Method of producing an edible, tubular collagen-gelatin sausage casing

An edible sausage casing comprises cohered tendon colagen fibrils and from 5% to 20% by weight of gelatin relative to the weight of the dry collagen solids. The collagen fibrils may be encapsulated in a matrix of gelatin and the casing may form a translucent hyaloid structure. Preferably, the collagen fibrils lie generally parallel to the surface of the casing, which may be in a shirred condition. The sausage casing is made by extruding a continuous fragile tubular body from a fluid mass of acid-swollen tendon collagen, containg gelatin in the proportion of 5% to 20% by weight relative to the weight of the dry collagen solids, into an aqueous coagulant solution containing an inorganic salt, preferably ammonium sulphate. Suit ably the collagen solids content in said fluid mass is greater than 2.5% by weight. The coagulated body may be subsequently subject to hardening and washing, the wall cracking. The dried casing may then be shirred, and is preferably then heat-cured. This treatment comprises storage for about eight hours at a rising temperature bringing the casing material from room temperature to about 80 DEG C. It is then maintained at 80 DEG C. for some 16 hours more, which completes the heat curing. The ultimate moisture content after heat curing is preferably 10% to 30% by weight. To maintain the desired moisture content for stuffing, the re-humidified casings are preferably packaged in hermetically sealed containers of metal foil. If a small amount of formaldehyde is added to the hardening or plasticizing solution, the heat curing treatment may be omitted.