Textured non-porous barrier transfer casing

A functional additive transferring (co)extruded thermoplastic food casing comprising:

• a water vapor barrier and/or oxygen barrier effect,
• wherein an inside surface of said thermoplastic food casing has a textured surface which forms a three-dimensional pattern of higher and lower retaining capacity for a functional additive,
• wherein said thermoplastic food casing having a textured surface is either a monolayer casing or a multilayer casing, for which the inside surface is the textured surface and comprises as a main component at least one thermoplastic copolymer material selected from the group consisting of (co)polyamides, (co)polyolefins, (co)polyester and vinylidenchloride (co)polymers,
• wherein said (co)extruded thermoplastic food casing does not comprise a net and/or a material forming a net or any other three dimensional structure on its outside surface,
• wherein the average thickness of the thermoplastic food casing in the areas having a higher retaining capacity is in a range of from 1 to 100 μm, and
• wherein the average thickness of the thermoplastic food casing in the areas having a lower retaining capacity is in a range of from 191 to 2000 μm, provided that the thickness difference between the average thickness in said areas having higher retaining capacity and the average thickness in said areas having a lower retaining capacity is in a range of from 160 to 1950 μm and that a ratio of the average thickness of the thermoplastic food casing in the areas having a higher retaining capacity and the average thickness of the thermoplastic food casing in the areas having a lower retaining capacity is in a range of from 0.002 to 0.25.