IE44780B1 - A process for humidifying ans shirring artificial sausage casing - Google Patents

Description

This invention relates to a process for humidifying and shirring an artificial sausage casing wherein a moisture-providing fluid is contacted with the inside wall of unshirred casing and the casing is subsequently shirred.

. I 5 To:raise the moisture content of artificial sausage casings to render them amenable to shirring, it has been proposed to internally humidify artificial sausage casings while simultaneously lubricating the casing on a shirring machine by spraying a stream of water and a separate stream of lubricant onto the walls df the casing through a shirring mandrel. Humidification has been also accomplished by spraying water onto shirring wheels or shirring belts and then causing these wheels or belts to contact the external surface of the casing. It has*been’proposed in these processes to add wetting agents in a proportion of from about 0.02-0.04% by weight of the solution to enhance the rate of wetting of the casing.

It has also been suggested to apply coatings to the interior of regenerated cellulose sausage casings during the shirring process. The coatings employed in these processes are applied to the casing for the purpose of improving the peelability of casings from sausages processed therein. In these particular processes, the lubricants employed are aqueous emulsions of vegetable, mineral or paraffin oil.

It has also been suggested to humidify artificial sausage casings after they have been shirred by spraying a mixture of water and lubricant over the surface of the shirred casing. The lubricants used in the mixture were aqueous emulsions of vegetable, animal or refined oils.

Other work shows a variety of coatings have been applied to the interior of artificial sausage casings of regenerated cellulose by spraying coating solutions through a shirring mandrel. These coating solutions typically contained from about 0.2-2% by weight of cetyl alcohol, acetylated monoglycerides of animal and vegetables fats, and to C-jg fatty ketene dimers in a 12% glycerin-water solution.

According to the invention there is provided a process for humidifying an artificial sausage casing formed from regenerated cellulose wherein a moisture-providing fluid is contacted with the inside wall of unshirred casing and the casing subsequently shirred, the moisture-providing fluid being a mixture comprising water and from 0,5 to 5% of a surfactant having lubricating properties which is applied to the casing in a proportion to provide from 0.015 to 0.15 mg. surfactant per squarh inch of casing.

By the practice of the invention, artificial sausage casings are produced with fewer defects in terms of damage on the shirring mandrel and fewer pin holes and greater elasticity to prevent breakage during stuffing. The casings humidified in accordance with the invention can be shirred on conventional shirring machines without jamming as so often happens when aqueous emulsions of mineral oil and vegetable oil are employed. The process of the invention also provides a casing which has substantially uniform moisture content which does not grow from its compacted state immediately after doffing.

The term artificial sausage casing as used herein includes synthetic - 3 aO casings formed from regenerated cellulose, and fibrous casings such as those prepared by forming a tube of long fibre hemp paper, impregnating the tube with viscose and regenerating cellulose in and on the tube.

The moisture-providing fluid for humidifying the casing is a substantially homogeneous mixture consisting of water and a water dispersible substance having lubricating properties. By surfactants having lubricating properties, it is meant to refer to those surfactants which have the ability to be absorbed onto the surface of the casing wall so that when the casing is passed over a shirring mandrel the shear forces, at least in a substantial proportion, are absorbed by the surfactant. If the surfactant does not have sufficient lubricating properties, the casing will tend to stick or adhere to the shirring mandrel and jam the machine. Jamming is commercially undesirable in an appreciable degree i.e., 1 per 10 reels, e.g. 50,000 to 60,000 feet.

The surfactant should be water-dispersible by simple agitation and ; in the absence of emulsifying agents. Also, it should remain in a stable dispersion when dispersed in water without agitation for a period of at least four hours. As stated previously, aqueous emulsions of lubricating oils have . been used for lubricating the inner wall of artificial sausage casings so that the casing will slide across the mandrel, but these oil lubricants, because of 2q‘ their water-insolubility or non-dispersability, tend to retard the wetting of the casing by the water. It is imperative to wet the casing in the short time period available between contact with the aqueous spray and contact With the shirring wheels to avoid damage to the casing.

