Influence of refining processes on content of bioactive compounds, rheology, and texture of olive pomace oil for use in topical formulations

Abstract

Retaining the bioactive ingredients of olive pomace oil is a crucial step in ensuring their functional or pharmaceutical value. To help select the best method for retaining bioactive compounds in olive pomace oil, three refining processes, namely, chemical, classical physical, or molecular distillation, were compared at different temperatures. For each method, the contents of triacylglycerols, fatty acids (oleic acid, linoleic, and linolenic acids), triterpenic acids (oleanolic and maslinic acids), and unsaponifiable matter (squalene, aliphatic, sterols, and terpenic) were studied. We observed that physical refining by molecular distillation provided oils with interesting amounts of bioactive compounds, especially triterpenic acids. Of these oils, the samples submitted to a temperature of 190°C exhibited a greater albeit low acidity compared with the other oils obtained by chemical and classical physical refining but exhibited higher amounts of all bioactive compounds. Conversely, the molecular distillation refining process had only a slight effect on the values of the consistency index. The firmness, cohesiveness, and adhesiveness parameters from texture profile analysis indicated that in general, all deodorized oils had high smoothness and spreadability but low adhesiveness. Molecular distillation was concluded to be the best refining process. Nevertheless, it is necessary to improve the working conditions of this process. Practical applications: Olive pomace oil has all functional compounds of extra virgin olive oil, but with a higher concentration of some minor components. It is, therefore, very interesting to use it in skin care formulations. However, for use in the pharmaceutical field must be refined. This study aimed to provide determine the influence of different refining processes (chemical refining, classical physical refining, or physical refining by molecular distillation at different temperatures) in determining the composition of bioactive compounds. The best refining process was selected based on the analytical determination of bioactive compounds by gas chromatography. Results indicated that molecular distillation is the best refining process. Nevertheless, it is necessary to improve the working conditions. Scheme of the extraction and refining processes to which olive pomace oil is subjected, to achieve the lowest losses of bioactive compounds for use in topical formulations.