Structure and IgE-binding properties of α-casein treated by high hydrostatic pressure, UV-C, and far-IR radiations. (1st August 2016) - Hu, Guanglan
Graphical abstract: Highlights: Allergenicity of α-casein was reduced by high-pressure and ultraviolet-C. Concentrations of allergen peptides reduced to minimum at 200 MPa (5 min). Ultraviolet-C treatments (15 min) decreased allergens maximally. Peaks of main allergenic domains affected were 15–17, 23–26, 40, 53, 59 and 85–88. Allergenicity is probably related to the morphology and structure of peptides. Abstract: α-Casein was treated by high hydrostatic pressure (HHP), UV-C, or far-IR (FIR). These treatments increased roughness, α-helicity, and β-turn, but decreased β-sheet and IgE-binding reactivity. One 5-min cycle at 600-MPa pressure caused maximum α-helicity, β-turn, and surface hydrophobicity (Ho), but minimum stimulated intestinal fluid from α-casein. UV-C (15 min) produced the maximum kurtosis, free sulfhydryl content (FSC), and stimulated intestinal fluid, minimum Ho, R, and simulated gastric fluid. FIR (15 min) caused the minimum α-helicity and FSC, but maximum R and β-sheet. The NMR peaks of the main allergenic characteristics affected were 15–17, 23–26, 40, 53, 59 and 85–88, respectively. Generally, all treatments decreased the allergenicity of α-casein by modifying its morphology, ultrastructure, characteristic domains, and peptides. Based on the stimulated digestion tests, UV-C (15 min) was more efficient for lowering α-casein allergenicity, thus decreasing the allergenicity of milk.