Effect of Thermal Processing on Food Allergenicity: Mechanisms, Application, Influence Factor, and Future Perspective

Thermally processed foods are essential in the human diet, and their induced allergic reactions are also very common, seriously affecting human health. This review covers the effects of thermal processing on food allergenicity, involving boiling, water/oil bath heating, roasting, autoclaving, steaming, frying, microwave heating, ohmic heating, infrared heating, and radio frequency heating. It was found that thermal processing decreased the protein electrophoretic band intensity (except for infrared heating and radio frequency heating) responsible for destruction of linear epitopes and changed the protein structure responsible for the masking of linear/conformational epitopes or the destruction of conformational epitopes, thus decreasing food allergenicity. The outcome was related to thermal processing (e.g., temperature, time) and food (e.g., types, pH) condition. Of note, as for conventional thermal processing, it is necessary to control the generation of the advanced glycation end products in roasting/baking and frying, and the increase of structural flexibility in boiling and water/oil bath heating, autoclaving, and steaming must be controlled; otherwise, it might increase food allergenicity. As for novel thermal processing, the temperature nonuniformity of microwave and radio frequency heating, low penetration of infrared heating, and unwanted metal ion production of ohmic heating must be considered; otherwise, it might be the nonuniformity and low effect of allergenicity reduction and safety problems.