Microencapsulation by Complex Coacervation : Effect of Cationic Surfactants (original) (raw)
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Micro-encapsulation by complex coacervation: influence of surfactant
Polymer International, 2003
Paraffin oil has been encapsulated using complex coacervation of gelatin and Arabic gum in the presence of a surfactant. Addition of an oppositely charged surfactant to a polyelectrolyte markedly increases the yield of the process. We report a two-layer encapsulation of paraffin oil, based on a primary layer of interface active polyelectrolyte-surfactant complex, followed by a second layer of the conjugate polyelectrolyte-polyelectrolyte complex. Surfactant concentration has been found to be a crucial parameter to obtain good quality microcapsules and optimal yield. This confirms the importance of formulation aspects when looking for optimization of these techniques of micro-encapsulation.
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...
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.
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%.
The aim of this work was to compare encapsulation of stearidonic acid soybean oil (SDASO) by complex coacervation in the classical gelatin (GE)-gum arabic (GA) system with that of a Maillard reaction product (MRP). A portion of the control (microcapsules based on the GE-GA system) was cross-linked with transglutaminase (TG) after encapsulation. In the Maillard reaction (MR)-modified system, the gelatingum arabic mixture was cross-linked under controlled dry-heating conditions before use as encapsulating agent. The applicability of control, TG-, and MR-modified microcapsules in formulating SDASOfortified yogurt was assessed for thermal and oxidative stability. SDS-polyacrylamide gel electrophoresis was used to confirm the covalent modification of encapsulants in TG-and MR-modified microcapsules. The MR-modified microcapsules displayed colloidal stability at conditions where the nonmodified and TG-modified microcapsules were highly flocculated. ABTS free radical scavenging activity of control and modified GA-GE sols showed that antioxidant capacity was enhanced by MR but reduced by TG. The MR-modified microcapsules displayed superior oxidative stability during 28 days of storage at 4 C compared to control, while the oxidative stability of TG-modified microcapsules was lowest. Based on the amount of oil released from microcapsules during heat treatment (85 C for 30 min) in yogurt milk base, MR-modified microcapsules displayed the highest thermal stability. Furthermore, yogurts formulated with MR-modified microcapsules had the best oxidative stability during 14 days of storage at 4 C demonstrating that the antioxidant components of MR-modified microcapsules had good carry-through properties.
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.
Tuna oil rich in omega-3 fatty acids was microencapsulated in whey protein isolate (WPI)–gum arabic (GA) complex coacervates, and subsequently dried using spray and freeze drying to produce solid microcapsules. The oxidative stability, oil microencapsulation efficiency, surface oil and morphology of these solid microcapsules were determined. The complex coacervation process between WPI and GA was optimised in terms of pH, and WPI-to-GA ratio, using zeta potential, turbidity, and morphology of the microcapsules. The optimum pH and WPI-to-GA ratio for complex coacervation was found to be 3.75 and 3 : 1, respectively. The spray dried solid microcapsules had better stability against oxidation, higher oil microencapsulation efficiency and lower surface oil content compared to the freeze dried microcapsules. The surface of the spray dried microcapsules did not show microscopic pores while the surface of the freeze dried microcapsules was more porous. This study suggests that solid microcapsules of omega-3 rich oils can be produced using WPI–GA complex coacervates followed by spray drying and these microcapsules can be quite stable against oxidation. These microcapsules can have many potential applications in the functional food and nutraceuticals industry.