Impact of Heat Treatment on the Structure and Properties of the Plant Protein Corona Formed around TiO2 Nanoparticles

Titanium dioxide (TiO2) nanoparticles are utilized within the food industry as an additive to alter food brightness and whiteness. Amphiphilic food ingredients, like proteins, can adsorb on to the surfaces of TiO2 nanoparticles and form protein coronas that could alter their gastrointestinal fate. At present, our understanding of the factors influencing the formation and properties of protein coronas was limited. In this study, we explored the influence of thermal treatments of proteins on the physicochemical properties of protein coronas formed on TiO2 nanoparticles. Four plant proteins (glutenin, soy protein isolate, gliadin, and zein) were heat-treated at different temperatures for 30 min. Heat treatment (100 °C) disrupted the structure of the original proteins and changed the structure properties of the protein and formed coronas. Quartz crystal microbalance with dissipation results showed that for the heat-sensitive proteins, such as glutenin, a high temperature treatment (100 °C) weakened the binding affinity between the protein and the nanoparticle surfaces. In contrast, for more heat-resistant proteins, such as gliadin, a high-temperature treatment had much less effect. In summary, this study showed that the structural properties of plant proteins affected by heat were an important factor affecting the formation of protein coronas on food nanoparticles.