Estabilidade térmica do óleo de abacate: um estudo comparativo ao óleo de arroz e azeite de oliva

Abstract

The avocado, because it contains 5 to 35% of lipids in its pulp, becomes a raw material of interest for obtaining oil. Avocado oil resembles olive oil, with similarities in the process of production, as well as in its physicochemical properties and composition, predominating in both, as the majority, oleic acid. It is known that heating the oil at high temperatures during food preparation can alter its composition, degrading fatty acids and minority compounds. Knowing the effects of heating on the composition of oils is fundamental to properly define its application, allowing to adopt better conservation strategies of its structure, sensorial and technological characteristics. The objective of this work was to evaluate the thermal stability of avocado oil compared to olive oil and rice oil submitted to a temperature of 180 ºC at different times and under two types of heating processes. The avocado oil of the Breda variety was donated by a producer from Minas Gerais (São Sebastião do Paraíso / MG), and rice oil and olive oil purchased locally. The oils were submitted to the heating of 180 ºC, in the times of 1:30, 3:00, 4:30 and 6:00 in a digester block and 3, 6, 9 and 12 minutes in microwaves. The acidity was evaluated; the indexes of peroxides, iodine, refraction and p-anisidine; the electrical conductivity, the specific extinction coefficient, the phenolic compounds, the chlorophylls, the carotenoids, the antioxidant activity and the color of the samples. It was verified that alterations of the evaluated parameters of the oils occurred due to the different heating times, as well as in relation to the type of heating applied. In general the olive oil was the product that proved to be more stable, followed by the oil of avocado. It was observed that the oils submitted to microwave heating presented greater changes, in relation to those submitted to heating in a digester block, at the same temperature. The acidity was the parameter that showed greater limitation for the oil of avocado in relation to the heating, however, adjustments in the process of extraction of this oil can help to obtain lower acidity levels, which allow greater stability to the product when heated.