In principle, the redox properties of copper should not change with or without gelatine. Gelatine is used to avoid aggregation and control diffusion of ions (mobility). Actually, gelatine-based pastes where used in photography for the formation of silver colloidal particles suspended in a highly viscous media (no precipitation).
I still do not understand why you call gelatine a protective agent? Well, maybe you want to avoid diffusion of whatever oxidant... by putting a protecting network (gel)...