Microwave-assisted encapsulation of citric acid using hydrocolloids

This study elucidates the capability of a novel technique for producing microcapsules at an enormously short time and low cost. This technique is based on the difference between dielectric constants of core and coat materials. Edible citric acid was mixed with various biomacromolecules at ratios of 1:5, 1:10, and 1:100. Each mixture was treated up to 600 s at various powers (120–1200 W) in a microwave oven. Subsequently, the microcapsules were separated by distinct sieves, and their apparent structure and quality were evaluated using binoculars, and photographs were taken for visual comparisons. Our observations showed that only five hydrocolloids were able to produce high-quality and efficient encapsulation [casein > inulin > carboxymethylcellulose (CMC) > low methoxyl (LM) pectin (9/5%) > sorbitol]. Moreover, the highest coating efficiency was seen at highest intensity (1200 W) at a mixing ratio of 1:10. Furthermore, the optimum treating time periods for those five efficient coating materials were about 400, 75, 400, 100, and 100 s.     

Core content and stability of n‐octadecane‐containing polyurea microencapsules produced by interfacial polymerization

Microencapsulation of phase change material (PCM) n‐octadecane was carried out by interfacial polymerization technique using core and bulk monomers as toluene‐2,4‐diisocyanate (TDI) and diethylene triamine (DETA), respectively. Cyclohexane was used as the solvent for TDI and n‐octadecane, which formed the oil phase. The effect of encapsulation procedure, core‐to‐monomer ratio (CM ratio) and PCM‐to‐cyclohexane (PC) ratio was investigated on core content, encapsulation efficiency, and stability of microcapsules. Using a modified procedure, the core content was found to increase with the increasing CM ratio and reached a maximum at 3.7, while the encapsulation efficiency continuously decreased with the increasing CM ratio. Also the encapsulation efficiency was found to have a strong dependence on PC ratio and a maximum encapsulation efficiency of 92%, along with the core content of 70% was obtained with CM ratio of 3.7 along with the PC ratio of 6. The microcapsules were well shaped, i.e., round and regular, with narrow size distribution at these conditions. The PCM microcapsules were found to be stable to heat treatment at 150°C for 8 h. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

The influence of powder morphology on the effect of rosemary aroma microencapsulation during spray drying

The influence of particle morphology of spray dried powders obtained by using different carriers on the efficiency of microencapsulation of rosemary aroma is shown in the present research. It was found that the type of the carrier influenced the size but not the shape of rosemary aroma capsules and all the capsules were spherical with cracks. The biggest particles, d₅₀ = 55 μm, were obtained with 25% maltodextrin (MD) as a carrier, and the smallest, d₅₀ = 29 μm with 30% gum arabic (GA). The efficiency of encapsulating aroma inside of the capsules depended on the particles size and apparent density. An increase in the quantity of microencapsulated aroma from 10% for 25% MD to about 60% for 30% GA as the carrier was seen, which co‐related with a decrease in the average diameter of the powder particles. Similarly, an increase in the efficiency of aroma retention was followed by an increase of apparent density of powders from 796 (25% MD) to 1156 kg m^?3 (30% GA).     

Encapsulation of magnetic nanoparticles in a pH-sensitive poly(4-vinyl pyridine) polymer: a step forward to a multi-responsive system

A multiresponsive system that consists on pH-responsive polymer microspheres with encapsulated iron oxide magnetic nanoparticles that rendered the core magnetic to enable externally controlled actuation under magnetic induction has been developed. The inorganic nanoparticles were first prepared and, then, further encapsulated in a pH-sensitive poly(4-vinylpyridine). These spheres have been obtained by a modification of the simple, rapid and high-reproducible nanoprecipitation method. Magnetic measurements showed that the iron oxide nanoparticles are superparamagnetic and, therefore, able to undergo a local increase of the temperature when an oscillating magnetic field is applied. Magnetically triggered heating and pH sensitivity can be useful for biomedical applications.     

微胶囊化红磷阻燃剂的应用

详细介绍了微胶囊化红磷阻燃剂的性能及其在聚丙烯、不饱和聚酯、环氧树脂、硬质聚氨酯泡沫、聚乙烯、聚酰胺等高分子树脂中的应用配方,并说明了微胶囊化红磷阻燃母料的制备过程.     

