Influence of whey protein hydrolysis in combination with dextran glycation on immunoglobulin E binding capacity with blood sera obtained from patients with a cow milk protein allergy

摘要

Food protein allergies are a major global concern.Hydrolysis of food proteins reduces their allergenicity,but another novel approach is the covalent attachmentof polysaccharides to proteins via the Maillard reaction(i.e., glycation), which blocks some IgE bindingepitopes on the protein allergen. We wanted to examinewhether enzymatic hydrolysis, combined with glycation,could further reduce IgE binding for people witha cow milk protein allergy. Whey protein isolate (WPI)was hydrolyzed by immobilized trypsin and chymotrypsinto degree of hydrolysis (DH) values of 17 to 27%.Immobilized enzymes were used to avoid heat-treatingthe hydrolysate (to inactivate the enzymes, becauseheating could also affect the IgE binding ability of theprotein). The resultant whey protein isolate hydrolysates(WPIH) were then glycated with 10-kDa dextran(DX) in aqueous solutions held at 62°C for 24 h. Weanalyzed the molar mass (MW) of WPIH samples andtheir corresponding glycates (WPIH-DX) using sizeexclusionchromatography with multi-angle laser lightscattering. We obtained blood sera from 8 patientswho had been diagnosed with a cow milk protein allergy,and we used a composite serum for IgE bindinganalysis. The average MW values of samples WPIH-1to WPIH-3 decreased from 11.15, 9.46, and 7.57 kDawith increasing DH values of 18.7, 22.5, and 27.1%.Glycation significantly reduced the high bitterness ofthe WPIH samples, as assessed by a trained sensorypanel. The WPIH-DX glycates had significantly reducedWPI-specific IgE binding capacity compared to WPI orunglycated WPIH; we found an almost 99% reductionin IgE binding for the WPIH-DX glycate made fromWPIH with a DH value of 27.1%. Hydrolysis of WPIfollowed by glycation with DX via the Maillard reactionsignificantly decreased the allergenicity of wheyproteins.