Location: Grain Quality and Structure ResearchTitle: Effect of high molecular weight glutenin subunit allelic composition on wheat flour tortilla quality Author
|Tilley, Michael - Mike|
Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/10/2012
Publication Date: 5/1/2012
Citation: Jondiko, T.O., Alviola, N.J., Hays, D.B., Ibrahim, A.M., Tilley, M. and Awika, J.M. 2012. Effect of high-molecular-weight glutenin subunit allelic composition on wheat flour tortilla quality. Cereal Chemistry. 89(3):155-161. Interpretive Summary: The tortilla industry is one of the fastest growing segments of the U.S. baking industry with annual sales surpassing $6 billion. The growing popularity of tortillas is attributed to their convenience as wraps that suit on-the-go lifestyle. In the US, consumers prefer refined wheat flour tortillas that are flexible, opaque, large in diameter that have a long shelf life. Currently, the tortilla industry uses bread wheat flour and chemical ingredients, e.g., reducing agents, to achieve the required functionality for tortilla production because protein functionality requirements for wheat flour tortilla differ from that required for good quality bread. The desirable protein network (gluten) for good quality tortilla production is extensible and mellow, while bread dough requires a strong, resilient gluten network to retain air bubbles during fermentation. The goal of the study was to evaluate the tortilla making properties of wheat lines possessing variations in the high molecular weight glutenin proteins that occur on each of the three (A, B and D) wheat genomes. Wheat lines in which one or more of the proteins were absent were used to make tortillas. The tortillas missing certain proteins had different quality in several parameters such as diameter, shelf stability and overall quality. This study shows that the variations in wheat protein can be identified and manipulated to produce a combination of flour protein profile and dough making attributes to produce wheat with optimum functionality for tortillas.
Technical Abstract: Wheat cultivars possessing quality attributes needed to produce optimum quality tortillas have not been identified. This study investigated the effect of variations in high molecular weight glutenin subunits encoded at the Glu-1 loci (Glu-A1, Glu-B1, Glu-D1) on dough properties and tortilla quality. Flour protein profiles, dough texture, and tortilla physical quality attributes were evaluated. Deletion at Glu-D1 resulted in reduced insoluble polymeric protein content of flour, reduced dough compression force, and large dough extensibility. These properties produced very large tortillas (181 mm diameter) compared to control made with commercial tortilla wheat flour (161 mm). Presence of 7+9 allelic pair at Glu-B1 increased dough strength (largest compression force, reduced extensibility, small diameter tortillas). Deletion at Glu-A1 produced large tortillas (173 mm), but with unacceptable flexibility during storage (score < 3.0 at day 16). In general, presence of 2* at Glu-A1, in combination with 5+10 at Glu-D1 produced small diameter tortillas that required large force to rupture (tough texture). Presence of 2+12 alleles instead of 5+10 at Glu-D1 produced tortillas with a good compromise between diameter (> 165 mm) and flexibility during storage (> 3.0 at day 16). These allele combinations, along with deletion at Glu-D1, show promise for tortilla wheat development.