Microencapsulation of Lactobacillus acidophilus ATCC 43121 with prebiotic substrates using a hybridisation system

The objective of this study was to evaluate the effects of prebiotic substrates on the growth of Lactobacillus acidophilus ATCC 43121 and to investigate the utilisation of these prebiotic substrates as coating materials for microencapsulation. The cell growth of L. acidophilus ATCC 43121 was significantly increased in the presence of fructooligosaccharide, lactulose and raffinose. The microencapsulation of L. acidophilus ATCC 43121 cells was carried out by dry surface reforming process (hybridisation) using the selected prebiotic substrates and the enteric coating material, Sureteric^TMsans. Scanning and transmission electron microscopy revealed that the double‐microencapsulated bacteria exhibited smooth, rounded external surfaces, with a thick external coating composed of the prebiotic substrates and the Sureteric. The acid (artificial gastric juice) or heat tolerance (55 °C) of the double‐microencapsulated preparations (prebiotic and enteric coating) was significantly higher than that of the uncoated and single‐coated (enteric coating) preparation at prolonged acid (5 h) or heat exposure (3 h). On the contrary, no significant differences were found in salt tolerance. During the storage up to 20 days at 25 and 37 °C, the stability of L. acidophilus ATCC 43121 was significantly improved by double‐microencapsulation.     

Preparation of microspheres with microballoons inside for floating drug‐delivery systems

The use of floating drug‐delivery systems is one method that is used to achieve prolonged gastric residence times. We developed a novel, multiple‐unit, floating drug‐delivery system of microspheres with microballoons inside from xanthan gum (XG) and gelatin (GA) by a water‐in‐oil method. With theophylline as the model drug, four formulations (FI–FIV) with different ratios of the two polymers were prepared. The size distribution, drug‐encapsulation efficiency, floating behavior, release characteristics, and morphological properties were investigated. The ratio of the two polymers influenced the size distribution, encapsulation efficiency, and drug release appreciably. With increasing amounts of GA, the percentage yield of the floating microspheres and the drug‐encapsulation efficiency decreased from 100 and 84.5% to 31 and 56.2%, respectively. The drug‐release rate also decreased with increasing GA content, which was attributed to an increase in the crosslinking extent. An initial burst was observed, and after that, the drug was released slowly by a near‐zero‐order pattern, which was attributed to the low solubility of theophylline and the possible complexes formed by XG and GA in the simulated gastric fluid (pH 1.2). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 197–202, 2004     

Protective Effect of Microencapsulation Consisting of Multiple Emulsification and Heat Gelation Processes on Immunoglobulin in Yolk

ABSTRACT: Two different emulsification methods involving multiple emulsification and heat gelation were used for preparation of whey protein-based microcapsules containing immunoglobulin in yolk (IgY). The residual activity of IgY during the emulsion preparation and the effects of microencapsulation on IgY stability under harsh conditions were investigated. The residual activity of IgY in an emulsion prepared with a membrane emulsifier was higher than for an emulsion using a homogenizer. Microencapsulated IgY showed remarkable stability against both pepsin and acid. Both microencapsulated IgY and nonencapsulated IgY were relatively stable in bile and artificial intestinal juice. Microencapsulated IgY retained 74% of initial activity during heat treatment. There were no significant differences in the residual activities of microencapsulated IgY under storage temperatures of 4, 25, and 37°C.     

维生素E功能及其微胶囊化

该文介绍维生素E的组成、结构和生理功能,比较维生素E微胶囊化各种方法,并重点介绍喷 雾干燥法工艺。     

一种天然维生素E微囊的制备及其性能表征

使用几种不同的壁材及乳化剂对天然维生素E进行微胶囊化,通过对比微囊化效果确定最佳选材及条件,并对最终产品各项性能指标进行测定.结果表明,最佳壁材为纯胶(GUM 2000)与蔗糖,最佳乳化剂为蔗糖酯S1570(HLB 15),壁材比例m(纯胶)∶ m(蔗糖)为2∶1,乳化剂加入量为0.5％,喷雾干燥进风口温度180～19...