水分散型天然虾青素/核酸/壳聚糖纳米复合体的研究

As a new source of food, natural astaxanthin is by far the most powerful antioxidants found in nature, often used as a food coloring additive. However, insolubility of astaxanthin limited its use in aqueous food. Till now, the carrier materials used in current research improved the water-dispersibility of astaxanthin to a certain extent, still difficult to solve these problems (such as unknown safety, poor resuspension and poor loading capacity) at once. Therefore, designing an efficient, natural and water soluble nanocarrier is very important. For the first time, we choose natural nucleic acids with negative charge as the nanocarrier material, astaxanthin could be efficiently loaded by intermolecular non-covalent interaction between nucleic acid and chitosan (natural polycationic polysaccharide). Well dispersed and stable astaxanthin/nucleic acid/chitosan nanocomposite could be finally obtained. By investigating nucleic acid depurination, chitosan molecular weight,the medium ionic strength, and other influencing factors,the formation mechanism as well as the stable mechanism of the nanocomposite will be studied. LD50 will be detected to evaluate the toxicity of the astaxanthin/nucleic acid/chitosan nanocomposite. The antioxidant activity of the nanocomposite will be determined by measuring the malondialdehyde content, and the superoxide dismutase activity in serum and liver of aging model mice. The project has important scientific significance on clarifying the formation mechanism and stability mechanism of the polyelectrolyte nanocomposite system, and providing a theoretical basis and technical support for the development of high activity and water-dispersible astaxanthin functional foods.

作为具有强大抗氧化活性和良好着色效果的新资源食品，天然虾青素因不溶于水而难以在水性食品配方中使用。目前研发的载体材料一定程度上改善了虾青素在水中的分散性，但仍很难同时解决重悬效果差、包结能力低、安全性未知等问题。因此，设计一种高效、纯天然的水溶性纳米载体用于包载虾青素意义重大。本项目首次以带负电荷的天然核酸作为载体材料，与天然聚阳离子多糖- - 壳聚糖通过分子间非共价相互作用，实现对虾青素的高效负载，获得在水中均匀分散、稳定的虾青素/核酸/壳聚糖纳米复合体。研究核酸脱嘌呤、壳聚糖分子量、介质离子强度等因素对粒子形成和纳米悬液稳定性的影响；通过测定半数致死量、体内丙二醛含量、超氧化物歧化酶活力等指标，评价其体内安全性和抗氧化活性。本项目的研究对于进一步阐明聚电解质纳米复合体的形成机制和稳定机制有重要的科学意义，同时为开发食用安全的水分散型天然虾青素功能食品提供理论依据和技术支持。

作为具有强大抗氧化活性和良好着色效果的新资源食品，天然虾青素因不溶于水而难以在水性食品配方中使用。目前研发的载体材料一定程度上改善了虾青素在水中的分散性，但仍很难同时解决重悬效果差、包结能力低、安全性未知等问题。本项目首次以带负电荷的鲑鱼精DNA和壳聚糖为载体材料，成功制得了水分散型虾青素/DNA/壳聚糖（ADC）纳米复合体。通过对ADC纳米复合体的微观结构和理化性质进行的表征，证实了该纳米结构是通过DNA与壳聚糖自组装形成规则结构的亲水性软凝聚物，并利用DNA与虾青素的特异结合和疏水微区共同实现对虾青素的高效包载。通过研究纳米悬液的稀释稳定性、静置稳定性和酶解稳定性，初步证实ADC纳米复合体在食品复配、消化吸收的可行性。通过提高ADC纳米复合体的载药量和包封率，以及使用冷冻干燥的手段最终获得了复溶效果好的ADC冻干粉，其中虾青素含量最高可达10.16%，ADC干粉的溶解度达到280 mg/ml，体外实验证实纳米粒浓度低于0.1 mg/ml时无显著细胞毒性作用，ADC纳米悬液中虾青素含量仅为3.35 nM 时即在细胞水平表现出卓越的抗氧化损伤的活性作用。本项目的研究实现了高度水分散、高含量虾青素纳米分散体系的制备，对于进一步阐明聚电解质纳米复合体的形成机制和稳定机制有重要的科学意义，同时为开发食用安全的水分散型天然虾青素功能食品提供理论依据和技术支持。. 截止目前，本项目已资助发表/接收SCI/EI论文4篇，发表/接收中文核心期刊2篇，申请国家发明专利3项（已受理），国际发明专利1项（PCT阶段）。培养博士研究生1名，硕士研究生5名（3名已答辩），参加国际学术会议1次。