END CLOSURE FOR AN EDIBLE COLLAGEN CASING AND A METHOD FOR OBTAINING THEREOF

Abstract

The invention relates to an edible tubular collagen film which has a closure at either of their ends. The closure is formed by an edible solid ring-like element which tightens the end portion of casing and seals the outlet of the same, in order to stop the filling mass upon beginning of a sausage stuffing process, whereby in such a process one can rescue the initial filled sausage for its further processing, whereafter the ring disappears. This edible closing element is characterized by being of an edible, and thermoplastic composition, which is preferably based on collagen or gelatine. The solid composition has a low melting temperature and becomes adhesive at fluid state onto the surface of a collagen film which contains a certain level of moisture. The strong cohesiveness of the material of said composition in the fluid state as well as the so narrow difference between its melting temperature and the temperature of solidification, makes that a welding of said material to be set very quickly. The closure can be made before or after the shirring of the collagen casing and the present invention provides also a process to perform such a closure by heat welding the closing element on the casing material.

Claims

1. Tubular casing for food made of an edible collagen film, having an end closure; said end closure consisting in a length of said casing whose section has been radially compressed toward its axis and/or twisted in such a way that said stretch of casing exerts the blocking of inner pathway therein; and where said stretch of compressed/twisted casing remains surrounded, fastened and tightened by a solid ring-like element which is thoroughly or partially welded to the surrounded portion of collagen casing, and wherein said ring is made up by a thermoplastic material which is characterized by being edible.

2. Tubular casing according to claim 1, wherein the tubular casing is shirred.

3. Tubular casing according to claim 1, wherein the thermoplastic material of the ring is an edible thermoplastic composition based on proteins, polysaccharides or a mixture thereof.

4. Tubular casing according to claim 1, wherein the thermoplastic composition of the closing ring, in the solid state, has a Young's modulus which lies in the range of 0.5 to 50 MPa, measured at environment conditions of 23 C. and 50% RH.

5. Tubular casing according to claim 4, wherein the thermoplastic composition of the closing ring has a fusion temperature (Tm) of between 40 C. and 98 C.

6. Tubular casing according to claim 1, wherein the thermoplastic and edible material of the closing ring is a non crosslinked and water soluble proteinic thermoplastic composition comprising a mixture of dry gelatine and a polyol, and wherein the content in weight of water is in the range of 0.5% to 15%; preferably between 1% and 5% and most preferably between 2% and 3% of the total weight of the composition.

7. Tubular casing according to claim 6, wherein the thermoplastic and edible material of the closing ring is a crosslinked and water insoluble composition.

8. Tubular casing according to claim 6, wherein said gelatine has a Bloom value higher than 150.

9. Tubular casing according to claim 6, wherein the polyol is glycerol.

10. Tubular casing according to claim 6, wherein the proteinic thermoplastic composition of the closing ring, in the solid state, has a Young modulus which lies in the range of 0.5 to 50 Mpa, measured at environment conditions of 23 C. and 50% RH.

11. Tubular casing according to claim 6 wherein the proteinic thermoplastic composition of the closing ring has a fusion temperature (Tm) of between 40 C. and 98 C.

12. Tubular casing according to claim 1, wherein the thermoplastic and edible material of the closing ring is a polysaccharide based thermoplastic composition comprising cellulose fibres, including microfibers and nano-fibres, admixed with other selected from the group of starch, methyl cellulose, hydroxyl-methyl cellulose, hydroxyl-propyl-methyl cellulose and mixtures thereof.

13. Tubular casing according to claim 12, wherein the polysaccharide thermoplastic composition of the closing ring, in the solid state, has a Young modulus which lies in the range of 10 to 50 MPa, measured at environment conditions of 23 C. and 50% RH.

14. Tubular casing according to claim 13, wherein the polysaccharide thermoplastic composition of the closing ring has a fusion temperature (Tm) of between 40 C. and 98 C.

