Storage Stability and Physicochemical Properties of Flaxseed Oil Microemulsions Stabilized with N-Octenylsuccinate-Derived Starch and Sodium Caseinate

Abstract

Background: Flaxseed oil is one of the richest sources of omega-3. The aim of this study was to investigate the effects of different wall materials, weight ratio (WR) and storage time on physicochemical properties and storage stability of flaxseed oil microemulsions. Methods: Encapsulation efficiency and emulsion oxidative stability were measured. Fatty acid composition of oil extracted from emulsions was analyzed by gas chromatography (GC). Particle size distribution and morphology of microemulsions were measured by dynamic laser scattering (DLS) technique and scanning electron microscopy (SEM), respectively. Results: The maximum encapsulation efficiency of 95.8% was obtained in the emulsion with the highest n-octenylsuccinate-derivatized (n-OSA) starch content. Increasing n-OSA starch concentration led to a higher microencapsulation efficiency and a lower lipid oxidation. Increasing n-OSA starch/sodium caseinate ratio led to a decrease in peroxide values and thiobarbituric acid contents. GC-FID results showed a superior stability of ω-3 fatty acids and improved nutritional quality in microencapsulated flaxseed oil upon storage. The average droplet size distribution of emulsions ranged from 428 to 728 nm. An increase in total solid content with the same oil concentration led to smaller droplets size. Morphological study performed by SEM confirmed the results obtained by DLS technique. Conclusion: Our findings have important implications for the design and utilization of emulsions as delivery systems for food enrichment.

Keywords

• flaxseed oil
• microemulsion
• n-octenylsuccinate-derivatized starch
• sodium caseinate
• gas chromatography