In this study, encapsulating fish oil, as a source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), with multi-layered interfacial membranes using electrostatic attraction between sodium caseinate and gum arabic and its usage in the enrichment of fruit juice was investigated. Initially, optimum conditions for forming a stable complex between sodium caseinate and gum arabic were determined at pH 4 and at a concentration of 0.1 g/100 ml sodium caseinate-0.2 g/100 ml gum arabic. This complex was utilized for nanoencapsulation of fish oil. Encapsulation efficiency and particle size were obtained as 78.88 +/- 2.89%, 232.3 nm, respectively. Fish oil nanocomplex containing 40-50-60 mg EPA + DHA were used in the enrichment of 100 ml fruit juice. After in vitro digestion, the bioaccessibility of EPA, DHA and EPA + DHA were found as 56.16 +/- 6.39, 36.25 +/- 538 and 47.37 +/- 10.65 percent, respectively (p < 0.05). This study indicates that stable protein polysaccharide complexes can be used for nanoencapsulating hydrophobic compounds such EPA and DHA, useful for enrichment of non- or low-fat beverages. (C) 2013 Elsevier Ltd. All rights reserved.