GB786355A - Improvements in or relating to the manufacture of artificial sausage casings - Google Patents

Abstract

Alginate sausage casings in the gel condition are subjected to a drying treatment to reduce their water-content to a value less than 50 per cent by weight of the dried casings, then rehumidified so that they become saturated with water and are finally inflated by fluid pressure so as to stretch them transversely. Drying may be effected by passing the casings over heated rollers or by inflating the casings and passing them through a tubular drying oven. Rehumidification may be effected by treatment with water or steam. The stretching may be effected with air, nitrogen or carbon dioxide under pressure or by a liquid, e.g. water or an aqueous solution of calcium chloride or of ethyl alcohol, under hydrostatic pressure. In the latter case the liquid is introduced into a portion of the casing, the casing then being passed down an inclined shoot and through a pair of driven nip-rollers which prevent passage of the liquid, the amount of inflation being controlled by the inclination of the shoot. The process is applicable to casings of water-insoluble alginates, e.g. calcium alginate, with or without a proportion of alginic acid, and the casings are, prior to drying, preferably washed, to remove soluble inpurities and treated with an aqueous solution of a softening agent, e.g. glycerine. In an example, aqueous sodium alginate is extruded through an annular orifice into an aqueous coagulating bath containing calcium chloride and hydrochloric acid. The so-formed tubular casing is then treated in an aqueous calcium chloride bath to effect conversion into calcium alginate, then washed, dried on rollers heated to 70 DEG C. to reduce its water-content to 5 per cent by weight, rehumidified in water and finally inflated with water under pressure. Specification 784,640 is referred to.