Ovalbumin interaction with polystyrene and polyethylene terephthalate microplastics alters its structural properties

• Published in: International journal of biological macromolecules 2024-05, Vol.267 (Pt 2), p.131564-131564, Article 131564
• Main Authors: Gligorijevic, Nikola, Lujic, Tamara, Mutic, Tamara, Vasovic, Tamara, de Guzman, Maria Krishna, Acimovic, Jelena, Stanic-Vucinic, Dragana, Cirkovic Velickovic, Tanja
• Format: Article
• Language: English
• Subjects: Adsorption; Animals; Chickens; Hydrogen-Ion Concentration; Interactions; Microplastics; Microplastics - chemistry; Ovalbumin; Ovalbumin - chemistry; Polyethylene terephthalate; Polyethylene Terephthalates - chemistry; Polystyrene; Polystyrenes - chemistry; Protein Structure, Secondary
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2024.131564

Contaminating microplastics can interact with food proteins in the food matrix and during digestion. This study investigated adsorption of chicken egg protein ovalbumin to polystyrene (PS, 110 and 260 μm) and polyethylene terephthalate (PET, 140 μm) MPs in acidic and neutral conditions and alterations in ovalbumin structure. Ovalbumin adsorption affinity depended on MPs size (smaller > larger), type (PS > PET) and pH (pH 3 > pH 7). In bulk solution, MPs does not change ovalbumin secondary structure significantly, but induces loosening (at pH 3) and tightening (at pH 7) of tertiary structure. Formed soft corona exclusively consists of full length non-native ovalbumin, while in hard corona also shorter ovalbumin fragments were found. At pH 7 soft corona ovalbumin has rearranged but still preserved level of ordered secondary structure, resulting in preserved thermostability and proteolytic stability, but decreased ability to form fibrils upon heating. Secondary structure changes in soft corona resemble changes in native ovalbumin induced by heat treatment (80 °C). Ovalbumin is abundantly present in corona around microplastics also in the presence of other egg white proteins. These results imply that microplastics contaminating food may bind and change structure and functional properties of the main egg white protein. •Ovalbumin binds to polystyrene and polyethylene terephthalate microplastic.•Affinity is highest for small size polystyrene MPs at pH 3.•Microplastics affect ovalbumin tertiary structure more than secondary.•Fibril formation process induced by heat is affected in soft corona ovalbumin.•OVA is main MPs soft and hard corona protein of the egg white protein extract.