Dissertation
Characteristics and significance of grain hardness of barley for food
Washington State University
Doctor of Philosophy (PhD), Washington State University
05/2010
DOI:
https://doi.org/10.7273/000006077
Abstract
Barley, Hordeum vulgare, a rich source of dietary fiber which has been proven to be effective in lowering cholesterol and glycemic index, is an ideal candidate for grain-based functional foods. The objectives of the research reported herein were to determine variation in grain hardness among U.S. barley germplasm, factors influencing barley grain hardness and the significance of barley grain hardness in food processing. Barley lines, provided by ten major U.S. barley breeding programs, exhibited a broad range of single kernel characterization system hardness index (SKCS HI) values ranging from 30.1 to 91.9. Vitreousness, evaluated visually using a light box, showed a clear distinction between hard and soft kernels. Hard kernels appeared translucent, while soft kernels appeared opaque on the light box. L*, determined as an indicator of kernel vitreousness using a Minolta chromameter, showed a significant negative correlation (r = -0.83, P<0.01) with SKCS hardness. Protein, [beta]-glucan and amylose content did not show any significant association with hardness. Under light microscopy, SKCS hard barley lines showed significantly thicker cell walls than SKCS soft barley lines. Both hard and soft barley lines showed similar patterns of cell size and distribution under the scanning electron microscopy. However, hard and soft barley lines showed variation in the degree of starch-protein association and continuity of protein matrix. Hard barley lines with a continuous protein matrix exhibited greater starch-protein adhesion than the soft barley lines, suggesting that starch-protein binding may be one of the major factors influencing barley grain hardness. Linkage disequilibrium based association mapping of diverse barley lines with mixed linear model showed significant single nucleotide polymorphism markers on chromosomes 1H, 2H, 3H, 4H and 7H, suggesting complex quantitative genetic control of barley grain hardness. Pearling loss of barley kernels after 325 sec abrasion showed significant negative correlation (r = -0.87, P<0.01) with hardness. Proportion of barley flour particles greater than 106 [mu]m (r = 0.93, P<0.01) and starch damage of barley flour (r = 0.93, P<0.01) showed significant positive correlations with hardness. These results suggest that barley grain hardness has significant influence on food processing.
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Details
- Title
- Characteristics and significance of grain hardness of barley for food
- Creators
- Sindhu Gopalkrishnan Nair
- Contributors
- Steven E. Ullrich (Co-Chair)Byung-Kee Baik (Co-Chair)Kulvinder Gill (Committee Member) - Washington State University, Department of Crop and Soil SciencesMichael Knoblauch (Committee Member) - Washington State University, School of Biological Sciences
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Crop and Soil Sciences
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 146
- Identifiers
- 99901055021701842
- Language
- English
- Resource Type
- Dissertation