【作者】 曾治平；

【导师】 姜建国；

【作者基本信息】 华南理工大学 ， 制糖工程， 2010， 硕士

【摘要】 叶黄素是一种着色能力强、富有营养和保健医疗作用的天然色素。由于它有多个共扼双键,具有鲜明的颜色和抑制自由基的能力,因而近年来被广泛地应用在食品和医药工业之中。但是由于稳定性差,易受光照、氧气等环境条件的影响而加速降解,使它的应用受到局限。近年来,由于微胶囊化可以保护敏感组分不被外界条件轻易破坏,微胶囊技术在食品工业的发展迅速。复凝聚法是经典的微囊化方法,操作简单,适合于难溶性食品药物的微囊化。本论文采用复凝聚法制备叶黄素微胶囊以此提高叶黄素的稳定性,使其更便于贮藏和应用。本论文以明胶和阿拉伯胶为壁材,采用复凝聚法制备叶黄素微胶囊,研究了微胶囊的制备工艺、理化性质以及贮藏稳定性。主要研究内容和结果如下：在复凝聚法制备叶黄素微胶囊的工艺的研究中,运用单因素实验确定最佳工艺参数范围：壁材浓度为0.5%-1.5%,芯壁比为2：1-1：2,复凝聚反应温度为40℃-50℃,pH值为4.1-4.7。在单因素实验的基础上,通过响应面分析来优化工艺条件。以壁材浓度、芯壁比、pH值为因素,以包埋效率作为响应值进行响应面回归实验分析,确定其最佳工艺条件：壁材浓度为1.0%,芯壁材比为1.25：1,pH值为4.2,理论最佳包埋率86.41%,验证此条件下得到实际包埋率为85.32%±0.63%。采用激光粒度仪、红外光谱仪、扫描电镜和差示量热扫描仪等对叶黄素微胶囊的理化性质进行考察。结果表明,通过激光粒度仪分析叶黄素微胶囊的颗粒大小在0-30μm的范围内具有广泛的分布,以10-20μm的颗粒占有的比例最大,分布最集中。粉体的比表面积为0.801m2/g,比表面积较大,其水溶性也相对较好。体积平均直径为14.198μm,在最佳工艺条件下制备的微胶囊粒径大小较为均匀。通过红外光谱证实微胶囊复合物是由明胶、阿拉伯胶经过物理相互作用而形成的,未发生化学键的连接作用。运用差式扫描量热仪对微胶囊的玻璃化转变温度进行分析,微胶囊产品的玻璃化转变温度约为40.5℃,高于常温贮存温度。因此,在常温下贮存处于玻璃态,比较稳定,具有较好的贮藏稳定性。对叶黄素及其微胶囊的稳定性实验中,研究相对湿度、光照、温度、氧气等对叶黄素微胶囊贮藏稳定性的影响。微胶囊在低湿条件下(相对湿度为33%)贮存很稳定,相对湿度超过80%,其保留率大大降低；避光贮藏与未避光贮藏两种条件相比,在未避光条件下叶黄素的损失率较高,而通过复合凝聚法包埋的叶黄素微胶囊,其保留率显著高于未经包埋的叶黄素；叶黄素微胶囊在4℃、25℃时贮存很稳定,而在50℃时稳定性降低；在有氧条件下和无氧条件下两种条件相比,在有氧条件下未包埋的叶黄素的损失率较高,而包埋后的叶黄素产品保留率相对显著提高。更多还原

【Abstract】 Lutein is a kind of natural pigments with strong colouring power, rich nutrition and health care role. As the number of conjugated double bonds it has vivid color and inhibiting ability of free radicals, which in recent years has been widely used in food and pharmaceutical industries. However, due to unstable and vulnerable to light, oxygen and other environmental conditions which accelerate degradation, its applications are limited greatly. In recent years, as microencapsulation can protect the sensitive components from the external conditions, the microencapsulation technology developed rapidly in the food industry. Coacervation microencapsulation method is the classic method with simple operation, suitable for insoluble drugs or food. In this paper, microcapsules of lutein were made with complex coacervation method in order to raise the stability of lutein and make it more convenient in storage and applications.In this paper, lutein was microencapsulated using complex coacervation of gelatin and gum arabic. The preparation processing, physical and chemical properties and storage stability were studied. Main contents and results are listed as follows:The technological parameters were investigated using single factor experiments:the wall material concentration is 0.5%-1.5%, core-wall ratio is 2:1-1:2, reaction temperature is 40℃-50℃, pH value is 4.1-4.7.On the basis of single factor experiment, response surface analysis was used to optimize the process conditions including three independent variables the wall material concentration, the ratio of core material to wall material, and the pH value. The optimal conditions were obtained for the lutein microencapsulation by complex coacervation method:wall material concentration 1.0%, the ratio of core material to wall material wall 1.25:1, pH value of 4.2. The theoretical optimal embedding rate was 86.41%, the embedding rate in practice by verifying was 85.32%±0.63%.The physical and chemical properties of lutein microcapsules were investigated using Laser particle size analyzer, FT-IR spectrum, scanning electron microscope (SEM), differential scanning calorimetry (DSC). The results showed that particle size of microcapsules was widely distributed in the range 0-30μm, and the average volume diameter was 14.198μm. It was proved the coacervate was formed by the physical interaction between gelatin and gum arabic using FT-IR spectrum, not chemical interaction. Glass transition temperature (Tg) of lutein microcapsules by DSC was at 40.5℃which indicated it had good storage stability.The influence of light, temperature, oxygen and relative humidity on the stability of lutein microcapsules was studied. Microcapsules products stored stably in low humidity (relative humidity=33%), when relative humidity rised to 80% or above, the reservation rate was decreased dramatically. Compared with the condition in light, the losing rate of lutein in light-proof condition was lower. Lutein microcapsules were stable in in 4℃,25℃, but the stability was reduced in 50℃. Compared with the condition in the presence of oxygen, the losing rate of lutein decreased in absence of oxygen.更多还原