复凝聚法制备农药微胶囊剂的研究

以壳聚糖和木质素磺酸钠为囊材,以三氟氯氰菊酯为囊芯,采用复凝聚法制备了微胶囊。考察了壳芯质量比、温度、搅拌速度、对包药率的影响,确定最佳工艺条件,并对其性能进行了研究。     

液晶微囊化制备及光学性能的研究

为解决液晶分子在应用时封装复杂、难以成膜的问题,采用复凝聚法,利用液晶为囊芯材料,阿拉伯胶与明胶为璧材,对向列液晶5CB进行了微囊化.分析了溶液pH值、反应温度、反应时间、壁材浓度、搅拌速率等因素对微胶囊产品质量的影响.通过偏光显微镜和紫外分光光度计对形貌及包囊情况进行表征.研究结果表明:制备液晶微胶囊的最佳工艺条件为明胶与阿拉伯胶浓度均为2%,且两者质量比为1:1,pH值为4.0,搅拌速度为1 500r·min-1,反应温度为55℃,凝聚时间为15~20min,固化温度为10℃,固化时间60min.     

假单胞菌多糖为壁材微胶囊的制备

对以明胶和假单胞菌PT-8胞外多糖为壁材制备红花油微胶囊的影响因素进行了研究,包括壁材质量浓度、交联剂质量分数、交联时间、壁材质量比、pH。通过单因素试验和正交试验确定最佳制备条件为:壁材质量浓度为50g/L,交联剂质量分数为3%,交联时间为140min,壁材质量比为5∶4,pH为3.6,此条件下微胶囊的包埋率为81.12%。经显微镜观察发现,微胶囊形态圆整,粒径均匀,分散性较好,粒径在1~10μm。假单胞菌PT-8胞外多糖可以作为制备红花油微胶囊的壁材。     

Process Optimization,Physical Properties,and Environmental Stability of an α-Tocopherol Nanocapsule Preparation Using Complex Coacervation Method and Full Factorial Design

α-Tocopherol (α-Toc) has valuable biological activity, but its activity is limited when exposed to environmental factors. Nanocapsules can be used to overcome this problem. Using nanocapsules in the range of 100–200 nm is more beneficial. A 2⁴ full factorial design was carried out to optimize the size of nanocapsules using the complex coacervation method. The four factors were the amount of the wall material, the ratio of core material to wall material, the pH of the solution, and the speed of the homogenizer. The smallest nanocapsules (176 nm) were obtained at a wall content (gelatine and pectin) of 0.8 mg, a percentage of core material (α-Toc) to wall material of 20%, a pH = 4.5, and a homogenizer speed of 12,000 rpm. The encapsulation efficiency was 90.6 ± 1.1%, and the encapsulation yield was 83.4 ± 1.6%. Assessment of the stability of α-Toc after 1 month showed that encapsulation could improve its stability in the presence of three influential factors: humidity, light, and temperature.     

Recent advances in the microencapsulation of omega-3 oil and probiotic bacteria through complex coacervation: A review

BackgroundFunctional foods are a fastest growing sector of the food industry. The development of functional foods comprising omega-3 fatty acids and probiotic bacteria, through complex coacervation process is an emerging area of research and product development.Scope and approachWe reviewed relevant literature concerning the use of complex coacervation in microencapsulation, focusing primarily on the inclusion of probiotic bacteria and omega-3 oils into a single delivery format. This review covers advantages and disadvantages of the complex coacervation process to microencapsulate bioactive ingredients, viability of probiotic bacteria and oxidative stability of omega-3 oil during the complex coacervation process, the bioaccessibility of omega-3 oil and probiotic bacteria during simulated gastrointestinal conditions and in-vivo testings.Key findings and conclusionsThe review describes the advantages of co-encapsulation using complex coacervation followed by spray drying. It also describes the technological hurdles that need to be resolved for further development of industrial applications of co-encapsulation of probiotic bacteria and omega-3 lipids. The co-encapsulation concept has been widely used in pharmaceutical delivery systems, but is a relatively new concept in food ingredient stabilisation and delivery. There is a commercial need of co-encapsulation of multiple bioactive ingredients within a single microcapsules, due to decreased cost and enhanced product quality. Complex coacervation has been shown to be a useful method for the co-encapsulation of multiple unstable bioactive ingredients. Although in-vitro evaluation deliver useful bioavailability information, additional in-vivo and clinical trials are needed to determine the efficacy of bioactive release, particularly for microcapsules containing multiple bioactive ingredients.     

