Aqueus extraction and fractionation of macauba kernel oil

Abstract

Macaúba (Acrocomia aculeata), is a native palm from tropical forests. It is found throughout the Brazilian territory in higher concentration in the states of Minas Gerais, Goiás, Mato Grosso and Mato Grosso do Sul. The Macaúba kernel is rich in lauric and oleic acid, presenting high oxidative stability and bioactive substances. It also has high levels of carotenoids. Its oil also has several applications, from the food sector to biofuels. Therefore, the objectives of this study were to optimize an aqueous extraction process of Macaúba kernel oil, evaluating the parameters pH, time and temperature in relation to yield and physical and chemical characteristics. The chemical, thermal and textural characteristics of fractions obtained from Macaúba kernel oil were also evaluated. The aqueous extraction method proved to be effective for the Macaúba kernel oil extraction. It was found that the oil yield and acidity and peroxide indices were influenced by the pH, time and process temperature. A surface of the response optimization showed that pH 11, room temperature (25 °C) and 60 min stirring time were suitable for high yield with low acidity and peroxide index. In fractionation, the fatty acid profile did not change significantly in fractions, but the oxidative stability of stearins was higher than that of oleins. It was possible to obtain 26% less solid fat olein at 25 °C and 22% less firm. Olein remained liquid to a temperature of 3 °C below oil with a firmer 23% stearin. Therefore, the extraction and modification methods used in this study were able to provide Macaúba kernel oil and derivatives with potential use as food lipid ingredients.