SOLUBILITY OF CARNOSIC ACID IN SUPERCRITICAL CO2+ ETHANOL AS A MODIFIER: MEASUREMENTS AND THERMODYNAMIC MODELLING

摘要: Rosmarinus officinalis L. and Salvia officinalis L. have been shown to have the strongest antioxidant activities among herbs [3]. Some of their phenolic compounds have active oxygens that can inhibite lipid peroxidation and therefore the corresponding extracts have been widely used to stabilize fat and fat-containing foods [4]. Several authors have demonstrated the high antioxidant activity of some rosemarys phenolic acids, phanolic diterpenes and flavonoids, namely, rosmanic acid, carnosic acid, and carnosol. However, it has also been demonstrated that some of the most effective antioxidant compounds, like carnosic acid and carnosol, are highly unstable depending of factors like temperature, light, oxygen, and solvent used in the extraction [5-7]. Supercritical Fluid Extraction (SFE) has important advantages over conventional extraction techniques. The absence of both light and air during the extraction process along with the low operating temperatures can reduce the incidence of degradation reactions, while the use of CO2 as extracting agent can allow the work in an environmentally clean media [8]. Pure carnosic acid can be isolated from rosemary extracts using SFE followed by a purifying step with, for example, Supercritical Fluid Chromatography [9]. The key factor in this separation technique is the possibility of adjusting the density-based solvent power of the supercritical mobile phase. Then, knowledge of carnosic acid solubility in the supercritical phase is important in order to analyze and optimize the separation process.