Effect of Spray Nozzle Design on Fish Oil–Whey Protein Microcapsule Properties

Abstract

Microencapsulation improves oxidative stability and shelf life of fish oil. Spray and freeze drying are widely used to produce microcapsules. Newer spray-nozzles utilize multiple fluid channels allowing for mixing of wall and core materials at the point of atomization. Sonic energy has also been employed as a means of atomization. The objective of this study was to examine the effect of nozzle type and design on fish oil encapsulation efficiency and microcapsule properties. A total of 3 nozzle types, a pressure nozzle with 1 liquid channel, a pressure nozzle with 2 liquid channels, and a sonic atomizer with 2 liquid channels were examined for their suitability to encapsulate fish oil in whey protein isolate. Physical and chemical properties of freeze dried microcapsules were compared to those of microcapsules produced by spray drying. The 2-fluid pressure and ultrasonic nozzles had the highest (91.6%) and the lowest microencapsulation efficiencies (76%), respectively. There was no significant difference in bulk density of microcapsules produced by ultrasonic and 3-fluid pressure nozzles. The ultrasonic nozzle showed a significantly narrower particle size distribution than the other nozzles. This study demonstrated that new nozzle designs that eliminate emulsion preparation prior to spray drying can be beneficial for microencapsulation applications. However, there is still a need for research to improve microencapsulation efficiency of multiple channel spray nozzles. Practical Application: Since this research evaluates new spray nozzle designs for oil microencapsulation, the information presented in this article could be an interest to fish oil producers and food industry.

Microencapsulation of chia seed oil using chia seed protein isolate⿿chia seed gum complex coacervates

“…The microcapsules obtained by freeze-drying process had lower bulk density compared to the corresponding spray-dried powders of the same composition. This can also be attributed to the irregular shape, larger surface area (BET surface area = 1.51 m 2 /g) and more porous structure (Mean pore width = 69.36 × 10 -10 m) of the freeze-dried microcapsules as compared to that of spray dried ones, which had average surface area of 0.82 m 2 /g and pore size of 41.16 × 10 -10 m. This agrees well with the observation made by Legako & Dunford [27] in case of fish oil microcapsules using whey protein isolate as encapsulating material and Desobry et al [28] also reported that the bulk density of spray-dried β-carotene produced by using maltrodextrin as wall material was higher than that of freeze-dried one at the same β-carotene and maltodextrin composition.…”

Microencapsulation of Flaxseed Oil by Spray Drying: Effect of Oil Load and Type of Wall Material

“…Legako and Dunford [44] found lower values for fish oil encapsulated with whey protein isolate, probably because the authors measured the bulk density of noncompacted powders.…”

Spray-Drying of Biopharmaceuticals

“…Freeze-drying is limited to a batch process as opposed to continuous processing with spray-drying. Both drying methods can achieve low residual moisture levels [7,52], which is important because high residual moisture content negatively affects chemical and physical stability [53]. Spray-drying offers the flexibility to tailor particle properties to suit varied purposes (e.g., controlled release, optimal size and morphology, etc.)…”

“…Many different modifications of these basic types of nozzles exist [7,8]. For instance, researchers have developed three-and four-fluid nozzles that have multiple feed streams in addition to the gas stream [9,10].…”