Abstract: Peanut is listed among the eight major food allergens by the FAO, and peanut allergy is life-long and could cause hives, vomiting or other symptoms. In the present study, thermal treatment and cysteine reduction were applied individually and in combination on peanut allergen Ara h 2 to study their effect on the allergenic protein. The changes in the structure and antigenicity of Ara h 2 were characterized by circular dichroism (CD) spectroscopy, UV spectroscopy and indirect competitive enzyme linked immunosorbent assay (ELISA), respectively. The results showed that thermal treatment and cysteine reduction could individually change the structure of Ara h 2, leading to a slight decrease in the antigenicity. But the combined treatment resulted in a significant decrease in the antigenicity of Ara h 2 due to the enhanced reducing capacity of cysteine under thermal conditions and consequent remarkable changes in the secondary and tertiary structures of the protein. Moreover, the disulfide bonds played important roles in the structural stability of Ara h 2. When they were destroyed by reduction and heating, the structure and antigenicity changed significantly. These results indicated that reduction combined with heating may be an effective method for eliminating the allergenicity of Ara h 2.

Key words: peanut, thermal treatment, Ara h 2, disulfide bond, structure, antigenicity