Effect of the degree of glycation on the stability and aggregation of bovine serum albumin

We report the wet-state glycation of Bovine Serum Albumin (BSA) with xylose through the Maillard reaction and its effect on protein aggregations during heat treatment. Using low doses of xylose, glycation stabilized the conformations of BSA and reduced the formation of large aggregates during heat treatment. However, using high doses of xylose, glycation promoted the conversion of alpha-helices to unfolded structures and beta-sheets, and induced the formation of short amyloid-like aggregates after heat treatment. Using high-resolution mass spectrometry, three possible glycation sites were determined on BSA treated with low dose of xylose, while six glycations sites were detected when high doses of xylose were used instead. Considering the importance of glycation to the food industry, this work not only provides new insights into the nonlinear effects of glycation on protein stability, but also provides a strategy to tune the nutritional value and functionality of proteins during food processing.