Outer Topography Research Articles

Application of Maillard reaction products on chia seed oil microcapsules with different core/wall ratios

This research studies the physical properties of microcapsules formulated with different concentrations of chia oil, using Maillard Reaction Products (MRPs) with different protein:carbohydrate ratio as encapsulants. Microcapsules were obtained from freeze-drying of O/W emulsions composed by non-heated/heated aqueous phases containing NaCas (10%wt) and lactose (10 or 20% wt/wt) blends. Chia oil (10, 15 or 20%wt/wt) constituted the oil phases. The moisture content of microcapsules was 0.31–2.23% d.b., while the water activity was ∼0.500. The dispersibility and color were also studied. The microencapsulation efficiency varied between 41.43 and 83.95%. The bulk density was 323–551 kg/m3 and 244–301 kg/m3 for tapped and aerated density, respectively. All microcapsules exhibited an outer topography characterized by flakes and agglomerates without cracks or dents. The particle size distribution and D[3,2] of reconstituted emulsions were analyzed. The heat treatment improved the protection of chia oil against lipid oxidation in most samples, partially due to the antioxidant properties of the MRPs. Also, the oil content and the protein:carbohydrate ratio affected de oxidative stability. Thus, MRPs produced by heat treatment of NaCas-lactose mixture with different protein:carbohydrate ratios were effective for conferring microencapsulated chia oil additional oxidative stability.

Magnetic Resonance Imaging in Endodontic Treatment Prediction

The necessary condition for successful endodontic treatment is the precise mapping of the shape of dental cavities. The aim of this work has been an elaboration and verification of the possibility of using three-dimensional (3D) spin echo magnetic resonance imaging (MRI) techniques in dentistry. Six extracted molar teeth were used for measurements without additional preparation and after endodontic preparation. MRI measurements were carried out on a 4.7 T research MRI system equipped with Maran DRX console. Figures show 3D images of outer surface and inner space of the teeth. The sizes of the presented volumes were calculated. Internal tooth volumes were determined before and after endodontic treatment; total tooth volumes were also measured. Because of the removal of pulp and treatment of chambers and root canals, their volumes increased. Before treatment, the internal tooth volume averaged 55.59 mm 3. After pulp removal and internal tooth treatment, the inner volumes grew from 55.59 mm 3 to a mean value of 125.46 mm 3. Results regarding internal teeth volumes before pulp removal and treatment are more scattered (variation coefficient 26.49%), whereas pulp removal and treatment significantly improve uniformity of results, which is shown by a very small value of the variation coefficient (6.85%). As a result of pulp removal and treatment of the internal tooth, the amount of hard tooth tissue is decreased from 854.40 mm 3 to an average level of 784.53 mm 3. These results indicate the possibility of employing the MRI technique for 3D mapping of the outer topography and inner structure of root canals. Indication of the measuring parameters may facilitate planning of endodontic procedures.

Calcium-alginate coated, whey protein-based microspheres: preparation, some properties and opportunities

An ‘all aqueous’ encapsulation process followed by a heat treatment was used to prepare calcium-alginate-coated, whey protein-based, water insoluble microspheres containing micronized calcium carbonate as a model core. Results obtained with this process were compared to those obtained with a similar process in which chemical cross-linking was utilized. At an initial core load of 25 or 50% (w/w), core retention ranged from 84.2–95.12% and was not significantly affected by the initial core load or by the cross-linking method. Regardless of the cross-linking method, protein retention during the process was high and ranged from 78.2–87.5%. Outer topography of the microspheres was not influenced by the cross-linking method, however, at a given composition, the inner structure of heat treated microspheres differed from that obtained with chemically-cross-linked microspheres. Swelling properties of denovo microspheres were affected by pH. Results indicated that the micronized calcium carbonate could be used as a porogenic core. Removal of the core, by an acid treatment, allowed preparing microporous delivery devices. In addition to offer opportunities for encapsulation and delivery of crystalline core, the investigated process can provide means to prepare ‘ghost’ microporous delivery systems that can, in potential, be loaded, following their preparation, with sensitive core materials at conditions that favour the stability and functionality of this core.

