Effect of polymer on the microencapsulation of fish oil by spray drying and supercritical anti-solvent processes and characterization of fish oil powder

Abstract

The demand for small particle engineering together with biocompatible or biodegradable carrier material to produce micro and nanoparticles is widely employed in the pharmaceutical, cosmetic and food industries. In this study, supercritical fluid precipitation and particle formation of menhaden fish oil using the supercritical anti-solvent method was developed which was compared with that of micro-encapsulation of the fish oil by spray drying method which is a continuing process to produce products with functional properties. Menhaden Fish oil (20 - 30% Omega-3) was used and encapsulated with two carrier material hydroxy propyl methyl cellulose (HPMC) 15 cP and HPMC 5 cP as a solid carrier and PEG 6000 as a plasticizer. Moreover, the effect of polymer composition on physicochemical characteristics of fish oil microcapsules produced by spray drying and supercritical anti-solvent (SAS) process was also investigated. The solid content (wt./vol. %) was in a range from 6.5 to 10.25% for all the formulations. Response surface methodology (RSM) was employed to optimize the encapsulation process of fish oil by spray drying technique where inlet air temperature and feed emulsion rate were used as the variables. The encapsulation efficiency (EE) of spray dried fish oil powder had an optimum value of 75% which indicated a promising feature of the microencapsulation process. Based on the optimum condition (inlet air temperature of 186 oC and emulsion feed rate of 404.4 mL/hr), eight (8) formulations (AF1-SD – AF4-SD, BF1-SD – BF4-SD) were selected. The same eight formulations were also produced by SAS process and it was found that the ratio and concentration of the polymer to the lipid phase influenced the reconstitution properties of fish oil powder. Scanning electron microscopy, EE and peroxide value conducted in this study revealed that the encapsulated oil produced by SAS process provided the highest protective and prolonged effect on the masking of fish oil aroma. Moreover, all the indices of powders prepared from HPMC 15 cP and HPMC 5 cP showed that the stability of the microencapsulated fish oil increased which was determined at 7d intervals over a 28d period. Microencapsulation produced by SAS process with high solid content (10.25 wt./vol. %) provided a stable fish oil powder compared with less solid content formulations. Among the formulations, AF1-SAS containing high concentration of HPMC provided highest encapsulation efficiency of 82% with very low peroxide value (5 mEq O2/kg oil) over a 28d period. It can be concluded that SAS process gave more stable powder particles than spray drying and can be recommended as a method to produce particles with long-term stability.