Continuous flow thin film microfluidic mediated nano-encapsulation of fish oil

Abstract

A facile process has been developed for the encapsulation of fish oil using a thin film vortex fluidic device (VFD) operating under continuous flow, allowing control over the size of the encapsulated particles which are spheroidal in shape with diameters ranging from 50 to nm. This microfluidic platform simplifies the processing procedure of water-in-oil-in-water (w/o/w) encapsulation, as now a time and cost saving one-step process devoid of any organic solvents, in contrast to the conventional homogenization process which is inherently complex, involving multiple-steps and the use of organic solvents. Moreover, use of homogenization (as a benchmark to encapsulate fish oil) afforded much larger macroparticles, ranging in size from 2 to 4 µm. Smaller encapsulated particles fabricated using VFD processing could lead to improved absorption from fish oil. Overall, VFD processing provides a new alternative bottom-up approach to easy, scalable processing, without the need for organic solvents which are counterproductive in the food industry.

Vortex fluidic mediated encapsulation of functional fish oil featuring in situ probed small angle neutron scattering

“…In comparison with particle sizes of samples produced by homogenization, the particle sizes of samples produced by VFD are drastically reduced. The difference between encapsulated particle size using VFD and homogenization processing for different lipid surfactants was similar to that for low concentrations of lipid 14 . Furthermore, VFD processing is able to provide continuous processing, whereas homogenization is only able to provide batch processing.…”

“…The VFD was operated at optimized conditions, where the rotation speed was 9000 rpm, flow rate 0.3 mL/min, tilt angle 45°, and 25°C. The tilt angle of 45°has been reported as the optimal angle in many previous studies regarding VFD operation 9,10,14,16,17 . Our previous study 14 regarding fish oil encapsulation at low concentration also reported that the particle size of encapsulated fish oil was the smallest when the tilt angle was set at 45°while operating the VFD, as measured by dynamic light scattering (DLS).…”

“…The tilt angle of 45°has been reported as the optimal angle in many previous studies regarding VFD operation 9,10,14,16,17 . Our previous study 14 regarding fish oil encapsulation at low concentration also reported that the particle size of encapsulated fish oil was the smallest when the tilt angle was set at 45°while operating the VFD, as measured by dynamic light scattering (DLS). Tween 20 was selected as the surfactant due to its food grade category and long-chain character, which are two fundamental requirements for fish oil encapsulation in high concentration for food application.…”

“…Each of these requirements has limitations for industrial applications of encapsulated fish oil, which can be overcome using the VFD. Our initial study 14 demonstrated that under low concentration in fish oil, VFD processing was able to overcome these two limitations, producing stable encapsulated fish oil in one step, for 20 mg fish oil, 20 mg lipid as surfactant in 10 mL water. The present study further demonstrates the utility of the VFD processing in overcoming the same limitations for producing stable solutions of encapsulated fish oil at much higher concentration (1 g fish oil, 1 g Tween 20 as surfactant in 8 mL water), depending on the choice of surfactant.…”

“…As a preliminary trial, our previous study 14 established that for low concentrations of the fish oil (fish oil: surfactant = 1:1 (w/w), fish oil + surfactant:water = 2 mg/ml), the VFD is effective in encapsulating fish oil particles below 300 nm, whereas those produced by homogenization are 3-4 µm in diameter. Though the low concentration in this study was not industry-applicable because of the high cost of concentrating and drying the material, this proof-of-concept achievement encouraged us to follow up with a high concentration study, to drastically reduce the cost of the overall processing.…”