Microencapsulation of fish oil using thiol-modified beta-lactoglobulin fibrils/chitosan complex: A study on the storage stability and in vitro release

Storage stability and in vitro release of microencapsulated fish oil that was produced via spray drying using thiol-modified beta-LG fibril/chitosan complex and different beta-LG fibrils variants were studied. The surface oil content, colour, peroxide value (PV), p-Anisidine value (p-A.V.), and fish oil release as triggered by different ionic strengths (0-200 mM), pH (3, 5, 7 and 9), and simulated gastrointestinal condition were evaluated. Results showed that fish oil microcapsules formed using thiol-modified beta-LG fibril/chitosan complex (TMFCC) exhibited lower surface oil content (<4%) and minimal changes in the L* and b* value over a 4-week storage period, indicating an enhanced entrapment of fish oil within the core. We found that these microcapsules displayed lower oxidative deterioration. This was attributed to the highly cationic nature and thicker wall layer provided by the addition of chitosan. Lower fish oil release (<22%) observed for the TMFCC-coated microcapsules at elevated ionic strength suggested an enhanced stability against the effect of NaCl compared to those stabilized using beta-fibrils (pH 2) and thiol-modified beta-fibrils (pH 9). We observed that TMFCC may protect its core fish oil from gastric enzymes as indicated by a lower fish oil release (<25%), and enhanced sustainable release of fish oil under intestinal condition. Therefore, TMFCC is a promising encapsulating agent for the encapsulation and delivery of bioactive compounds. (C) 2018 Elsevier Ltd. All rights reserved.