【作者】 鲍士宝；

【导师】 王璋；

【作者基本信息】 江南大学 ， 食品科学， 2009， 博士

【摘要】 本文系统研究了成膜基质─鮰鱼鱼皮明胶的提取工艺、茶多酚纳米粒的制备工艺、茶多酚纳米粒对明胶膜的结构与性质的影响以及茶多酚纳米粒复合明胶膜中茶多酚的释放动力学。首先研究了制备鮰鱼鱼皮明胶的工艺,并对明胶性质作了分析。采用酸溶胀、打浆、溶解、沉淀的方法得到制备鮰鱼鱼皮明胶的中间产物─鮰鱼鱼皮胶原纤维;在45°C、pH7.0条件下,对鮰鱼鱼皮胶原纤维经热提胶6h得鮰鱼鱼皮明胶,明胶提取率可达95%以上,明胶溶液胶凝温度与明胶凝胶熔化温度分别为19.6°C、25.2°C。确定了乙醇注入─超声法制备了茶多酚纳米脂质体悬浮液的最佳工艺为:卵磷脂浓度为1.0 mg/mL,胆固醇/卵磷脂质量比为1:5,Tween80/卵磷脂质量比为4:5,茶多酚添加量为25 mg,乙醇用量为8 mL,水合介质离子强度为0.05 mmol/L,水合时间及水合温度分别为30 min、50 oC,超声破碎后处理(380 W,4 min,1 s开,1 s停),按此工艺制备的茶多酚纳米脂质体悬浮液中颗粒粒径分布均匀,大小约为126 nm,表面电位约为-11.6 mV。以鮰鱼鱼皮明胶为基质,添加茶多酚纳米脂质体悬浮液制备了茶多酚纳米脂质体复合明胶膜。研究发现,茶多酚纳米脂质体通过自身的空间位阻效应以及同明胶分子上的C=O形成的氢键作用,降低了明胶分子之间的氢键交联,改变了明胶膜的性质:增加了明胶膜的厚度、断裂伸长率、透氧系数及对紫外光的吸收能力;降低了明胶膜的拉伸强度、透湿系数、透明度;显著提高了明胶膜的抗氧化能力。确定了离子交联─超声法制备茶多酚-壳聚糖纳米粒悬浮液的最佳工艺为:壳聚糖浓度为2.0 mg/mL,pH为5.5,TPP/CTS为1:3,茶多酚添加量为25 mg,TPP以注射方式加入,搅拌速度为800 r/min,超声破碎后处理(380 W,4 min,1 s开,1 s停)。按此工艺制备的茶多酚-壳聚糖纳米粒悬浮液颗粒粒径分布均匀,大小约为300 nm,Zeta电位约为44.6 mV。以鮰鱼鱼皮明胶为基质,添加茶多酚-壳聚糖纳米粒悬浮液制备了茶多酚-壳聚糖纳米粒复合明胶膜。研究发现,茶多酚-壳聚糖纳米粒的空间位阻效应以及壳聚糖分子上的羟基与明胶分子上的活性基团形成氢键,干扰了明胶分子之间的氢键作用,影响了明胶膜的性能:增加了明胶膜的厚度,对紫外光的吸收能力以及透湿系数;降低了明胶膜的拉伸强度、断裂伸长率及透氧系数;大大提高了明胶膜的抗氧化能力。研究了茶多酚-纳米粒悬浮液中的茶多酚在PBS中释放动力学、茶多酚-纳米粒中的茶多酚在明胶膜中释放动力学以及茶多酚-纳米粒复合明胶膜在PBS中释放茶多酚的动力学。结果发现:①在PBS中,茶多酚-纳米粒悬浮液内的茶多酚的释放均符合一级动力学模型,但茶多酚-壳聚糖纳米粒悬浮液内茶多酚的累计释放率高于茶多酚纳米脂质体悬浮液内茶多酚的累计释放率;②在明胶膜中,茶多酚-纳米粒包埋的茶多酚的释放同样符合一级动力学,但茶多酚-纳米粒悬浮液内的茶多酚在PBS中释放的速率要慢很多,且茶多酚-壳聚糖纳米粒内的茶多酚的释放较茶多酚纳米脂质体内茶多酚的释放受到的影响更大;③茶多酚从茶多酚-纳米粒复合明胶膜向PBS中的释放与茶多酚-纳米粒复合明胶膜在PBS中的溶胀、溶蚀有关,茶多酚纳米脂质体复合明胶膜在PBS中快速溶蚀,茶多酚纳米脂质体从复合明胶膜中分散到PBS中释放茶多酚;茶多酚-壳聚糖纳米粒复合明胶膜在PBS中经历了一个先溶胀后溶解的过程,茶多酚先是从茶多酚-壳聚糖纳米粒释放到溶胀的明胶膜内,然后通过水分子渗透剂在膜内形成的扩散通道再释放到PBS中,释放速率较茶多酚纳米脂质体复合明胶膜内茶多酚的释放大大下降。更多还原

