Location: Corn, Soybean and Wheat Quality Research
2016 Annual Report
Objectives
Objective 1: Develop accurate and efficient laboratory methods for end-use quality evaluation of soft winter wheat breeding lines and varieties. Sub-objective 1a: Improve the cake baking test procedure of non-chlorinated flour by identification of ways to increase cake volume. Sub-objective 1b: Determine the feasibility of flour batter and extract viscosities for prediction of the cake baking quality potential of wheat flour.
Objective 2: Establish quality characteristics of soft winter wheat non-conventional and whole grain food products and enable new and/or expanded commercial uses. Sub-objective 2a: Identify the quality traits of eastern soft winter wheat required for making steamed bread. Sub-objective 2b: Determine variation in the characteristics of soft wheat bran among wheat varieties, and identify ways to improve the functional properties of bran for making whole grain soft wheat foods with improved product quality and sensory acceptance. Sub-objective 2c: Develop eastern soft wheats with different complements of waxy alleles.
Objective 3: Identify the biochemical, physical and genetic factors associated with flour yield and endosperm separation from bran during milling. Sub-objective 3a: Determine the variation in bran micro-structural characteristics and remnant endosperm among soft wheat genotypes in relation to flour yield. Sub-objective 3b: Evaluate effect of TaSus2 alleles at QTL on chr. 2B on milling yield and flour quality. Sub-objective 3c: Compare expression of TaSus2-2B transcripts in near-isogenic lines carrying different complements of HapL, HapH and HapG.
Objective 4: Congressionally designated as a direct mission of service, and non-hypothesis driven, the USDA-ARS will identify, evaluate, and screen the intrinsic end-use quality to enhance cultivar development.
Approach
Sub-Objective 1a: Evaluate the cake baking performance of non-chlorinated flour with heat and/or acid pretreatments. Determine the effects of waxy, cold water swelling and pre-gelatinized starches on the cake baking performance of non-chlorinated flour. Establish an improved cake baking method and validate its effectiveness. Conduct a collaborative study for the established cake baking method with the AACCI Soft Wheat Flour Technical Committee (SWFTC). Sub-Objective 1b: Determine the viscosities of cake batter, simplified batter and aqueous flour extract using various viscosity tests. Determine the relationships between batter and flour extract viscosity, and cake quality attributes. Establish the batter or extract viscosity test as a routine test of flour for cake baking quality. Sub-Objective 2a: Determine the flour characteristics of soft red winter wheat varieties important for making steamed bread. Determine the quality of steamed breads prepared from soft red wheat flours. Determine the influences of protein and starch characteristics on steamed bread quality. Develop a quality profile of soft red wheat flour for making steamed bread. Sub-Objective 2b: Determine the variation in characteristics of bran among soft red winter wheat varieties. Evaluate the quality of whole grain biscuits and pancakes prepared from a blend of wheat flour and bran from different varieties. Identify bran characteristics of soft red wheat affecting whole wheat biscuits and pancakes. Improve functional properties of bran. Sub-objective 2c: Waxy alleles from fully and partial waxy lines will be introgressed into regionally grown, good milling soft red and white winter wheats to produce lines needed for testing the role of high amylopectin flours on the quality of conventional and non-conventional soft wheat products. Sub-objective 3a: Evaluate the starch content of bran as an estimate of remnant endosperm on bran. Determine the residual endosperm content of bran as an indicator of endosperm separation efficiency. Determine arabinoxylan content of residual endosperm of bran. Evaluate the microstructural differences of bran of contrasting remnant endosperm content. Sub-objective 3b: HapH and HapG alleles will be introgressed by three backcrosses to the recurrent parent. Seed will subsequently be increased for field trials. Sub-objective 3c: We will characterize the sequence and expression of TaSus2-2B to determine if there is a correlation between gene structure and/or expression and high flour yield and kernel softness. Goal 4: Annually evaluate over 6,000 soft red and white wheat grain samples for milling and baking quality from about 21 public and private wheat breeding programs in the eastern half of the United States. Wheat grain samples are classified into ‘preliminary’, ‘intermediate’ or ‘advanced’ groups, depending on the stage of breeding generation and the intensity of quality evaluation needs, and evaluated for their end-use quality potential using AACCI Methods and established procedures.
