DisplayTitle

Transgenic Enhancement of High-Molecular-Weight Glutenin Subunit 1Dy10 Concentration: Effects in Wheat Flour Blends and Sponge and Dough Baking¹

¹Joint contribution of the United States Department of Agriculture, Agricultural Research Service (USDA-ARS) and the Department of Agronomy and Horticulture, University of Nebraska–Lincoln. Mention of firm names or trade products does not imply that they are endorsed or recommended by the USDA or the University of Nebraska over other firms or products not mentioned. ²USDA-ARS, 137 Keim Hall, East Campus, University of Nebraska, Lincoln, NE 68583, U.S.A. ³Corresponding author. E-mail: bob.graybosch@ars.usda.gov ⁴USDA-ARS, Hard Winter Wheat Quality Laboratory, Manhattan, KS, U.S.A. ⁵USDA-ARS, Western Regional Research Center, Albany, CA, U.S.A.

Dough strength is needed for efficient breadmaking quality. This property is strongly influenced in wheat (Triticum aestivum L.) by gluten seed storage proteins and, in particular, by high-molecular-weight (HMW) glutenin subunit composition. Experiments were designed to elevate expression of a key native HMW glutenin subunit (1Dy10) via genetic engineering and to determine whether resultant flours can be used in sponge and dough applications, the most common commercial bread-baking procedure. Both unblended and blended samples from transgenic and nontransgenic sister lines were tested, with blended samples being formed by addition to a control sample. Dough properties, as determined by farinograph evaluation, were improved by the transgene-encoded increases in 1Dy10 in both undiluted and blended flours. Mean farinograph stability of transgenic samples was twice that of the control, and blends with transgenic samples demonstrated increases in stabilities proportional to the amount of transgenic flour included. Mean farinograph quality numbers of transgenic samples, and of all blends containing transgenic flour, were significantly higher than both the control and all nontransgenic treatments. In the sponge and dough bake procedure, undiluted transgenic samples induced lower scores, relative to both control and undiluted nontransgenic samples, for water absorption, crumb body firmness, and loaf volume. In blends, however, the transgenic samples resulted in improvements in some sponge and dough loaf attributes, including loaf symmetry and crumb color score, without any concomitant loss of loaf volume in transgenic blends. These improved variables relate to finished product appearance and to consumer selection in markets. The use of transgenic flours with increased 1Dy10 glutenin content in commercial blends could provide advantages in sponge and dough bake applications.