15. Stick of a shirred tubular casing of an edible collagen film, having an end closure according to claim 1.

16. Method for obtaining an end closure, said end closure according to claim 1, characterized by the following steps: a) providing a length of smooth or deshirred tubular casing b) providing a stock of molded c-shaped open rings according to description and drawings; made of a thermoplastic and edible composition according to claims 1 to 12, c) clamping and twisting a short ending stretch of the length of casing from (a) to form a short strand; d) pushing and inserting the twisted strand obtained in point (c) inside the C-shaped open ring through the entry gap of the ring, until the longitudinal axis of that strand coincides with the axis of the ring's hollow; or alternatively e) pushing and inserting the twisted strand until being fitted inside the ring's hollow, according to the point (d) and applying a source of heating by means of the pushing element at least on one side; then retiring the pushing element and simultaneously firmly closing the c-shaped ring until the opposite sides of both tips come into contact, to weld the contact between them as well as the contact between the ring and the strand of twisted casing now entrapped therein; f) maintaining the closing pressure on the ring during 0.5 to 5 seconds and liberate the closing pressure to release the so formed closure; g) cutting the remaining end of the strand, and h) inserting the ringed end closure inside the bore of the shirred strand.

17. Method according to claim 16 wherein the step (g) is simultaneously done with step (e).

18. Foodstuff encased in a tubular casing, made of an edible collagen film, having an end closure according to claim 1.

Description

DESCRIPTION OF THE DRAWINGS

[0070] To complement the description that is being made and for the purpose of aiding to better understand the features of the invention according to a preferred practical embodiment thereof, a set of drawings is attached as an integral part of said description in which the following is depicted with an illustrative and non-limiting character:

[0071] FIG. 1 shows several hollow worm-shaped rods with a longitudinal V-shaped opening, molded by injection molding.

[0072] FIG. 2 shows how the worm has been molded with a longitudinal groove whose section is V-shaped, that reaches the axial hole, so that any segment transversely cut from the worm has a ring shape open at c. The view 2a shows a tightening element that is a solid ring-like element, made of an edible and water soluble thermoplastic composition, which has a smoothly curved v-shaped entry gap which leads to the central hollow, whereas the view 2b shows another embodiment wherein the ring-like element is made up of a proportion of gelatine/glycerol which allow the ring to exert a strong tightening effect onto the twisted portion of casing, while the same composition material has a sufficiently elastic behaviour as to allow the ring to be opened, without breaking, during the short fraction of time that lasts the fitting of the twisted string of casing.

[0073] FIG. 3 shows three views where: View 3a shows one end of the shirred casing strand that is caught by a forceps located at the end of a rod whose axis coincides with the axis of the strand. The rod retracts and pulls it for unshirring a length of not more than 5 cm of casing. Immediately a shutter (a motorized iris diaphragm) closes its blades and collapses the unshirred casing, as shown in view 3b, in a point between its connection with pleated part (about 10 mm of it) and the point of gripping the forceps. Further, upon the closing of the shutter, the forceps rod rotates on its axis and twists the rest of the section of casing creating a string (string) in the direction of the axis of the strand of shirred casing, as shown in view 3c, of about 3 cm long.

[0074] FIG. 4 shows the open ring of thermoplastic material being closed by means of mobile clamps to create the annular form.

[0075] FIG. 5 shows a detailed view of FIG. 3a.

[0076] FIGS. 6-9 show sequential perspective view of the process of the invention.

[0077] FIG. 10 shows the stick finally obtained thereof.

PREFERRED EMBODIMENT OF THE INVENTION

Preferred Embodiment of the Closure

[0078] In a preferred and simplest embodiment, the closure of the invention is made up by a short length of casing which has been twisted and clamped by a tightening element. The tightening element is a solid ring-like element, made of an edible and water soluble thermoplastic composition, which has a smoothly curved v-shaped entry gap which leads to the central hollow (see FIG. 2a) wherein a previously constricted and/or twisted portion of casing will be placed by pushing it with a wedge shaped piece.

[0079] The ring can be manufactured by means of any of the known method in the art of moulding plastics and can occur joined to a plurality of repeated elements (rings) linked to one another by a weak sewing in a strand or rod (as is shown in the FIG. 1), as the staples of a stapler, to facilitate the machinability of the feeding process of ring units, and in such a way that all the rings are open before individual use.

