W/O Nano-Emulsions with Olive Leaf Phenolics Improved Oxidative Stability of Sacha Inchi Oil

Natural phenolic compounds have been drawn a wide attention to replace the synthesis antioxidants due to the food safety issues, while, natural phenolic compounds are usually polyhydroxy derivatives which exhibit hydrophilic capacity, limiting their applications directly in lipid systems. In this work, olive leaf phenolics (OLP) are extracted by ultrasound from five cultivars and the optimal cultivar is chosen to prepare W/O nano-emulsions of Sacha Inchi oil (SIO, containing more than 90% polyunsaturated fatty acids). The droplet size could reach 2.15 +/- 0.13 nm and remaines stable without phase separation during 30-day storage. Oxidative stabilities of SIO containing 0.02%, 0.05%, and 0.1% OLP (w/w) are evaluated by Rancimat test and accelerated storage test. The release of OLP by preparation of W/O nano-emulsions is capable of controlling the oxidative progress of SIO, by prolonging the induction time, preventing the production of primary and secondary oxidative products and also the deterioration of polyunsaturated fatty acids and tocopherols.