Extraction of boldo (Peumus boldus M.) leaves with supercritical CO2 and hot pressurized water

• Published in: Food research international 2005-01, Vol.38 (2), p.203-213
• Main Authors: Valle, J.M. del, Rogalinski, T, Zetzl, C, Brunner, G
• Format: Article
• Language: English
• Subjects: alkaloids; antioxidant activity; antioxidants; Aroma and flavouring agent industries; Biological and medical sciences; boldine content; carbon dioxide; chemical composition; essential oils; flavanoids; flora; Food engineering; Food industries; Fundamental and applied biological sciences. Psychology; General aspects; herbal medicines; hot water treatment; indigenous species; leaves; medicinal plants; medicinal properties; natural additives; Peumus boldus; plant extracts; supercritical fluid extraction
• ISSN: 0963-9969; 1873-7145
• DOI: 10.1016/j.foodres.2004.09.010

High-activity fractions in boldo leaves were extracted with supercritical CO2 (SC-CO2) and hot pressurized water (HPW). Total yield after 3 h of extraction (0.6-3.5%) in low-pressure SC-CO2 experiments increased with process pressure (60-150 bar) and decreased with temperature (30-60 degrees C), as expected. The extract obtained with SC-CO2 at 50 degrees C and 90 bar contained approximately 50% of essential oil components. In higher pressure experiments with solvent mixtures, the yield increased with pressure (300-450 bar) and modifier concentration (2-10% ethanol), ranging 0.14-1.95 ppm for the alkaloid boldine and 1.8-4.8% for total solids following 1.5 h treatment at 50 degrees C. Boldine recovery was solubility-controlled, reaching 7.4 ppm after 7-h extraction at 450 bar and 50 degrees C using an ethanol-SC-CO2 mixture (5% co-solvent). Boldine solubility and yield decreased when using pure CO2 at higher pressure (600 bar, 50 degrees C). The extract yield after 3 h batch-wise HPW extraction increased from 36.9% at 100 degrees C to 53.2% at 125 degrees C, and then decreased as temperature was increased to 175 degrees C. Boldine yield decreased from 26.8 ppm at 100 degrees C to 0.7 ppm at 125 degrees C, and was negligible at greater than or equal to 150 degrees C. The essential oil yield increased to a maximum at 110 degrees C and was negligible at greater than or equal to 150 degrees C also. The ranking of antioxidant potency of various extracts was as follows: HPW at 110 degrees C > methanol (soxhlet extraction) >> high-pressure SC-CO2 with or without polar co-solvent > low-pressure SC-CO2.