Protein and gossypol extractability from cotton seed flour.

The extractability of protein and free-gossypol from fully gossypolised cottonseed
flour was investigated. The various parameters studied include ( i ) effect of pH (ii)
effect of salts and (iii) the combined effect of pH and salts. The results indicated that
it is possible to obtain a protein isolate free from free-gossypol by alkaline extraction
at pH values of 9 and 10. Highest protein extraction (5773, highest protein recovery
(967);) and highest protein content of the precipitate (75%) occurred at pH 10. In
general, dilute aqueous electrolytes did not accomplish significantly higher extractabilities
although they resulted in comparatively lower free-gossypol contents in the
protein precipitate. However, with 1 . 0 ~Ca Cls protein extraction was 75% but both
protein recovery (61 %) and the protein content of the precipitate (61 %) was comparatively
low. Extraction in the presence of salts and alkali did not improve protein
extractability and gave a protein isolate high in free-gossypol content.