Quantitative Glutenin Composition from Gel Electrophoresis of Flour Mill Streams and Relationship to Breadmaking Quality

Abstract

ABSTRACTThree samples of Nekota (hard red winter wheat) were milled, and six mill streams were collected from each sample. The 18 mill streams were analyzed separately as well as recombined to form three patent flours. The methods of multistacking (MS)‐SDS‐PAGE and SDS‐PAGE were used to separate the unreduced SDS‐soluble glutenins and the total reduced proteins, respectively. The separated proteins were quantified by densitometry. The quantity of unreduced SDS‐soluble proteins was significantly different among the mill streams at the 4% (largest molecular weight polymeric glutenins) and at the 10 and 12% (smaller molecular weight polymeric glutenins) origins of the MS‐SDS‐PAGE gels. The quantities of total HMW‐GS, LMW‐GS, 2*, 7+9, and 5+10 subunits and the ratio of HMW‐GS to LMW‐GS in polymeric protein samples isolated using preparative MS‐SDS‐PAGE and in total reduced protein extracts were significantly different among mill streams. The quantities of HMW‐GS, LMW‐GS, 2*, 7+9, and 5+10 subunits from total reduced proteins were positively and significantly correlated with loaf volume. The quantities of glutenin subunits (both HMW‐GS and LMW‐GS) from unreduced SDS‐soluble proteins were positively or negatively correlated with loaf volume at the various MS‐SDS‐PAGE gel origins but the levels of correlation were not significant. These results showed that the glutenin protein composition was different among the various mill streams and demonstrated that electrophoretic analysis of the proteins in these fractions is a useful tool for studying the variation in functional properties of flour mill streams.