Page Banner

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

2007 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
Functional quality of wheat starch - 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 was isolated from 98 hard red winter wheats (HRW) and 100 hard red spring wheats (HRS). Granule size/volume distributions of the isolated starches were analyzed using laser diffraction. The distributions were compared and contrasted between the two classes, and correlations were compared to various quality parameters. There were significant differences in the size distribution between HRW and HRS. Numerous wheat, flour, and breadmaking quality traits showed significant correlation to starch size distributions.

Relationship of bread quality to kernel, flour, and dough properties – A study was conducted to measure the relationship between bread quality and 49 hard red spring (HRS) or 48 hard red winter (HRW) grain, flour, and dough quality characteristics. The estimated bread quality attributes included loaf volume, bake mix time, bake water absorption, and crumb grain score. Models for predicting loaf volume, bake mix time, and water absorption from various quality parameters contained in the data set were successful, although crumb grain score was not well estimated. For loaf volume models, grain or flour protein content was the most important parameter included. Bake water absorption was best estimated when using mixograph water absorption, and flour or grain protein content. Bake water absorption models could generally be improved by including farinograph, mixograph, or alveograph measurements. Bake mix time was estimated best when using mixograph mix time, and models could be improved by including protein composition data. When the data set was divided into calibration and prediction sets, the loaf volume and bake mix time models still looked promising for screening samples. When including only variables that could be rapidly measured (protein content, test weight, single kernel moisture content, single kernel diameter, single kernel hardness, and bulk moisture content, and dark hard and vitreous kernels), only loaf volume could be predicted with accuracies adequate for screening samples.


4.Accomplishments
4a. QUALITY OF SPELT WHEAT AND ITS STARCH Spelt is the only husked wheat that is currently grown in the United States for human food consumption. Market promotions for human consumption increased from less than 40 ha to over 3200 ha between 1987 and the present. Spelt products are available through health food outlets as grain, whole grain and white flours and processed products. These products include assorted pasta, cold and hot cereals, and pre-packaged bread, muffin, and pancake mixes. Spelt in the United States remains a commodity in the health food and specialty markets with limited crop production. While the gluten fraction of spelts has received most of the attention with respect to its possible unique products and functionality, the starch fraction has received little attention. This study assessed the composition and properties of flour and starch from five spelt varieties grown in the same location over three growing seasons. Our correction model for starch size distribution by laser diffraction particle sizing was used to develop some of the correlations in this study. The environment impact on spelt properties seemed to have a greater effect on bread baking quality and various starch properties than genetic control.

4b. THE ENVIRONMENTAL IMPACT ON WHEAT STARCH SIZE DISTRIBUTION DURING GRAIN FILLING. The environmental impact on the starch size distribution during grain filling of hard red winter wheat has been collected and collated. These samples were all grown at the the Kansas State University Agronomy Study plots over a 6 year period of time. Statistical analysis of this data is nearing completion and correlations to some weather conditions have been noted. The larger starch size distributions (everything > 20 µm) are positively correlated to increased cumulative precipitation, while the 5-20 µm starch size distributions are negatively correlated to decreased cumulative precipitation and decreased cumulative and average evapo-transpiration rates. Decreasing soil and air temperatures also appear to have a negative correlation to the 5-20 µm starch populations, while increasing soil and air temperatures has a positive correlation to the 20-30 µm starch populations.

4c. THE EFFECT OF THE 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 in the analysis phase but soon we expect to get a more complete picture of how the environment affects wheat quality, specifically the quality of starch.

4d. IDENTIFICATION OF PROTEIN COMPOSITION FOR IDEAL TORTILLAS: 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. The results indicated better tortillas with a longer shelf-life were obtained with higher protein content flours containing HMW-GS 5+10. This data will allow wheat breeders to target the characteristics for development of tortilla or multi-use wheat lines and decrease the addition of additives to adjust flour quality in the tortilla industry.

All of these research accomplishments fall 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
Akdogan, H.P., Tilley, M., Chung, O.K. 2006. Effect of emulsifiers on textural properties of whole wheat tortillas during storage. Cereal Chemistry. 83(6): 632-635.

Park, S., Bean, S., Chung, O.K., Seib, P.A. 2006. Levels of protein and protein composition in hard winter wheat flours and the relationship to breadmaking. Cereal Chemistry. 83(4):418-423.

Maghirang, E.B., Lookhart, G.L., Bean, S., Pierce, R.O., Xie, F., Caley, M.S., Wilson, J.D., Seabourn, B.W., Chung, O.K., Dowell, F.E. 2006. Comparison of quality characteristics and breadmaking functionality of hard red winter and hard red spring wheat. Cereal Chemistry. Vol. 83(5):520-528.

Tilley, M., Pierucci, V., Tilley, K.A., Chung, O.K. 2006. Effects of Processing on Wheat Tortilla Quality: Benefits of Hard White Wheat. Journal of Food Science. 27(11):152-158.

Last Modified: 9/10/2014
Footer Content Back to Top of Page