Zein-based anti-browning cling wraps for fresh-cut apple slices

The usage of cling wraps is emerging as an easy and cost-effective approach to protect fresh-cut fruits and vegetables from dust, whilst improving visual appeal on retail counters. This study focused on developing an alternate, protein-based packaging material as a food grade cling wrap for food packaging applications. Zein-based cling wraps were produced, and their physical and mechanical characteristics were evaluated and compared with conventionally used chitosan biopolymer films and commercial synthetic polymer films. Antioxidant potential of the prepared films was studied, and the effectiveness of the developed films as anti-browning cling wraps was evaluated using studies conducted on fresh-cut apple slices at ambient conditions. Anti-browning effects were in par with polymeric counterparts; however, zein cling wraps could better prevent weight loss in apple slices. Zein-based films can be adopted as biodegradable food grade cling wraps as an alternative to chitosan and synthetic polymeric materials.     

缓香型玉米醇溶蛋白微胶囊乳液的制备及应用

为改善皮革的特殊气味并提升其应用性能,该研究以玉米醇溶蛋白（Zein）、艾叶香精（AAE）以及普兰尼克F127等为原料,通过反溶剂法制备缓香型玉米醇溶蛋白微胶囊（AAE@ZMs）乳液,再将AAE@ZMs乳液与成膜剂己内酰胺改性酪素复配后应用于皮革涂饰。结果表明,Zein与F127、AAE和戊二醛通过化学交联和氢键相互作用,同时F127和AAE可使Zein中的氨基酸重排并发生荧光猝灭;制得的AAE@ZMs乳液中微胶囊平均粒径约为298.6 nm且具有较好的分散性和稳定性;AAE@ZMs的包覆率和负载率分别可以达到73.2%和5.8%,在良溶剂中释放120 h时的AAE累积释放率约为83.1%。将AAE@ZMs应用于皮革涂饰后,涂饰革样中AAE的释放周期为6周,对金黄色葡萄球菌和大肠杆菌均具有较好的抑制效果,同时涂饰革样还展现出较好的机械性能。     

玉米醇溶蛋白水解物分离条件的选择

利用Bacillus natto菌所产蛋白酶水解玉米醇溶蛋白,得到水解产物,采用凝胶层析技术,对水解产物的分离条件进行选择。结果表明,Sephadex G-25作为分离介质,流速为1.0 mL/min,上样体积为1.5 mL,在此条件下其分离效果较好,得到5个组分。     

玉米醇溶蛋白的耐热性研究

对玉米醇溶蛋白的耐热性进行了探讨。实验表明，玉米醇溶蛋白在７０％乙醇溶液中，当水浴温度８０℃，放置１２０ｍｉｎ后，其醇溶性及其在ＰＲＯＴＥＩＮＰＡＫ柱上的色谱行为，与室温处理的玉米醇溶蛋白所表现出的性能是完全一致的。     

PDMDAAC改性玉米醇溶蛋白负载阿维菌素纳米颗粒的制备与性能

为提高阿维菌素叶面沉积率及其抗紫外分解性能,本文设计构建了叶面亲和的纳米载体。通过自由基聚合将聚二甲基二烯丙基氯化铵（PDMDAAC）改性玉米醇溶蛋白（Zein）,得到表面携带正电荷的改性玉米醇溶蛋白,并将其用于负载阿维菌素。采用红外光谱（FTIR）、扫描电镜（SEM）等手段对改性产物结构和形貌进行表征。通过反溶剂沉淀法制备了平均粒径为64.92nm的载药纳米粒子,载体对阿维菌素的包封率为(34.75±0.18)%。与植物表面的静电作用提升了纳米粒子悬浮液在植物表面的润湿性能,接触角大小随PDMDAAC接枝量增大而降低,由77.38°减小到64.60°;叶面滞留量可达33.69mg/cm²。改性玉米醇溶蛋白对阿维菌素的包覆提升了其抗紫外性能,半衰期由15min延长至40min,且阿维菌素的释放速率可通过PDMDAAC接枝率进行调控。     

