The effect of ultra-high pressure and heat on the allergenicity and structural properties of bovine serum albumin

The objective of this study is to investigate the impact of Ultra-High Pressure (UHP) combined with moderate heat treatment on the allergenic properties of Bovine Serum Albumin (BSA). The effects of high pressure treatment at 100-500 MPa on allergenicity and structural properties of BSA were investigated. This study was performed using Competitive Indirect-Enzyme Linked Immunosorbent Analysis (CI-ELISA) to get the allergenicity change of BSA and the spectroscopy technology to get the structural properties change. At 500 MPa and 55°C, the inhibition of IgE decreased and reached a maximum of 17.5% relative to untreated BSA. At 100-500 MPa and 25-40°C, the free Sulfhydryl (SH) content, relative surface hydrophobicity (H0) and the fluorescence intensity of BSA significantly (P<0.05) increased at first and then decreased with increasing pressure. A pressure of 100 MPa gave the maximum increase, but using 55°C resulted in a significantly decrease in SH, H0 and fluorescence intensity. This might be due to protein refolding and subsequent aggregation or association. A significant change in the secondary structure was also detected at higher temperatures. UHP combined with higher temperature treatments resulted in a significant decrease in the number of α-helices and a significant increase in β-sheets, β-turns and random coils. These interactions and the secondary results provide direct explanation for the UHPand heat-induced modification of BSA. This could alter the allergenicity of BSA and enhance the security of beef, milk and beef products.