Technical Abstract: The oxidative cross-linking of arabinoxylan and protein polymers is partially responsible for variation in end-use quality of wheat flour; specifically, differences in batter viscosity as well as variation in bread and cookie quality. A better understanding of the variation in oxidative cross-linking potential among flour mill streams can improve flour quality through the formulating of superior flour blends, and hence end-product attributes. and understanding sources of variation in current flour blends. The purpose of this research was to study the variation of oxidative cross-linking among 10 Miag Multomat pilot mill streams from 31 hard, soft and club wheat varieties via Bostwick viscosity measurements. Flour slurries were made with either water alone (to measure the endogenous oxidative cross-linking viscosity) or with added hydrogen peroxide-peroxidase (to measure the enhanced oxidative cross-linking viscosity). Mill streams with high oxidative cross-linking potential were those with the largest differences between water and peroxide-peroxidase viscosity; these included: 1st Break, 1st and 2nd Middlings, and 1st Midds Re-dust. Conversely, mill streams 3rd Break and 4th and 5th Middlings were the least likely to form oxidative cross-links. The ability to form oxidative cross-links is dependent on the availability of ferulic acid and tyrosine residues. Therefore, the arabinoxylan and protein polymers in mill streams that have a high oxidative cross-linking potential have a structure that is more conducive to form oxidative cross-links.