Extraction of lipids from cottonseed tissue: IV. Use of hexane‐acetic acid

Abstract

Hexane and mixtures of hexane and 2-25% acetic acid (v/v) were used to prepare oil and protein from glanded cottonseed by solvent extraction. As the amount of acetic acid in the solvent increased, the amounts of total lipid, phospholipid, neutral oil, and gossypol in each miscella increased, but the amount of free fatty acids did not change significantly. However, the solubility of protein in 0.02 N NaOH decreased as the amount of acetic acid in the solvent used to prepare each meal increased. Other aspects of using acidified hexane are described.

Solvent extraction of lipids from soybeans with acidic hexane

“…For instance, apparent phospholipid content (P X 32) and "refining loss" (total lipid minus neutral oil) was 0.32 mg/g of meats and 23 mg/g of meats, respectively, for hexane extraction at room temperature and 10.34 mg/g of meats and 28 mg/g of meats, respectively, for acidic hexane at room temperature. Since free fatty acid amounts are constant, regardless of solvent acidity (5), then extraction of an additional, "strongly bound" neutral oil was accompanied by a disproportionate amount of phospholipid. This would happen if neutral and polar lipids of membranes were extracted.…”

“…Physiochemical characterizations (2) and electron microscopical observations (3) proved that the limiting, half-unit membrane (4) of these organelles are acid labile. In a previous communication, we showed that this acid lability could be exploited to acheive thorough extraction of lipids from cottonseed (5). Addition of 2-25% (v/v) acetic acid to hexane resulted in the extraction of up to 9.8% more total lipids, up to 4.4% more neutral oil, and up to 10-fold more phosphorous than that extracted by hexane alone.…”

Acidic hexane extraction of oilseeds: Product quality

“…Earlier, we reported that the separation of miscella from marc by filtration was about twice as fast in acidic hexane as that in hexane alone (1,3). Figure 2 shows that a faster separation of miscella from marc was also obtained by setfling; the faster settling rate of marc particles is another demonstration of the rapid marc-miscella separation in acidic hexane.…”

“…Dehulled glanded and gtandless cottonseed meats were dry-milled in an impact stud mill as described previously (1,3). Meals were prepared by solvent extraction with filtration through fritted glass Buchner funnels as described previously (1,3) or by tube differential settling (4-7).…”

“…The effect of contact time on the pigment content of miscella was determined by extracting 1 g of glanded cottonseed with 5 mL of hexane or acidic hexane with filtration (1,3). Absorbances at 360 nm of the miscella were determined after contact times of 0.5-3 hrs.…”