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Physicohemical and Genetic Approches for the Improvment of Wheat Bran Quality
Wheat bran is often used in baking formulations as a good source of vitamins, antioxidants, minerals, and dietary fiber. Due to the composite effect of these components, consumption of bran-containing products leads to a reduction in the risk of type 2 diabetes, obesity, and heart disease. However, despite their health benefits, bran components negatively impact flour functionality by hindering gluten network formation. Therefore, the present work was focused on evaluation of the effects of bran chemical components and physical properties on the functionality of whole grain flour. Based on a correlation analysis of brans from 80 wheat cultivars and 8 measured characteristics, bran particle size distribution after the milling (friability) and water retention capacity (WRC) were identified as the most important quality traits for wheat bran functionality. High WRC of bran was negatively correlated with bread loaf volume, on the other hand, high bran friability leads to reduction of bran particle size, which is beneficial for the performance of whole grain flour. A genome wide association study (GWAS) was then conducted to identify genomic regions associated with bran friability and WRC. Two single nucleotide polymorphisms (SNPs), BS00000020_51 (5D, R2=0.12) and Excalibur_c49805_63 (5D, R2=0.11), were significantly associated with bran friability. For WRC, GWAS analysis did not reveal any markers that were significantly associated with WRC after Bonferroni correction. However, there were two markers that stood out from among the other SNPs: IWA4867 (4A, R2=0.046) and IWA4698 (4A, R2=0.044). Finally, since WRC of bran has a negative impact on bran functionality, a study was conducted to determine if wheat tempering conditions could be manipulated to reduce wheat bran WRC. Tempering moisture and pH had the most significant impact on controlling WRC. Reducing sugar analysis suggested that a reduction in bran WRC under elevated moisture and decreased pH conditions may be due to activation of polysaccharide hydrolyzing enzymes. In conclusion, bran friability and WRC were identified as the most important quality traits for bran functionality. Genetic markers that are associated with these traits were identified to inform breeding efforts for whole grain wheats. Acidic and elevated moisture conditions were also identified as practical ways to possibly reduce bran WRC at the mill.
Navrotskyi, Sviatoslav, "Physicohemical and Genetic Approches for the Improvment of Wheat Bran Quality" (2019). ETD collection for University of Nebraska - Lincoln. AAI27665198.