Effect of Dark,Hard, and Vitreous Kernel Content on Protein Molecular Weight Distribution and on Milling and Breadmaking Quality Characteristics for Hard Spring Wheat Samples from Diverse Growing Regions

Kernel vitreousness is an important grading characteristic for segregation of subclasses of hard red spring (HRS) wheat in the United States. This research investigated the protein molecular weight distribution (MWD) and the flour and baking quality characteristics of different HRS wheat market subclasses. The U.S. regional crop quality survey samples obtained from six regions for three consecutive growing years were used for subclass segregation based on the dark, hard, and vitreous (DHV) kernel percentage. Flour milled from HRS wheat with greater percentages of DHV kernel showed higher water absorption capacity for breadmaking. Protein MWD parameters could be related to the association between DHV kernel level and water absorption. Specifically, flour protein fractions rich in gliadins and high‐molecular‐weight polymeric proteins in the SDS‐unextractable fraction were identified to have significant and positive correlations with both DHV kernels and flour water absorption levels. An example further showed the importance of flour water absorption on potential economic incentives that can be gained with having a greater percentage of vitreous kernels. This information could help the flour milling and baking industry to segregate the different subclasses of HRS wheat with varying DHV content for their intended end‐use applications.     

Effects of Kernel Vitreousness and Protein Level on Protein Molecular Weight Distribution,Milling Quality,and Breadmaking Quality in Hard Red Spring Wheat

Dark, hard, and vitreous kernel content is an important grading characteristic for hard red spring (HRS) wheat in the United States. This research investigated the associations of kernel vitreousness (KV) and protein content (PC) levels with protein molecular weight distribution (MWD), milling quality, and breadmaking quality characteristics of HRS wheat. The U.S. regional crop quality survey samples from three consecutive growing years were combined into three composite samples with different levels of wheat PC and then further segregated into separate samples with three different levels of KV. Analysis of variance showed that KV level had significant (P < 0.001) effect on variation in test weight, break flour yield, and damaged starch content. Among protein MWD parameters analyzed by size‐exclusion HPLC, the high‐molecular‐weight polymeric proteins in the SDS‐unextractable fraction had significant (P < 0.01) association with KV. Regression analysis indicated that addition of KV to the PC level improved the model for both farinograph and baking water absorption values in all three growing years. This information could help the flour milling and baking industries to further segregate HRS wheat based on KV levels in addition to PC levels for their intended end‐use applications.     

Effect of Kernel Size and Mill Type on Protein,Milling Yield,and Baking Quality of Hard Red Spring Wheat

Optimization of flour yield and quality is important in the milling industry. The objective of this study was to determine the effect of kernel size and mill type on flour yield and end‐use quality. A hard red spring wheat composite sample was segregated, based on kernel size, into large, medium, and small kernels, as well as unsorted kernels. The four fractions were milled in three roller mills: Brabender Quadrumat Jr., Quadrumat Sr., and Bühler MLU‐202 laboratory mills. Large kernels had consistently higher flour yield than small kernels across mills, with the Quadrumat Jr. mill showing the lowest flour yield. Mill type and kernel size significantly affected variation in flour protein molecular weight distribution. When compared with larger kernels, flour milled from the small‐kernel fraction contained a higher gliadin fraction and SDS‐unextractable high‐molecular‐weight polymeric proteins, which had positive correlations with bread loaf volume (r = 0.61, P < 0.05) and mixograph peak time (r = 0.84, P < 0.001). Overall, small kernels could contribute to enhancing flour breadmaking quality while having a detrimental effect on milling yield.