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