[0080] The Thermoplastic Composition

[0081] The instant thermoplastic composition comprises a dry gelatine, an anhydrous glycerol and water. The content of water does correspond to a residual amount of water that remains after drying the commercial gelatine (whose initial content in water usually varies between 10% and 13%) and that practically is not available but only to avoid the crosslinking of gelatine. The content of water of the composition will be less than 15% and preferably between 1% and 10% and most preferably between 2% and 3%.

[0082] According with all exposed above, the most appropriate gelatine is one of food grade with a Bloom higher than 150, preferably between 200 and 300 Bloom; what provides with a higher cohesiveness to the resultant resin since the distribution of molecular weights in this grade of gelatine corresponds to bigger molecules. One example of commercial gelatine with the related features is one of Type A or B from Gelita AG, Germany (f.e. Gelita Hardgel, G. RXL, G. Advanced, G. PA etc), of 8-30 mesh, 200-300 Bloom, viscosity 25-55, with a moisture content 8.5-12.0%; another one is Junc Gelatines (Mikel Junc Gelatines, Banyoles, Gerona) within the same range of features and with a moisture content of 10.5%, which is used in the examples below. A reduction in the water content of the composition will be carried out further by desiccation in an oven.

[0083] Preparation of a Rod of Linked Rings

[0084] The composition may be homogenized through a well known process inside a single screw extruder as a Rheomex 302, or a double screw co-rotatory such as a Krupp Werner & Pfleiderer ZSK25, inside which a pressure increase occurs and of shear forces on the mixture as it travels through the interior while the temperature is increased significantly above the melting temperature of gelatinous composition. As is well known by any person skilled in the art, this process is suitable for modulating the increase of temperature, by means a controlled cooling of the extruder jacket. Inside temperature can vary between 80 and 120 C. During the plasticizing process the pressure inside the extruder is usually low related to the pressure in the next step of injection molding. The pressure during mass plasticizing lies generally between 20 and 75 bar, depending on the ratio polymer/polyol of the composition. The plasticized resin can be injection molded either directly or preferably in a next step, through a conventional process, into the cavity or cavities of a mold. Once the step of plasticizing has finished the mass is extruded into endless strands through a die furnished with regular round holes, those which have an individual diameter of 2 to 4 mm. Afterwards the strands are cooled and granulated in a conventional granulating machine. Granules are passed to the next operation of injection molding wherein the pressure inside the extruder increases until 70 to 120 bar and where finally, a solid body with the form of a rod or worm of linked rings is obtained, which after cooling can be ejected from the mold once this has been opened.

[0085] Needless to say that the injection molding operation can be used to manufacture not only worms of serial rings but also individual rings, although the election shall depend on how the closing machine has been designed for its best performance.

[0086] In order to change (a reduction) of the residual water content of the molded solid bodies, this process will take place inside an oven at 10.sup.3 mm pressure Hg vacuum at temperatures of 25 to 105 C. The calculation of the hydration level is performed by taking the weight of the specimens before and after the drying process, and assuming a starting water content derived from the stated specifications on raw materials.

[0087] The worm may have a length of several centimeters, and an outside diameter of between 6 and 8 mm, depending on the diameter of the bore of the shirred strand of casing. The diameter of the longitudinal bore (axial hole) of the worm ranges between 1 and 4 mm, also depending on the thickness of the cord of twisted casing to be embraced. The worm has been molded with a longitudinal groove whose section is V-shaped, that reaches the axial hole, so that any segment transversely cut from the worm has a ring shape open at c as shown in FIG. 2. The opening (1) (gap) is the route by which the collapsed strech of twisted cord is going to be fitted in to the fastener ring-hollow.

[0088] The Ring

[0089] One tightening element or ring of the invention can be cut, rather than being unitarily manufactured, from a moulded worm-shaped preform (FIG. 1), from which a multiplicity of rings will be obtained by cross-sectional cutting. As stated above the worm-shaped preform has a segmented aspect promoted by a uniform sequence of chokes giving it a ringed appearance.

