GB676139A - Improvements in or relating to a method of treating waste liquor obtained on the isolation of protein from protein-containing materials - Google Patents

Abstract

Waste liquor left after extracting vegetable globulins from de-oiled material such as groundnut or soya meal with aqueous alkali, clarifying, precipitating globulins by addition of sulphite or bisulphite ions until the pH is within the isoelectric range, and separating the precipitate, is made re-utilizable by treating with lime, separating the precipitate formed, and refortifying the liquor with alkali. Sewage treatment of the liquor is thus made unnecessary while soluble constituents of the meal are recovered on the residue which is more valuable as an animal food. In an example, de-oiled groundnut meal is extracted with caustic alkali solution, the extract clarified, and SO2 introduced to a pH of 5. The separated liquor is treated with lime to precipitate calcium sulphite, and caustic soda added to give a liquor for further extraction. After a number of extractions, the concentration of the water soluble constituents of the meal reaches equilibrium. The combined protein extract is then clarified and the protein precipitated.ALSO:An animal foodstuff comprises the residue left after extracting vegetable globulins from de-oiled material such as groundnut or soya meal with aqueous alkali, clarifying, precipitating globulins by adding sulphite or bisulphite ions until the pH is within the isoelectric range, separating the precipitate, treating the waste liquor with lime to precipitate calcium sulphite, separating, refortifying the liquor with alkali, and using it for further extraction. Soluble constituents of the meal thereby accumulate on the residual meal.