Extension properties of wheat flour dough fortified with characterised wheat gluten fractions

A method [Fu BX and Sapirstein H.D., Cereal Chemistry 73 (1996) 143-152] for fractionation of monomeric and polymeric proteins from flour was used for the fractionation of commercial gluten in a 50% n-propanol soluble (50 PS) and 50% n-propanol insoluble (50 PI) fraction. This solvent extracts most of the monomeric proteins (90.5%) and resulted in the isolation of a relatively pure glutenin (89.5%). The 50 PI fraction was used to investigate the effect of glutenin on dough rheology with almost no interference by monomeric proteins. A part of the glutenin (43%), however, was extracted along with the monomeric proteins. Reconstitution of gluten largely (but not completely) restored the impact on extension parameters. Compared to the effect of reconstituted gluten, addition of the 50 PS fraction significantly decreased maximum resistance and increased extensibility whereas addition of the 50 PI fraction had opposite effects. It is possible that the different impact of the glutenin in the 50 PS and 50 PI fractions can be ascribed to differences in molecular weight. (C) 2002 Elsevier Science Ltd. All rights reserved.