Microencapsulation is a process of building a functional barrier between the core and wall material to avoid chemical and physical reactions and to maintain the biological, functional, and physicochemical properties of core materials. Microencapsulation of marine, vegetable, and essential oils has been conducted and commercialized by employing different methods including emulsification, spray-drying, coaxial electrospray system, freeze-drying, coacervation, in situ polymerization, melt-extrusion, supercritical fluid technology, and fluidized-bed-coating. Spray-drying and coacervation are the most commonly used techniques for the microencapsulation of oils. The choice of an appropriate microencapsulation technique and wall material depends upon the end use of the product and the processing conditions involved. Microencapsulation has the ability to enhance the oxidative stability, thermostability, shelf-life, and biological activity of oils. In addition, it can also be helpful in controlling the volatility and release properties of essential oils. Microencapsulated marine, vegetable, and essential oils have found broad applications in various fields. This review describes the recognized benefits and functional properties of various oils, microencapsulation techniques, and application of encapsulated oils in various food, pharmaceutical, and even textile products. Moreover, this review may provide information to researchers working in the field of food, pharmacy, agronomy, engineering, and nutrition who are interested in microencapsulation of oils.

Microencapsulation of Oils: A Comprehensive Review of Benefits, Techniques, and Applications

In the last decades, the discovery of metabolites from marine resources showing biological activity has increased significantly. Among marine resources, seaweed is a valuable source of structurally diverse bioactive compounds. The cell walls of marine algae are rich in sulfated polysaccharides, including carrageenan in red algae, ulvan in green algae and fucoidan in brown algae. Sulfated polysaccharides have been increasingly studied over the years in the pharmaceutical field, given their potential usefulness in applications such as the design of drug delivery systems. The purpose of this review is to discuss potential applications of these polymers in drug delivery systems, with a focus on carrageenan, ulvan and fucoidan. General information regarding structure, extraction process and physicochemical properties is presented, along with a brief reference to reported biological activities. For each material, specific applications under the scope of drug delivery are described, addressing in privileged manner particulate carriers, as well as hydrogels and beads. A final section approaches the application of sulfated polysaccharides in targeted drug delivery, focusing with particular interest the capacity for macrophage targeting.

https://www.mdpi.com/1660-3397/14/3/42/pdf

Sulfated Seaweed Polysaccharides as Multifunctional Materials in Drug Delivery Applications.

Background Bioactive compounds possess plenty of health benefits, but they are chemically unstable and susceptible to oxidative degradation. The application of pure bioactive compounds is also very limited in food and drug formulations due to their fast release, low solubility, and poor bioavailability. Encapsulation can preserve the bioactive compounds from environmental stresses, improve physicochemical functionalities, and enhance their health-promoting and anti-disease activities. Scope and approach Micro and nano-encapsulation based techniques and systems have great importance in food and pharmaceutical industries. This review highlights the recent advances in micro and nano-encapsulation of bioactive compounds. We comprehensively discussed the importance of encapsulation, the application of biopolymer-based carrier agents and lipid-based transporters with their functionalities, suitability of encapsulation techniques in micro and nano-encapsulation, as well as different forms of improved and novel micro and nano-encapsulate systems. Key findings and conclusions Both micro and nano-encapsulation have an extensive application, but nano-encapsulation can be a promising approach for encapsulation purposes. Maltodextrin in combination with gums or other polysaccharides or proteins can offer an advantageous formulation for the encapsulation of bioactive compounds by using encapsulation techniques. Electro-spinning and electro-spraying are promising technologies in micro and nano-encapsulation, while solid lipid nanoparticles and nanostructure lipid carriers are exposing themselves as the promising and new generation of lipid nano-carriers for bioactive compounds. Moreover, phytosome, nano-hydrogel, and nano-fiber are also efficient and novel nano-vehicles for bioactive compounds. Further studies are required for the improvement of existing encapsulate systems and exploring their application in food and gastrointestinal systems for industrial application.

Advances in micro and nano-encapsulation of bioactive compounds using biopolymer and lipid-based transporters

Alginate microparticles as oral colon drug delivery device: A review

Complex coacervation: Principles, mechanisms and applications in microencapsulation

Encapsulation of active ingredients in polysaccharide-protein complex coacervates.

