Effects of Superheated Steam Treatment on the Allergenicity and Structure of Chicken Egg Ovomucoid

Abstract

The aim of this study was to explore the effects of an emerging and efficient heating technology, superheated steam (SS), on the allergenicity and molecular structure of ovomucoid (OVM). OVM was treated with 120–200 °C of SS for 2 to 10 min. The allergenicity (IgG/IgE binding abilities and cell degranulation assay) and molecular structure (main functional groups and amino acids modification) changes were investigated. The IgG-binding ability of OVM decreased and the releases of β-hex and TNF-γ were inhibited after SS treatment, indicating that the protein allergenicity was reduced. Significant increases in oxidation degree, free SH content and surface hydrophobicity were observed in SS-treated OVM. The protein dimer and trimer appeared after SS treatment. Meanwhile, obvious changes occurred in the primary structure. Specifically, serine can be readily modified by obtaining functional groups from other modification sites during SS treatment. Moreover, the natural OVM structure which showed resistance to trypsin digestion was disrupted, leading to increased protein digestibility. In conclusion, SS-induced OVM aggregation, functional groups and amino acids modifications as well as protein structure alteration led to reduced allergenicity and increased digestibility.

Reduced Allergenicity of Shrimp (Penaeus vannamei) by Altering the Protein Fold, Digestion Susceptibility, and Allergen Epitopes

“…Surface hydrophobicity is closely related to the conformation of protein, 33 which is an essential indicator of the binding ability between antibodies and antigens and plays an important role in assisting in epitope recognition. 34 It has been shown that roasting could induce the unfolding of the protein structure, and the internal hydrophobic amino acids were exposed to a non-polar microenvironment, which enhanced surface hydrophobicity and exposed more epitopes to increase IgG/IgE binding ability. The surface hydrophobicity decreased obviously after roasted + reverse-pressure sterilization (Figure 5D), which is a sign of protein aggregation.…”

Tracking a Major Egg Allergen to Assess Commercial Food Label Compliance: Towards a Simple and Fast Immunosensing Device

“…However, other allergens (e.g., ovomucoid) may be resistant to high temperatures. This fact explains why some individuals only present allergic symptoms/reactions to raw egg and/or foods containing raw egg, while others do to both raw and cooked eggs (even if subjected to a high-temperature cooking process) [ 29 ]. Thus, the results in Figure 5 elucidate that individuals hypersensitive to ovotransferrin should pay attention to the cooking process, which must be carried out at high temperatures or in an acidic medium.…”

Effects of unfolding treatment assisted glycation on the IgE/IgG binding capacity and antioxidant activity of ovomucoid

“…Paper lower than that using other processing methods reported, which reduced it to about 60% and 70% of the original value, respectively. 18,33 Considering the fact that L-cysteine unfolded the ovomucoid molecule but the induced structural change did not reduce its IgE binding capacity, we speculated that its IgE reactivity reduction after glycation under the optimized conditions was due to sugar conjugation on its linear epitopes. The specific glycation sites of the ovomucoid after the optimized treatment were determined by HPLC-MS/MS.…”

“…17 This evidence suggests that the efficacy of glycation could be limited by the physicochemical properties of this allergen including heat stability, a high ratio of glycosylation (20-25%), and its singular conformation stabilized by nine pairs of disulfide bonds that are involved in the preservation of the IgE-binding capacity of this allergen. 18,19 In this work, we sought to determine whether a prior disruption of the ovomucoid disulfide bonds using L-cysteine may enhance the glycation of this allergen and modify its allergenicity. Moreover, the antioxidant properties of the ovomucoid samples before and after simulated infant and adult gastrointestinal digestion were also evaluated.…”