[0090] The ring, which is made up of an edible resinous thermoplastic composition based on gelatine is capable, once placed embracing the collapsed casing stretch, of displaying the following essential features: [0091] a) to sufficiently adhere, in the melt state, to the contact surface (even in wet state), in order to ensure the fastening of the element over the casing material and so avoiding that this element to slide away the material, [0092] b) having sufficient modulus (although not too much toughness) as for exerting sufficient radial tension of tightening against the twisted/constricted portion of casing to which it fastens, and [0093] c) to be safe and edible as well as water soluble.

[0094] In a preferred embodiment this ring-like element is made up of a proportion of gelatine/glycerol which confers the composition a modulus higher than 10 MPa and more preferably higher than 20 MPa, what is sufficiently elevated as to allow the ring to exert a strong tightening effect onto the twisted portion of casing, while the same composition material has a sufficiently elastic behaviour as to allow the ring to be opened, without breaking, during the short fraction of time that lasts the fitting of the twisted string of casing (see FIG. 2b).

[0095] In another preferred embodiment the tightening element is a solid ring-like element, similar to that described above which is open before to be placed around a previously constricted portion of casing (see FIG. 2a), to be then closed and heat-sealed for resting firmly tight upon the casing material. All this is possible owing to the fact that, the thermoplastic composition with which the ring is made, is able to make a welding with itself by heating at a low temperature and also by having a quick weld-setting.

[0096] The opening (1) of this c-shaped ring is the pathway whereby the ring is fitted on the collapsed and/or twisted stretch of casing, that is to say the place whereby the casing stretch enters towards the ring centre. Once this stretch of casing fits on the central hollow of the ring, this one is mechanically closed. The closing operation carries with itself the heat sealing of the now joined extremes of the c-shaped ring as well as the welding of the ring over the stretch of embraced casing.

[0097] As the open ring of thermoplastic material is being closed by means of mobile clamps (FIG. 4) to create the annular form, the two opposed sections of its opening are previously molten by contact with a metallic wedge shaped element that is heated at suitable temperature as to fuse at least one of the contacted surfaces; then both surfaces get close until their contact and, at this moment, it is important that the slight lowering of the initial contact temperature along with the compression exerted by the clamps which force the closing, promotes a rapid increase of the cohesiveness of this welding of material which is about to solidify, which is already strong enough to prevent the opening of the ring before total solidification (weld-setting) and avoiding that a premature loosening of the clamping occurs, once the clamps release the just formed ring.

[0098] Proceeding of Closing Operation

[0099] The closing operation is a cycle that takes place as follows: [0100] a) One end of the shirred casing strand is caught by a forceps (FIG. 3a, not shown) located at the end of a rod whose axis coincides with the axis of the strand. The rod retracts and pulls it for unshirring a length of not more than 5 cm of casing. Immediately a shutter (a motorized iris diaphragm) closes its blades and collapses the unshirred casing (FIG. 3b) in a point between its connection with pleated part (about 10 mm of it) and the point of gripping the forceps. [0101] b) Upon the closing of the shutter, the forceps rod rotates on its axis and twists the rest of the section of casing creating a string (string) in the direction of the axis of the strand of shirred casing (FIG. 3c), of about 3 cm long. [0102] c) The opened c-shaped locking ring is moved upwardly (FIG. 4a) below the newly formed string of casing. The ring goes clamped inside the open mouth of a tongs-type device, by a type of open-tightening grip, whose function is to ring closure and simultaneous cutting the string. The ring moves up with the opening in V facing up to fit the string of casing inside its axial hollow. The stop of the lifting of the clip occurs just when the axes of both the ring and the string coincide. [0103] d) While the locking ring rises, a push rod descends to push the string of casing inside the hollow of the ring (FIG. 7). The end of the rod, which is of steel, has got a flattened wedge-section and straight edge on its end and is kept preheated to temperature sufficient to melt the resin ring. The rod axis coincides with both the direction and axis of the ring lifting. While the cord fits into the axial hole of the ring, the push rod does contact and melts at least by one side, but preferably by both, a layer of the opposing surfaces to be joined to seal the ring; [0104] e) While the push rod is again removed,the clamp which carries the ring (FIG. 8) closes, causing, by one side, that the contact surfaces to fuse together and onto the twisted cord of casing and, at same time, by the other side, the cutting of the excess end thereof. The clip exerts a moderate and continuously force on the ring for a predetermined time, which can vary from 2 to 5 seconds. After this time of welding, the clamp opens and falls to its rest position, where it is loaded with the next clamping ring. [0105] f) Immediately the shutter is opened. The ring is closed and the welding also acts on the gut section embedded therein and in a further optional step [0106] g) The closure is pushed inward (bore) of the shirred bar of casing.