Smart porous microparticles based on gelatin/sodium alginate polyelectrolyte complex

Complex coacervation of gelatin A and sodium alginate was carried out to obtain the maximum coacervate yield. Turbidity and coacervate yield (%) measurements were carried out to support the ratio of the two polymers and pH that produced maximum coacervation. The optimum ratio between gelatin A-sodium alginate and pH to form the maximum coacervate complex was found to be 3.5:1 and 3.5–3.8, respectively. Olive oil microencapsulation was carried out at the optimized ratio and pH. Microcapsules were crosslinked by using glutaraldehyde. Scanning electron microscopy studies confirmed the formation of free flowing spherical microcapsules of different sizes. The size of microcapsules increased with the increase in the concentration of the polymer. The encapsulation efficiency and the release rates of olive oil were dependent on the amount of crosslinker, oil loading and polymer concentration. Thermogravimetric study revealed improvement of thermal stability with crosslinking. Fourier Transform Infrared Spectroscopy study showed that there was no significant interaction between olive oil and gelatin-alginate complex.

Study of Complex Coacervation of Gelatin A and Sodium Alginate for Microencapsulation of Olive Oil

Microcapsules containing neem seed oil (NSO) were prepared using complex coacervation technique and employing gelatin A and κ-carrageenan polyelectrolyte complex. The yield of the coacervate was dependent on the ratio of the two polymers and on the pH of the medium. Viscosity and turbidity measurements were carried out in order to support the ratio of the two polymers that produced the highest yield. The encapsulation efficiency and the release rates of NSO were dependent on the amount of crosslinker, oil loading and polymer concentration. Scanning electron micrographs showed the formation of free flowing spherical microcapsules. The size of microcapsules increased with the increase of the concentration of the polymer. Fourier Transform Infrared Spectroscopy and Differential Scanning Calorimetry study showed that there was no significant interaction between NSO and carrageenan–gelatin complex.

Genipin crosslinked microcapsules of gelatin A and κ-carrageenan polyelectrolyte complex for encapsulation of Neem (Azadirachta Indica A.Juss.) seed oil

The ratio of gelatin to sodium carboxymethyl cellulose (SCMC) at which maximum yield was obtained was optimized. This optimized ratio of gelatin to SCMC along with other parameters was used to prepare microparticles of different sizes. Vegetable oil was used as emulsion medium. Effect of various factors like amount of surfactant, concentration of polymer on the formation, and size of the microparticles was investigated. These microparticles were used as carrier for isoniazid. Among different cross-linkers, glutaraldehyde was found to be the most effective cross-linker at the temperature and pH at which the reaction was carried out. The loading efficiency and release behavior of loaded microparticles were found to be dependent on the amount of cross-linker used, concentration of drug, and time of immersion. Maximum drug loading efficiency was observed at higher immersion time. The release rate of isoniazid was more at higher pH compared to that of at lower pH. The sizes of the microparticles were investigated by scanning electron microscope. In all the cases, the microparticles formed were found spherical in shape except to those at low stirring speed where they were agglomerated. Fourier transform infrared study indicated the successful incorporation of isoniazid into the microparticles. Differential scanning calorimetry study showed a molecular level dispersion of isoniazid in the microparticles. X-ray diffraction study revealed the development of some crystallinity due to the encapsulation of isoniazid.

/pdf/preparation-and-evaluation-of-gelatin-sodium-carboxymethyl-wkfb07wl4a.pdf

Nirmala Devi

Papers

Encapsulation of active ingredients in polysaccharide-protein complex coacervates.

Smart porous microparticles based on gelatin/sodium alginate polyelectrolyte complex

Study of Complex Coacervation of Gelatin A and Sodium Alginate for Microencapsulation of Olive Oil

Genipin crosslinked microcapsules of gelatin A and κ-carrageenan polyelectrolyte complex for encapsulation of Neem (Azadirachta Indica A.Juss.) seed oil

Preparation and evaluation of gelatin/sodium carboxymethyl cellulose polyelectrolyte complex microparticles for controlled delivery of isoniazid.