Wheat α-amylase inhibitors (α-AIs) are known anti-nutritional factors, respiratory allergens, and they can sporadically cause food allergy. α-AIs are therefore expected to reach the enteric mucosae in an immunologically active form, but information on their stability to gastric digestion is not available. Resistance to pepsinolysis is nonetheless a key factor for any food allergen. We therefore investigated whether α-AIs could resist pepsin digestion in simulated gastric fluids (SGF) and in emulsified SGF, the latter simulating more realistically the multiphase nature of stomach bolus. Since α-AIs comprise a huge family of proteins, we investigated 0.19 α-AI as a prominent member. The digestion patterns were analyzed by immunoblotting using anti-0.19 polyclonal antibodies and sera from wheat allergic patients sensitized to 0.19 α- AI. The results show that the immune epitopes of α-AI are detectable up to 120 min of digestion in emulsifying conditions. Intra-molecular disulfide bonds and, in particular, emulsification were found to be crucial factors for protein stability. The results show that 0.19 α-AI must be considered a potential food allergen.

Emulsification of Simulated Gastric Fluids Protects Wheat α-Amylase Inhibitor 0.19 Epitopes from Digestion

CONSOLINI, Marica;SEGA, Michela;ZANETTI, Chiara;FUSI, Marina;CHIGNOLA, Roberto;RIZZI, Corrado;ZOCCATELLI, Gianni
2012

Abstract

Wheat α-amylase inhibitors (α-AIs) are known anti-nutritional factors, respiratory allergens, and they can sporadically cause food allergy. α-AIs are therefore expected to reach the enteric mucosae in an immunologically active form, but information on their stability to gastric digestion is not available. Resistance to pepsinolysis is nonetheless a key factor for any food allergen. We therefore investigated whether α-AIs could resist pepsin digestion in simulated gastric fluids (SGF) and in emulsified SGF, the latter simulating more realistically the multiphase nature of stomach bolus. Since α-AIs comprise a huge family of proteins, we investigated 0.19 α-AI as a prominent member. The digestion patterns were analyzed by immunoblotting using anti-0.19 polyclonal antibodies and sera from wheat allergic patients sensitized to 0.19 α- AI. The results show that the immune epitopes of α-AI are detectable up to 120 min of digestion in emulsifying conditions. Intra-molecular disulfide bonds and, in particular, emulsification were found to be crucial factors for protein stability. The results show that 0.19 α-AI must be considered a potential food allergen.
α-Amylase inhibitors; Emulsion; Pepsin; Simulated gastric fluids (SGF); Wheat allergy
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11562/393931
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