脂溶性茶多酚-复合可食膜的可控制备及控释机理研究

Oxidation leads to decreased oil quality, reduced nutritional value and shortened shelf life. Lipid soluble tea polyphenols (LTP) has prominent antioxidant ability, while, adding LTP directly into oil system affects the taste of oil, moreover, LTP is more susceptible to oxidation in this situation. The nanoparticle/polymer composite film system offs good way to protect and controlled-release these environmentally sensitive functional factors. In this project, LTP- esterified high amylose nanoparticle/hydroxypropyl methylcellulose (HPMC) based microporous composite film system is going to be built up, two regulators——degree of esterification and sodium citrate concentration is going to be set up to regulate the structure of nanoparticle and composite film substrate, respectively, to achieve protection of LTP, double fine regulation of the release of LTP and continuous antioxidation in the oil system. The effects of regulators on multiscale structures of films will be studied by Fourier transform infrared spectroscopy, nuclear magnetic resonance, wide angel X-ray diffraction, small angle X-ray scattering and scanning electron microscope, etc. The dynamic change of multiscale structures of these different-structured films during the release process and their relationships with the release behavior will be further investigated to disclosure the controlled-release mechanism of this system systematically, to verify the protective effect of the composite film on Perilla seed oil. This study can provide new ideas for the designation of controlled-release system for hydrophobic functional factors, enrich the controlled-release theory of the composite films, and promote the application of the composite film systems in the storage of oil to achieve safe storage.

油脂氧化导致油品质及营养价值下降，保质期缩短。脂溶性茶多酚（LTP）具有显著的抗氧化效果，但直接向油脂中加入LTP影响油脂口感且LTP易被氧化，纳米粒/高分子复合膜可实现对环境敏感的功能因子的保护和缓释。本项目拟构建LTP-酯化高直链淀粉纳米粒/羟丙基甲基纤维素（HPMC）基微孔复合膜，通过设置双调控因子—酯化度和柠檬酸浓度，分别对纳米粒结构和膜基材结构调控，进而实现对LTP的保护及其在油相中控制释放和持续抗氧化作用。运用红外光谱、核磁共振、广角X射线衍射、小角X射线散射、扫描电镜等技术研究调控因子对复合膜多尺度结构的调控作用；并进一步探究复合膜在油脂模拟体系释放过程中的多尺度结构变化与释放行为之间的关系，揭示复合膜的控释机理，验证复合膜对紫苏籽油的持续抗氧化保护作用。本研究可为疏水性功能物质的控释提供新的设计思路，丰富复合膜的控释理论，推进此复合膜在油脂保藏中的应用，实现油脂安全保藏。

脂溶性茶多酚（LTP）有很好的抗氧化功能活性，但直接向食品中加入LTP易导致LTP氧化而降低其对食品的抗氧化保护作用。本项目构建了LTP-酯化淀粉纳米粒和LTP-酯化淀粉纳米粒/羟丙基甲基纤维素（HPMC）基微孔复合膜控释体系，通过设置纳米粒调控因子和HPMC膜基材调控因子可实现双重调控复合膜多尺度结构和对LTP的保护和控释作用。酯化高直链玉米淀粉及普通玉米淀粉均可络合LTP生成晶型为V型的LTP-酯化淀粉纳米粒。纳米粒的加入可不同程度地减弱复合膜的分子内/间氢键、降低其结晶度和表面粗糙度、改变其孔洞数量及尺寸；HPMC种类也可调控复合膜体系中的分子内/间氢键、表面粗糙度、孔洞数量及尺寸。LTP-酯化淀粉纳米粒对LTP的结合程度、载荷及聚集程度决定其释放行为和持续抗氧化效果；复合膜的释放行为及抗氧化效果除了以上纳米粒影响因素外，还受纳米粒的分布、膜材孔洞结构及复合膜溶解溶胀的影响。LTP-酯化普通玉米淀粉纳米粒可以降低复合膜的透氧率，四种LTP-淀粉纳米粒均可提高复合膜的疏水性能，HPMC分子量的升高可提高复合膜的机械性能。LTP-酯化淀粉纳米粒对紫苏籽油有很好的持续抗氧化效果；LTP-酯化淀粉纳米粒/HPMC 基微孔复合膜有好的胃部环境抵抗作用和结肠靶向递送潜力。该研究为疏水性功能物质的运载和控释提供了新的设计思路，丰富了复合膜的控释理论。该控释材料在食品和医药等领域有广泛应用前景。