基于玉米醇溶蛋白/甜菜果胶界面复合构建营养素载体及其输送特性研究

Zein nanoparticles, with excellent small size and surface effects as well as the potent loading capacity for nutraceuticals, have promising potential for the bioactive delivery. However, the zein nanoparticles are usually not water-soluble at neutral pH, and are easy to aggregate during the drying process of zein particle dispersions. In particular, the classical anti-solvent approach used to produce zein nanoparticles is discontinuous and difficult to scale up. The objective of this research is to fabricate novel zein/sugar beef pectin (zein/SBP) complex nanoparticles by manipulating zein self-assembly through sugar beet pectin as steric and electrostatic stabilizers, based on the processing procedures suitable for commercial process. This work attempted to explore the functional roles of zein/SBP nanoparticles by understanding their physical stability and nutraceuticals deliveries. This kind research can provide an entirely new technique approach for designing novel functional foods. The research included: (1) Fabrication of solid and hollow zein/SBP nanoparticles with laccase crosslinking of SBP molecules to consolidate the nanoparticles. The topography and physical performance of the particles were carefully characterized by DLS, SEM, IR and ITC to explore the possible formation pathway of the zein/SBP particles. (2) The interfacial complex behavior of zein and SBP, and its influence on dispersing behavior in aqueous systems and loading capability for nutraceuticals (3) Structural change zein/SBP nanoparticles and release dynamics of the bioactives from the particles during the in vitro digestion states. (4) The in vitro caco-2 cell model is employed to evaluate the transmembrane ability of zein/SBP nanoparticles, and the in vivo animal experiments were employed to investigate the bioavailability and bioconversion of bioactives in zein/SBP nanoparticles.

玉米醇溶蛋白纳米粒子具有优异的尺寸效应、表面效应和对疏水性营养素的优异的荷载能力，可望成为具有广泛应用前景的营养素输送载体。但在中性条件下玉米醇溶蛋白自组装颗粒分散稳定性差，干燥后不能复溶，难以实现规模化制备。本项目基于具有工业应用前景的制备技术，试图通过环境因素的调节策略，精确控制玉米醇溶蛋白的自组装行为及其与甜菜果胶的相互作用，构建以甜菜果胶为静电及空间稳定剂的复合纳米粒子；从分散稳定性及营养输送两个角度研究该复合纳米粒子的功能性质，为其在食品中的应用提供理论基础与技术支撑。研究内容：①采用反溶剂法制备实心、空心的玉米醇溶蛋白与甜菜果胶复合纳米粒子，然后以漆酶交联甜菜果胶。研究该复合纳米粒子的形成机制，并对其进行表征。②研究玉米醇溶蛋白与甜菜果胶界面复合行为及其对颗粒的分散稳定性和营养素荷载能力的影响；③以模拟体外消化实验研究载体的结构变化及营养素释放行为；④通过细胞和动物模型实验评价载体中的营养素的吸收及生物利用度。

构建了玉米醇溶蛋白（zein）与甜菜果胶（SBP）界面复合颗粒负载递送系统，旨在提高生物活性物质的生物利用率。主要包括：①zein与甜菜果胶界面复合颗粒（ZP / SBP）的形成机制、条件、性质及环境因素的影响。SBP：Zein≥0.3时，ZP / SBP的粒径280-340nm，ζ-电位与SBP相近，且随pH变化趋势一致；②负载姜黄素后的复合颗粒的性质无显著改变，有酶体系体外模拟消化150min颗粒保持原来的形态，显示出较强的抗消化能力，且具有缓释功能。③Wister大鼠实验以姜黄素悬浊液及未与SBP复合zein颗粒作为对照，SBP：Zein=0.5的复合颗粒目标样品，采用灌胃方式，不同时段取眼眶血，用Elisa 试剂盒检测血液中姜黄素的浓度。20min对照组的姜黄素含量达到峰值，血液中姜黄素浓度4.45ng/mL和 4.83ng/mL，随后下降。目标组60min后姜黄素的浓度为3.5ng/mL，120min4.6ng/mL至 240min血液中至5.21ng/mL持续增长，目标组在大鼠十二指肠中最大含量时间为 120min。对照上述实验，对肠组织进行显微镜结合激光共聚焦观察，与十二指肠和回盲肠内姜黄素量测定值具有一致性。④构建了zein与壳聚糖（CS）复合颗粒ZP / CS，研究了形成机制、性质及环境因素的影响，三相接触角，ζ-电位与壳聚糖相近，且随pH变化趋势一致；zein与壳聚糖是界面复合。制备课油相为十四烷烃的Pickering乳液。⑤构建了ZP / SBP双水相Pickering乳液，并成功包埋了酵母菌。⑥以ZP/CS-cur构建了油相溶解姜黄素的双负载的Pickering，具有超高的负载能力及缓释功能。⑦首次发现并提出蛋黄酱是由蛋黄颗粒稳定的Pickering乳液机理的观点。相关研究成果以第一作者或通讯作者分别发表在Food Chem (Ⅱ区TOP） 和 J Sci Food Agric(Ⅱ区TOP）期刊上；在中文核心期刊上发表了1篇相关论文；另有两篇基本完稿，近期拟投稿在Food hydrocolloids(Ⅱ区TOP）和J Sci Food Agric(Ⅱ区TOP）杂志上； 研究成果申请了3项国家发明专利。