My PhD thesis aimed to investigate the protein quality of plant protein-based ingredients and food, such as meat analogues. The main parameter analyzed for protein quality was protein oxidation, which involves chemical modifications that can hamper food application. We investigated the effect of incorporating free and encapsulated iron to meat analogues and the effect of thermomechanical process conditions on protein oxidation of meat analogues and protein ingredients. The main findings of this thesis were that processing conditions increase protein oxidation and that commercial plant protein-based ingredients are already oxidized. Such new insights will help to develop strategies to control those chemical modifications in plant protein-based foods. We hope to motivate the need for less processed plant protein-based foods.