The Effect of the Food Matrix on the In Vitro Bio‐Accessibility and IgE Reactivity of Peanut Allergens

Scope Factors such as food processing, the food matrix, and antacid medication may affect the bio‐accessibility of proteins in the gastrointestinal tract and hence their allergenic activity. However, at present they are poorly understood. Methods and Results Roasted peanut flour was incorporated into either a chocolate dessert or cookie matrix and bio‐accessibility were assessed using an in vitro digestion system comprising a model chew and simulated gastric and duodenal digestion. Protein digestion was monitored by SDS‐PAGE and immunoreactivity analyzed by immunoblotting and immunoassay. IgE reactivity was assessed by immunoassay using serum panels from peanut‐allergic subjects. Roasted peanut flour proteins proved highly digestible following gastro‐duodenal digestion even when incurred into a food matrix, with only low molecular weight polypeptides of Mr < 8 kDa remaining. When gastric digestion was performed at pH 6.5 (simulating the effect of antacid medication), peanut proteins are not digested; subsequent duodenal digestion is also limited. IgE reactivity of the major peanut allergens Ara h 1, Ara h 2, and Ara h 6, although reduced, was retained after oral‐gastro‐duodenal digestion irrespective of digestion conditions employed. Conclusion Peanut allergen bio‐accessibility is unaffected by the dessert or cookie matrices whilst high intra‐gastric pH conditions render allergens more resistant to digestion. Roasted peanut flour proteins prove highly digestible irrespective of being incorporated into either a chocolate dessert or cookie matrix. High intra‐gastric pH conditions modelling antacid medication rendered allergens more resistant to digestion. However, the IgE reactivity of major peanut allergens, although reduced, persist irrespective of the food matrix or digestion conditions employed.