ISOPROPYL ALCOHOL EXTRACTION OF COTTONSEED COLLETS: CRUDE OIL COMPOSITION

Abstract

ABSTRACT Isopropyl alcohol (IPA) is an attractive alternative solvent to hexane for use in vegetable oil extraction. The relative efficiencies of IPA and hexane extractions using both cottonseed collets and flakes were evaluated in terms of product composition. The aqueous IPA extracted crude cottonseed oils from expander pretreated collets were analyzed for their nonacylglycerol compositions. The IPA extraction (88, 93, 95 and 97% IPA) resulted in more free fatty acids in the crude oils than did hexane extraction, and the level of the free fatty acids increased as the IPA concentration increased. The phosphorus content was higher in the IPA‐extracted oils compared to those of their hexane‐extracted counterparts. The HPLC analysis showed that the IPA extractions increased concentrations of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylinositol (PI) in the crude cottonseed oils. More sugar and less gossypol were found in IPA‐extracted oils and the level of sugar decreased as the IPA concentration increased. The oil extracted with 95% IPA from the expander‐produced collets were lower in free fatty acid, sugar, and gossypol than those obtained from the flakes. The amount of phosphorus in the oil extracted from the collets was approximately 45% higher than that from the flakes. The IPA extraction, in combination with expander pretreatment, produced cottonseed meals with free gossypol of 366 ppm, making them suitable for feeding nonruminant animals.