负载茶多酚的三元共混膜的制备及性能

以壳聚糖、玉米醇溶蛋白、茶多酚为原料,采用溶剂浇铸法制备得到一种三元共混膜。考察了茶多酚负载量(基于壳聚糖和玉米醇溶蛋白的总质量,下同)对壳聚糖/玉米醇溶蛋白膜液静态和动态流变学特性、粒径分布以及凝胶强度的影响。采用SEM、FTIR、XRD及DSC对共混膜进行了表征,并测定了三元共混膜的机械性能和阻隔性能。结果表明,茶多酚与成膜基质之间的交互作用使膜液中产生了高度纠缠网络结构,有利于均匀稳定共混膜的形成。负载适量茶多酚对膜性能具有良好的改善作用,当茶多酚负载量为1%时,共混膜具有最佳的抗张强度[(10.966±2.111)MPa]。茶多酚与壳聚糖、玉米醇溶蛋白之间发生了强烈的相互作用。此外,茶多酚负载量为0.5%和2.0%时,共混膜具有较高的热稳定性。     

油酸对壳聚糖/玉米醇溶蛋白膜性能的影响

为了提高壳聚糖/玉米醇溶蛋白膜的机械性能,将壳聚糖液与玉米醇溶蛋白液共混,向其中加入含量为0、15%、30%、45%(以复合膜液中壳聚糖和玉米醇溶蛋白的总质量为基准,下同)的油酸进行改性,制得复合膜液。考察了膜液的粒径、Zeta电位、静态和动态流变特性;分析了油酸添加量对膜阻隔性能、机械性能和相容性的影响。结果表明:添加油酸后,膜液体系粒径增大、分散均匀,添加30%油酸的膜液分散性更好,PDI为0.34,粒径为1307.5 nm。随着油酸含量增大,膜液黏度减小,流动指数增大,弹性模量和黏性模量增加。含30%油酸的膜机械性能较好,抗拉强度为36.37 MPa,断裂伸长率为22.32%。与不含油酸的膜相比,添加45%油酸膜的阻隔性增强,水蒸气、氧气透过率分别降低了44.21%和67.52%。复合膜中壳聚糖与玉米醇溶蛋白分子相容性较好,表面光滑平整。     

油酸对壳聚糖/玉米醇溶蛋白复合膜液流变及膜性能的影响

为了提高壳聚糖/玉米醇溶蛋白膜的机械性能，将壳聚糖液与玉米醇溶蛋白液共混，向其中加入0%、15%、30%、45%（w/w）的油酸改性，研究膜液的粒径、zeta电位、静态和动态流变特性；然后，分析油酸添加量对膜阻隔性能，机械性能和相容性的影响。结果表明：添加油酸后，膜液体系粒径增大、分散均匀，添加30%油酸的膜液分散性更好，PDI为0.34，粒径为1307.5nm。随着油酸含量增大，膜液粘度减小，流动指数增大，弹性模量和粘性模量增加。OA-30膜机械性能较好，抗拉强度达到36.37MPa，断裂延伸率达到22.32%。膜的阻隔性增强，水蒸气、氧气透过率分别降低了44.21%和66.52%。复合膜中壳聚糖与玉米醇溶蛋白分子相容性好，表面光滑平整。综上所述，油酸改性改善了壳聚糖/玉米醇溶蛋白复合膜性能。     

负载茶多酚的三元共混膜液与膜性能分析

将不同质量分数的活性成分茶多酚加入到壳聚糖/玉米醇溶蛋白共混膜液中，采用溶剂浇铸法制备得到一种三元共混膜。分析茶多酚对壳聚糖/玉米醇溶蛋白膜液静态和动态流变学特性、粒径分布以及凝胶强度的影响；测定三元共混膜的机械性能和阻隔性能；同时对共混膜进行形貌、红外、晶体学和热力学分析。结果表明：茶多酚与成膜基质之间的交互作用使膜液中产生了高度纠缠网络结构，有利于均匀稳定共混膜的形成；负载适量茶多酚对膜性能具有良好的改善作用，当茶多酚负载量为1%时，膜材料具有最佳的抗拉强度10.966 Mpa；SEM和XRD结果显示茶多酚与壳聚糖、玉米醇溶蛋白之间发生了强烈的相互作用，具有良好的相容性；FT-IR图谱显示茶多酚与成膜基质之间产生了氢键相互作用；通过热力学分析发现负载茶多酚质量分数为0.5%和2%时，共混膜具有较高的热稳定性。     

