1Departamento de Ciencias básicas, Facultad de Ciencias, Universidad Santo Tomás, Talca, Chile, 2Escuela de Nutrición y Dietética, Facultad de Salud, Universidad Santo Tomás, Talca, Chile, 3Hospital Regional de Talca, Talca, Chile.
Background and objective. Avocado oil has a high percentage of monounsaturated fatty acids, followed by saturated fatty acids and in a lower proportion of polyunsaturated fatty acids. In addition to antioxidant components, such as phenolic compounds, tocopherols and sterols. Avocado oil has shown to have a good behavior against thermal deterioration processes compared to unrefined oils such as extra virgin olive oil. However, there is a lack of knowledge of its behavior when hydrolysis processes are involved in conjunction with oxidation processes, before recommending it for frying processes. Objective. To evaluate the thermo-oxidative behavior during a deep frying process of commercial cold-pressed olive and avocado oil.
Methods. The behavior of cold-pressed olive and avocado oil of commercial origin in a domestic frying process with natural potatoes was studied, subjecting both oils to successive frying cycles, the analyzes applied to the study were; degree of acidity, peroxide number, p-anisidine number, TOTOX number, polar compounds, total phenol content and the fatty acid profile.
Results. A gradual increase was observed in the degree of acidity, p-anisidine, TOTOX, polar compounds and a decrease in the content of total phenols during the deep frying period for both oils. The indicator percentage of polar compounds was critical to determine that avocado oil takes 10 days to reach a limit value of 25 %, compared to olive oil that takes 13 days.
Conclusion. It was shown that both vegetable oils are suitable for a domestic frying process, where oxidation and hydrolysis processes are generated, due to the high number of deep frying cycles; 50 for olive oil and 40 for avocado oil, which could be carried out without exceeding the limit of polar compounds established by health regulations.
Keywords: avocado oil, olive oil, frying process, thermostability, total polar compounds and total phenols.