Immunogenic and structural properties of ovalbumin treated by pulsed electric fields

Abstract

In this study, the immunogenic and structural properties of ovalbumin (OVA) induced by pulsed electric fields (PEF) treatment were investigated. The immunogenic properties were estimated by the IgG and IgE binding abilities, which were determined by enzyme-linked immunosorbent assay (ELISA) using rabbit polyclonal antibodies and egg-allergy patients' sera, respectively. The structural changes were monitored by circular dichroism (CD), ultraviolet absorption, and fluorescence spectroscopy. When the OVA samples were treated at low electric field intensity (below 25 kV/cm, for 180 μs) or for short time (less than 60 μs, at 35 kV/cm), the IgG and IgE binding capacities gradually increased due to the partial unfolding of OVA. This was reflected in the increase in free SH content, surface hydrophobicity, and UV absorption. However, when the OVA samples were treated at high electric field intensity (exceeding 25 kV/cm, for 180 μs) or for long time (more than 60 μs, at 35 kV/cm), the IgG and IgE binding abilities significantly reduced due to the aggregation of OVA. This was also reflected in the decrease in free SH content, surface hydrophobicity, and UV absorption. Moreover, high-intensity PEF treatment caused a loss of the α-helix structure. The results showed that the largest decrease in the immunogenic properties was observed at 35 kV/cm for 180 μs. Therefore, PEF processing has the potential for utilization as a method for egg desensitization.

The Mechanism of Decreased IgG/IgE-Binding of Ovalbumin by Preheating Treatment Combined with Glycation Identified by Liquid Chromatography and High-Resolution Mass Spectrometry

“…Preheating treatment induced the conformation of ovalbumin to partially unfold, reflecting in the increase in β-sheet and β-turn contents and the reduction in the total amount of α-helix and random coil, intrinsic fluorescence intensity, and surface hydrophobicity. At present, studies have shown that linear IgG and IgE epitopes were transmitted through the entire amino acid sequence of ovalbumin. , The partial unfolding aroused via preheating treatment may lead to the exposure of linear and structural IgG and IgE epitopes originally masked in ovalbumin molecules. Therefore, H-Oval was insignificantly enhanced.…”

Can food processing produce hypoallergenic egg?

“…Both interactions with epigallo‐catechin 3‐gallate and chlorogenic acid reduced IgE‐binding capacity of ovalbumin, due to the shielding of the linear IgE epitope (Lu et al., 2018; Ognjenović et al., 2014). Pulsed electric field treatment > 25 kV/cm (for 180 µs) or at 35 kV/cm for long time (>60 µs) was proven to reduce the IgE binding of ovalbumin, due to aggregate formation (Yang, Zhang et al., 2017).…”

High Hydrostatic Pressure-Assisted Enzymatic Hydrolysis Affect Mealworm Allergenic Proteins

“…Different food processing methods, such as boiling [9,10], autoclaving [11], extrusion [12], microwave [13], pulsed-electric field [14], ultrasound [15], and HHP [16,17], may alter the intrinsic structure of food proteins and, consequently, decrease their allergenic properties. These processes may be coupled to enzymatic hydrolysis to further decrease the allergenicity of a wide range of conventional food proteins and generate protein hydrolysates that could potentially be integrated into specific formulations for food-allergic patients [18].…”