Browsing by Author "del Valle, J. M."

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    Extraction of garlic with supercritical CO2 and conventional organic solvents
    (2008) del Valle, J. M.; Mena, C.; Budinich, M.
    Garlic (Allium sativum L.) and garlic extracts have therapeutical properties that stem from their sulfur-containing compounds, mainly allicin. The main objective of this work was to compare conventional and "premium" garlic extracts in terms of yield and quality, with the latter being obtained using supercritical carbon dioxide (SC-CO2) as the solvent. Yield ranged between 0.65 and 1.0% and increased with extraction pressure (150-400 bar) at a constant temperature 50 degrees C. Extraction temperature (35-60 degrees C), on the other hand, had little effect at a constant pressure of 300 bar. Based on yield and quality considerations, the best extraction conditions using SC-CO2 were 35-50 degrees C and 300-400 bar. A yield of 5.5% was obtained by conventional extraction using ethanol as the solvent, but ethanol appeared to be less selective for valuable components than SC-CO2. The use of fresh garlic resulted in extracts that more closely resembled commercial products, possibly because of thermal and oxidative degradation of valuable microconstituents during drying.
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    EXTRACTION OF OIL AND MINOR LIPIDS FROM COLD-PRESS RAPESEED CAKE WITH SUPERCRITICAL CO2
    (BRAZILIAN SOC CHEMICAL ENG, 2012) Uquiche, E.; Romero, V.; Ortiz, J.; del Valle, J. M.
    This study examines the extraction of oil from cold-press rapeseed cake using Supercritical CO2 (SC-CO2). The effects of pressure (20, 30, and 40 MPa), temperature (40, 50, and 60 degrees C), and extraction time (60, 90, and 120 min) on oil yield and composition (tocopherols and carotenoids) were studied using response surface design. The results indicated that pressure influenced the most the yield of oil, followed by temperature and extraction time. Extraction time had no effect on oil composition. Extraction pressure and temperature did not affect the tocopherol concentration of the oil to a great extent, whereas temperature had no affect in its carotenoid concentration. A comparison was made between the relative qualities of oil extracted with SC-CO2 at 40 MPa and 60 degrees C and with n-hexane. Neither solvent affected the unsaponifiable matter content or the composition of phytosterols (mainly beta-sitosterol, campesterol and brassicasterol) of the oils, although there was a significant difference (p<0.05) in tocopherol. Extraction with SC-CO2 at 40 MPa and 60 degrees C is recommended to obtain rapeseed-oil enriched with tocopherols and carotenoids as important functional components.