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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

2008 Annual Report


1a.Objectives (from AD-416)
Determine roles and interactions of the major biochemical components of cereals (starch, non-starch carbohydrates, storage proteins and enzymes) as they relate to food quality and functionality, while defining the environmental impact upon functional properties of biochemical components that affect end-use properties, then applying that information generated to the development and improvement of methods to rapidly predict grain quality.


1b.Approach (from AD-416)
Isolate large quantities of starch, separate into size fractions for baking and chemical testing. Continue testing the correction model for starch size distributions on the LDS. Initiate bake studies using reconstituted gluten and starch fractions. Begin testing, amylose /amylopectin ratios, pasting profiles, DSC temperatures and lipids of A, B, and C-type starch fractions. Complete chemical analysis of the starch fractions. Correlation analysis comparing bake data, starch size distributions and chemical analysis.

Identify wheat of different oxidation requirements and determine effect of oxidative enzymes and transglutaminase upon quality characteristics. Begin biochemical analysis on the effect of enzymes on protein interactions. Characterize enzyme effects on protein interactions between glutenin and albumins. Characterize effect of HMW-GS contribution of wheat on enzyme mediated crosslinking.

Identify and begin to collect wheat samples to represent various growing environments. Begin isolating starch for analysis. Use LDS and our correction model to detect environmental differences in starch ratios. Isolate the starch fractions from different environments for chemical analysis. Compare starch size distributions and chemical analysis to different environments.

Characterize by RP-HPLC and SEC-HPLC, the protein fractions of the various near- isogenic lines that are produced in year 1 study by our collaborators. Relate the period of formation and amount of particular glutenin (polymeric) and gliadin (monomeric) proteins to the HMW-GS in the various near-isogenic lines. Correlate information obtained in this year 1 and 2 study with the data on bread or tortilla quality characteristics, provided by the HWWQL. Characterize the protein fractions of the various near-isogenic lines that were produced by our collaborators. Determine the sizes of the polymeric fractions and the MW distributions of the polymeric proteins. Relate polymer sizes and molecular weight distributions to quality characteristics, provided by the HWWQL. Determine if particular proteins are markers for quality traits.

Develop inexpensive lab-on-a-chip technology to extract and separate wheat gliadins in less than 1 min. Develop lab-on-a-chip system to extract, separate and identify wheat varieties in seconds. Develop a portable lab-on-a-chip system to extract, separate wheat proteins, and identify wheat varieties and/or the quality of wheat varieties or mixtures in seconds.


3.Progress Report
Starch was isolated from 98 hard red winter wheats (HRW) and 99 hard red spring wheat (HRS). There were significant differences in the size distribution between HRW and HRS wheat. The B-type granules (< 10 µm in diameter) occupied volumes in the range 28.5 - 49.1% (mean, 39.9%) for HRW wheat, while HRS wheat B-type granules occupied volumes in the range 37.1- 56.2% (mean, 47.3%). The mean granule sizes of the distribution peaks less than 10 µm in diameter also showed a significant difference (HRW, 4.32 vs. HRS, 4.49 µm), but the mean sizes of the distribution peaks larger than 10 µm were not significantly different (21.54 vs. 21.47 µm). Protein content was inversely correlated with parameters of B-type granules. Crumb grain score appeared to be affected by starch granule size distribution, showing significant inverse correlations with B-type granules. Furthermore, the linear correlations were improved when the ratio of B-type granules to protein content was used, and the polynomial relation was applied. It seems that starch granule size distribution is a unique property that affects physiochemical properties of wheat, flour and breadmaking properties in conjunction with its counterpart, protein.

One commercial bread flour with medium strength (11.3% protein content, 14% mb) was fractionated into starch, gluten, and water solubles by hand washing. The starch fraction was separated further into large and small granules by repeated sedimentation. Large (10-40 µm diameter) and small (1-15 µm diameter) starch fractions were examined. Crumb grain and texture were significantly affected. The bread made from the reconstituted flour with 30% small granules and 70% large granules starch had the highest crumb grain score, the highest peak fineness value and second highest elongation ratio. Inferior crumb grain scores and low fineness and elongation ratios were observed in breads made from flours with starch fractions with 100% small granules or 100% large granules. As the proportion of small granules increased in the reconstituted flour, it yielded bread with softer texture that was better maintained than the bread made from the reconstituted reference flour during storage. Tortillas were made from wheat deletion lines and lines over-expressing individual high molecular weight glutenin subunits (HMW-GS). Both elimination and overproduction of certain HMW-GS alter distinct, but critical aspects of tortilla quality such as diameter, shelf stability and overall quality.

This research falls under the National Program 306 "Quality and Utilization of Agricultural Products”, specifically on component 1 “Quality Characterization, Preservation, and Enhancement”. Multiple Problem Areas of this component are directly addressed in the objectives -- Problem Areas 1a (Definition and Basis for Quality); 1b (Methods to Evaluate and Predict Quality) and 1c (Factors and Processes that Affect Quality). The elucidation of fundamental biochemical processes and their role in determining product quality is paramount for the development of accurate methods for quality measurement.


