PARTIAL-PURIFICATION OF A WATER-EXTRACTABLE RYE (SECALE-CEREALE) PROTEIN CAPABLE OF IMPROVING THE QUALITY OF WHEAT BREAD

Rye water-soluble extracts contain a protein fraction that, when added at low concentrations to a straight-dough breadmaking recipe, signifi cantly increased bread volume. Enrichment of the active component is p ossible by anion-exchange fractionation with diethylaminoethyl-cellulo se (DEAE), by ammonium sulfate precipitation, or by using rye bran or shorts milling fractions as the starting material. The active material was not bound to DEAE-cellulose. With ammonium sulfate precipitation, the fractions obtained at 30, 40, and 50% saturation were active in s traight-dough baking experiments. Iso-electric focusing revealed that fractions active in breadmaking invariably contained alkaline protein fractions (pI > 7.5). Inactivation of enzyme material by boiling the w ater-soluble extract from rye destroyed all breadmaking activity. The activity of the bread improver was additive to that of potassium broma te but not to that of ascorbic acid. It was not counteracted by catala se, showing that it does not work by a mechanism involving the product ion of hydrogen peroxide. The extract was not able to overcome the det rimental effect on bread quality resulting from mixing dough in a nitr ogen atmosphere.