Preparation and Characterization of Chitosan-Based Core–Shell Microcapsules Containing Clove Oil

Abstract

The biodegradable microcapsules based on chitosan for a controlled delivery of clove oil were prepared by the single coagulation process. The effect of chitosan concentration, core to shell ratio, types of emulsifier, flocculating agent and hardening agent on the microcapsule diameter and the particle size distribution of microcapsule were investigated. The optimized conditions for the preparation of microcapsules with well-defined structure and narrow dispersibility were under that (1) the concentration of chitosan was 1.0 wt%, (2) clove oil to chitosan ratio was 75:25, (3) OP-10 and 10 wt% sodium sulfate were used as emulsifier and flocculating agent respectively, and (4) the concentration hardening agent glyoxal was 1 wt% based on the weight of chitosan. The uniform spherical structures with smooth surfaces with a particle size distribution of 1-15 μm were evidenced by SEM images of microcapsules. Core-shell, hetero-structures were confirmed by optical micrograph. The chemical component of the microcapsules was determined by FTIR. Thermal analysis showed the microcapsules were thermally stable below 150 degrees C. It was found that the pH value and temperature play important roles on the release rate of clove oil from the microcapsules. The release volume of clove oil from microcapsules at pH = 7, and pH = 10 were smaller than that at pH = 2. And the release volume of Clove oil from microcapsules at 60 degrees C was smaller than that at 20 degrees C and 40 degrees C, which showed a sustained and prolonged release.

Sustainable Chemistry Considerations for the Encapsulation of Volatile Compounds in Laundry-Type Applications

“…Lower release rates of clove oil were observed when the temperature of the release study was increased from 20 to 40 °C or 60 °C. This was linked to contraction of pores of the chitosan shell at higher temperatures …”

“…This was linked to contraction of pores of the chitosan shell at higher temperatures. 65 Gelatin is a mixture of peptides and proteins, produced via irreversible collagen hydrolysis. Due to the specific amino acid compostion of gelatin, with proline inducing close-packed chains and locking certain conformations, it is often used as a gelling agent.…”

Chitosan-based nanocapsules of core-shell architecture

“…The hydrophilic nature of the molecule provides its good solubility in acidic aqueous solutions due to the protonation of amino groups which makes chitosan material of high utility. The presence of charged functional groups and the ability to modify the macromolecules by the compounds having permanent electrostatic charge promote the use of chitosan as a material for the construction of oil-core microcapsules [29] or biocompatible multilayer polymeric films [30,31] serving as coatings for nanoparticles [32,33] or protecting the cells during the low temperature storage [34]. Importantly, chitosan is a biocompatible and biodegradable material capable of chelating and binding metal ions and organic compounds, characterized by high adhesiveness to negatively charged membrane proteins [35].…”

Microcapsules-based multifunctional coatings for anticorrosion and antibacterial applications

“…Besides that, biodegradable microcapsules based on chitosan were synthesized by the single coagulation process. These biodegradable microcapsules containing clove oil were successfully synthesized and prolonged the release of clove oil [170].…”

“…as by using liposomes [167], single coagulation [170], spray dried [168], coacervation phase [169] and envelope binding methods [218]. However, some problems were surfaced, such as high agglomeration tendency and irregular shape of the microcapsules, which affect the release of clove oil for practical uses.…”