[0107] Other Versions of the Invention

[0108] It is contemplated also in the invention that after performing the closure operation the casing can be everted, or the closure introduced into the lumen of the stick, so that the ring closure lies in the internal bore of the stick (as in FIG. 13 of EP-2266410, the ring should surround the point marked as 14). After stuffing, the closure of the invention can remain then in the outer surface of the sausage, or in the surface contacting the sausage. In this case, some of the closure can remain after cooking, but as the closure is edible this should cause no problem.

[0109] The ring of the invention can have other form as hexagonal, etc., not necessarily round. Also, the ring does not need to be necessarily edible (can be applied to other casings), nor soluble.

Examples

Example I: Preparation of Different Samples of the Composition

[0110] For the embodiment of the composition there has been used a food-grade gelatin dry powder of Junc M. (Girona, Spain) of 240 to 260 Bloom, average particle size (0.3 to 0.8 mm equivalent to 20-50 mesh, in this case particularly 35 mesh), with an apparent moisture content of 13%. To obtain compositions with increased ratios Gel/Gly between 2:1 and 1:2.5 are taken in each case 100 parts of commercial gelatin with a residual water content of 13% and combined with the appropriate parts of anhydrous glycerol, yielding compositions with various contents in apparent moisture as shown in the following table:

[0111] The polyol is a food-grade anhydrous glycerin from Sigma-Aldrich. The composition is made by dissolving gelatin directly in commercial glycerol by vigorous stirring and temperatures which vary between 80 and 120 C. The resulting ratios expressed in Table X refer to the weight ratio of anhydrous pure products.

TABLE-US-00001 TABLE I Residual Gelatine Glycerol Water Ratio Sample (Parts) (Parts) (%) Gly/Gel A1 100 174.0 4.7 2:1 A2 100 130.5 5.6 1.5:1.sup. A3 100 87.0 6.9 1:1 A4 100 58.0 8.2 .sup.1:1.5 A5 100 43.5 9 1:2 A6 100 34.8 9.6 .sup.1:2.5

Example II: Determination of Melting Temperature

[0112] From the samples made in Example I with different compositional ratios, there are determined the thermal transitions by the technique of differential scanning calorimetry (DSC). The average results are shown in the table:

TABLE-US-00002 TABLE II Ratio Glycerol/Gelatine Tg Tm 2:1 29.55 46.95 1:1 30.8 47.25 1:2 3.5 60.9 Tg = Glass Transition Temperature; Tm = Melting Temperature.

Example III: Determination of Fluency Index

[0113]

TABLE-US-00003 TABLE III No. of MVR average Estndar Glycerol/Gelatine values (cm3/10 min) deviation Ratio 2:1 (100 C.) 8 723.00 9.31 Ratio 2:1 (80 C.) 11 220.28 8.15 Ratio 1:1 (80 C.) 25 12.51 0.12 Ratio 1:2 (80 C.) 11 2.74 0.20 load 21.6 Kg Ratio 1:2 (120 C.) 25 16.69 0.56 load 5 Kg MVR means Melting Volume Ratio.

