Oilseed processing
Crushed and de-fatted oilseed is extracted with water at neutral, mildly basic or mildly acidic pH; and is filtered. The filter media allows passage of small fragments of solid cell meat into the filtrate. The filtrate is treated with a base to increase pH to over pH 9, and solids are separated out. Protein is separated from other constituents of the liquid and concentrated, for example by heat-induced or isoelectric precipitation and/or ultrafiltration. The remaining liquid is rich in sugars. The process results in one or more protein products suited for human or animal food ingredients or for production of cosmetics, a sugar rich product suitable for fermentation or use as a feed ingredient, and a fiber-protein animal feed ingredient.
1. A process of treating defatted oilseed, which comprises:
(a) slurrying the defatted oilseed in water at a pH of 7-9 to create a slurry;
(b) separating the slurry into a first solid product and a first predominantly liquid fraction,
(c) adding sufficient alkaline compound to the first predominantly liquid fraction to increase its pH to in excess of pH 9, whereby a second solid product precipitates from said first predominantly liquid fraction, leaving an alkaline second liquid fraction,
(d) separating out said precipitate from the predominantly liquid fraction, whereby to obtain a second solid product and a second liquid fraction, and
(e) adding water and a sufficient amount of an acidic compound to said second solid product, to acidify the second solid product to a pH 1-5, whereby a portion of said second solid product dissolves in the water to form a third liquid and the remainder of the second solid product does not dissolve.
2. A process as claimed in claim 1 , in which a sufficient amount of an acidic compound is added to acidify said second solid product to a pH of 2-4.
3. A process as claimed in claim 2 , in which the non-dissolved portion of the second solid product is separated from the acidified mixture to form a third solid product.
4. A process as claimed in claim 2 , in which the third liquid is reacted with phytase, and inositol is recovered from the reaction mixture.
5. A process as claimed in claim 1 , including the additional step of:
(f) precipitating protein from said alkaline second liquid fraction, whereby to obtain a fourth solid precipitate which is rich in protein and a fourth liquid which remains after the precipitation.
6. A process as claimed in claim 5 , in which the fourth liquid is ultrafiltered to yield a protein rich retentate and a sugar-rich permeate.
7. A process as claimed in claim 6 , in which the ultrafiltering is controlled to control the protein concentration of the retentate whereby to get a protein-rich first retentate having a desired protein concentration in the range of 50-100% protein by weight on a dry matter basis, less than 1% phytate by weight on a dry matter basis and a Protein Dispersibility Index of greater than 40%.