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Supercritical fluid extraction of oil from millet bran
Author(s) -
Devittori C.,
Gumy D.,
Kusy A.,
Colarow L.,
Bertoli C.,
Lambelet P.
Publication year - 2000
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-000-0092-7
Subject(s) - chemistry , wax , extraction (chemistry) , chromatography , supercritical fluid extraction , solvent , fatty acid , raw material , rice bran oil , bran , food science , organic chemistry
Proso millet bran [ Panicum miliaceum (L.)], variety Dakota White, was extracted with supercritical carbon dioxide (SC‐CO 2 ) to yield crude oil. The effects of operating parameters (pressure, temperature, and specific solvent flow) and of features of the raw material (moisture content and particle size) on oil extraction were investigated. Complete de‐oiling of ground millet bran pellets was achieved under 300 bar at 40°C with a specific solvent flow of 2–10 h −1 within 200 to 500 min. Solvent requirements were 20–30 kg CO 2 /kg raw material. Composition of crude SC‐CO 2 oil extracted under optimal conditions, i.e., fatty acid profile, amount of unsaponifiables, tocopherols, free fatty acids, sterols, sterol esters, waxes, hydrocarbons, and phospholipids, was compared to that of crude oil obtained by petroleum ether extraction. These two oils were similar in terms of fatty acid profile and amount of free fatty acids, unsaponifiables, peroxides, and tocopherols. They differed in respect to phospholipids (present in petroleum etherextracted oil and absent in SC‐CO 2 extracted oil), metals, and waxes (lower levels in SC‐CO 2 extracted oil). The effects of extraction procedures on oxidative stability of crude SC‐CO 2 oil were studied. Ensuring that all pieces of the extractor in contact with the oil were in stainless steel; cleaning the separator, i.e., washing with KOH, rinsing, purging with N 2 and CO 2 , and heating; performing a couple of extractions before the main extraction; and achieving the extraction without interruption all positively influenced the oxidative stability of the oil. Conversely, increasing CO 2 purity above 99.5% had no effect. Oxidative stability of the SC‐CO 2 oil extracted under these conditions was only slightly lower than that of the oil extracted with petroleum ether.