2005 Annual Report
Similarly, ingredient and processing variability translates into large economic losses in the baking industry. The U.S. baking industry annually uses about 42 billion pounds of flour, valued at about $4.2 billion, to produce an estimated $33 billion of baked goods. Variability in flour quality means that there are opportunities for large savings in the areas of raw material selection, processing, and distribution. Further, improved methodologies to better analyze the root causes of flour variability will open the door to the production of higher value products. The baking industry has limited tools at its disposal to deal effectively with the variability of wheat flour, its major raw material. All currently utilized industry tools for assaying and/or testing flour are highly empirical, offering little insight into the biochemical basis of (a) what constitutes a “quality” flour, (b) how a particular lot of flour can be characterized for its suitability for a given application, or (c) how a particular lot of flour should be processed to maximize product quality.
The objectives of this project are to: (1) Determine the roles and interactions of the major biochemical components of cereal grains (starch, storage proteins and enzymes) as they relate to food quality and functionality; (2) Define the role of the environment on functional properties of biochemical components that affect end-use properties; (3) Apply information generated in previous objectives towards development and refinement of methods to rapidly predict grain quality. Towards this end, investigation to determine role(s) of wheat starch granule size distributions on variations in functionality during bread-making will be performed. These approaches will utilize differential scanning calorimetry to provide thermal data on individual starch granule populations and starch fractions (pure A- and B- type granules) will be used for reconstitution experiments to determine how size classes affect bread-making quality. The mechanism(s) of action of oxidative enzyme addition to flour on storage proteins and non-storage proteins will be determined by addition of enzymes followed by functional analysis and examination of protein fractions and polymers using SDS-PAGE, size exclusion HPLC, and multi-angle laser light scattering. Environmental effects on starch and storage proteins will be determined using the above approaches with samples that have been exposed to controlled temperature and irrigation regimes during development. The potential of novel microfluidic devices will be thoroughly examined as a means to develop extremely rapid and highly reproducible separations of proteins for grain cultivar identification and quality prediction.
Advances in the knowledge of grain biochemical characteristics that determine the physical and functional properties critical to processing and end-product quality, and development of rapid, accurate methods to measure these quality determinants are essential to maintain a competitive position for U.S. grain in global markets. This project will provide the cereal food industry with the tools needed to define the end-use performance of cereal grains.
The research is under 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.
• Isolation of large quantities of starch, separated into size fractions for baking and chemical testing. Continued testing the correction model for starch size distributions by laser diffraction sizing (LDS). Bake studies using reconstituted gluten and starch fractions. Begin testing, amylose /amylopectin ratios, pasting profiles, differential scanning calorimetry (DSC) temperatures and lipids of A, B, and C-type starch fractions. Chemical analysis of the starch fractions. Correlation analysis comparing bake data, starch size distributions and chemical analysis.
• Determination of the effects of oxidative enzymes and transglutaminase upon quality characteristics. Biochemical analysis on the effect of enzymes on protein interactions. Characterization of enzyme effects on protein interactions between glutenin and albumins. Determination of the contribution of individual glutenin subunits on enzyme mediated crosslinking in gluten functionality. Objective 2: Define the environmental impact upon functional properties of biochemical components that affect end-use properties. Specific milestones include:
• Use LDS and our correction model to detect environmental differences in starch ratios and chemical analysis of starch. Compare starch size distributions and chemical analysis to different environments. Relate polymer sizes and molecular weight distributions to quality characteristics, provided by the HWWQL.
• Determine if particular proteins/ starch granule ratios are markers for quality traits.
• Correlate information obtained in this year 1 and 2 study with the data on bread or tortilla quality characteristics, provided by the HWWQL. Objective 3: Apply information generated in objectives 1 and 2 to the development and improvement of methods to rapidly predict grain quality. Specific milestones include:
• Develop rapid microfluidic “lab-on-a-chip” technology to extract and separate wheat proteins, and identify wheat varieties and/or the quality of wheat varieties or mixtures in seconds.
Starch size distribution and bake quality.
