CASING FOR FOOD PRODUCTS

Abstract: Sausage skin consisting of animal intestines is preferably used in the manufacture of sausages. Such sausage skins are limited in dimension. Furthermore, difficulties may arise in obtaining the necessary quantity of sausage skin consisting of intestines. For this reason, sausage skin is also manufactured synthetically from various materials which may or may not be edible. It is desirable for a sausage skin to be edible and attempts have therefore been made to produce sausage skin from collagen obtained from cutaneous fissures. To release the collagen from the cutaneous fissures chemicals are necessary which make the exposed collagen inedible and complicated processes must be resorted to in order to make the collagen edible. The invention relates to sausage skin containing collagen from parts of an animal other than cutaneous fissures. The object of the present invention is thus to obtain collagen for the manufacture of sausage skin. According to the invention collagen has been successfully produced in an extraordinarily simple manner without the use of cutaneous fissures as starting material. According to the invention one or more of the digestive organs is instead used as starting material, said organs consisting of intestines, stomach, rumen, reticulum or third stomach. Other starting products which can be used are any of the other by-products obtained when animals are slaughtered.

Description: Casing for food products The present-invention relates to a casing for a food product. The food products having casings are in most cases sausages and it is desirable for the casing or sausage-skin to be edible. For this reason intestines from various animals are usually used as sausage skin. The dimensions of the sausages manufactured are in this case determined by the dimensions of the intestines. If automisation of variations in sausage manufacture is desired, the use of animal -intestines is a disadvantage since the dimen¬ sions of the intestines may always vary within certain limits. It is therefore desirable to be able to mechanically manufacture intestines having exactly the dimensions desired by the sausage manufacturer. It has therefore also been proposed to manufacture sausage-skin from a slurry- like compound which is shaped to a tube by means of extrusion. The tube formed constitutes the sausage skin and may be either edible or inedible. If the material is to be edible it should be made of collagen which can be found, inter alia, in the intestines. Sausage-skin containing collagen is being manufactured. Collagen has always been extracted from cutaneous fissures. Since the cross-links between the collagen molecules in the cutaneous fissures is extremely strong, calcium must be used to release the collagen molecules. The use of calcium is a drawback since collagen molecules released by calcium are inedible. Collagen molecules from fissures must therefore be treated in various complicated ways in order to make them edible. The aim of the present invention is to select such parts of an animal's body where the existent collagen molecules can easily be exposed without the use of additives which make the collagen molecules inedible. It has been found that organs of the digestive system contain collagen molecules which are easier to expose that the collagen molecules in fissures and they can therefore be relased without affecting the edibility of the mole¬ cules. It has also proved easy to remove collagen molecules from other slaughter products such as from the lungs, udders, etc. The object of the present invention is also to manufacture a casing uti¬ lizing collagen molecules selected in accordance with the invention as described above. According to the invention animal digestive organs are used in the first place, which have been thoroughly cleaned and cut into strips or pieces which are deep-frozen. The deep-frozen product is minced and suspended in liquid together with an agent to release the collagen molecules. The collagen molecules are collected and suspended, an * agent being preferably added which causes the collagen to mature, i.e. to bring the molecules into a form facilitating cross-linking between them. A suitable period for maturing is about 24 hours. After maturing the composition containing mature collagen molecules should be subjected to treatment ' to remove air bubbles. This is best done by centrifuge. An agent, such as glutar aldehyde, glyoxal or the like, is added to the composition to effect cross-linking. Plasticizers such as polyalcohols may also be added, for instance glycero The composition should preferably be given such a consistency that it can act as a bath into which food products can be immersed to acquire a casing. Alternatively the composition may be in the form of a slurry and can be sprayed out through an extruder to form a tube. In order to age or cure the casing formed it may be subjected to a temper ture in the vicinity of 60 C or even higher, within the range 70-80 C. By curing or ageing is meant increased cross-linking. Further characteristics of the present invention are revealed in the follo claims. The following is a more detailed explanation of the manufacture of a compo tion in which food products can be immersed and provided with a casing and a composition having such a consistency that it is suitable to produce C -I a tube with the help of an extruder, said tube being suitable for use as sausage-skin. According to the invention one or more of the organs of the digestive system may be used, or one or. more of other bi-products obtained when slaughtering animals and containing collagen molecules- However, it has been found best to use intestines as the starting material. The intestines . are trimmed from the animal body, emptied and thoroughly cleaned. They are then cut into pieces about a centimeter in size. These pieces are then also cleaned and the chopped intestines are deep-frozen. The frozen pieces are disintegrated, preferably at low temperature, a temperature less than 10 C, for instanoe, to pieces some millimeter in size. A mincing machine having a disc with holes about 3 mm in diameter is used. The minced intestine is suspended in water. 200 g of minced intestine should suitably be suspended in about 1000 ml water. Tne suspension is known as a slurry and has a pH value of about 6.8. The slurry is heated to around 40 C and its pH value adjusted to 8.3 with the help of sodium hydroxi 1.3 ml 4 NaOH was used per 200 g minced intestine in about 1000 ml water. * A proteolytic enzyme such as alkalas from the Danish company Novo is added to the 40 C slurry. The purpose of the enzyme is to wash away proteins other than collagen and this is done by hydrolysis of these proteins. A suitable hydrolysis time is 2-5 hours. A suitable quantity of enzyme is about 60 Anson units per kilogram dry substance. The collagen fibres of the intestine are also released during hydrolysis. The collagen fibres are suitably collected from the slurry and washed extremely carefully 1) so that both enzyme and hydrolysis products are removed. The collagen molecules can be washed with distilled water. From 200 g minced intestine, 87 g collagen molecules are obtained, having a pH value of about 8.2. 2) The collagen molecules are homogenized in a mixer. The collagen molecules are mixed with liquid to give a slurry with a dry substance content of x) 1.5---1 % . Lactic acid is added to the slurry to give a pH value of about xx) 3- Air is whipped into the slurry to give a suitable consistency. After this the slurry is allowed to mature for about 24 hours. During the maturin process collagen molecules are released in groups of three intertwined collagen molecules. Such a group is termed a collagen fibril. After 1). Residues of fat can, if necessary be removed from the collagen fraction by extraction uith a solvent. 2) at 50 - 300 kgpond per cm 2 x maturing the slurry is centrifuged in order to remove air bubbles. Therea it is given a suitable consistency for use as a bath for food products. The bath may suitable contain a cross-linking agent such as glyoxal or glutar aldehyde and a plasticizer which may consist of a polyalcohol such as glycerol. Foodstuffs to be provided with a casing are then immersed in the bath. Instead of the bath containing both plasticizer and cross- linking agent, the product with the casing obtained after immersion in the bath is immersed in a bath of cross-linking agent and thereafter in another bath with plasticizer. If the slurry with the collagen molecules is instead to be used ,to make a tube by means of extrusion, the mature slurry should be given a consistency suitable for an extruder. The slurr may in this case contain both cross-linking agent and plasticizer. In this case also the finished tube may be immersed in a bath containing cross-linking agent and then a bath containing plasticizer. In order -to initiate cross-linking it may be advisable to start with an ammonium sulphate solution and then change to glutar aldehyde or glyoxal. Matured slurry containing collagen molecules is a particularly advantageou starting material since the slurry can form a coherent network of slurry molecules if a cross-linking agent is added. A slurry of collagen molecul can thus be used for manufacturing surgical thread and for films of variou types to be used in medical care as well as in other fields. 1) It has been mentioned above that a slurry is used containing collagen molecules from the digestive organs and from other slaughter bi-products. A slurry containing said collagen molecules can be mixed with collagen molecules from cutaneous fissures, which are in this case treated in a manner to make them edible. ) As examples of other usages can be mentioned skins, edible or non- edible for foods, material for lamp-shades coatings in the paper in¬ dustry, additive to cured meats and provisions, (small amounts), and additive in the manufacture of paints.

