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Glutenin Protein Changes During Breadmaking of Four Spring Wheats: Fractionation by Multistacking SDS Gel Electrophoresis and Quantification with High-Resolution Densitometry¹

¹Published with the approval of the director, Agricultural Experimental Station, North Dakota State University, Fargo, ND. ²Graduate doctoral student and professor, respectively, North Dakota State University, Department of Cereal Science, Fargo, ND 58105. ³Corresponding author, E-mail: kkhan@prairie.nodak.edu

A multistacking SDS-PAGE procedure coupled with high-resolution densitometry was used to fractionate, characterize, and quantify unreduced glutenin proteins at various stages of the breadmaking process of four wheat cultivars differing in functional characteristics. Unreduced protein aggregates of the highest molecular weight (4% origin) showed an initial decrease after mixing and a subsequent increase during fermentation. Proteins retained at the 6% origin remained unchanged while protein aggregates retained at 8 and 10% origins decreased during breadmaking. Proteins retained at the 12 and 14% origins tend to increase during bread-making. At all multistacking gel origins, subunits 2* and 5 (wheat cultivar Len) increased initially after mixing and then remained constant. Glutenin subunits 2*, 5, and 7 of cultivar Marshall exhibited the same pattern of change during breadmaking in all the protein aggregate groups (4–14%). Their proportion initially decreased (after mixing) and then increased in later stages. In contrast, subunits 9 and 10 of Marshall increased in the initial stages (after mixing) and then decreased in the later stages. Len, a good quality cultivar, contains gluten aggregates of higher molecular weight than the poorer quality cultivar, Marshall. The changes that occurred in the high molecular weight glutenin fraction revealed that Len had fewer changes in the proportion of the high molecular weight glutenin subunits distributed at various multistacking gel origins throughout the breadmaking process. The high molecular weight glutenin subunit stability for Len was greater than for a poorer quality cultivar such as Marshall. This may have enhanced the performance of Len during breadmaking.