GENETIC IMPROVEMENT AND EVALUATION OF HARD WINTER AND SPRING WHEATS
Location: Grain, Forage & Bioenergy Research
Title: Effects of transgene-encoded high-molecular weight glutenin proteins in wheat flour blends and sponge and dough baking
Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 14, 2012
Publication Date: March 4, 2013
Citation: Graybosch, R.A., Seabourn, B.W., Chen, Y.R., Blechl, A.E. 2013. Effects of transgene-encoded high-molecular weight glutenin proteins in wheat flour blends and sponge and dough baking. Cereal Chemistry. 90(02): 164-168.
Interpretive Summary: Commercial bakeries in the United States mass produce bread using a technique known as “sponge and dough.” This is a demanding procedure, which requires strong gluten flours to withstand the rigors of mechanical processing. Genetic engineering was used to elevate production of a key gluten protein known to contribute to dough strength. Wheat lines engineered to over-express this specific, known as HMW glutenin subunit 1Dy10, were found to produce excellent flour for sponge and dough applications. When used in blends with control flours, the transgenic lines were able to improve final product quality. In addition, blends from these transgenic lines may be used to elevate mixing times in a defined and predictable manner. Use of such flours in commercial settings would improve uniformity, reduce down-time due to poor functioning flours, and allow bakers the ability to manipulate mix times to match those necessary in automated bakery procedures.
HMW glutenin subunits are the most important determinants of wheat (Triticum aestivum L.) bread-making quality, and subunit composition explains a large percentage of the variability observed between genotypes. 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 non-transgenic 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 transgenic event, both in 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 all blends containing transgenic flour, were significantly higher than both the control and all non-transgenic treatments. The transgenic samples resulted in improvements in some sponge and dough loaf attributes, without any concomitant loss of loaf volume in transgenic blends. The transgenic samples provided obvious advantages in specific attributes, including loaf symmetry and crumb color scores. These improved variables relate to finished product appearance and to consumer selection in markets.