明胶与羧甲基纤维素钠的复合凝聚作用及其微胶囊制备

发布时间：2018-06-24 01:12

本文选题：复合凝聚 + 羧甲基纤维素钠　；参考：《江南大学》2017年硕士论文

【摘要】：复合凝聚微胶囊具有载量高、可控制释放等优点。目前复合凝聚微胶囊多以明胶和阿拉伯胶为壁材,其中阿拉伯胶价格昂贵且性质不稳定,羧甲基纤维素钠(CMC)来源广且价格低廉,有望替代阿拉伯胶从而降低复合凝聚微胶囊的成本。然而,由于CMC、明胶的类型及性质参数众多,明确适合于复合凝聚微胶囊包埋的CMC与明胶的关键属性,对于拓展复合凝聚微胶囊壁材的选择范围具有重要意义。本论文研究了CMC粘度及明胶凝冻强度对复合凝聚物形成与性质的影响,探讨了优选所得的明胶/CMC复合凝聚行为,在此基础上,优化并确定了复合凝聚法制备肉桂醛微胶囊的工艺参数。以体系浊度、复聚物产率、显微形态及粒径分布差异为指标,研究CMC粘度及明胶凝冻强度对复聚物形成与界面性质的影响。结果表明,不同粘度CMC及不同凝冻强度明胶的复合凝聚体系,均在明胶/CMC之比为9:1(w/w)、复凝聚pH为4.50时具有较高的复聚物产率。基于明胶(200,Bloom g)/CMC(FL9)的复合凝聚体系具有较高的乳化活性和较低的界面张力,可形成大小均一的球形多核微胶囊,产率及效率可达87.56%、91.03%。通过改变总浓度、明胶/CMC混合之比和混合顺序确立了明胶/CMC/水/三元体系的相边界,绘制明胶/CMC复合凝聚体系的相图,研究了明胶与CMC之间的复合凝聚行为。结果发现,pH对明胶/CMC体系的相分离行为有重要影响,相比于pH 4.50时的三相图,pH 3.50时的相分离区域要更大,表明相分离需要在更高的电荷浓度下才能发生。借助浊度滴定曲线,确定了明胶/CMC混合质量比为1:5,1:3,1:1,3:1,5:1,9:1的体系开始形成不可溶性复聚物所对应的临界pH值(pHφ1)分别为2.97,3.10,3.76,4.23,4.71,4.80。通过软粒子理论、傅里叶红外光谱、圆二色谱技术对明胶/CMC复聚物的形成过程进行分析。结果表明,在不同明胶/CMC之比对应的pHφ1值下,不可溶性复聚物形成过程中明胶与CMC所带电荷的绝对值相等;明胶与CMC之间无化学键生成;明胶、CMC复凝聚过程中明胶分子由无规卷曲状态转变为有序的PPII螺旋。采用明胶/CMC复凝聚体系对肉桂醛进行微胶囊化。通过比较不同pH、壁材浓度、乳化条件、搅拌速率下肉桂醛微胶囊的显微形态、粒径分布、包埋效果,确定了最佳制备条件:pH 4.50,壁材质量浓度为1.0%,明胶/CMC质量之比为9:1,乳化条件(10000r/min、2 min),搅拌速率400 r/min,微胶囊产率及效率可达88.92%、92.13%。对芯材浓度分别为1.0%、2.0%肉桂醛微胶囊的热稳定性、高盐离子稳定性进行研究,发现芯材浓度1.0%时制备的微胶囊的热稳定性及高盐离子稳定性更佳。将芯材浓度1.0%肉桂醛微胶囊应用于卷烟中,结果表明肉桂醛微胶囊化后进入主流烟气的转移率有所提高,并且在烘丝过程中的损失率降低。
[Abstract]:Composite condensed microcapsules have the advantages of high loading and controllable release. At present, gelatin and Arabic gum are used as wall materials in compound condensed microcapsules, among which Arabic gum is expensive and unstable, and sodium carboxymethyl cellulose (CMC) comes from a wide range of sources and the price is low. It is expected to replace Arabic gum so as to reduce the cost of composite condensed microcapsules. However, due to the large number of types and properties of CMC gelatin, it is of great significance to define the key properties of CMC and gelatin which are suitable for the encapsulation of composite condensed microcapsules, which is of great significance to expand the selection range of wall materials for composite condensed microcapsules. In this paper, the effects of CMC viscosity and gelatin freezing strength on the formation and properties of composite condensate were studied. The process parameters for the preparation of cinnamaldehyde microcapsules by complex coagulation method were optimized and determined. The effects of CMC viscosity and gelatin freezing strength on the formation and interfacial properties of the polymer were studied based on the differences of turbidity, yield, morphology and particle size distribution of the system. The results show that when the ratio of gelatin / CMC is 9:1 (w / w) and the pH of complex coagulation is 4.50, the composite condensing system with different viscosity CMC and different freezing strength has a higher yield. The composite condensate system based on Gelatin (200m Bloom g) / CMC (FL9) has higher emulsifying activity and lower interfacial tension, and can form uniform spherical polynuclear microcapsules. The yield and efficiency can reach 87.56% and 91.03%. The phase boundary of gelatin / CMC / water / ternary system was established by changing the total concentration, the mixing ratio and the mixing sequence of gelatin / CMC. The phase diagram of gelatin / CMC composite condensate system was drawn, and the composite condensation behavior between gelatin and CMC was studied. The results show that pH has an important effect on the phase separation behavior of gelatin / CMC system, and the phase separation region is larger than that at pH 4.50, which indicates that the phase separation takes place at a higher charge concentration. With the help of turbidimetric titration curve, the critical pH value (pH 蠁 1) corresponding to the formation of insoluble polymer was determined to be 2.97% 3.103.103.64.234.71.80 for the gelatin / CMC mixed mass ratio of 1: 5: 1, 1: 1, 1: 1, 1: 1. The formation process of gelatin / CMC complex was analyzed by soft particle theory, Fourier transform infrared spectroscopy and circular dichroism. The results show that the absolute value of the charge between gelatin and CMC is equal during the formation of insoluble polymer under the condition of pH 蠁 1 corresponding to the ratio of gelatin / CMC, and there is no chemical bond formation between gelatin and CMC. The gelatin molecules changed from random coiling state to an ordered PPII helix during the complex condensation of gelatin and CMC. The gelatin / CMC complex condensation system was used to microencapsulate cinnamaldehyde. The micromorphology, particle size distribution and embedding effect of cinnamaldehyde microcapsules under different pH, wall material concentration, emulsification conditions and stirring rate were compared. The optimum preparation conditions were determined as follows: ph = 4.50, mass concentration of wall material 1.0, mass ratio of gelatin / CMC 9: 1, emulsification condition (10000r / min ~ 2 min), stirring rate 400rmin), yield and efficiency of microcapsule up to 88.92% ~ 92.13%. The thermal stability and high salt ion stability of cinnamaldehyde microcapsules with 1.0% core concentration were studied. It was found that the thermal stability and high salt ion stability of the microcapsules were better when the core material concentration was 1.0%. The application of 1.0% cinnamaldehyde microcapsule in cigarette showed that the transfer rate of cinnamaldehyde into mainstream smoke increased and the loss rate decreased during the drying process.
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TS426;TB332

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