ENCAPSULATION OF FISH OIL IN SOLID ZEIN PARTICLES BY LIQUID-LIQUID DISPERSION

In this work, a liquid-liquid dispersion process was studied for encapsulation of fish oil in solid zein particles as an alternative to emulsions. The process involved the preparation of stock solutions by dissolving different amounts (4.0, 5.3, and 6.7%) of zein and fish oil (zein: oil ratios of 2:1, 4:1, 6:1, and 8:1) in 90% isopropanol. The stock solution was then subsequently sheared into deionized water. The decrease of overall isopropanol concentration resulted in the precipitation of oil-loaded zein particles with diameters of 350-450 nm. After freeze-drying, samples with a zein - oil ratio of 4:1 or lower - generally showed good oxidative stability evaluated based on the development of lipid hydroperoxide values during storage. The approach used in this work may provide a simple method to prepare submicrometer-sized solid particles, and can be extended to encapsulate other types of lipophilic bioactive compounds.