Protein aggregation in foam fractionation of bovine serum albumin: Effect of protein concentration

In foam fractionation of proteins, a clear understanding of their aggregation induced by the gas-liquid interface has great importance to reducing the loss of their bioactivity. In this work, the effects of the concentration of bovine serum albumin (BSA) on its aggregation induced by the gas-liquid interface were investigated at the molecular level to clearly explain how this protein aggregated in foam fractionation. The results show that reducing the BSA concentration made the protein structure more unfolded so that it enhanced the protein aggregation induced by the gas-liquid interface. In foam fractionation, the BSA aggregates were mainly formed in the desorption of the BSA molecules from the gas-liquid interface. Their formation was closely related to the BSA enrichment ratio. In the concentration from 0.05 g/L to 0.20 g/L, the highly unfolded BSA structure and the high enrichment jointly resulted in the formation of insoluble aggregates.