4.Accomplishments
1. Environmental events affecting starch size distribution in developing hard red winter wheat caryopsis: Starch constitutes the greatest weight portion of the wheat endosperm (65-75%) and contributes its own unique functional qualities such as texture, volume, consistency, aesthetics, moisture, and shelf stability to various baked products. Starch particle size has long been recognized as an important variable in the efficiency of a range of processes including predicting rheology and flow behavior. While genetics is the dominant determinant in caryopsis development the environment also has a critical role in quality variability. The objective of this work is to study starch size distribution in identical varieties of developing hard red winter wheat grown in the same location over 7 consecutive years and correlate differences to various environmental factors. The samples were collected from the Kansas State University Agronomy field plots in Manhattan, KS. The heads were tagged as to flowering dates and samples were collected starting at 7 days-after-flowering (DAF) and regularly sampled until harvest. The starch was isolated, then freeze-dried and starch size distribution was analyzed on a laser diffraction particle size analyzer. Trends were observed within varieties between starch size distribution and temperature as well as total precipitation in 10, 17, 28 DAF and just prior to harvest. These trends included total volume fluctuations and shifts in peak diameters of 10-20% of the A-type granules. Studying starch size distribution during development of the wheat caryopsis may provide needed insight into critical environmental growth phases. This accomplishments falls under the National Program 306 "Quality and Utilization of Agricultural Products", specifically on component 1 "Quality Characterization, Preservation and Enhancement." Multiple Problem Areas of this component are directly addressed in the objectives -- Problem Areas 1a, 1b and 1c.

2. Identification of protein expression on tortilla quality: The wheat tortilla is a chemically leavened circular light colored flat bread. Desirable characteristics for good quality tortilla include large diameter, softness, flexibility and long shelf stability. Important components influencing quality are wheat flour properties, which have not been optimized for tortilla industrial production thus far. The objective of this research was to determine the effects of over-expression of high molecular weight glutenin subunits (HMW-GS) 10 on tortilla quality. Analysis of protein expression and protein extractability were conducted to characterize wheat flours. Dough properties were determined. Tortillas were prepared by the hot-press method and quality parameters were measured. Tortillas derived from transgenic flours over-expressing HMW-GS 10 exhibited an undesirable appearance with decreased diameter, greater thickness and rupture force, lower rollability scores and stretchability. Over-expression of HMW-GS 10 in a wheat line containing 1RS-translocation did not promote the same deleterious effects in tortilla quality as it did in transgenic lines without 1RS translocation. This accomplishments falls under the National Program 306 "Quality and Utilization of Agricultural Products”, specifically on component 1 “Quality Characterization, Preservation, and Enhancement”. Multiple Problem Areas of this component are directly addressed in the objectives -- Problem Areas 1a (Definition and Basis for Quality); 1b (Methods to Evaluate and Predict Quality) and 1c (Factors and Processes that Affect Quality). The elucidation of fundamental biochemical processes and their role in determining product quality is paramount for the development of accurate methods for quality measurement.

3. Effects of environment on starch size distribution of Canadian wheat varieties: This study was done in collaboration with the University of Manitoba. Large qualities of starch were isolated from ~350 established Canadian wheat varieties grown throughout the country. Detailed environmental data has been compiled to correlate starch size distribution to various quality parameters. Laser diffraction starch size distributions were collected in duplicate to incorporate into a “G X E quality model system”. The data is currently being incorporated into the model, we expect to get a more complete picture of how the environment affects wheat quality, specifically the quality of starch. This accomplishment falls under the National Program 306 "Quality and Utilization of Agricultural Products”, specifically on component 1 “Quality Characterization, Preservation, and Enhancement”. Multiple Problem Areas of this component are directly addressed in the objectives -- Problem Areas 1a (Definition and Basis for Quality); 1b (Methods to Evaluate and Predict Quality) and 1c (Factors and Processes that Affect Quality). The elucidation of fundamental biochemical processes and their role in determining product quality is paramount for the development of accurate methods for quality measurement.


5.Significant Activities that Support Special Target Populations
Collaboration with Kansas State University on research on Teff (Eragrostis tef) grain quality. This project supports a grant to the Kansas Black Farmers Association.


6.Technology Transfer

Number of Non-Peer Reviewed Presentations and Proceedings8

Review Publications
Mondal, S., Tilley, M., Alviola, J., Waniska, R.D., Bean, S., Glover, K.D. and Hays, D.B. 2008. Use of Near-Isogenic Wheat Lines to Determine the Glutenin Composition and Functionality in Flour. Journal of Agricultural and Food Chemistry. 56:179-184.

Pearson, T.C., Wilson, J.D., Gwirtz, J., Maghirang, E.B., Dowell, F.E., Mccluskey, P., Bean, S. 2007. The Relationship Between Single Wheat Kernel Particle Size Distribution and the Perten SKCS 4100 Hardness Index. Cereal Chemistry. 84(6):567-575. Online. doi:10.1094/CCHEM-84-6-0567.

Park, S., Chung, O.K., Seib, P.A. 2006. Hard Winter Wheat and Flour Properties in Relation to Breadmaking Quality of Straight-dough Bread: Flour Particle Size and Bread Crumb Grain. Food Science and Technology International (Chinese). 11:164-170.

Wilson, J.D., Bechtel, D.B., Wilson, G.T., Seib, P.A. 2008. Quality of Spelt Wheat and Its Starch. Cereal Chemistry. 85(5):629-638.

Last Modified: 8/27/2014
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