Solvent Extraction of Cottonseed and Peanut Oil

Abstract

Study of the effect of heat on cottonseed oil miscella in a practical approach to the problem of objectionable color fixation during heating and solvent removal operations in the solvent extraction process. Heating of cottonseed oil miscellas at various temperatures and definite time periods under appropriate reduced pressures was carried out to determine the effect of heat on the resulting refined and bleached oils. Color fixation became objectionable between 150°and 180°F., and beyond 180°increased rapidly.Properly prepared solvent-extracted cottonseed oils from a MANY attempts have been made in the United States to apply the solvent extraction process to cottonseed. There is considerable activity in this field at present, but only a few publications have appeared (7, 8). The early commercial efforts (16, 18, 19) to produce an industrially useful oil from cottonseed by solvent extraction were abandoned largely because of the dark color of the resulting oil.Cottonseed pigments, such as gossypol and related substances, extracted with the oil from the cottonseed flakes or meal by organic solvents, impart to the miscella its characteristic color (1-5, 7, 9, 10). It is claimed that an aliphatic hydrocarbon such as hexane dissolves only a small portion of gossypol present in uncooked flakes or meal (4, 7, 9

Characterization and processing of cottonseed oil obtained by extraction with supercritical carbon dioxide

“…In order to achieve acceptable color (2.5-6 R) in refined, bleached and deodorized products, hexane-extracted oil required 0.2 to 0.5% excess of 10% lye, whereas the CO2 oil required only 0.1-0.2% excess of the same lye. Processing of crude cottonseed oil presents a problem known as color fixation (9,10). Solvent-extracted and expeller-pressed oils contain appreciable amounts of pigments that, upon heating, become difficult or impossible to remove by refining and/or bleaching.…”

“…The raw germ was dried in a forced air draft oven at 27 C until a moisture level of 13% was achieved. Organoleptic evaluations were conducted according to Moser et al (10,11). Representative samples of crude wet-and drymilled corn oils were obtained from commercial sources.…”

Supercritical carbon dioxide extraction of cottonseed oil

“…Besides, processing of cottonseed oil presents a problem known as colour fixation. Solvent-extracted and expellerpressed oils contain appreciable amounts of pigments that, upon heating, become difficult or impossible to remove by even refining/and or bleaching (List, Friedrich, & Pominski, 1984;Vix, Pollard, Spadaro, & Gastrock, 1946).…”

Solvent extraction of cottonseed and peanut oils. VII. Effect of drying flaked prime cottonseed on color of oil and meal properties

“…The apparatus used for steam stripping the remaining solvent from the concentrated miscella and its operation are described in detail in a previous publication (5). The apparatus used for steam stripping the remaining solvent from the concentrated miscella and its operation are described in detail in a previous publication (5).…”

“…[previous work (5) having shown that color fixation of miscellas occurred at temperatures above 150~ The colors of the refined and bleached oils obtained were determined by the L0vibond calorimeter.…”