Cottonseed soapstock samples, collected during the 1993-1994 crushing
season from oilseed extraction mills throughout the United States Cott
on Belt, were analyzed by chemical and chromatographic methods. Volati
les averaged 48.7 +/- 10.6% (mean +/- SD, n = 39). On a dry basis, the
samples averaged 33.3 +/- 7.3% fatty acids, 26.3 +/- 6.9% phospholipi
ds, 8.4 +/- 6.4% triglycerides, and 7.5 +/- 3.0% gossypol. The analyti
cal techniques accounted for 93.3 +/- 8.6% of the dry soapstock matter
. The AOCS method for total fatty acids in soapstock yielded values in
agreement with the chromatographic and phosphorus analyses. In contra
st, the AOCS method for neutral oil in soapstock gave values that were
significantly higher than those obtained by chromatography. The amoun
t of nonlipid material in the samples correlated with the phosphorus c
ontent. Total gossypol and nitrogen levels were also related.