【作者】 王丽娟；

【导师】 杨晓泉；

【作者基本信息】 华南理工大学 ， 粮食、油脂及植物蛋白工程， 2014， 博士

【摘要】 玉米醇溶蛋白（zein）是玉米蛋白的主要成分，含有大量的约50%的疏水性氨基酸，不溶于水性介质，在食品体系中利用较少。但是zein具有独特的自组装特性及成膜特性、粘附性及生物兼容性，可作为生物活性物质输送载体、可食性包装材料及涂层及乳液的颗粒稳定剂等，具有良好的商业应用潜力。本文利用zein与多糖及蛋白质的相互作用合成了多种zein复合胶体颗粒，系统研究了其在营养物质输送、乳液稳定及可食性包装材料等领域的应用，研究结果如下：1、采用反溶剂技术构建了粒度为300~400nm的zein/甜菜果胶（SBP）复合胶体颗粒（ZP/SBP），并研究了ZP/SBP胶体颗粒的储藏稳定性、对疏水性生物活性物质姜黄素（curcumin）的荷载及输送能力，及其模拟胃肠消化特性。研究表明，甜菜果胶可通过静电作用和空间位阻作用稳定ZP胶体颗粒。ZP/SBP复合胶体颗粒具有比ZP颗粒更好的pH稳定性和耐盐能力，对姜黄素具较高的荷载率，具有良好的抗消化能力和结肠靶向输送特性。可作为良好的食品配料及活性物质输送载体。2、首次构建了玉米醇溶蛋白/壳聚糖(CH)复合胶体颗粒（ZP/CH），并制备了ZP/CH复合胶体颗粒稳定的Pickering乳液，系统研究了zein浓度、zein/CH比值、及pH与离子强度对Pickering乳液物理稳定性的影响。结果表明壳聚糖与zein发生了静电相互作用、氢键、范德华力、疏水等相互作用，实现了zein颗粒的表面修饰导致zein胶体颗粒产生絮凝性；当zein/CH比值达到10:1-20:1时，ZP/CH复合胶体颗粒的三相接触角（θOW）接近90o，可制备稳定的Pickering乳液。研究表明，zein/CH复合胶体颗粒形成的乳液具有超强的长期存储物理稳定性（＞9个月）。稳定机理包括多尺度的胶体颗粒稳定作用，壳聚糖作为颗粒絮凝连接的多层次颗粒复合界膜，有效的抵御颗粒的聚并、奥氏熟化等失稳机制。3、构建了荷载姜黄素的ZP/CH双功能复合胶体颗粒，制备了ZP/CH复合胶体颗粒稳定的玉米胚芽油Pickering乳液，系统研究了乳液的微结构、储藏稳定性及抗氧化性质。研究结果表明姜黄素的荷载没有改变ZP/CH胶体颗粒的表面润湿性和Pickering乳液形成能力，通过加速氧化实验测定了初级氧化产物和次级氧化产物，并结合GC-MS测定了次级氧化产物己醛含量，显示荷载姜黄素的ZP/CH胶体颗粒稳定的Pickering乳液，具有超级优异的抗氧化性，其氧化产物含量比可比较的大豆蛋白/白藜芦醇稳定的乳液低一个数量级，标记实验结合激光共聚焦显微镜（CLSM）观察显示ZP/CH荷载的姜黄素进入了油/水界面，姜黄素处于油/水界面比混合在油相中有更好的抗氧化效果，且具有剂量效应。4、采用微射流高压均质乳化结合溶剂（乙酸乙酯）辅助蒸发技术，制备出了Zein/酪蛋白酸钠（SC）复合胶体颗粒稳定的可食性乳液粒子包装膜，研究了可食性膜的机械性质与水/气阻隔性质。研究表明，采用溶剂蒸发法获得的ZP/SC复合膜的具有良好的透明度，水汽阻隔能力优异。其水汽透过量仅为SC膜的40-50%。Zein纳米粒子对油滴产生Pickering稳定作用，阻止了成膜过程的油滴的聚并。溶剂蒸发法制备的液滴粒径小，油相和zein颗粒相互交错排列，形成三维的空间复合网络结构，阻碍了油滴的重力分层，呈现均匀的分布的状态。而酪蛋白酸钠稳定的乳液膜SCE呈现出油滴的梯度的不均匀分布的微观结构。因而其透明度差和水汽透过率高。更多还原

