增塑剂对玉米醇溶蛋白膜阻隔性能影响北大核心

玉米醇溶蛋白具有较好成膜性,但其形成膜较脆,需通过添加不同增塑剂加以改善;但添加增塑剂会使膜阻隔性能受到影响。该实验以甘油、聚乙二醇(PEG)400、单甘油酯为增塑剂,研究在不同乙醇浓度时制备玉米醇溶蛋白(zein)膜阻湿性及阻油性;结果表明,当乙醇浓度为80%、甘油添加量为0.3 g/g zein,PEG–400添加量为0.2 g/g zein,单甘油酯添加量为0.3 g/g zein时,膜的水蒸汽透过率最小,透油率最大。     

不同增塑剂对玉米醇溶蛋白膜机械性能的影响

本试验主要研究了几种不同增塑剂对玉米醇溶蛋白膜机械性能（抗拉强度、延伸率）的影响。结果发现：添加复合增塑剂的蛋白膜延伸率较大、抗拉强度差；甘油和乙二醇的延伸率都较其他两种小得多，但乙二醇的抗拉强度比甘油的大；添加油酸所制备的蛋白膜抗拉强度较低、延伸率较大，并且蛋白膜柔软、有光泽和富有弹性。     

可食性玉米醇溶蛋白膜研究进展

该文介绍目前国内外可食性玉米醇溶蛋白膜研究现状及对发展趋势进行分析,指出制备以玉米醇溶蛋白为基质可食性复合包装膜是一个新的发展方向。     

成膜温度对玉米醇溶蛋白膜储藏稳定性影响

不同成膜温度下制备玉米醇溶蛋白膜,在不同环境温度下储藏24天,以蛋白膜抗拉强度和断裂延伸率为指标,研究储藏过程中蛋白膜机械性能变化。实验结果表明,随储藏时间延长,玉米醇溶蛋白膜抗拉强度呈先增加、后回落,断裂延伸率先降低、后上升;在储藏温度较高时,蛋白膜抗拉强度和断裂延伸率分别呈增大和减小趋势。不同成膜温度下制备蛋白膜其稳定性也不相同,5℃储藏时80℃水浴成蛋白膜更稳定,常温和35℃储藏时成膜温度90℃蛋白膜机械性能稳定性较好。     

不同多糖对玉米醇溶蛋白膜性质的影响

利用差示扫描量热仪（DSC）测定玉米醇溶蛋白溶液与多糖混合溶液的变性温度范围为80℃-95℃,在玉米醇溶蛋白和山梨醇体系中加入不同的多糖后（果胶、玉米淀粉、魔芋精粉、羧甲基纤维素和阿拉伯胶）测定膜性质,结果表明添加果胶的效果最好,加入果胶的膜透水率为0．760×10^-4kg·mm／（kPa·h·m^2）,拉伸强度为23．5×10^-5N／m^2。     

玉米醇溶蛋白的增塑改性研究

通过实验研究玉米醇溶蛋白 (zein)在不同介质表面上成膜的效果、成膜条件以及各增塑剂对成膜效果的影响 ,确定了抗拉强度较大、吸水性低的最佳成膜条件     

玉米醇溶蛋白膜研究进展

玉米醇溶蛋白膜作为一种绿色环保包装材料,具有良好的阻气性、阻湿性。因材料的可食性及可降解性使玉米醇溶蛋白膜在包装材料或可降解薄膜方面具有潜在商业价值,为其在食品、医药和化工等方面的应用奠定基础。文章对玉米醇溶蛋白的提取工艺、成膜工艺、膜的性能及存在的问题等方面进行了综述,为进一步扩大玉米醇溶蛋白膜的应用范围提供依据。     

制备条件对玉米醇溶蛋白膜水溶性的影响

以玉米醇溶蛋白为原料制备蛋白膜,甘油和聚乙二醇-400为增塑剂,半胱氨酸为还原剂,改善玉米醇溶蛋白膜的水溶性。在单因素试验的基础上采用响应面方法对蛋白膜的制备工艺进行了优化,结果为:蛋白质浓度0.103 4g/ml,甘油质量分数30%,聚乙二醇-400质量分数24%,半胱氨酸质量分数0.80%,乙醇体积分数为75%,水浴温度70℃,在此条件下制备的玉米醇溶蛋白膜的水溶性为28.06%。所制备的玉米醇溶蛋白膜的水溶性随着pH值的升高而增加,且随着水温的升高而增加的趋势更为明显,可以作为方便食品的调料包应用。     

