Title: Effect of high molecular weight glutenin subunit composition in common wheat on dough properties and steamed bread quality Authors
|Zhang, Pingping -|
|Jondiko, Tom -|
|Awika, Joseph -|
Submitted to: Journal of the Science of Food and Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 3, 2014
Publication Date: N/A
Interpretive Summary: Steamed bread is a popular food in Asian markets, especially China, where it represents more than 40% of national wheat consumption. Northern-style Chinese steamed bread is the most common type and is a daily staple in northern China and consistent product quality is becoming more important with rapid urbanization and mechanized/centralized processing. Wheat quality requirements for steamed bread are significantly different from those of pan bread, which is mainly due to the different processing methods, i.e. steaming versus baking. Medium protein content flour with moderate gluten strength and good extensibility is desirable for both mechanized and handmade methods as excessive elasticity causes difficulty in steamed bread processing resulting in shrinkage and wrinkles of finished product. The high molecular weight glutenin subunit (HMW-GS) proteins are important in the formation of the gluten matrix, however, little is known about the relationship between glutenin characteristics and steamed bread quality. The objective of this study was to investigate and compare the function of HMW-GS in determining dough properties and steamed bread quality among a set of American hard white wheat cultivars with variable HMW-GS composition or deletions. Results demonstrated that specific deletions of HMW-GS viable strategy to develop new wheat genotypes for steamed bread processing.
Technical Abstract: Steamed bread is a popular staple in Asia with different flour quality requirements from pan bread. Little is known about how glutenin characteristics affect steamed bread quality. This work investigated how deletions of high molecular weight glutenin subunits (HMW-GS) influence gluten properties and Chinese steamed bread quality using 16 wheat lines grown in Texas. Although similar in protein content (134-140 mg/g), gluten composition and dough properties differed widely among the lines. Compared to non-deletion lines, deletion lines had lower (P<0.05) unextractable polymeric protein, 294 vs 470 mg/g; HMW-GS to low molecular weight glutenin subunits ratio, 0.25 vs 0.41; dough force to extend, 0.16 vs 0.44 N; and mixing peak time, 2.03 vs 4.52 min. Deletion lines with HMW-GS composition of 2*/17+_/5+_, and 2*/17+_/2+12 showed moderate gluten strength (mixing peak time, 1.96 – 2.94 min; force to extend, 0.18 – 0.23 N), and high dough extensibility (106 – 129 mm). These lines also produced good steamed bread quality (score, 60.8 – 65.0) with good elasticity and crumb structure. Deletion at Glu-B1y and/or Glu-D1y loci in high strength hard wheat produced good dough properties for steamed bread. This suggests that wheat functionality for steamed bread can be improved by manipulating HMW-GS composition.