Progress Report
This project aimed to improve the milling and baking quality potentials of eastern soft wheat varieties by developing accurate and reliable quality testing methods, identifying biochemical and genetic characteristics of wheat important for extended uses and whole grain foods as well as for flour milling yield, and contributing to the development of wheat varieties by conducting the end-use quality evaluation of wheat breeding lines.
Accurate and efficient laboratory methods development: The current experimental cake baking test requires flour chlorination, raising safety concerns and making the test laborious, slow and difficult to perform for a large number of samples. To develop an experimental cake baking test applicable to non-chlorinated flour, we examined improvements in the volume and contour of cakes baked from non-chlorinated flour after pretreating the flour with heat and acid, selecting the best baking powder, and reducing the amounts of sugar and shortening in the formula. Based on the results, we identified the optimal formula for an experimental cake baking test using non-chlorinated flour. The performance of the new cake baking test for non-chlorinated flour in differentiating flour quality for baking cakes was compared to that of the standard AACCI 10-90 method using chlorinated and non-chlorinated flours of ten soft wheat varieties. We determined the viscosity of cake batter for non-chlorinated flours using a flow viscometer to examine its potential use for predicting flour quality for making cakes.
Quality characteristics of soft winter wheat for non-conventional and whole grain food products: Starch constitutes more than 80% of wheat flour; thus its characteristics are believed to influence the textural properties and shelf life of wheat products. To determine the effect of the starch amylose content of soft red winter (SRW) wheat flour on the quality attributes of steamed bread, SRW wheat flours of varying starch amylose content were prepared by blending wheat flours of normal starch content with 0 to 30% waxy wheat flour of 5.1% starch amylose content. The reduction in starch amylose content by the addition of waxy wheat flour generally increased the specific volume and crumb softness of steamed bread. SRW wheat flour blended with 15-20% waxy wheat flour to obtain a starch amylose content of 20.5-22.7% showed retarded staling of steamed bread with comparable quality to the steamed bread of 100% SRW wheat flour.
The differences in nutritional characteristics and product quality between refined and whole grain wheat foods come from bran, which we hypothesized to differ widely among wheat varieties. We analyzed variations in bran characteristics among 17 SRW wheat varieties. Protein content, total dietary fiber, total arabinoxylan, phytate content and water retention capacity of bran ranged from 12.3 to 16.4%, 43.51- 50.3%, 11.1-17%, 25.0-35.1 mg/g of bran and 2.0-2.45 g of water/g of bran, respectively. The compositional and biochemical characteristics of bran could be the major factors affecting processing and product quality of whole grain foods, and need to be considered in the selection of appropriate wheat varieties.
Waxy wheat grain contains starch primarily composed of amylopectin molecules and could be used for preparing fillings with non-gelling properties and extending the shelf life of baked goods. Currently, waxy winter varieties adapted to grow in the northeastern U.S. do not exist. Two fully waxy varieties, each homozygous for the three waxy alleles, were crossed into three northeastern soft red winter wheat cultivars with low, medium, or high flour yield.
Biochemical, physical and genetic factors associated with flour yield: Easy and clean separation of endosperm from bran during roller milling of wheat is believed to be crucial for milling efficiency and improved flour yield. To identify biochemical and physical factors associated with flour yield, the amount of endosperm remaining on bran after roller milling of wheat grain was determined to be an indicator of endosperm separation. We showed that the dimethyl sulfoxide extraction of bran yielded a consistent and reliable estimate of bran residual endosperm content. Residual endosperm content of bran varied significantly among soft red winter wheat varieties, ranging from 33.9 to 47.4% (w/w), and correlated more strongly with flour yield than test weight, kernel hardness and kernel weight, suggesting it is a major contributor to flour yield and should be considered in the development of soft wheat varieties with improved flour yield potential.
