Influence of OSA-starch on the physico chemical characteristics of flax seed oil-eugenol nanoemulsions

Flax seed oil (FSO) is rich in a-linolenic acid (ALA) and its application as a functional ingredient in oil-in water systems is limited due to its high vulnerability towards oxidation. To overcome this, flax seed oil nanoemulsions were formulated using eugenol (EUG) as a natural antioxidant and two modified starches (Purity Gum Ultra and Purity Gum 2000) as emulsifier. The effect of eugenol addition and emulsifier type on the size, charge, rheological properties and oxidative stability of nanoemulsions stored under different temperatures (4, 25 and 40 degrees C) for 4 weeks was investigated. Nanoemulsions containing eugenol, stabilized by Purity Gum Ultra, showed better physical and oxidative stability during storage as compared to Purity Gum 2000 stabilized emulsions. Results revealed higher % retention of ALA (66.34%) and EUG (63.20%) in Purity Gum Ultra stabilized emulsions containing FSO + EUG stored for 4 weeks at 40 degrees C as compared to Purity Gum 2000 stabilized emulsions containing FSO + EUG. This was attributed to the role of eugenol as antioxidant as well as the formation of a thick protective layer at interface by Purity Gum Ultra due to its higher molecular weight and density. (C) 2016 Elsevier Ltd. All rights reserved.