Micro-encapsulation by complex coacervation: influence of surfactant (original) (raw)
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Microencapsulation by Complex Coacervation : Effect of Cationic Surfactants
We have encapsulated paraffin oil using complex coacervation of gelatin and arabic gum in the presence of a cationic surfactant. The presence of an anionic surfactant is known to increase the microcapsule yield dramatically. We report that this is true for cationic surfactant also. The concentration of the surfactant is a crucial parameter in obtaining optimal yield and good quality microcapsules. We also propose a two-step process for the formation of the microcapsules.
Food Research International, 2013
Food grade sunflower oil was microencapsulated using cold water fish gelatine (FG)-gum arabic (GA) complex coacervation in combination with a batch stirred cell or continuous pulsed flow membrane emulsification system. Oil droplets with a controllable median size of 40 − 240 µm and a particle span as low as 0.46 were generated using a microengineered membrane with a pore size of 10 µm and a pore spacing of 200 µm at the shear stress of 1.3 − 24 Pa. A biopolymer shell around the oil droplets was formed under room temperature conditions at pH 2.7-4.5 and a total biopolymer concentration lower than 4% w/w using weight ratios of FG to GA from 40:60 to 80:20. The maximum coacervate yield was achieved at pH 3.5 and a weight ratio of FG to GA of 50:50. The liquid biopolymer coating around the droplets was crosslinked with glutaraldehyde (GTA) to form a solid shell. A minimum concentration of GTA of 1.4 M was necessary to promote the crosslinking reaction between FG and GTA and the optimal GTA concentration was 24 M. The developed method allows a continuous production of complex coacervate microcapsules of controlled size, under mild shear stress conditions, using considerably less energy when compared to alternative gelatine types and production methods.
Microencapsulation of Orange Oil by Complex Coacervation and its Release Behavior
Microencapsulation of liquid orange oil as a common flavoring agent in food industries by complex coacervation in a gelatin – gum Arabic polymeric wall system was studied. At a fixed ratio of 10% w/v as concentration of the materials used in this study, trend of changes of microencapsulation process variables using different wall polymeric contents along with varying levels of the core to wall ratio were investigated. Distribution pattern of the coacervate particle size showed that more than 70% of the particle with the average diameter of 9.68 mm were reasonably encapsulated in those treatments having core to wall ratio at the level of 1:1 and 1:2 while gelatin to gum arabic content of the wall system were set to be 1:1 and 2:1 ratio, respectively. The yield of the process as ratio of the amount of coacervate microcapsules produced to the amount of materials initially present in the emulsion was highest (69%) for the treatment described. Moreover, the release and swelling data have...
Microchannel emulsification using gelatin and surfactant-free coacervate microencapsulation
Journal of Colloid and Interface Science, 2004
In this study, we investigated the use of microchannel (MC) emulsifications in producing monodisperse gelatin/acacia complex coacervate microcapsules of soybean oil. This is considered to be a novel method for preparing monodisperse O/W and W/O emulsions. Generally, surfactants are necessary for MC emulsification, but they can also inhibit the coacervation process. In this study, we investigated a surfactantfree system. First, MC emulsification using gelatin was compared with that using decaglycerol monolaurate. The results demonstrated the potential use of gelatin for MC emulsification. MC emulsification experiments conducted over a range of conditions revealed that the pH of the continuous phase should be maintained above the isoelectric point of the gelatin. A high concentration of gelatin was found to inhibit the production of irregular-sized droplets. Low-bloom gelatin was found to be suitable for obtaining monodisperse emulsions. Finally, surfactantfree monodisperse droplets prepared by MC emulsification were microencapsulated with coacervate. The microcapsules produced by this technique were observed with a confocal laser scanning microscope. Average diameters of the inner cores and outer shells were 37.8 and 51.5 µm; their relative standard deviations were 4.9 and 8.4%.
