Journal of cereal science vol:29 issue:2 pages:129-138
The effect of several additives (1.215 mu mol KIO3, 0.892 mu mol cysteine, endo-xylanase and 0.5% (w/w) rye-water-extractable arabinoxylans) on changes in the level and glutenin subunit composition of the sodium dodecyl sulphate (SDS)-unextractable protein during breadmaking was investigated. Protein extractability drastically increased during dough mixing and was enhanced both by cysteine and KIO3. The mixing-induced increase in protein extractability was partly reversed during fermentation. Fermenting doughs containing endo-xylanase had a higher level of SDS-unextractable protein than control doughs: while with KIO3 the amount of SDS-unextractable protein remained very low. During baking most protein became SDS-unextractable, Bread baked from doughs with added KIO3 contained a significantly higher level of SDS-extractable protein. Changes in subunit composition of the SDS-unextractable glutenin polymers, determined with RP-HPLC, coincided with changes in protein extractability during dough processing. Mixing decreased the ratio of high to low M-r glutenin subunits. Simultaneously, the relative proportions of the different high M-r glutenin subunits in the unextractable glutenin polymers changed. During fermentation changes in subunit composition of the SDS-unextractable glutenin were opposite to those during mixing. (C) 1999 Academic Press.