Physical characteristics of fish oil encapsulated by β-cyclodextrin using an aggregation method or polycaprolactone using an emulsion-diffusion method

Fish oils have many dietary benefits, but have strong odours and are easily oxidised. For these reasons, beta-cyclodextrin (beta-CD) a water-soluble polymer and polycaprolactone (PCL) a water-insoluble polymer were used to encapsulate fish oil in this study. In addition, the stabilities of freeze-dried fish oil (FO) in encapsulated complexes were investigated to determine fish oil release rates at different relative humidities and storage temperatures. In order to facilitate the practical applications of the water-soluble and insoluble fish oil complexes produced, release studies of fish oil were performed in de-ionised water, NaCl solution and fish sauce. Based on our studies, fish oil loaded beta-CD at a mixing ratio of 10:20 (beta-CD:FO (w:w)) was the best composition in terms of encapsulation efficiency (84.1%), fish oil loading (62.7%), fish oil leakage after freeze-drying (11.0%), and eicopentaenoic acid (EPA) encapsulation efficiency (6.5%). In addition, fish oil release rates from beta-CD particles were slower in de-ionised water and in 15% and 25% Nacl than in fish sauce at all mixing ratios between beta-CD and FO. The storage stabilities of freeze-dried beta-CD-FO complexes at 10:20 (w:w) mixing ratio at various relative humidities retained 97% of fish oil within the particles during 3 days. However, the release rate of fish oil from beta-CD-FO complexes of 10:20 mixing ratio was accelerated in fish sauce. In terms of the emulsion-diffusion method, PCL more efficiently retarded the release of FO in liquid or powder form, although particles were broken by freeze-drying. It is supposed that PCL better protected FO because of its water insolubility. (C) 2009 Elsevier Ltd. All rights reserved.