DETECTION OF CONFORMATIONAL MODIFICATIONS OF HEATED BETA-LACTOGLOBULIN BY IMMUNOCHEMICAL METHODS

摘要

beta-Lactoglobulin (beta LG) was submitted to various thermal treatments (75 and 90 degrees C), and its conformational modifications were assessed by competitive radioimmunoassay (RIA) with rabbit antisera against native beta LG (beta LG(NAT)) or chemically modified beta LG obtained by performic oxidation (beta LG(OX)). Heat-processed beta LG reacted with both antisera. Molecule alteration was accompanied by an increased binding of polyclonal antibodies. Whatever the serum used, the RIA test revealed a thermal dependence that was influenced by pH (6.5 and 7.5). However, anti-beta LG(OX) antiserum was shown to be the most useful tool for monitoring slight denaturation structural changes after heating. The test accurately detected local modifications of beta LG epitopes that occurred after thermal processing of an industrial beta LG isolate.