辛烯基琥珀酸淀粉酯对柑橘黄酮的增溶规律及其作用机理

Citrus flavonoids (CF) own multiple biological functions but poor water solubility. To enhance their water solubility to increase bioavailability and broaden application scope has become crucial problem to be solved urgently in the CF utilization industry. Encapsulation by amphiphilic small molecules including surfactants is one of the methods to solubilize CF, but has certain defects. To solve this problem, the project, based on the previous work, will use octenyl succinic anhydride modified starch (OSAS), a kind of natural biological macromolecule derivative, as a solubilizing agent to improve the solubility of typical CF (i.e. hesperidin, hesperetin, and nobiletin) in water. Different systems of saturated CF/OSAS/water will be designed to investigate the relationship between the structural parameters of OSAS of different origin (i.e. molecule weight, degree of substitution, ratio of amylose to amylopectin) and CF solubility, as well as external influencing factors and dynamic process of solubilizing CF in water as affected by OSAS. Based on these, correlation models between the solubility of CF and concentration and structural parameters of OSAS will be established and the solubilization behavior of CF in water will be disclosed. The solubilization effect of OSAS on CF will be further investigated using multiple spectrometry, fluorecence probe, H1nuclear magnetic resonance (NMR), X-ray diffraction, differential scanning calorimetry, and transmission electron microscope to understand the interactions between OSAS and CF, the solubilization sites and micro-environment in these systems. The success of this project will provide foundamental new knowledge on how OSAS increase the solubility of CF in water and then may have potential to expand the applications of bioactive activities of CF in a wide range of industries including food sectors.

柑橘黄酮（CF）具有多种生理功效，但其水溶性较差。增加水溶性以提高生物利用率、拓宽应用范围已成为CF利用产业急需解决的关键问题。表面活性剂等两亲性小分子包埋是黄酮主要增溶方法之一，但存在一定的缺陷。项目在前期研究基础上以不同结构的代表性CF（橙皮苷、橙皮素和川陈皮素）为研究对象，采用生物大分子衍生物-辛烯基琥珀酸淀粉酯（OSAS）为增溶辅料，构建不同的饱和CF/OSAS/水体系，研究OSAS增溶CF的构效关系、外界影响因素和动力学过程，建立溶解度与不同来源OSAS分子量、取代度、直链/支链比、浓度的关联模型，揭示CF在OSAS中的增溶规律；采用多种光谱、H1NMR、X射线衍射、差示扫描量热法、透射电镜等手段探讨CF 与OSAS 相互作用、CF 在OSAS聚集体中增溶位点与微环境，阐明OSAS介导的 CF 增溶机理。项目研究可为CF的增溶设计和调控提供理论基础，有助于促进在食品等行业中应用。

柑橘黄酮（CF）具有多种生理功效，但其水溶性差。增加水溶性以提高生物利用率、拓宽应用范围已成为CF利用产业急需解决的关键问题。表面活性剂等两亲小分子包埋是黄酮增溶主要方法之一，但存在副作用、增溶能力不强、稳定性差等缺陷。OSAS为一类天然生物大分子衍生物，具有安全无毒、生物相容性好、体内可降解等优点和高效包封、营养和流变等特性，在食品工业中常作乳化剂、稳定剂和微胶囊壁材等，但其对CF的增溶规律及作用机理的研究尚未见报道。项目针对该现状以不同结构的代表性CF（橙皮苷、橙皮素、柚皮苷、柚皮素）为研究对象，制备不同淀粉来源、取代度、浓度和分子量的OSAS并对其进行物化特性分析和结构表征，构建饱和CF/OSAS/水体系，研究OSAS增溶CF的构效关系、外界影响因素等，并对效果理想的包合物进行增溶前后的结构表征和相互作用分析，确定OSAS与CF 的增溶方式与位点，初步阐明OSAS介导的CF增溶机理。重要结果有：（1）淀粉OSA酯化后糊稳定性和粘度增加，表面粗糙或损伤，但形状和晶型未改变，结晶度随取代度的增加而显著降低，表明酯化反应主要发生在无定形区和淀粉颗粒的表面。（2）OSAS分子量的降低导致了黏度、膨胀度、凝沉性下降，酶解作用使其颗粒破裂，不会引入其他物质。（3）在最适条件下红薯OSAS增溶橙皮苷、玉米OSAS增溶橙皮素的倍数分别为6.52倍和9.87倍，发现橙皮苷/橙皮素的苯环从H-3质子宽端口一侧进入OSAS的内腔，推测出橙皮苷和红薯OSAS、橙皮素和玉米OSAS的包合模型。（4）中等分子量的蜡质玉米OSAS增溶柚皮苷和柚皮素倍数分别达848.83倍和1023倍，增溶体系稳定性良好；包合物颗粒为球形，粒径分别为257.07 nm 和222.53 nm，在水溶液中呈分散状态。项目对主要CF在OSAS水体系中的增溶行为及差异性进行了系统的研究，获得了良好的增溶效果，初步阐明了OSAS对主要CF的增溶规律及机制，丰富了相关研究内容，为改善CF的生物利用率奠定了基础。增溶的CF可用于食品功能强化或作为靶向药物用于临床辅助治疗某些疾病，应用前景十分广阔。