Materials, Methods & Technologies, Volume 5, 2011

Rezumat: The extraction with supercritical fluids is an environmentally clean technology for producing ingredients for pharmacological, cosmetics, and food applications. Among the different natural compounds with bioactive properties, antioxidants are being intensively studied. The important role of antioxidants for human health being well known, an increased interest and demand of such products by the consumers is observed. The most commonly used supercritical fluid is carbon dioxide. However, because of its low polarity, it is less effective as a solvent for extraction of polar compounds. To overcome this shortcoming, polar modifiers (co-solvents) might be mixed with the solvent. This study investigates the influence of a polar compound ethanol, added as a modifier to the basic solvent CO2. The system under study is extraction of rosmarinic acid (RA), a polar substance with strong antioxidant capacity, from the plant Lemon balm (Melissa Officinalis L.). The results obtained show that the quantity of RA extracted from a unity of raw material with co-solvent ethanol is at least five times greater than in case of use of CO2 only. The concentration of rosmarinic acid in the extracts is also about five times higher. The general conclusion is that the polar co-solvent ethanol, by inducing some polarity to the supercritical solvent, boosts significantly its extraction capacity with respect to compounds having polar molecular structure.