Natural antioxidants obtained with supercritical CO2

FACUNDO MATTEA; DAMIÁN A. CARDARELLI; JORGE D. DAGHERO; MIGUEL A. MATTEA

Floranopolis

Encuentro; V Encontro Brasileiro de Fluidos Supercríticos - V Brazilian Meeting on Supercritical Fluids; 2004

The general objective of this work was to analyze the recovery of active chemical compounds with antioxidant properties from herbs matrix using supercritical CO2 (SCO2). An important quantity of antioxidant agent, related to phenolic compounds, has been identified in spices extracts (oleoresin and essential oils) and herbs, particularly in labiates family such as rosemary, sage and thyme. Different operatives scheme, in order to recover and concentrate extracts of high antioxidant power from vegetable matrix using SCO2 were tested. The experiences were carried out with rosemary (Rosmarinus officinalis). In all cases, the fraction of volatile compounds was eliminated in a first stage using different methods (steam distillation and SCO2). Afterwards, in a second stage, valuable compounds were extracted with isopropyl alcohol. In an alternative method, the first extraction stage was made at low pressure with SCO2 (18MPa) followed by a high-pressure stage with the same solvent (40MPa) in order to recover the valuable fraction (antioxidants). The antioxidant power of extracts was determined by measuring the oxidative stability of crude soybean oil by the addition of well-known extracts quantities. As comparison, synthetic antioxidants of wide commercial use (BHT) were also tested. The extracts obtained with SCO2 and isopropyl alcohol showed an antioxidant activity equivalent to BHT.