制备条件对玉米醇溶蛋白膜机械性能的影响

以玉米醇溶蛋白为原料制备蛋白膜时,研究了乙醇浓度、蛋白质浓度等制备条件对蛋白膜机械性能的影响。在单因素实验基础上,以蛋白质浓度、甘油添加量、聚乙二醇400添加量、半胱氨酸添加量4个因素为变量进行响应面优化,结果表明:当乙醇体积分数为75%、水浴成膜温度70℃、蛋白质浓度0.103 4g/ml、甘油质量分数30%、聚乙二醇400质量分数24%、半胱氨酸质量分数0.80%时,蛋白膜的拉伸强度为7.5MPa,断裂延伸率为202.7%。     

添加丁香精油对玉米醇溶蛋白膜性能及结构的影响

以玉米醇溶蛋白为原料制备可食性膜,将丁香精油添加到玉米醇溶蛋白膜中,研究其对玉米醇溶蛋白膜物理性能及微观结构的影响。结果表明,丁香精油体积分数在0.5%～2.0%范围内时,随着体积分数的增加,玉米醇溶蛋白膜的厚度、断裂伸长率和水蒸气透过系数逐渐增加。丁香精油体积分数为0.5%～1.0%时,玉米醇溶蛋白膜的拉伸强度显著增加（P＜0.05）。添加丁香精油改善了膜的机械性能,增加了阻光性和透湿性。通过红外光谱和扫描电镜分析表明,添加丁香精油并未显著改变玉米醇溶蛋白的结构,且添加丁香精油的成膜液在干燥过程中会产生微孔,使得玉米醇溶蛋白膜的表面粗糙不均匀。     

冻藏温度对玉米醇溶蛋白膜的影响

冻藏温度对玉米醇溶蛋白膜特性有一定影响。结果表明:蛋白膜的机械特性、平衡水分含量和水蒸气透过率随冻藏温度的变化而发生变化。随着冻藏温度的降低,蛋白膜的抗拉强度和延伸率都呈下降的趋势;蛋白膜的平衡水分含量随冻藏温度的降低先上升,而后又略有下降;水蒸气透过率随冻藏温度的降低而上升。     

Wettability, surface microstructure and mechanical properties of films based on phosphorus oxychloride-treated zein

BACKGROUND: Zein, the predominant protein in corn, has been extensively studied as an alternative packaging material in edible and biodegradable films. However, films made from 100% zein are brittle under normal conditions. The aim of this investigation was to improve the film‐forming properties of zein by chemical phosphorylation. The surface hydrophobicity, surface microstructure and mechanical properties of films based on untreated and phosphorus oxychloride (POCl₃)‐treated zein were evaluated and compared. The effect of POCl₃ treatment on the rheological properties of zein solutions was also studied. RESULTS: POCl₃ treatment, especially at pH 7 and 9, led to an increase in the apparent viscosity of zein solutions. Atomic force microscopy (AFM) analysis showed that the film based on POCl₃‐treated zein at pH 7 had a stone‐like surface microstructure with a higher roughness (R_q) than the untreated zein film. The AFM data may partially account for the phenomenon that this film exhibited high surface hydrophobicity (H₀). POCl₃ treatment diminished the tensile strength (TS) of zein films from 4.83–6.67 to 1.3–2.29 MPa. However, the elongation at break (EAB) of the films at pH 7 and 9 increased from 3.0–4.5% (control film) to 150.1–122.7% (POCl₃‐treated film), indicating the potential application of zein films in wrapping foods or in non‐food industries such as sugar, fruit or troche that need good extension packing materials. CONCLUSION: The data presented suggest that the properties of zein films could be modulated by chemical phosphorylation treatment with POCl₃ at an appropriate pH value. Copyright © 2011 Society of Chemical Industry     

玉米醇溶蛋白膜的应用研究

蛋白膜的阻隔性能可用于控制食品与环境之间的水分、氧气、二氧化碳的交换和风味组分等的迁移,防止食品的品质劣变,延长食品的货架期.以玉米醇溶蛋白为原料制备蛋白膜,对膜的应用研究表明,在不同pH条件下,蛋白膜的水溶性均随着水温的升高呈现增加趋势,而蛋白膜在水中的破裂时间则随着水温的升高而缩短,说明玉米醇溶蛋白膜可以在热水中迅速破裂释放出包容物.采用玉米醇溶蛋白膜包装花生油及脱水蔬菜和调料,在储存125 d之后,花生油的酸值(KOH)和过氧化值分别为0.47 mg/g和5.44 meq/kg,低于国家标准规定的3 mg/g和19.7 meq/kg;调料包和蔬菜包的水分与聚乙烯塑料膜包装的水分以及初始水分数据之间无明显差别,说明玉米醇溶蛋白膜具有作为方便食品的风味料包包装材料的可能性.     

