Óleos de chia (Salvia hispanica) e perilla (Perilla frutescens): extração com fluidos pressurizados, caracterização química e compostos bioativos

Abstract

The objective of this work was to obtain chia and perilla oils with two different pressurized solvents (CO2 and LPG), varying the pressure and temperature conditions in the extraction process, in order to evaluate the effect of these variables on oil yield, antioxidant activity, composition of fatty acids and phytosterols. For this, an experimental design with 2 levels and 2 variables (22) with triplicate was carried out at the central point, and the conditions used were 10-25 MPa and 20-60 °C for CO2 and 0.5-2.5 MPa and 20-40 °C for GLP. The best performance conditions (optimum points) for the chia and perilla oils were physicochemically characterized for acidity index, iodine index, peroxide index and refractive index. The evaluation of the antioxidant activity was performed by the DPPH method and the profile of fatty acids and phytosterols by Gas Chromatography. Finally, a comparison between chia oil and perilla was performed at 17.5 MPa/40 °C for CO2 and 1.5 MPa/30 °C for GLP for oil content, antioxidant activity, unsaturated fatty acids and phytosterols. For chia oil, optimum yield points were obtained at 25 MPa/60 °C for CO2 (21.93%) and 2.5 MPa/40 °C for GLP (27.13%). Under these same conditions, the oil extracted with LPG had higher antioxidant activity than that extracted with CO2 (70.16 AA% and 20.15 AA%, respectively). The fatty acid profile was similar between the conditions used and there was predominance of α-linolenic acid (maximum values of 62.97% for CO2 and 61.43% for LPG). Squalene and β-sitosterol were identified. For the perilla oil the highest yield points were 25 MPa/20 °C in the extraction with CO2 (31.80%) and 0.5 MPa/20 °C in the extraction with LPG (42.29%). In these points, the oil extracted with GLP had higher antioxidant activity than that obtained with CO2 (50.20 AA% and 46.44 AA% respectively). The fatty acid profile found no significant difference between the extraction conditions used having a predominance of polyunsaturated fatty acids, particularly α-linolenic fatty acid (maximum values of 62.80% for CO2 and 57.55% for LPG). β-sitosterol was the major phytosterol in perilla oil. The physical chemical characterization of chia and perilla oil showed that they are within the limits allowed by the legislation. The perilla seed had a high oil content in relation to chia. The oil of perilla in the concentration of 20 mg mL-1 presented superior antioxidant activity to chia oil in the concentration of 40 mg mL-1 when extracted with CO2. However, chia oil showed a higher concentration of C18:2 and C18:3 in the two types of extractions and higher values of squalene and β-sistosterol in CO2 extractions.