[0114] The dramatic drop in the flow is clearly seen (and thus increasing the viscosity and therefore the cohesiveness) owing to both the variation of the ratio of gelatine and glycerol as to the lowering of the temperature applied. This gives an idea about what is the most appropriate composition for best welding performance of the fastener ring closure of the invention at the time of its execution, i.e at a relatively low environment temperature and rapid fixation of welding.

Example IV: Determining the Elastic Modulus

[0115] Tensile properties of the various samples from Example I were estimated by ASTM method D638-10 (equivalent to ISO 527-2) that specifies the test conditions for determining tensile properties of plastics molding and extrusion, based on the general principles given in ISO 527-1 using for this dog-bone shaped specimens. using dog-bone shaped specimens testing. The results are listed in Table IV.

TABLE-US-00004 TABLE IV Ratio Average Average Tensile Length Elastic Glycerol/ thick width strength to break modulus Gelatine (mm) (mm) (MPa) (cm) (MPa) 2:1 4.638 3.362 0.71 144 0.53 1:1 5.237 3.527 2.45 228 1.98 1:2 2.229 3.953 3.9 205 20.3 .sup.1:2.5 4.664 4.009 7.37 253 42.3

[0116] A dramatic increase of the elastic modulus values between the transit of ratios 1 to 2 can be observed in the table.

Example V: Determining the Adhesiveness

[0117] Adhesiveness was tested for various specimens made of all samples according to Example I. In addition to that, an amount of composition whose content of polymer/diluent (Gelatine/glycerol) corresponding to a ratio of 2:1 and whose residual water content is 9% was dried in an oven at 60 C. and a vacuum pressure of Hg 10.sup.3 mm until reaching several water contents of 6%; 3%, 1.5% and 0.5% (given rise respectively to the samples A7 to A10).

TABLE-US-00005 TABLE V Adhesiveness of resins of different compositions and water contents onto collagen casings with a moisture content of 12%, 21% and 35% (based on the total weight of the casing). Adhesivity Adhesivity Adhesivity (gr) on (gr) on (gr) on casing casing casing Residual having having having Water Ratio humidity humidity humidity Sample (%) Gly/Gel of 12% of 21% of 35% A1 4.7 2:1 500 300 300 A2 5.6 1.5:1.sup. 700 700 600 A3 6.9 1:1 1000 1000 900 A4 8.2 .sup.1:1.5 Not Not Not peelable peelable peelable A5 9 1:2 Not Not Not peelable peelable peelable A6 9.6 .sup.1:2.5 Not Not Not peelable peelable peelable A7 6 1:2 Not Not Not peelable peelable peelable A8 3 1:2 Not Not Not peelable peelable peelable A9 1.5 1:2 Not Not Not peelable peelable peelable A10 0.5 1:2 Not Not Not peelable peelable peelable A11 12 1:2 Not Not Not peelable peelable peelable A12 15 1:2 Not Not 1000 peelable peelable A13 18 1:2 Not 1000 1000 peelable A14 20 1:2 900 1000 1000 A15 25 1:2 900 900 1000

[0118] It is also noted that the compositions with very low amounts of water improve their natural adhesivity once molten, especially the higher the amount of polymer in the resin.

[0119] Not peelable means the fact when upon trying to strip one film of resin, from the surface of gut to where it was casted by melting, the resin film, once cooled and solidified is able to rip and drag the material from the gut rather than be separated from it.

Example VI: Preparation by Injection Molding of Several Rods of Sealing/Fastening Rings of Gelatin and Glycerol

[0120] Several hollow worm-shaped rods with a longitudinal V-shaped opening, as is depicted in FIG. 1 of drawings, were molded by injection molding. The starting composition of extruded resinous material was formed by Gelatine of 200 Bloom (Junc); glycerol (food grade glycerol from Sigma-Aldrich) and a residual amount of water, and the final proportions of each component in the mixture were correspondent to the samples A4 and A8. Dimensions of these elements were, for every composition by one side of 20 cm length by 8 mm in diameter with a centred hollow of 2 mm in diameter; and by the other side of 12 mm in diameter with a central hollow of 4 mm of diameter.

