Assessment of liquid−liquid phase separation in the composition and oxidation stability of partially hydrolyzed olive oil

Process optimization for producing diacylglycerol-enriched oils has received great attention due the importance of these products for healthier and more balanced diets. This work reports experimental data of liquid-liquid phase equilibrium of hydrolyzed olive oil (which comprises on its composition triacylglycerols, diacylglycerols, monoacylglycerols and free fatty acids) with ethanol and water, and subsequent analysis of oxidative stability of the oil obtained from the liquid phases. Liquid-liquid equilibrium experimental data obtained were modeled using the UNIQUAC thermodynamic model, which was well fitted to experimental data with a root mean square deviation of 1.76 wt%. The results obtained demonstrated the potentiality of liquid-liquid extraction as a suitable procedure for olive oil enrichment in diacylglycerol, after a hydrolysis procedure. It was also observed that liquid-liquid phase separation has a significant effect on the content of important antioxidants present in the olive oil, what affects the oxidative stability of the samples submitted to the liquid phase extraction. From the results obtained in this study, it has been also noticed that the acylglycerols and free fatty acids profile in of the oil samples presented a major rule on their stabilities.