The underlying mechanism of food allergy is not well understood. Research has increasingly focused on the characterization of food allergens.... Show moreThe underlying mechanism of food allergy is not well understood. Research has increasingly focused on the characterization of food allergens. Since most foods are cooked prior to consumption, information relating to the impact of thermal processing on the properties of allergenic proteins is critical for allergen risk assessment. This study examined the impact of thermal processing on the structure and the antigenic potential of the major egg and milk allergens, ovomucoid (OVO) and -lactoglobulin (BLG) both A and B variants respectively. OVO and BLG were subjected to thermal processing under moist and dry heat conditions for 10 min. No significant changes in the solubility of both proteins were observed after boiling, autoclaving or dry heating up to 204C. At 232C, a significant protein loss was observed. Inhibition ELISA was used to determine the effect of heat treatment on the capacity of these proteins to bind rabbit derived IgG antibodies. While boiling and autoclaving caused a decrease in IgG binding of OVO, an increase in IgG binding of BLG was observed under the same experimental conditions. A similar pattern that a decrease in antigen binding potentials by OVO and an increase in antigen binding potentials by BLG A and B variants was noticed during dry heat treatment at temperatures 232C and above. Structural analyses were performed using circular dichroism spectroscopy (CD) and differential scanning calorimetry (DSC). Both proteins showed variations in the secondary structure when subjected to heating in water and PBS. In the presence of water, variable temperature scan with CD resulted in transition temperatures of OVO and BLG variants in the range of 70-75oC and 80-85oC respectively. There is no significant change in the secondary structure of BLG variants prepared in PBS. DSC study showed the transition temperatures of 84oC, 129oC for OVO and at 80oC, 195oC for BLG (A & B) variants under moist and dry heat conditions respectively. Overall, both proteins were highly resistant to thermal denaturation and retained their antigenic potential at typical cooking temperatures. M.S. in Food Safety and Technology, May 2011 Show less