Oxidative Stability, Structure, and Physical Characteristics of Microcapsules Formed by Spray Drying of Fish Oil with Protein and Dextrin Wall Materials

ABSTRACT: Maltodextrins and a highly branched cyclic dextrin (HBCD) were tested for their ability to serve as wall materials for microcapsules with proteins. HBCD or a maltodextrin of DE18 with sodium caseinate (SC) improved the oxidative stability of encapsulated fish oil; however, the DE18/SC wall system had 2 disadvantages: browning induced by the Maillard reaction and agglomeration. The oil load level and the selection of dextrin strongly affected the outer topography and the inner structure, as well as the ratio of the oil to dextrin on the surface of the microcapsules. It is stated that drying speeds of dextrin and oil load levels were shown to be likely related to the structural difference in the microcapsules.

Microencapsulation of theophylline in whey proteins: effects of core-to-wall ratio

Effects of core-to-wall ratio ranging from 1:1.5 to 5:1.5 on formation, properties and core release from whey protein-based microcapsules containing theophylline were investigated. Microcapsules were cross-linked by glutaraldehyde-saturated toluene (GAST) in an organic phase. Size distribution of microcapsules, core content and core retention were affected by core-to-wall ratio. Proportion of small capsules was inversely related to core-to-wall ratio. Core content in microcapsules ranged from 6.7 to 65.7% (w/w) and core retention ranged from 16.8 to 85.4%. Outer topography and inner structure of microcapsules were influenced by core-to-wall ratio. Core release into simulated intestinal- and gastric-fluids was influenced by a combined effect of type of dissolution medium and core-to-wall ratio, through its influence on size, core content and structure of microcapsules. Results indicated that in order to attain a desired core content and release profile, the ratio of core-to-wall components, in suspensions consisting of whey proteins and theophylline, has to be carefully considered and adjusted.

Whey Protein-based Microcapsules Prepared by Double Emulsification and Heat Gelation

Whey protein-based microcapsules containing a model apolar core, anhydrous milkfat, were prepared using a process consisting of double emulsification and subsequent heat gelation. Wall solids concentration and core load ranged from 15 to 30 g/100 g and from 25 to 50 g/100 g (on dry basis), respectively. In all cases, spherical microcapsules, 10–100μ m in diameter, were obtained and their outer topography and inner structure was affected by the pH of the core-in-wall emulsion. Microcapsules prepared from pH 7.2 core-in-wall emulsions exhibited smooth, dent-free surfaces. Surface porosity of microcapsules prepared from pH 4.5, 5.5 and 5.5 core-in-wall emulsions was inversely related to pH. Core retention during microencapsulation was higher than 90% and core losses could be attributed mainly to removal of core droplets from the outer surface and to some core extraction from inner parts of microcapsules by the solvents used to wash the microcapsules. Water solubility of microcapsules prepared from pH 4.5 or pH 7.2 core-in-wall emulsions was very limited and ranged from 0.2 to 6.3%, was inversely related to the pH of core-in-wall emulsion and was affected by incubation conditions. Results suggested that the microencapsulation process might be used to prepare whey protein-based microcapsules for controlled core-release applications in food systems.

Preparation and some properties of water-insoluble, whey protein-based microcapsules

A method, consisting of double emulsification and chemical cross-linking with glutaraldehyde was used to prepare whey protein-based microcapsules containing anhydrous milk fat as a model core. Effects of emulsion composition and pH on core retention, microstructure, and water-solubility of microcapsules were investigated. In all cases, core retention higher than 88% was accomplished and, in most cases, was not significantly affected by emulsion composition. In all cases, spherical microcapsules, 10-80 mum in diameter, were obtained. Outer topography and the inner structure of microcapsules were significantly affected by the pH of the emulsion. In all cases, microcapsules were practically waterinsoluble. Microcapsules similar to the developed prototype may be suitable for controlled core release in application fields where chemical cross-linking is acceptable.