基于黄原胶糖基化改性玉米醇溶蛋白胶囊壁材的性能研究

目的 通过黄原胶糖基化改性玉米醇溶蛋白(Zein)提升胶囊壁材的抗拉强度、阻隔性能及肠溶性。方法 以Zein为原料,黄原胶作为羰基供体,进行干法糖基化反应,得到玉米醇溶蛋白-黄原胶改性产物(zein xanthan gum conjugates,Zein-xg),将其制备成膜,并通过机械性能、阻隔性能等指标研究糖基化改性对膜的性能的影响,考察胶囊壳外观性状、干燥失重、松紧度、炽灼残渣、脆碎度指标,并进行模拟体外释放研究。结果 与玉米醇溶蛋白相比,玉米醇溶蛋白-黄原胶膜的抗拉强度提高至21.59 MPa,提高了3.6倍,水蒸气透过系数提高了34.79%,过氧化值降低19.51%,吸水率由45.70%升高至47.03%,透油系数为0 g·mm/(cm²·d)。在模拟胃液中胶囊壳装载的小分子罗丹明B和大分子牛血清白蛋白3 h累积释放率为0,转至肠液累积释放率分别达到了98.03%和77.14%。结论 改性后的玉米醇溶蛋白-黄原胶膜的机械性能、阻隔性能等均得到显著改善。改性后的胶囊壳外观性状、干燥失重、松紧度、炽灼残渣、脆碎度等指标均符合《中华人民共和国药典(第四部)》(...     

玉米醇溶蛋白生产新工艺的研究

通过对脱色步骤和沉淀步骤的改进，找到一条玉米醇溶蛋白生产的新工艺，分别研究了脱色，提取和沉淀３个步骤中各种工艺参数生产的影响，摸索出本工艺的最佳工艺条件：脱色：乙醇回流温度下，萃取５ｈ；提取：温度６０℃，时间２ｈ，乙醇浓度７０％，液固比１０：１（ｍｌ／ｇ）；沉淀：沉淀温度０℃，沉淀剂与醇溶蛋白浓缩提取液比３０：１（ｖ／ｖ）。     

中链甘油三酯/玉米醇溶蛋白核壳结构微胶囊载体的构建及表征

以中链甘油三酯（medium-chain triglyceride,MCT）为油相内核,以玉米醇溶蛋白（Zein）为外壳主要成分,低剪切条件下反溶剂法制备大粒径核壳结构的MCT/Zein微胶囊微米载体。通过考察微胶囊载体的宏观形态、微观形态及粒径分布,优化得到微胶囊载体的最佳制备工艺为质量分数0.5%的阿拉伯胶（gum arabic,GA）作为乳化剂、乳化速率800?r/min、Zein沉淀溶液为“30?mL水＋100?mL?GA溶液”、Zein沉淀溶液加入速率6?mL/min,并采用扫描电子显微镜、激光共聚焦显微镜、激光粒度分析仪表征冻干MCT/Zein微胶囊载体的结构特征和粒径特性,结果表明该法制备的微胶囊载体具有典型的核壳结构,粒径均一、稳定性良好。本实验建立MCT/Zein核壳结构微胶囊的反溶剂制备法,该法简单易行,适用于多种油溶性活性组分的包埋和保护研究。     

响应面法优化超声波提取玉米醇溶蛋白工艺

利用响应面法对玉米黄粉中醇溶蛋白的提取工艺进行优化。根据中心组合试验设计原理采用4因素5水平响应面分析法,对各个因素的显著性和交互作用进行分析。结果表明:玉米醇溶蛋白超声提取的最佳条件为超声时间27 min、超声功率480 W、乙醇体积分数70%、液料比10:1(mL/g),该条件下玉米醇溶蛋白提取率可达70.71%,纯度为90.33%。     

Electrospinning formaldehyde‐crosslinked zein solutions

In order to develop zein fibers with improved physical properties and solvent resistance, formaldehyde was used as a crosslinking reagent before spinning. The crosslinking reaction was carried out in either acetic acid or ethanolic HCl where the amount of crosslinking reagent was between 1 and 6%. Reactions were carried out at various times and temperatures. When carried out in acetic acid, the maximum amount of formaldehyde that could be used was 1.5% as gelation occurred at higher levels. In ethanolic HCl, 6% formaldehyde could be incorporated into zein. All solutions were successfully electrospun, producing predominantly ribbon and round fibers; the morphology was strongly dependent on solvent and spinning solids. The formaldehyde‐crosslinked zein fabrics had double the tensile strength of control fabrics. SDS‐PAGE analysis clearly showed crosslinking had occurred. Electrospun fabrics from all formaldehyde‐treated zein solutions required an additional heating step in order to be resistant to dissolution in acetic acid, a known very good solvent for zein. Copyright © 2011 Society of Chemical Industry