【Abstract】 The extraction method of channel catfish skin gelatin and tea polyphenol loaded nanoparticles was developed. The influence of tea polypheno loaded nanoparticles on gelatin film was evaluated. Furthermore, the release kinetics of tea polyphenol from composite films was investigated.Gelatin was extracted from channel catfish skin with a novel method and characterized. The skin was allowed to swell in acetic acid, and then was mashed with triturator, dissolved in dilte acid, precipitated by adding NaOH to obtained collagen fibers. Finnally, the collagen fibers were extracted for gelatin in the water of 45°C、pH7.0 within 6 hours. It was found that the yield of gelatin had exceeded 95%, the gelation temperature of gelatin solution and gelatin gel melting point were 19.6°C、25.2°C, respectively.Tea polyphenols nanoliposomes (TP-L) were prepared with by ethanol injection- sonication method. Higher encapsulating efficiency of 25 mg tea polyphenols was obtained with lecithin concentraction of 1.0 mg/mL, cholesterol to lecithin mass ratio of 1:5, Tween 80 and lipid to the molar ratio of 4:5, hydration temperature of 50°C, hydration time of 30 min and 50 mL of PBS (0.05 mol/L, pH7.0). The particles of nanoliposomes were about 120 nm and zeta potential was in the range of -10 and -20 mV. With the incorporation of TP-L, a kind of composite films (TP-L F) based on channel catfish skin gelatin was obtained. Due to the steric effects from TP-L and the formation of hydrogen between TP-L and gelatin molecules, the hydrogen bonds between the gelatin-gelatin stabilizing the network of gelatin film had been reduced, consequently, the properties of the composite film had been changed. With a respect, antioxidative activity of the film had been enhanced siginficantlly.Technical route of preparation for tea polyphenols loaded chitosan- sodium tripolyphosphate nanoparticles (TP-CTS-TPP) were confirmed. The optimum technical parameters with highest encapsulating efficiency were: chitosan concentraction of 2.0 mg/mL, pH5.5, TPP to chitosan mass ratio of 1:3, TP of 25 mg, time of 30 min. The resulted nanoparticels was about 300 nm and zeta potential was in the range of 40 and 50 mV. The composite gelatin film (TP-CTS-TPP F) incorporated TP-CTS-TPP was prepared and its antioxidative activity and properties were investigated. It showed, the incorporation of TP-CTS-TPP interfered with hydrogen forming between gelatin molecules, owing to the steric effects from TP-CTS-TPP and the formation of hydrogen including interaction of amino-group on chitosan with amino-group on gelatin and interaction of hydroxyl-group on chitosan with amino-group on gelatin. So, the properties of composite film were modified, but its antioxidative ability was improved to a large extent.Finally, the release kinetics of TP-L and TP-CTS-TPP in PBS, the release kinetics of TP-L and TP-CTS-TPP in gelatin films as well as the release kinetics of TP-L F and TP-CTS-TPP F in PBS were characterized. The first, the release kinetics of TP-L and TP-CTS-TPP in PBS fitted the first release kinetic model well; however, the cumulative release rate of TP-L was higher than that of TP-CTS-TPP. The second, the release kinetics of TP-L and TP-CTS-TPP in gelatin films also were consistent with the first release kinetic model; however, the release rate of TP-L and TP-CTS-TPP were lower than their in PBS. The third, the release characteristicas of TP from TP-L F and TP-CTS-TPP F in PBS were related to the swelling ability and dissolutions of the composite films. TP-L F corroded in PBS quickly, and TP was released from TP-L dispersed in PBS. At the first stage, the TP-CTS-TPP F in PBS happened to limited dissolution and to became hydrogel, TP released from TP-CTS-TPP fixed in hydrogel and then diffused from hydrogel to PBS through the channel formed by water in the course of swelling procdure.更多还原