Patent GB-1122504-A (GB)
Title: Production of edible collagen casing
Inventor: TALTY ROBERT DEAN
IPC: B29C48/09
Filed: 1966-03-22
Abstract: 1,122,504. Tubular films. TEE-PAK Inc 22 March, 1966 [26 March, 1965], No. 12442/66. Heading B5B. An edible translucent sausage casing comprising cohered limed hide collagen fibrils is made by treating a fresh or salt-cured animal hide with a lime-containing solution for a time, in the range 1.5 to 24 hours, sufficient toatleastpartially dehair the hide without degrading the collagen; removing the epidermal layer and remaining hair, neutralizing the lime in the hide by treatment at a pH of 2.5 to 6.5 with a non-toxic acid capable of forming a calcium salt, sufficiently soluble to be washable from the hide, and washing to remove by-product salts, grinding the hide at a temperature less than 20 C. to produce a slurry of finely-divided collagen in water, treating the slurry with acid at a pH of 2.5 to 3.7 for a time sufficient to swell the collagen and burst the fibre bundles to form fibrils. extruding the slurry through an annular die to form a collagen tube, immersing the tube in a coagulating bath, tanning the collagen tube, and washing, plasticizing, and drying the tube to produce a translucent non- fibrous edible product. Suitably the lining treatment is effected for 3 to 12 hours. Preferably, the epidermal layer and remaining hair are removed mechanically, and the neutralized hide is defieshed and cut into pieces prior to grinding. Suitably the slurry contains 2-6% collagen, and especially 3À5-5%. The lime solution is preferably a solution containing excess solid lime, sodium sulphhydrate, and dimethylamine sulphate. The acid used for neutralizing the lime and for swelling the collagen is suitably a weak organic acid, especially acetic acid, lactic acid, citric acid, or propionic acid. Acids which may be used to neutralize the limed hide may be selected from malic acid, maleic acid, butyric acid, isobutyric acid, fumaric acid, succinic acid, valeric acid, glutamic acid, levulinic acid, lactic acid, citric acid, acetic acid, propionic acid, caprylic acid, gluconic acid, benzoic acid, malonic acid, ascorbic acid, glycerophos phoric acid, hydrochloric acid, and phosphoric acid. The coagulating bath preferably contains a salt selected from alkali metal sulphates and ammonium sulphate, and the following baths are used in examples: (1) 42% ammonium sulphate; (2) 40% ammonium sulphate; (3) 42% sodium sulphate; (4) 42% sodium sulphate; (5) 30% ammonium sulphate; (6) 30% ammonium sulphate; (7) 42% ammonium sulphate; (8) 42% ammonium sulphate. The tanning bath suitably contains a tanning agent selected from soluble ferric and aluminium salts, and the following baths are used in Examples: (1) 10% ferric ammonium sulphate and 20% ammonium sulphate; (2) 10% ferric ammonium sulphate and 20% ammonium sulphate; (3) 10% ferric chloride and 20% ammonium sulphate; (4) a conventional alum tanning bath; (5) 10% ferric sulphate; (6) a conventional alum tanning bath; (7) 10% ferric ammonium sulphate and 20% ammonium sulphate; (8) 10% ferric ammonium sulphate and 20% ammonium sulphate. In general, plasticization is effected with an aqueous solution of glycerol. Drying is effected in warm air. In Fig. 2, a collagen slurry is introduced through inlet conduit 1 into die 2 having an annular die outlet 3 through which casing 4 is extruded. Die 2 has an inner tube 5 which extends upwardly within the extruded casing to remove coagulating bath from therewithin. Die 2 is located at the bottom of container 6 containing coagulating bath 7, which circulates through conduit 8 from tube 5 for removal of the coagulatng bath from inside the extruded casing. Casing 4 which is coagulated in bath 7 passes over a series of rollers (not shown) and is directed successively through tanning, wash, and plasticizing baths, and thence to a hot air drier, and finally to wind-up on a reel, or alternatively to a shirring machine.