Wheat storage proteins have received a greater amount of attention compared to starch due to their unique properties of extension and elasticity, which gives them their unique dough forming properties. Starch, however, constitutes a much greater weight portion of wheat endosperm (~75% v. ~15%) and it contributes to foods its own unique functional qualities such as volume, texture, appearance and staling rate. Varying ratios of large type-A and smaller type-B granules has been proposed to change the baking potential of bread. Bread made from reconstituted flour with 30% type-B to 70% type-A ratios gave optimum crumb grain scores and peak fineness values and second highest elongation ratios. As the proportion of type-B granules increased, it yielded bread with a softer texture and maintained that texture better during storage. Due to the unique properties of the different size starch granules in wheat, it is reasonable to consider starch size distribution as having a significant impact on baking performance.
Environmental effect on starch size distribution. Environmental changes not only affect protein quality but may affect starch size distribution and its chemical composition. Work has been initiated to contrast weather conditions (temperature and precipitation) to starch size distribution in developing wheat. With samples collected over multiple years it will be possible to trace the impact of changes in environmental growing conditions to critical growing phases in starch development. This may be useful in developing a data base incorporating environmental information during the growing season to ideal starch development for optimum end-use quality. A differential scanning calorimeter (DSC) has been purchased which will be used to study gelatinization profiles (melting) of isolated starches and differences within the various size populations. This information is important in detecting biochemical changes such as amylose/amylopectin ratios and lipid content in these isolated starches.
Wilson, J. D. and Maningat, O. 2004. Symposium --Starch: Size Does Matter. Cereal Foods World 49:205.
Park, S., Chung, O.K., Seib, P.A. 2005. Effects of varying weight ratios of large and small wheat starch granules on experimental straight dough bread. Cereal Chemistry. 82:166-172
Park, S., Chung, O.K., Seib, P.A. 2004. Size distribution and properties of wheat starch granules in relation to crumb grain score of pup-loaf bread. Cereal Chemistry. Vol 81 (6): 699-704.
Tilley, M., Benjamin, R.E., Tilley, K.A. 2004. Non-enzymatic preparative-scale synthesis of dityrosine and 3-bromotyrosine. Analytical Biochemistry. 334:193-195
Tilley, M., Tilley, K.A. 2005. Modifying tyrosine crosslink formation in wheat dough by controlling innate enzymatic activity. p. 142-146. Using cereal science and technology for the benefit of consumers. Proceedings of the 12th ICC Cereal and Bread Congress. S.P. Cauvain, S.B. Salmon, and L.S. Young, eds. CRC Press. Boca Raton, FL.
Benjamin, R.E., Tilley, M., Reamer, E.M., Srivarin, P., Tilley, K.A. 2005. Detection of tyrosine crosslink in wheat kernels at various stages of development. Program Book of the 3rd International Wheat Quality Conference. 2005. Abstract p. 393. Meeting Abstract.
Tilley, M. 2005. Glucose oxidase effects on wheat flour albumins and gliadins. Program Book of the 3rd International Wheat Quality Conference. Meeting Abstract. p. 392
Tilley, M., Tilley, K.A. 2005. Tyrosine crosslink formation in wheat dough: Innate enzymatic activity. Program Book of the 3rd International Wheat Quality Conference. Meeting Abstract. p.392
Wilson, J.D., Bechtel, D.E. 2005. Laser diffraction sizing: studying wheat flour and starch particle sizes. Program Book of the 3rd International Wheat Quality Conference. Meeting Abstract. p.397
Wilson, J.D., Bechtel, D.B. 2004. Measuring wheat starch size distribution using image analysis and laser diffraction technology. Presented to the symposium titled "Starch: Size Does Matter" for the American Association of Cereal Chemists held in San Diego, CA, Sept. 19-22, 2004. Meeting Abstract.
Park, S., Bean, S., Wilson, J.D. 2005. Investigation of conditions for rapid cereal starch isolation using sonication. Program Book of the 3rd International Wheat Quality Conference. 2005. Abstract. p.397