Micro-encapsulation

Abstract: Microcapsules of vitamin A palmitate were prepared by gelatin-acacia complex coacervation The effects of colloid mixing ratio, core-to-wall ratio, hardening agent, concentration of core solution, and drying method on the coacervation process and the properties of the microcapsules were investigated The microcapsules of vitamin A palmitate were prepared using different weight ratios of gelatin and acacia, that is, 2:3, 1:1, and 3:2 under controlled conditions The other factors studied were 1:1, 1:2, and 1:3 core-to-wall ratios; 30, 60, and 120 min of hardening time; 2, 5, and 10 ml of formaldehyde per 280 g of coacervation system as a hardening agent; and 30%, 40%, and 50% w/w vitamin A palmitate in corn oil as a core material The drying methods used were air drying, hot air at 40 degrees C, and freeze-drying The results showed that spherical microcapsules were obtainedfor all conditions except for 30 min of hardening time, which did not result in microcapsules The optimum conditions for free-flowing microcapsules with a high percentage of entrapped drug were 1:1 gelatin-to-acacia ratio and 1:2 core-to-wall ratio when hardening with 2 ml formaldehyde for 60 min and using 40% w/w vitamin A palmitate in corn oil as the core concentration In addition, drying the microcapsules by freeze-drying provided microcapsules with excellent appearance

Abstract: As by-products of grape juice and wine production, grape seeds are a rich source of procyanidins but are usually discarded as waste. We have treated grape seeds with supercritical fluid extraction to remove the oils and have extracted the procyanidins from the residues. In order to extend the shelf life, micro-encapsulating methods for procyanidins were studied: the use of gum arabic and maltodextrin as wall materials (the contents of arabic gum and maltodextrin were 40% and 60%, respectively). The raw materials were then mixed (the ratio of core substance to wall material was 30:70 w/w and the content of the slurry was 20% w/v). After homogenisation, spray drying was used to prepare microcapsules. The micro-encapsulation efficiency was up to 88.84%. Analysis of the product showed that the procyanidin was not changed during the processing and the procyanidin microcapsule membrane was uninterrupted and with fairly good integrity. The stability of the products was also obviously improved. Copyright © 2007 Society of Chemical Industry