Influence des procédés thermiques sur l’allergénicité de l’arachide

Abstract

Peanuts are one of the allergens most often responsible for food allergy [1]. Nevertheless, the occurrence of peanut allergy varies between countries and appears to result from both the amount of peanuts in the diet and the way they are consumed. In addition, processing influences the allergenicity of peanut proteins. The aim of the present study was to examine the effect of some thermal processes on the IgE binding capacity of peanut allergens, using sera of patients allergic to peanuts. Protein extracts were prepared from raw, roasted and boiled peanuts. In each case, the proteins were isolated, purified and characterised by electrophoresis. The immunoreactivity of each protein extract was analysed using the Enzyme Allergo Sorbent Test (EAST) and EAST inhibition with sera from 37 peanut allergic patients. Western blots were also performed. The biochemical analysis of the whole protein extracts revealed slight modifications in the protein composition, particularly after boiling. The IgE binding capacity of the boiled peanut protein extract was reduced by 50% compared to raw and roasted peanut extracts. This difference on the recognition of peanut allergens by patients’ IgE was confirmed by the inhibition assays. Impaired IgE recognition mainly involves proteins of low molecular weight. No difference in immunoreactivity was observed between raw and roasted peanut protein extracts. Roasting peanuts does not modify their allergenicity while boiling decreases it considerably. This decrease of boiled peanut allergenicity comes from a loss of some allergens into the boiling water. It may also be due to structural modifications of peanut proteins that occur in boiling water.