[0121] The material was plasticized and extruded by a single screw extruder as it is widely applied in polymer processing industries at a temperature in a range of 87 C. and 104 C., with a pressure range of about 50-100 bar. The plasticized material was extruded through a round section die with six bores of 2 mm of diameter each. The cooled-down endless strands were then granulated in a conventional granulator. Granules were used to fabricate the worm-shaped rods on a conventional injection molding machine. The mass was so injected at a pressure range of 1000-1200 bar into a stainless steel mold and the molded piece was removed from the mold. The stick was placed on a rack and was set to dry until the water content was of between of 2% and 3%. The final stick was flexible and tough.

[0122] Several short lengths (25) of 8 mm were obtained from this stick by means of cross sectional cuttings with a cutter. The cross section of each segment has an open-ring shape or c-shaped ring. The opening of this c-shaped ring is the via whereby the ring is embedded in the collapsed and/or twisted casing stretch.

Example VII: Embodiment of the Closure; Test of Stuffing of Closed Casings and Cooking of the Obtained Sausages Along with their Closures

[0123] To test the performance of the closure, there were selected two sizes of edible collagen casings; namely a caliber 21 where small rings (8 mm diameter) of compositions named A2, A4 and A8 were applied; and a caliber 28, to which the rings 12 mm from the same compositions were applied.

[0124] In every case the pleated sticks were sealed manually, as follows: one proceeded to deshirring of about two-inches of casing and then a manual shutter was used to collapse the deployed casing within an inch from the starting of the shirred stick. The remaining portion of casing, once hold by the shutter blades, was twisted to form a string with a diameter of about two millimeters for the casing of caliber 21 and about four millimeters for the one of caliber 28.

TABLE-US-00006 TABLE VI Results of resistance of closures to stuffing process. No of not No of No Closures Caliber heat-sealed heat-sealed surviving after Ring- of closures closures stuffing Composition casing (NTS) (TS) NTS TS R1A2 21 18 18 7 18 R1A4 21 18 18 18 18 R1A8 21 18 18 18 18 R2A2 28 18 18 18 18 R2A4 28 18 18 18 18 R2A8 28 18 18 18 18

[0125] Immediately a ring closure of each composition was applied, by choosing sizes as indicated. Half of rings of each composition and each diameter were sealed as described in the memory, using a heat applicator of trapezoidal head of those used for tinning heated to 85 C. The applicator is used first to push the casing string into the central hole of the ring; once fitted, the sides of the applicator are contacted with the joint faces of the rings, what causes the immediate fusion of a surface layer; then one proceeds to remove the heat applicator, the process being simultaneous to the ring closing. Once the fused faces of the ring took mutual contact, a welding with sufficient cohesion as to being able to remove the closing pressure in less than 2 seconds was formed. After removing the pressure on the rings, they remained closed forming a tightening ring. The other half of the rings were not welded but solely were pressed after the fitting of the casing in their central hole.

[0126] The shirred and sealed sticks of casing were stuffed with sausage meat mass on a type-Robby Vemag 2 machine at a speed of 80 portions/minute, using the brake control of the filler machine.

[0127] The result of the stuffing process was as set forth in the Table VI. As reflected in said results, those rings made with the composition A2 and unsealed, can withstand relatively the stuffing process depending on the diameter thereof, so that the larger ones are more resistant to opening according to the respective calibers to which they are applied. In the case of the small rings made of the composition A2, their lesser wall thickness added to a lower elastic modulus also favors the opening of some of them during the stuffing process, so in these cases it is advisable to use a heat-sealing thereof.

[0128] Subsequently the sausages were hung on hangers for baking in a simple cycle at 90 C. for four hours. In all cases the first sausage, namely the carrier of the ring, maintained its integrity well into the starting point of the cooking cycle. During this cycle time the meat mass was coagulated and the sausage maintained its shape until the end of the cycle. During that time the sealing rings of every first sausage are gradually dissolved to disappear before the end of the cycle. The final result was satisfactory, not only for the good closing performance but also because of the true possibility of using the sausage which carries the closure in the same way than the rest.