玉米蛋白粉中醇溶蛋白的提取工艺研究

利用超声波技术提取玉米蛋白粉中的玉米醇溶蛋白。采用双缩脲法测定蛋白质的含量,通过单因素和正交实验得到的最佳工艺条件为:料液比为1∶15,乙醇体积分数为65%,超声时间为50 min,超声温度为60℃。玉米醇溶蛋白提取率可达61.78%。     

玉米醇溶蛋白的研究及应用

本文对玉米醇溶蛋白的特性、提取工艺、脱色工艺以及应用方面进行了介绍。玉米醇溶蛋白具有很强的韧性、疏水性、可降解性、抗茵性等特点，广泛用于食品、医药、纺织、造纸等工业。     

肉桂醛的研究与应用进展

详细综述了近年来肉桂醛的抗癌、抗糖尿病、抗炎等药理活性,对西瓜和鸡肉等保鲜功能,肉桂醛衍生物的合成与应用,肉桂醛抗菌膜以及淬灭玉米醇溶蛋白等特殊用途,旨在进一步推动肉桂醛的研究与应用,开发具有较高实用价值的功能产品。     

玉米醇溶蛋白的应用

玉米醇溶蛋白的应用程嘉豪（兰州化学工业公司化工研究院·７３００６０）前言玉米蛋白粉是玉米淀粉生产过程中产生的副产品之一，对其进行深加工利用，可制得玉米醇溶蛋白。玉米中约含干物重１０％蛋白质，其中５０％～６Ｏ％为醇溶蛋白。据Ｅｓｅｎ分类，玉米醇溶蛋白共...     

玉米醇溶蛋白的特性与应用

介绍丁玉米醇溶蛋白的溶解性和成膜性等特性,以及应用概况,其用于制取油脂模拟品、肽,作为成膜剂、保鲜剂,用于提取β-胡萝卜素。     

响应面法优化小麦醇溶蛋白膜热压工艺

以小麦蛋白为原料,从中提取小麦醇溶蛋白(Gliadin)与聚乙二醇(PEG200)混合、热压制备透明生物塑料。以PEG200含量、热压温度、热压时间为影响因子,以膜的断裂强度、断裂伸长率、吸湿率、溶胀度、溶解度为主要评价指标,通过响应面试验确定了制备PEG200增塑小麦醇溶蛋白膜的最佳工艺条件。试验结果表明:PEG200含量15%(PEG200与Gliadin的质量比)、热压温度154℃、热压时间3 min制备的小麦醇溶蛋白膜的综合性能最好;在最优工艺条件下,膜的断裂强度为18.38 MPa,断裂伸长率为5.95%,吸湿率(相对湿度65%)为4.65%,溶胀度为103.99%,溶解度为15.52%。     

The combined effects of lysozyme and ascorbic acid on microstructure and properties of zein-based films

Edible zein-based films containing lysozyme(LY) and ascorbic acid(AA) were developed in the presence of polyethylene glycol 400(PEG 400), the combined effects of LY and AA on the microstructure, mechanical properties and release properties of developed zein films were investigated in detail. The results of microstructure characterization indicated that zein-based films became compact and smooth, and LY aggregates were well distributed in the zein matrix because of the simultaneous addition of LY and AA. The results of mechanical tests showed that because of the synergistic effects of LY and AA on zein film, elongation at break of zein-based film could be up to 138%, which was 34.5 times higher than that of zein control film. LY release tests showed that when the concentration of AA was less than 3.1 mg·cm~(-2), the release rate of LY significantly decreased by 33.7%, and the total release increased by 80.6%. While the release profiles of AA showed that the release rate and total release of AA from the films containing LY increased by approximately 68.9% and 61.7% than the films without LY. Good antioxidant and sustained antimicrobial activities were found for the developed zein films.     