Influence of the Oil Phase on the Microencapsulation by Complex Coacervation

The influence of oil type on the process yield, efficiency of encapsulation, particle size and morphological aspects of coacervated microparticles was investigated. Firstly, several factors affecting microencapsulation of oils by complex coacervation were simultaneously examined. The results indicated that the process yield is mainly dependent on the velocity of homogenization, temperature and polymer ratio. Using optimum conditions for producing microparticles [pH 4.0, 14,000 rpm, 50 °C, gelatin:gum arabic (GE:GA) 1:1 and 2.5 % w/v], different core materials were tested: a vegetable oil (almond oil), an oil with higher hydrophilic lipophilic balance (vetiver essential oil) and a highly hydrophobic oil (mineral oil). The oil phase exerted an influence on microparticle formation, disturbing the complexation of polymers and modifying the core distribution within the particles. Some of the polymers were complexed when mineral oil was used, and the highest efficiency of encapsulation (91.8 %) was obtained with vetiver oil, followed by the almond (70.6 %) and mineral (38.0 %) oils. Particles produced with vetiver oil were larger (43.5 μm) than those produced with mineral oil (35.0 μm) and almond oil (19.2 μm), and the increase in the size is due to the encapsulation of many small droplets of emulsion, characterizing these particles as multinucleate ones.     

转动式电凝聚破乳技术在金属加工乳化液处理中的应用

研究转动式电凝聚技术用于乳化液破乳处理的效果和可行性。结果表明 ,废水破乳效果明显 ,同时可去除一定量的COD和油等污染物 ,有效地提高废水的生化性能 ,有利于废水的后续处理。     

Complex Coacervation of O-Carboxymethylated Chitosan and Gum Arabic

The effects of O-carboxymethylation modification on the coacervation of chitosan with gum arabic (GA) were investigated. O-carboxymethylated chitosan (O-CMC) carried less net positive charge in acidic solutions and its optimum pH and biopolymer ratio for coacervation with GA were lower than those of native chitosan. O-carboxymethylation modification decreased the optimum coacervation temperature from 45 to 25°C and greatly increased the sensitivity to ionic strength. Meanwhile, insoluble O-CMC–GA coacervates were formed in relative lower critical total biopolymer concentration than chitosan–GA coacervates. It was concluded that the O-carboxymethylation modification markedly influenced the electrostatic interaction of chitosan with GA.     

Structure and Technofunctional Properties of Protein-Polysaccharide Complexes: A Review

Food proteins and polysaccharides are the two key structural entities in food materials. Generally, interactions between proteins and polysaccharides in aqueous media can lead to one- or two-phase systems, the latter being generally observed. In some cases of protein-polysaccharide net attraction, mainly mediated through electrostatic interactions, complex coac-ervation or associative phase separation occurs, giving rise to the formation of protein-polysac-charide complexes. Physicochemical factors such as pH, ionic strength, ratio of protein to polysaccharide, polysaccharide and protein charge, and molecular weight affect the formation and stability of such complexes. Additionally, the temperature and mechanical factors (pressure, shearing rate, and time) have an influence on phase separation and time stability of the system. The protein-polysacchaide complexes exhibit better functional properties than that of the proteins and polysaccharides alone. This improvement could be attributed to the simultaneous presence of the two biopolymers, as well as the structure of the complexes. Consequently, the interesting hydration (solubility, viscosity), structuration (aggregation, gelation) and surface (foaming, emulsifying) properties of these complexes can be used in a number of domains. Among others, these could be macromolecular purification, microencapsulation, food formulation (fat replacers, texturing agents), and synthesis of biomaterials (edible films, artificial grafts).