Antigenicity elimination of ovalbumin by cold plasma-induced covalent binding with Gallic acid

The effect of cold plasma (CP) treatment in promoting the covalent grafting of ovalbumin (OVA) with gallic acid (GA) were investigated, along with identifying the binding sites in the OVA-GA complex and exploring its potential for reducing the antigenicity of OVA. The results showed that the GA content of 22.97 ± 1.27 mg/g in OVA-GA complex was obtained following 60 s of CP treatment. Using LC-MS/MS, four regions (T⁵²-R⁵⁹, V²⁰¹-K²⁰⁷, I²⁷⁹-R²⁸⁵, and V²⁸¹-K²⁹¹) were identified, containing 12 GA binding sites in the OVA-GA complex. Additionally, a significant reduction in IgE binding capacity (70.83 ± 0.90 %) was observed, as confirmed by ELISA analysis. The masking/steric-hindrance effect on linear epitopes and the disruption of conformational epitopes of OVA as a result of GA grafting may be the key factors leading to the reduction in OVA antigenicity. This study highlights that promoting the grafting of polyphenols onto proteins using CP treatment is an effective strategy for reducing the antigenicity of protein allergens.