Formation and characterization of microcapsules by complex coacervation with liquid or solid aroma cores
ABSTRACT The process parameters typically reported in the literature for the encapsulation of aroma compounds via coacervation are reviewed and their effects on capsule formation discussed. We then report on our approach to produce coacervates [liquid (limonene or medium chain triglycerides) or solid core (menthol)] using gum acacia/gelatin as wall materials. Manufacturing parameters were optimized to allow the production of consistent batches of coacervate microcapsules. Capsules were cross-linked with glutaraldehyde and freeze-dried. Coacervates were characterized for their structure and shape, size distribution, flavour load and water uptake rate. In addition, a brief storage study compared the ability of coacervate capsules and spray-dried capsules (using modified starch as carrier material) to protect limonene from oxidation. No detectable increase in limonene oxide could be detected in capsules made by coacervation over 25 days in storage at 45 °C, whereas a significant increase in limonene oxide was detected in spray-dried powder over the same period. Encapsulation by coacervation (as described in this paper) appears to be an effective technique for encapsulating aroma compounds and provides a good barrier against oxidation of sensitive material. Copyright © 2008 John Wiley & Sons, Ltd.
- SourceAvailable from: Juan Francisco Rodríguez[Show abstract] [Hide abstract]
ABSTRACT: PRS® paraffin wax was encapsulated by means of suspension-like copolymerization of methyl methacrylate (MMA) with butyl acrylate (BA). The effects of the polymeric shell dry glass transition temperature (Tg) and the reaction temperature (Tr) were then studied. Additionally, the evolution of particle diameter, molecular weight, conversion, and Tg during polymerization was also researched. The chemical properties of the shell material (acrylic polymer), together with those found in the core material (PRS® paraffin wax), for instance: polarity and interfacial tensions, largely determine whether the morphology of the microcapsules will be thermodynamically favored or not. The high polarity of MMA (γ0 = 18 mN m−1) and BA (γ0 = 24 mN m−1) should provide a thermodynamic driving force to cover the paraffin wax droplet which would result in a core/shell thermodynamically favored structure. However, most systems are defined by kinetics rather than thermodynamics such as the monomers dry Tg and Tr. It was observed that penetration of polymer radical chains was severely limited when the dry Tg was ≥10°C above the reaction temperature, resulting in irregular and undifferentiated particles. However, penetration did occur when the copolymeric shell dry Tg was ∼10°C below the reaction temperature which led to uniform and spherical particles being synthesized. POLYM. ENG. SCI., 54:208–214, 2014. © 2013 Society of Plastics EngineersPolymer Engineering and Science 01/2014; 54(1). · 1.24 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Chitosan (CS) exhibits non-toxicity, biocompatibility and antibacterial activity in the pharmaceutical field. Fragrance is obtained by blending a large number of different spices and odorous materials in a specific ratio. However, their main ingredients are labile and volatile. Most volatile fragrances are easily lost during manufacture, storage and use of the perfumes or the perfumed consumer products. In this study, tuberose fragrance (TF) was encapsulated inside CS nanoparticles (TC-NPs) via the ionic gelification in emulsion system. The influence of reaction conditions, such as weight ratio of CS to tripolyphosphate (TPP) as well as CS and TF concentration, on the properties of nanoparticles (particle size and zeta potential) was investigated in detail. TC-NPs were characterized with transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transformation infrared spectroscopy (FTIR), gas chromatography–mass spectrometry (GC–MS) and thermogravimetric analysis (TGA). TC-NPs (174 nm) were obtained with the weight ratio of CS/TPP 5:1, 1.5 mg/ml CS and 100% TF. FTIR demonstrated that TF can be functioned with CS via intermolecular forces and hydrogen bonds. TGA displayed that the thermal stability of TC-NPs was improved compared with that of TF and that TF loading capacity was 29.5%. GC–MS showed that 90% fragrances in TF had been encapsulated into TC-NPs. GC with flame ionization detector (FID) displayed that the contents of fragrant components released from NPs were much less than that of TF after heating for 30 h. The antimicrobial activities of TC-NPs were higher than that of TF. TC-NPs displayed lower cytotoxicity to the cells. It is shown that CS-NPs is a multifunctional carrier material for fragrance. Copyright © 2013 John Wiley & Sons, Ltd.Flavour and Fragrance Journal 01/2014; 29(1). · 1.82 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: In their active forms, the organic structures become the packaging units and carriers of nutrients intended for targeted delivery by nature, providing protection for the encapsulated active materials. This packaging and delivery role is mimicked in the microencapsulation process. One complex problem juxtaposes encapsulation effectiveness against accessibility and bioavailability of the entrapped nutrients; the others include providing nutrients that improve health and well‐being instead of drugs, and the daily use of the “whole” foods including the “active” components only to prevent future health problems. Presently, new foods and functions are being delivered through new technologies such as functional hydrogels, nanoemulsions and nanoparticles. Future foods such as nutraceuticals and pharmafoods may be delivered in forms that control the amounts of bioactives released at targeted organs. Nutrients may be delivered through foods tailored to individual genetic makeup (nutrigenomics), for an individual's metabolic needs, related to a specific element, metabolomics. PRACTICAL APPLICATIONSMicroencapsulation mimics nature by packaging active components within structures that provide protection and delivers nutrients at appropriate sites. As such, it provides a benefit to bioactive functional food components by limiting the adverse food processing environment, which can be deleterious at times, such as the presence of water and oxygen. By controlling the structure matrix, the release time and dosage of bioactive contents are controlled for intentional site‐time delivery. This knowledge is leading the way bioactive components will be delivered for personal and body function and health‐enhancing benefits through functional foods.Journal of Food Processing and Preservation 01/2013; 37(5). · 0.45 Impact Factor