【Abstract】 Zein, the main corn protein, contains over50%hydrophobic amino acids. Zein is notsoluble in water, and its usage in food industry was usually limited. Zein contains sharplydefined hydrophobic and hydrophilic domains at its surface, and is capable of self-assemblyto form a wide variety of mesostructures. Therefore, zein is a good candidate for fabricatingnaturally renewable films and/or colloidal particles as vehivles for actives, edible films aswell as Pickering emulsifier in view of due to its biocompatibility, biodegradability andmucoadhesive ability. The objective of this work was to modify zein colloids particles via theinteraction of zein and chitosan, to explore their possible application in nutrition delivery,Pickering emulsifier, and edible films. The main results are as following：Fabrication and characterization of zein/SBP complex particles. We prepared zein/SBPcomplex particles with particle sizes300–400nm via a simple antisolvent procedure. Storagestability, and loading capacity and delivery for curcumin, as well as in vitro gastrointestinaldigestion of zein/SBP colloid particles were extensively evaluated. Zein/SBP complexparticles were stable at high salt and various pH ranges from2.0to10.0. These complexparticles possessed strong loading capacity (above50%) and high encapsulation efficiency(above90%) for curcumin. Meanwhile, zein/SBP complex particles had strong anti-digestionin in vitro gastrointestinal tract, and can be used for colon-specific drug delivery. This kind ofcolloid particles facilitated to the design of functional food formulation.Fabrication and characterization of Pickering emulsions stabilized by Zein/CH complexparticles. The effects of the ratios of zein/CH, pH values and ion strength on Pickeringemulsion formation and physical stability were carefully explored. The interaction betweenzein and chitosan induced the flocculation of zein colloid particles, the three-phase contactangles of zein complex particles were close to90owhen the zein/CH ratios were10:1and20:1. These complex particles can be used as particle emulsifier to fabricate super-stablePickering emulsions over9month storages. The possible formation pathway can be attributedto the CH-induced ridge flocculation of zein colloid particles at the oil/water interface and theformation of multi-layer framework of zein colloid particles at the oil/water interface. Thiskind of interface fabric contributed to the high resistance of the formed Pickering emulsions to coalescence and Oswald ripening.Fabrication of curcumin-loaded zein/CH complex particles with double functions,Pickering emulsions were fabricated via corn oil and alga oil as oil phase. Microstructure,storage and oxidant stability of Pickering emulsion were extensively investigated. Curcuminloading did not change the wettability of zein/CH complex particles, which were also suitableto produce stable Pickering emulsions. Primary (lipid hydroperoxides) and secondary oxidantproducts (malondialdehyde, MDA) of Pickering emulsions after thermally acceleratedoxidation were monitored, and hexanal was measured using GC-MS techniques. Pickeringemulsion stabilized by curcumin-loaded zein/CH complex particles present super antioxidantcapacity, the primary products was significantly lower than the antioxidant emulsions viatargeted accumulation of resveratrol via during the complete stevioside micelles stabilized bycompetitive absorption of soy protein isolate (SPI) and stevioside (STE). CLSM indicatedthat the absorption and accumulation of zein/CH complex particles at the oil/water interface,and targeted accumulation of cucurmin at the interfaces was achieved via Pickeringemulsifier (zein/CH complex particles).Novel zein-sodium caseinate nanoparticles-stabilized emulsion films were fabricated viamicrofluidic emulsification (ZPE films), or in combination with solvent (ethyl acetate)evaporation techniques (ZPE-EA films). Some physical properties, including tensile andoptical properties, water vapor permeability (WVP) as well as microstructure of ZP-stabilizedemulsion films were evaluated and compared with SC emulsion (SCE) films. ZP-andSC-stabilized emulsion films exhibited a completely different microstructure, nanoscalar lipiddroplets were homogeneously distributed in ZPE film matrix and interpenetrating protein-oilcomplex networks occurred within ZPE-EA films, whereas SCE films presented aheterogeneous microstructure. The different stabilization mechanisms against creaming orcoalescence during the film formation accounted for the preceding discrepancy of themicrostructures between ZP-and SC-stabilized emulsion films. Interestingly, ZP-stabilizedemulsion films exhibited a better water barrier efficiency, the WVP values were only4050%of SCE films. The structural characteristics gave ZPE and ZPE-EA films improvedwater barrier capability, moderate mechanical resistance and extensibility, and hightransparency.更多还原