Cereal Chem 50:465 - 474.  |  VIEW ARTICLE
Condensed Phosphates for Precipitation of Protein from Gluten-Washing Effluent.

J. W. Finley, M. A. Gauger, and D. A. Fellers. Copyright 1973 by the American Association of Cereal Chemists, Inc. 

Washing wheat flour doughs for production of vital gluten and starch produces a waste effluent containing from 1 to 6% solids. Such effluents were treated with various condensed phosphates at pH levels 2.0 to 8.0 to complex and precipitate proteins. Metaphosphate, pyrophosphate, tripolyphosphate, trimetaphosphate, tetrametaphosphate, and hexametaphosphate were studied. Lower pH was generally more effective, especially with hexametaphosphate. Nearly 90% of the protein can be precipitated and recovered. Gel electrophoresis and gel filtration suggest that various phosphates were specific for various proteins in the effluent. The excess phosphates can be removed from residual effluent after protein removal by treatment with calcium ions at neutral or slightly alkaline pH. Treatment of the protein precipitates with alkali resolubilizes the protein, and the phosphate can then be removed by ion exchange.