FRACTIONATION OF WHEAT PROTEINS BY COUNTERCURRENT DISTRIBUTION USING AQUEOUS 2-PHASE SYSTEMS CONTAINING PROPIONIC-ACID

Wheat proteins, soluble in diluted acid (glutenins), have been fractio nated by counter-current distribution (CCD) using an aqueous two-phase system. The phase system is based on poly(ethylene glycol) and dextra n but contains also 1% propionic acid and 6 mM magnesium sulfate. Appr oximately half of the bulk proteins partitioned to the upper phase whi le starch and other particles were recovered only into the lower phase . Whole wheat flour could be applied as sample for the CCD and 57 tran sfers were carried out. Starch and insoluble proteins remained station ary, while proteins followed the mobile phase to various degrees givin g rise to a distribution pattern. The CCD pattern of the proteins show ed distinct differences when various kinds of wheat flour were analyse d. The patterns indicate that at least six subpopulations of proteins can be obtained by using two-phase extraction.