Hydroxytyrosyl oleate is a promising safe additive to inhibit the oxidation of olive oil

The antioxidants used in food oils that are prone to oxidation have attracted broad attention from the food industry. Hydroxytyrosol is a potent antioxidant, but due to its low solubility in oil, hydroxytyrosyl oleate was prepared, and its antioxidant capacity in the bulk oil was comprehensively evaluated. Hydroxytyrosyl oleate exhibited moderate free radicals scavenging, Fe3+ reducing, and oxygen adsorption abilities. Moreover, during accelerated oxidation, hydroxytyrosyl oleate delayed olive oil's peroxide value generation, acid value increase, and hydroperoxides production better than hydroxytyrosol (HT), tertiary butylhydroquinone (TBHQ), butylated hydroxytoluene (BHT), and Vitamin E (VE). The induction period of olive oil containing hydroxytyrosyl oleate was 77.12 h, which was 1.6, 8.7, 3.0, and 4.0 times that of HT, VE, BHT and TBHQ, respectively. Furthermore, hydroxytyrosyl oleate significantly prevented fatty acid oxidation and undesirable odors production in olive oil. These results indicate that hydroxytyrosyl oleate is a safe antioxidant that could be widely used in foods rich in polyunsaturated fatty acids, thus reducing lipid oxidation and food spoilage.