To improve milling quality traits of eastern soft wheat we have continued to introgress into elite wheat cultivars a potential superior allele of a sucrose synthase gene that might impact multiple quality traits. We have successfully introgressed the favorable allele into seven cultivars and generated enough seed to plant in the field for the 2017 harvest. Field-grown wheat will be processed to analyze quality traits and compared to the original cultivars.
We have produced near isogenic lines for three alleles of a sucrose synthase gene in three cultivars. Homozygous sets of each allele in each background were verified using a marker we developed based on a small deletion in the gene promoter. This marker can differentiate the superior allele in a single step and will be useful to breeders for marker assisted selection.
Fertilizer rate on grain quality and volatile organic compounds of wheat grain:
The proper rate of nitrogen fertilizer application is essential for the improvement of grain yield and protein content, and could affect the grain characteristics related to milling and baking quality. We found that with an increased nitrogen application rate, test weight, kernel hardness, and grain protein content and strength increased with no apparent negative influences on milling quality and the water and solvent absorption capacities of flour.
The volatile organic compound (VOC) profile of wheat grain affects the flavor of wheat foods and serves as an indicator of grain soundness. By analyzing wheat grain collected at various maturation stages for VOCs using gas chromatography, we established an inherent VOC profile of wheat grain, unaffected by extrinsic factors (including fungal infestation and weathering). We observed 57 VOCs in wheat grain at 20 DPA, a number that decreased with further maturation. Based on concentration, we selected 3-methyl-1-butanol, 2-methyl-1-butanol, 1-pentanol, hexanal and 1-hexanol as the prominent VOCs. We also found that wheat grain stored for five months or infected with fungal diseases exhibited a markedly different VOC profile, supporting the potential use of the VOC profile for the effective determination of grain soundness.
Milling and baking quality evaluation of wheat breeding lines: ARS in Wooster, OH worked cooperatively with 19 regional public and private wheat breeding programs on the development of eastern soft wheat varieties carrying desired end-use quality by evaluating 5,068 wheat breeding lines and varieties harvested in 2015. These efforts are essential for, and directly contribute to, the development of wheat varieties possessing superior quality. We contributed to the development of sixteen new SRW wheat varieties released for licensing and potential commercial production in 2015.
We have also worked cooperatively with eastern soft winter wheat researchers at five universities by conducting comprehensive milling and baking quality evaluations for research projects including: the effects of row spacing on milling and baking quality of soft red winter wheat, the effects of nitrogen fertilizer rate on milling and baking quality, soft red winter wheat quality for making baguettes, quantitative trait loci mapping for grain quality traits in double haploid populations, and the effects of harvest time on grain quality characteristics.
The ARS laboratory in Wooster, OH was recognized as the winner of the best cookie analysis and the best pH analysis, and was first runner-up in overall quality analysis in 2015 among the 50 institutions competing in the American Association of Cereal Chemists International (AACCI) Cincinnati Section check sample evaluation. The ARS scientists authored or co-authored 9 refereed journal articles during this reporting period.
Accomplishments
1. Effects of clean separation of endosperm from bran on flour yield. Wheat grain characteristics required for high flour yield, the most important quality concern of flour millers, have not been clearly understood. The amount of endosperm remaining on bran after roller milling could be an important grain trait affecting flour yield. ARS researchers in Wooster, Ohio, found that dimethyl sulfoxide extraction of bran can be used to estimate residual endosperm and the degree of endosperm separation from bran. The procedure provides a reliable and consistent determination of the residual endosperm content of bran, revealed a wide variation among varieties and correlates more closely with flour yield than other grain traits. These findings substantiate that endosperm separation from bran is the primary grain trait affecting milling efficiency and flour yield, and needs to be considered in the development of wheat varieties with improved milling quality.
2. Volatile organic compound (VOC) profile of soft winter wheat grain. Wheat grain VOCs determine the odor and often modified by extrinsic factors such as fungal infestation and post-harvest weathering. Accordingly, the grain VOCs contributed solely by the intrinsic components, once profiled, can serve as an indicator of grain soundness. ARS scientists in Wooster, Ohio, profiled major VOCs in eastern soft wheats, demonstrating that four alcohols and one aldehyde vary in grain during maturation. These results suggest the inherent VOC profile of wheat grain could be used to develop accurate and rapid methods for assessing grain soundness, fungal infection levels and post-harvest spoilage.