油酸与甘油对玉米醇溶蛋白膜机械性能的影响及机理探讨

主要研究了两种性质不同的增塑剂（油酸和甘油）对玉米醇溶蛋白（zein）膜机械性能的影响和可能的机理,以抗拉伸强度（TS）、伸长率（E）、透水率（WVP）为指标,结果发现油酸和甘油都能显著改善zein膜的机械性能,且添加量都以20%（g/g zein）最优;复合增塑研究发现,当添加20%混合增塑液对zein膜进行增塑时,以油酸∶甘油为3∶1复合增塑的效果最好,其中与未增塑的zein膜相比,TS提高190%,E提高70%。进一步统计学分析表明,油酸与甘油在对zein膜增塑时有正协同作用。对未增塑、20%油酸增塑、20%甘油增塑及20%复合增塑（油酸∶甘油为3∶1）zein膜的玻璃态转化温度（Tg）及红外光谱（FT-IR）分析发现,增塑后的zein膜Tg有所下降,其中复合增塑降幅最大;FT-IR图谱分析发现,复合增塑时甘油的特征峰向高波长方向移动,显示增塑作用加强;蛋白二级结构分析发现,复合增塑后,二级结构虽有小幅改变,但并未达到显著水平,因此增塑剂与zein之间的非共价键相互作用（疏水力和氢键）可能是其增塑的化学基础。      

谷朊粉与玉米醇溶蛋白可食性复合膜的研究

研究了谷阮粉和玉米醇溶蛋白可食性复合膜的成膜条件及复合膜的特性。结果表明:复合膜中玉米醇溶蛋白的适宜添加量为25%。在各自最佳成膜条件下,复合膜的水蒸气透过率为5.97g·mm/m2·d·kPa,比对照降低了12.1%;拉伸强度为3.45MPa,比对照提高了22.6%。综合考虑水蒸气透过率与拉伸强度两项指标,确定适宜的成膜条件为:pH12、热处理温度70℃、乙醇浓度55%、甘油浓度10%,此条件下复合膜的水蒸气透过率为6.01g·mm/m2·d·kPa,比对照降低11.5%;拉伸强度为3.39MPa,比对照提高20.7%。该复合膜同时具有良好的热封性。     

Effect of plasticizing sugars on water vapor permeability, surface energy and microstructure properties of zein films

Sugars are natural plasticizers for food biopolymers and zein is the most important protein of corn. In this research, sugars (fructose, galactose and glucose) were used as plasticizers and the water vapor permeability (WVP), contact angle and microstructure of the zein films were studied. The pure zein film had high WVP and adding of sugars to 0.7 g/g zein caused to decrease of WVP. Films containing galactose had the lowest WVP.All samples had the lowest contact angle with ethanol and the highest contact angle with water. The zein films containing galactose had the highest water contact angle within the plasticized films. The pure zein films and the films containing fructose had higher critical surface tension of wetting (γ_c) than the films containing glucose and galactose. Adding sugar plasticizer to zein films increased the surface tension of zein films. In the unplasticized zein films, loose structures with a lot of cavities and voids were observed. The films plasticized by fructose had smooth surface and plasticizer particles distributed throughout of the films.     

Temperature Effect on Oxygen Permeability of Edible Protein-based Films

Edible films from corn zein, wheat gluten, and wheat gluten/soy protein isolate (2.1:0.9) were produced and their oxygen permeabilities were determined at 7, 15, 25, and 35°C under 0% relative humidity. Mean oxygen permeability values for the 3 films were in the range of 1.8–11.2, 0.9–6.1, and 0.6–3.8 amol/m.s.Pa, respectively. Data for all 3 films showed very good agreement with the Arrhenius activation energy model. No structural transitions were indicated within these films in this temperature range. Calculated activation energy values for the oxygen permeation process were 11.1, 11.9, and 10.8 kcal/mol, respectively. Comparisons with some non-protein edible coatings and plastic packaging materials showed dry protein films were very efficient oxygen barriers.