Trisodium phosphate (TSP) is a common food additive used as a processing aid and pH regulator. In the case of Cinnamon Toast Crunch, it may play a role in enhancing the texture and ensuring the cereal's components stick together, as well as contributing to its overall stability during production and storage.
If you remove TSP from Cinnamon Toast Crunch, the cereal might still taste similar because the main flavor components come from the cinnamon and sugar coating, as well as the base cereal itself. However, you might notice differences in texture, crunchiness, or how the cereal holds up in milk. Without TSP, the cereal may become more prone to becoming soggy or less cohesive, which can affect the overall eating experience.
In essence, while the flavor might remain largely unchanged, the absence of TSP could result in a different mouthfeel and texture, which could affect the overall enjoyment of the cereal.