3. Effect nitrogen fertilizer on the milling and baking quality of soft red winter wheat. The proper rate of nitrogen fertilizer application is essential for the improvement of grain yield and protein content, and could also affect the grain characteristics related to milling and baking quality. Compared to hard wheat, much less is known about the effects of nitrogen fertilizer rate on soft wheat grain quality characteristics. ARS researchers in Wooster, Ohio and collaborators, determined that nitrogen application rate significantly influenced the quality characteristics of wheat grain. We found that even though the increased application of nitrogen fertilizer produced grain of increased kernel hardness, it imparts no undesirably changes in water and alkaline retention capacities of flour. This information will serve as a guide for the application of nitrogen fertilizer to achieve the maximum yield of wheat grain with desirable milling and baking quality.
4. Quality improvement of steamed bread by reduction of starch amylose content of wheat flour. Starch constitutes more than 80% of wheat flour and consists of amylose and amylopectin molecules, which widely differ in structure and physical properties. Accordingly, the proportion of amylose and amylopectin has a considerable influence on the textural properties and shelf life of wheat products. The effects of starch amylose content on the quality of many wheat foods is not well understood. ARS researchers in Wooster, Ohio, demonstrated that reducing the starch amylose content of soft red winter wheat flour to 20.5-22.7% by the addition of waxy wheat flour had positive influences on the volume, crumb softness and shelf life of steamed bread. This information suggests that the development of soft red winter wheat varieties producing wheat grain with reduced starch amylose content will be helpful for extending the utility and marketability of soft winter wheats.
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Review Publications
Park, E.Y., Baik, B.-K., Miller, P.R., Burke, I.C., Wegner, E.A., Tautges, N.E., Morris, C.F., Puerst, E. 2015. Functional and nutritional characteristics of wheat grown in organic and conventional cropping systems. Cereal Chemistry. 92(5):504-512.
Ji, T., Baik, B.-K. 2016. Storage conditions affecting increase in falling number of soft red winter wheat grain. Cereal Chemistry. 93:263-267.
Ma, F., Baik, B.-K. 2016. Quality requirements of soft red winter wheat for making northern-style Chinese steamed bread. Cereal Chemistry. 93:314-322.
Kong, L., Baik, B.-K. 2016. Degree of starchy endosperm separation from bran as a milling quality trait of wheat grain. Journal of Cereal Science. 69:49-56.
Cai, L., Choi, I., Park, C., Baik, B.-K. 2015. Bran hydration and physical treatments improve the bread-baking quality of whole grain wheat flour. Cereal Chemistry. 92:557-564.
Clark, A., Sarti-Dvorjak, D., Brown Guedira, G.L., Dong, Y., Baik, B.V., Van Sanford, D. 2016. Identifying rare FHB-resistant transgressive segregants in intransigent backcross and F2 winter wheat populations. Frontiers in Microbiology. 7:277.
Van Sanford, D.A., Clark, A.J., Hershman, D., Brown Guedira, G.L., Cowger, C., Dong, Y., Baik, B.V. 2016. Registration of ‘Pembroke 2014’ soft red winter wheat. Journal of Plant Registrations. 10:41-46.
Cabrera, A., Guttieri, M., Smith, N., Souza, E., Sturbaum-Abud, A.K., Hua, D., Griffey, C., Barnett, M., Murphy, P., Ohm, H., Uphaus, J., Sorrells, M., Heffner, E., Brown Guedira, G.L., Van Sanford, D., Sneller, C. 2015. Identification of milling and baking quality QTL in multiple soft wheat mapping populations. Journal of Theoretical and Applied Genetics. 128(11):2227-2242. doi: 10.1007/s00122-015-2580-3.
Park, E., Fuerst, E.P., Baik, B.-K. 2016. Phytate negatively influences wheat dough and bread characteristics by interfering with cross-linking of glutenin molecules. Journal of Cereal Science. 70:199-206.
