| 摘要 |
1,210,859. Tubular collagen films. TEEPAK Inc. 8 Nov., 1968 [20 Nov., 1967], No. 52945/68. Heading B5B. An edible extruded tubular collagen casing is tanned by passing it through an aqueous solution of an acid phosphate salt at a pH of 4-6 containing 0À05-5À0% by weight glutaraldehyde. The casing is then washed and plasticized by passing through a bath consisting of an aqueous solution of glycerin, sorbitol, dipropylene glycol or triethylene glycol, prior to drying. Preferred acid phosphates at a pH of 4-6 are monosodium dihydrogen phosphate, trisodium phosphate and disodium monohydrogen phosphate, the concentration of which may be 20% by weight in the tanning bath. After leaving the drier where the casing is also inflated, it is preferably reeled and eventually shirred and can be used as sausage casing. The collagen used is preferably limed or unlimed hide collagen, and is washed, ground at a temperature of less than 20‹ C. to produce a slurry of finely-divided collagen in water which is then swollen with e.g. lactic acid at a pH of 2À5 to 3À7. The swollen slurry is extruded through an annular die preferably having a pair of counter-rotating members into a coagulating bath comprising a concentrated solution of an alkali metal sulphate or ammonium sulphate or a neutral or slightly acidic phosphate salt. The casing is then passed through the tanning solution and treated as described above. The tanned casing may be passed through at least one treating bath comprising an aqueous solution of an alkali metal acid phosphate and then a water wash prior to plasticizing and drying. |
