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United States Department of Agriculture

Agricultural Research Service

Research Project: CHARACTERIZATION OF GRAIN BIOCHEMICAL COMPONENTS RESPONSIBLE FOR END-USE QUALITY

Location: Grain Quality and Structure Research Unit

Title: Functionality of Gliadin Proteins in Wheat Flour Tortillas

Authors
item Mondal, Suchismita - TEXAS A&M UNIVERSITY
item Hays, Dirk - TEXAS A&M UNIVERSITY
item Tilley, Michael
item Alviola, Noviola - TEXAS A&M UNIVERSITY
item Waniska, Ralph - TEXAS A&M UNIVERSITY
item Bean, Scott
item Glover, Karl - SOUTH DAKOTA STATE UNIV

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 15, 2008
Publication Date: January 26, 2009
Citation: Mondal, S., Hays, D.B., Tilley, M., Alviola, N.J., Waniska, R.D., Bean, S., Glover, K.D. 2009. Functionality of Gliadin Proteins in Wheat Flour Tortillas. Journal of Agricultural and Food Chemistry. 57:1600-1605.

Interpretive Summary: The tortilla industry is one of the fastest growing segments of the U.S. baking industry with annual sales surpassing $6 billion. Flour used in tortilla production has been typically optimized for bread making and thus the flour properties that determine good quality bread do not necessarily provide good quality tortillas. In this study gliadin functionality in tortilla quality was studied using gliadin deletion wheat lines. Gliadins are proteins in wheat that may play an important role in determing the functional properties of wheat flour. Deletions in some gliadin proteins produced dough with greater extensibility which improved the diameter and overall quality of the tortillas while not altering the rollability. Deletions in another set of gliadins had the opposite result producing a stronger dough that decreased the diameter and overall quality of the tortillas. The data suggests that altering certain gliadin proteins could be a viable strategy to develop cultivars improved for the specific functionality requirements needed for the rapidly growing tortilla market.

Technical Abstract: Gliadins are monomeric proteins that are encoded by the genes at the locus Gli 1 and Gli 2 present on the short arm of homeologous wheat chromosomes 1 and 6, respectively. Studies have suggested that gliadins may play an important role in determining the functional properties of wheat flour. The main objective of this study was to understand the functionality of gliadins with respect to tortilla quality. The important tortilla quality attributes are diameter, opacity, and shelf stability designated here as rollability or the ability to roll or fold the tortilla without cracking. In this study gliadin functionality in tortilla quality was studied using near-isogenic wheat lines that have deletions either in Gli A1, Gli D1, Gli A2, or Gli D2 gliadin loci. The deletions lines are designated by the same abbreviations. Dough and tortillas were prepared from the parent line used to derive these deletion lines, each individual deletion line, and a control commercial tortilla flour. Quantitative and qualitative evaluations were performed on the dough and tortillas derived from the flour from each of these lines. None of the deletions in the gliadin loci altered the shelf stability versus that found for the parent to the deletion lines or control tortilla flour. However, deletions in the Gli 2 loci, in particular Gli A2, reduced the relative proportion of a and ß-gliadins with a greater cysteine amino acid content and gluten crosslink function versus the chain terminating '-gliadins in Gli 1 which was still present. As such, the dough and gluten matrix appeared to have greater extensibility which improved the diameter and overall quality of the tortillas while not altering the rollability. Deletions in the Gli 1 loci had the opposite result with increased crosslinking a and ß -gliadins, polymeric protein content, and a stronger dough that decreased the diameter and overall quality of the tortillas. The data suggests that altering certain Gli 2 loci through null alleles could be a viable strategy to develop cultivars improved for the specific functionality requirements needed for the rapidly growing tortilla market.

Last Modified: 4/17/2014
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