Claims: CLAIMS 1. Casing, preferably an edible casing, such as sausage skin for. food products such as sausage-meat, characterised in that it is formed of collagen extracted from animal bodies, primarily from one or more of the organs of the digestive system such as intestines, stomach, rumen, reticulum, third stomach or other slaughter bi-products such as lungs and udders. 2. Casing according to claim 1, characterised in that it also contains collagen obtained from cutaneous fissures. 3. Method of manufacturing casings from collagen extracted primarily from intestines and possibly the stomach in accordance with claim 1 or 2, characterised in that cleaned intestine or stomach is reduced to strips or pieces, that said strips or pieces are deep-frozen, that the deep-frozen pieces are minced, that the minced product is suspended together with an additive such as an enzyme in order to enable separation of the collagen, that the separated collagen is subjected to maturing, preferably with the help of a maturing agent such as lactic acid and that the matured collagen is either used as a bath in which to immerse food products to be covered with a casing, or an extruder is added to enable it to be shaped to a casing. 4. Method according to claim 3, characterised in that the casing produced is fixed with an additive such as glyoxal or glutar aldehyde in order to facilitate cross-linking of the invididual collagen molecules. 5. Method according to claim 3 or 4, characterised in that a plasti¬ cizer such as glycerol is added to the matured collagen or the finished casing. c::?ι . V/Ii-O

Inventors: SJOELANDER E
Applicants: SJOELANDER E
Application year: 1981
Main classification: A22C13
IPC codes: A22C13, A23J1, A23J3, C12P21