Influence of preparation conditions on the physical properties of zein films

Zein is a hydrophobic protein produced from maize. Biodegradable zein films without additional reagents were prepared using various controlled drying conditions. The zein films were transparent. Mechanical properties (tensile strength and puncture strength), gas permeability, and water vapor permeability (WVP) of the zein films were measured. The tensile strengths of the zein films were between 7 and 30 MPa and the puncture strengths between 37 and 191 MPa. The zein films had higher oxygen permeability than carbon dioxide permeability. The lowest WVP of the zein film was 0.012×10⁻⁹ g·m/m²·s·Pa. We found differences in the WVP between the sides of the zein films; i.e., the air side of the zein film had a higher WVP than the basal side of the zein film when the films were exposed to high humidity during testing. This indicates a relationship between the WVP of the zein film and the contact angle of the zein film. The mechanical properties of the zein film depended on the drying conditions during preparation. Zein films with various useful physical mechanical properties were produced.     

Effect of corn‐zein coating on the mechanical properties of polypropylene packaging films

In this study, a novel film structure of corn zein coated on polypropylene (PP) synthetic films for food packaging applications was developed, and the mechanical properties of the resulting coated film, as affected by the coating formulation, were investigated. Composite structures of PP films coated with corn zein were obtained through a simple solvent casting method. Different amounts of corn zein (5 and 15%) were dissolved in 70 and 95% aqueous ethanol solution at 50°C. Solutions of corn zein plasticized with poly(ethylene glycol) and glycerol (GLY) at various levels (20 and 50%) were applied on corona‐discharge‐treated PP. A statistical analysis based on full factorial design was performed to examine the influence of the coating formulation on the final properties of the corn‐zein‐coated PP films. A significant (p < 0.05) improvement in the coated film's mechanical properties was observed compared to those of the uncoated PP. The effect of the plasticization of the coating solutions was also quite significant. In general, GLY provided better improvements in the mechanical properties of the corn‐zein‐coated PP films. The statistical analysis of the results showed that the corn‐zein and plasticizer concentrations and plasticizer type used in the coating formulations were more effective parameters and had significant effects on the mechanical behavior of the coated PP films. In conclusion, corn‐zein coatings could have potential as alternatives to conventional synthetic polymers used in composite multilayer structures for food packaging applications. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Water-repellent films from corn protein and tomato cutin

Flexible and hydrophobic biobased films were obtained using zein esterified with methanol and para-toluene (p-toluene) sulfonic acid, cutin from tomato peels and ethanol. Esterification was confirmed by proton nuclear magnetic resonance and attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR). Non-modified zein films were brittle and hydrophilic. ATR-FTIR demonstrated that zein esterification increased zein hydrophobicity. Without cutin, esterified zein films were hydrophobic but brittle. Addition of cutin yielded films that were flexible and hydrophobic, as demonstrated by contact angle measurements. Principal component analysis (PCA) of ATR-FTIR data showed that intensities at 3195 cm⁻¹ and 3490 cm⁻¹ were correlated to the relative hydrophobicity of zein films. PCA also showed that films of esterified zein and cutin were more hydrophobic than their counterparts (non-modified zein without cutin). Optical and scanning electron microscopy demonstrated that esterified zein was compatible with cutin and yielded cohesive films, which did not fracture upon bending.     

Improved zein films using polyethylenemaleic anhydride

The effect on the physical properties and solubility of corn protein (zein) films was studied after reaction of zein with polyethylenemaleic anhydride (PEMA). Reactions were carried out in dimethylformamide (DMF) solution where the concentration of PEMA was varied between 0 and 6%. After reaction at room temperature, cast films were prepared, and the physical and solubility properties were determined. Incorporating more than 2% PEMA provided films with increased tensile strength and elongation. Incorporating 6% PEMA provided films with higher tensile strength (32–42 MPa) and improved solvent resistance (100–21% solubility) relative to control. If the films were heated in an oven, the film's solubility decreased further. Solution rheology experiments demonstrated that the zein and PEMA formed a cross‐linked gel with time in DMF. Dynamic mechanical analysis experiments have shown that the PEMA‐modified zein films undergo a dramatic loss in modulus on reaching 116°C, whereas the control experiences this loss at 98°C. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40122.     