Food Chemistry, 2019
In this study, Sacha Inchi oil (SIO) (Plukenetia volubilis L.) was microencapsulated via complex coacervation of ovalbumin (OVA) and sodium alginate (AL), and the microcapsule properties were characterized. The omega-3 content in the SIO was evaluated after in vitro gastric simulation and microencapsulation. The coacervate complex between OVA and AL was evaluated based on electrostatic interactions and developed for use as a wall material via the SIO microencapsulation process. The best mass ratio for the biopolymers (OVA:AL) was 4:1 at pH 3.8, and the complex exhibited a thermal resistance at 189.86 °C. The SIO microcapsules showed a high encapsulation efficiency of approximately 94.12% in the ratio (OVA:AL) of 1:1. Furthermore, microencapsulated SIO presented resistance under gastric conditions with a low release of acyl (ω-3) units. These results demonstrate that it is possible to use OVA:AL as encapsulating agents to protect bioactive compounds and to improve the thermal behavior of microcapsules.
Formation of microcapsules by complex coacervation
The Canadian Journal of Chemical Engineering, 2014
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Microencapsulation of krill oil using complex coacervation
Journal of Microencapsulation, 2014
The research work was aimed at the development of a process to yield gelatin-gum Arabic multinuclear microcapsules of krill oil (KO), via complex coacervation. On the basis of the experimental results of the screening trials, a three-level-by-three-factor Box-Behnken design was used to evaluate the effects of the ratio of the core material to the wall (RCW; x 1 ), the stirring speed (SP; x 2 ) and the pH (x 3 ) on the encapsulation efficiency (EE). The experimental findings indicated that x 3 has the most significant linear and quadratic effects on the EE of KO and a bilinear effect with x 1 , whereas x 2 did not have any significant effect. The optimal conditions for a 92% of EE were: 1.75:1 for RCW, 3.8 for pH and 3 for SP. The microcapsules, formed by complex coacervation and without any cross-linking agent, were multinucleated, circular in shape and had sufficient stability to maintain their structure.
The Use of Polymer and Surfactants for the Microencapsulation and Emulsion Stabilization
2017
Polymer/surfactant mixtures have a wide range of industrial and technological applications, one of them being the use in microencapsulation and emulsion stabilization processes. These mixtures are able to form adsorption layers at the surface of oil droplets and so affect the emulsion stability, which depends on the polyelectrolyte/surfactant nature, concentrations ratio, method of the emulsification, etc. Polyelectrolytes alone show low surface activity in contrast to surfactants, which adsorb at the water/oil interface, making the droplets charged, but they are insufficient to stabilize emulsions. When an oppositely-charged polymer is added to the surfactant solution, a steric barrier is formed, which prevents coalescence and enhances the stability. The present review is devoted to the recent studies of the use of polymer/surfactant mixtures for the encapsulation of active ingredients and stabilization of single and double emulsions. Active ingredients are added to the oil phase p...
MATEC Web of Conferences, 2016
Citronella oil (CO) can be an effective mosquito repellent, but due to its nature which having high volatility, oils rapidly evaporates causing loss of efficacy and shorten the repellent effect. Therefore, microencapsulation technology was implemented to ensure the encapsulated material being protected from immediate contact with environment and offers controlled release. In this study, microencapsulation of CO was done by employing complex coacervation using chitosan-gelatin (B) system and utilized proanthocyanidins as the crosslinker. Remarkably, nearly all material involved in this study are from natural sources which are safe to human and environment. In designing operating process condition for CO encapsulation process, we found that wall ratio of 1:35 and pH 5 was the best operating condition based on zeta potential and turbidity analysis. FT-IR analysis found that gelatin-B had coated the CO droplet during emulsification stage, chitosan started to interact with gelatin-B to form a polyelectrolyte complex in adjust pH stage, CO capsules solidified at cooling process and were hardened during crosslinking process. Final product of CO capsules after settling process was identified at the top layer. Surface morphology of CO capsules obtained in this study were described having diameter varies from 81.63 Pm to 156.74 Pm with almost spherical in shape.