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Particle size effects on supercritical CO 2 extraction of oil‐containing seeds
Author(s) -
del Valle José M.,
Uquiche Edgar L.
Publication year - 2002
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/s11746-002-0637-9
Subject(s) - supercritical carbon dioxide , gravimetric analysis , extraction (chemistry) , supercritical fluid , particle size , chromatography , solubility , supercritical fluid extraction , yield (engineering) , materials science , particle (ecology) , substrate (aquarium) , chemistry , bar (unit) , analytical chemistry (journal) , chemical engineering , composite material , organic chemistry , oceanography , physics , meteorology , engineering , geology
Rosehip seeds were milled, sieved, and extracted with 26.3 g/g substrate/h of supercritical carbon dioxide (CO 2 ) at 40°C and 300 bar. The extraction kinetics were characterized by an initial solubility‐controlled period (8.78 g oil/kg CO 2 at 40°C and 300 bar), followed by a transition period to a final mass transfer‐controlled process. The integral yield of oil approached an asymptotic value that was dependent on the particle size of the substrate: 57.1 g oil/kg dry oil‐free substrate (large particles), 171.0 g/kg (medium‐size particles), or 391.5 g/kg (small particles). Based on gravimetric determinations and microscopic analysis, our size‐classification process segregated seed parts having different oil contents. Particles ≥0.85 mm were mainly composed of tough, lignified testa fragments devoid of oil, whereas particles ≤0.425 mm contained mostly brittle, oil‐rich germ fragments. The segregation of seed in fractions with different oil contents may be a common occurrence in supercritical extraction experiments, especially for seeds with thick and/or hard testa and small germ, whose fractions can be separated by sieving.