X‐ray diffraction characterization of the structure of zein–Oleic acid films

Wide‐angle (WAXS) and small‐angle X‐ray scattering (SAXS) studies of dry granular zein, zein fibers, zein–oleic acid resin, and zein–oleic acid films are reported. WAXS patterns showed two diffuse rings for these samples indicative of noncrystalline structures. Measured d‐spacings of ∼ 4.6 Å and ∼ 10.5 Å were found for zein–oleic acid resins and films, consistent with the presence of α‐helical segments. The granular zein and zein fibers had ∼ 4.6‐Å and ∼ 9.5‐Å spacings. Neither the films nor the fibers showed evidence of orientation of the molecular axes. SAXS studies of zein–oleic acid films indicated that the structure of the films was affected by preparation method. Biaxially drawn resin films showed periodicities of ∼ 170 Å along the film surface direction and ∼ 135 Å in the thickness direction, while the cast films had weaker intensity periodicities of ca. 80 Å for all beam directions; a weak, diffuse 45‐Å spacing was also observed for both samples. The 170‐Å periodicity was present in the resin before deformation and following uniaxial deformation. No SAXS periodicity was observed for the granular zein or zein fibers. Several structural models are presented for the resin films that are consistent with reports in the literature that zein, in solution, consist of prism‐like particles consisting of four or more molecules. ? 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1267‐1281, 1999     

Zein/polyvinyl alcohol-based electrospun nanofibrous films reinforced with nano-hydroxyapatite for efficient Cu(II) adsorption

To solve the problem of the presence of heavy metals in water causing water pollution, the biodegradable film based on zein/polyvinyl alcohol (PVA) with the incorporation of nano-hydroxyapatite (nHAP) was fabricated through an electrospinning technique. The copper ion was taken as the representative of heavy metal ions in this study. The result showed that the incorporated nHAP nanoparticles were dispersed within the zein/PVA matrix, and strong hydrogen bonding interactions were formed between the filler and matrix, improving the hydrophobicity of the nanofibrous films and maintaining thermal stability. The adsorption mechanism was analyzed by fitting the adsorption process with pseudo-first-order model and pseudo-second-order model. Based on the ion exchange effect, electrostatic interaction, and complexation, the adsorption capacities of nanofibrous films for Cu(II) were significantly increased after adding nHAP. When the nHAP content was 20 wt.%, the Cu(II) adsorption capacity reached up to 23.86 mg/g, and the adsorption efficiency was 13.94% higher than that of neat zein/PVA nanofibers. This work suggests the potential of the electrospun zein/PVA/nHAP nanofibrous films as desirable eco-friendly materials in metal removal applications.     

Studies on glass transition temperature of mono and bilayer protein films plasticized by glycerol and olive oil

Thermomechanical and thermal properties of whey protein, maize prolamin protein (zein), and the laminated whey protein–zein films were studied. The dynamic mechanical (thermal) analysis (DMTA) results showed that the single zein film had higher T_g than single whey protein and zein–whey laminated films. The shift in the T_g values of films from 31.2°C in whey protein film and 88.5°C in the zein film to 82.8°C in the laminated whey protein–zein films may be implied some interaction formation between the two polymers. The small tan δ peaks were observed at ?50°C in zein–glycerol films and at ?22.37°C in the whey protein films and can be related to β‐relaxation phenomena or presence of glycerol rich region in polymer matrix. Zein‐olive oil and zein–whey protein–olive oil films showed tan δ peaks corresponded the T_g values at 113.8, and 92.4°C, respectively. Thus, replacing of glycerol with olive oil in film composition increased T_g. A good correspondence was obtained when DSC results were compared with the tan δ peaks in DMTA measurements. DSC thermograms suggested that plasticizers and biopolymers remained a homogeneous material throughout the cooling and heating cycle. The results showed that T_g of zein–glycerol films predicted by Couchman and Karasz equation is very close to value obtained by DSC experiments. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation of polypropylene/octadecane composite films and their use in the packaging of cherry tomatoes

Polypropylene (PP)/octadecane (OD) composite films were prepared via twin‐screw extrusion, and their chemical, morphological, thermal, and surface properties and oxygen and water vapor permeabilities were analyzed as functions of the OD content and temperature. OD was dispersed well in the PP matrix, and two phases (i.e., the PP and OD portions) were present in the PP/OD composite films. When the temperature was increased from 10 to 30 °C, both the oxygen transmittance rate and the water vapor transmittance rate of the PP/OD composite films increased sharply because of the influence of the OD content. These results were related to the temperature‐dependent changes in the morphological structure, such as changes in the the tortuous paths and crystallinity in the composite films because of the addition of OD. In the storage test, the PP/OD (83:17) composite films continuously controlled the gas concentration of the headspace and protected against environmental factors; this reduced the enzymatic activity and led to higher quality cherry tomatoes compared to the case when the pure PP and MP33000 films were used. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44087.