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。     

Property and Stability of Astaxanthin Emulsion Based on Pickering Emulsion Templating with Zein and Sodium Alginate as Stabilizer

Astaxanthin loaded Pickering emulsion with zein/sodium alginate (SA) as a stabilizer (named as APEs) was developed, and its structure and stability were characterized. The encapsulation efficiency of astaxanthin (Asta) in APEs was up to 86.7 ± 3.8%, with a mean particle size of 4.763 μm. Freeze-dried APEs showed particles stacked together under scanning electronic microscope; whereas dispersed spherical nanoparticles were observed in APEs dilution under transmission electron microscope images. Confocal laser scanning microscope images indicated that zein particles loaded with Asta were aggregated with SA coating. X-ray diffraction patterns and Fourier transform infrared spectra results showed that intermolecular hydrogen bonding, electrostatic attraction and hydrophobic effect were involved in APEs formation. APEs demonstrated non-Newtonian shear-thinning behavior and fit well to the Cross model. Compared to bare Asta extract, APEs maintained high Asta retention and antioxidant activity when heated from 50 to 10 °C. APEs showed different stability at pH (3.0–11.0) and Na⁺, K⁺, Ca²⁺, Cu²⁺ and Fe²⁺ conditions by visual, zeta potential and polydispersity index measurements. Additionally, the first order kinetics fit well to describe APEs degradation at pH 3.0 to 9.0, Na⁺, and K⁺ conditions. Our results suggest the potential application of Asta-loaded Pickering emulsion in food systems as a fortified additive.     

玉米醇溶蛋白水解酶菌株的筛选

从Aspergillus oryzae3042、Aspergillus oryzaeIF-39、Aspergillus oryzae3800、Aspergillus oryzaeJ-rapid4种霉菌中通过优化培养条件,筛选出产蛋白酶酶活力高的菌株,结果表明,Aspergillus oryzaeIF-39所产蛋白酶酶活力最高。培养条件为麦麸豆粕比1∶1,pH值7.5,水的质量分数50%,温度30℃,培养96 h,接菌量3环。菌种产酶酶活达到220.78 U/mL,玉米醇溶蛋白的水解度达到33.5%。     

zein静电纺丝的过程优化和直径预测模型

以冰乙酸为溶剂,对玉米醇溶蛋白（zein）进行静电纺丝,用扫描电镜观察zein纤维的形态。利用响应面法中的Box-Behnken设计,选取zein质量分数、电场强度和挤出率3个主要因素作为影响因子,以zein纤维直径作为考察对象,通过回归分析建立了二次多元回归模型。结果表明：zein质量分数对纤维直径的影响最为显著,其次是电场强度和挤出率的交互项;模型预测的纤维直径与真实值能较好的拟合,说明该模型能有效地预测电纺zein纤维的直径。采用响应面法设计,不仅简化了实验设计,且根据建立的定量关系可设计出所需结果的实验条件,对利用静电纺丝技术制备纳米纤维具有重要的意义。     

淀粉-玉米醇溶蛋白可食性膜的筛选与性能研究

以玉米淀粉和玉米醇溶蛋白作为基础原料,研究可食性膜的成膜条件和膜性能。玉米淀粉液经糊化、掺入脱色的玉米醇溶蛋白、添加甘油增塑剂、匀浆、脱泡、成膜后,检测膜的抗拉强度、断裂伸展率、溶解度、透明度、微观表面特征。配制质量分数为4%、5%、6%、7%的玉米淀粉液分别制膜,检测并筛选一适宜浓度,同时筛选制备脱色玉米醇溶蛋白液。玉米淀粉糊化后,分别按其体积的0%、10%、15%、20%、25%、30%掺入脱色玉米醇溶蛋白液,制膜,筛选适宜掺入比例。测试筛选添加质量分数为1.0%、1.2%、1.4%、1.6%的甘油增塑剂的成膜效果。结果显示,添加玉米醇溶蛋白液能够提高抗拉强度和断裂伸展率,降低透明度和溶解度,但添加10%有反抗拉强度现象。筛选确定淀粉质量分数5%,按体积分数15%掺入含玉米醇溶蛋白0.5%的脱色液,添加1.2%的甘油增塑剂,获得的可食性淀粉-玉米醇溶蛋白膜具有良好的机械性能和表观特征。     

纳米TiO2对魔芋葡甘聚糖/玉米醇溶蛋白复合膜结构和性能的影响

本文以魔芋葡甘聚糖、玉米醇溶蛋白为成膜基质,添加不同含量（1%、2%、3%）的纳米TiO₂,以流延方式制备纳米TiO₂/魔芋葡甘聚糖/玉米醇溶蛋白复合膜,并对复合膜的微观结构、热性能、力学性能、疏水性、水蒸气透过率和抑菌性能进行了分析。结果表明,纳米TiO₂与魔芋葡甘聚糖、玉米醇溶蛋白间发生相互作用,有良好的相容性;添加纳米TiO₂使复合膜表面粗糙度增加,复合膜热稳定性和疏水性增强,力学性能降低;纳米TiO₂添加量为1% wt时,复合膜的水蒸气透过率（5.7×10?13 g·cm/（cm2·s·Pa））和溶胀率（16.4%）最小,水接触角值（99.6 °）最大;复合膜对金黄色葡萄球菌和大肠杆菌有明显的抑制作用,对枯草芽孢杆菌的抑制作用不明显。本研究为纳米TiO₂/魔芋葡甘聚糖/玉米醇溶蛋白复合膜作为包装材料的开发与应用提供一定参考依据。     

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）。     

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。     

Reactive extrusion of zein with glyoxal

Cross‐linked zein has been produced using glyoxal (GLY) as the cross‐linking reagent via reactive extrusion for the first time in a twin screw extruder using dilute sodium hydroxide as catalyst. Tri(ethylene glycol) was used as a plasticizer for various items. The extrudate was then ground and processed using either compression or injection molding. At the highest level of GLY (6%), tri(ethylene glycol) was used at 10% as a plasticizer to allow further processing to take place. With this formulation, samples could be obtained from the injection mold, however, the samples did not hold their molded shape due to the elasticity of the sample at the mold temperature. When lower levels of GLY were used, injection molded sample bars of similar quality to control were obtained. The physical properties of these samples were similar to control. At GLY levels of 1.75% and higher, the samples were resistant to dissolution by acetic acid. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009