The water-dispersible surfactants of this invention not only enhance wet-out and spreading for permitting rapid humidification of the casing but also provide for a thin, uniform coating of a libricant over the surface,of the casing so that it will readily; slide across the shirring mandrel. The surfactant lubricant does not retard wet-out as is experienced with non-water dispersible lubricants. - 4 UVS0 The surfactant having lubricating properties is employed in the moisture-providing fluid in a proportion of from 0.5 to 5% by weight of the fluid. When a proportion of surfactant having lubricating properties is employed in less than 0.5% by weight, there is insufficient surfactant applied to the surface of the casing to permit adequate lubrication of the casing for passage over the shirring mandrel. This aspect is distinguished from the prior art in that surfactants were added to water and sprayed onto the inner wall of the casing at a proportion of about 1/20 and quite often about 1/40 of that required for achieving the lubricating qualities required in the shirring operation, even though wet-out was effected. However, most of the surfactant employed in the prior art was for enhancing the humidification of the casing, i.e., the penetration of water into the casing wall and not lubrication.

When the proportion of surfactant having lubricating properties exceeds 5% by weight of the moisture-providing fluid there is a tendency to load the casing with too much surfactant at the appropriate humidity level.

This loading causes the shirred strand to grow or become incoherent. By growing, it is meant that the strand does not remain in compacted form and expands after doffing. The pleats do not adhere at high levels, and the strand may be incoherent, i.e., the pleats do not adhere to each other, and are difficult to handle without breaking. Broken strands are unacceptable for high speed automatic stuffing machines.

In practicing the invention, the preferred surfactant having lubricating qualities is a partial fatty acid ester or sorbitol and particularly sorbitan trioleate. Sorbitan trioleate is a nonionic surfactant which is a relatively viscous oily liquid and dispersible in water, even though it is insoluble therein. When combined with water in proportions of 0.5 to 5%, preferably 0.8 to 1.5% by weight of the moisture-providing fluid for application to the inner wall of the casing, the amount of surfactant on the wall after 2 humidification ranges from 0.015 to 0.15 mg/in . At this level of surfactant, the casing has outstanding physical properties. The sorbitan trioleate produces casingshaving fewer pinholes and a higher resistance to breaking than has been achieved in any of the commercial processes. Another benefit o... of the surfactant is that the lubricating qualities of sorbitan trioleate are such that the frequency of jamming on the shirring machine for a sausage casing is less than 1 per50,000 to 60,000 feet of casing shirred. This is substantially lower than is.achieved with casings humidified with water through the shirring mandrel employing an aqueous emulsion of mineral oil or vegetable oil as the; lubricating medium.

A further advantage of sorbitan trioleate as a surfactant is that it enhances humidification of the casing for achieving excellent flexibility by the time the casing gets to the shirring wheels. As a result, the compacting of the casing into a plurality of pleats does not cause pinholes to develop.

In fact the frequency of pinhole occurrence in casings previously described is remarkably low. Coupled with the production of casings having relatively few pinholes is*the production of a casing that does not have a tendency to grow after it has been shirred. Thus the shirred strand can be readily handled without danger of breaking.

• - \ · Although excellent results are obtained by spraying the-inside wall of the artificial· casing with the mixture of water and surfactant and particularly sorbitan trioleate, Sometimes it is desirable during shirring to add additional lubricant with the air stream. Lubricants can also be sprayed on the external surface to reduce wear on the shirring wheels. Conventional lubricants for such use are vegetable and mineral oils in admixture, acetylated monoglycerides and polyoxyethylene monoesters, e.g. polyoxyethylene 400 monostearate.

The humidification fluid of the invention should be applied to the casing prior to shirring and a number of ways are suitable. One of the better ways of introducing the humidification fluid to the interior of artificial casings prior to shirring is during the actual shirring process. The apparatus described “’’«ο in U.S. Patent No. 3,451,827 is well suited for accomplishing application of the humidification of the casing prior to shirring. This apparatus is provided with a spray system for applying the humidification fluid to the inner wall of the casing immediately before contact of the casing with the shirring wheels of the apparatus.

The following examples are provided to illustrate the preferred embodiments of the invention. A11 percentages are expressed as weight percentages.

EXAMPLE 1.

Artificial sausage casings of regenerated cellulose were substantially simultaneously humidified and lubricated during the shirring process by employing the apparatus described in U.S. Patent No. 3,451,827. Although this type of apparatus is preferred as it includes a spray system for applying the fluid to the inner wall of the casing, other apparatus permitting the introduction of a moisture-providing fluid as a thin coating on the inner wall of the casing during shirring can be employed.

Six moisture-providing liquids were prepared by dispersing 0.255!, 0.5%, 1%, 1.5%, 5% and 10% sorbitan trioleate in water solutions. Reels of dry i.e., 10% water,, regenerated cellulose casing flat stock having a diameter of 24 mm, and a wall thickness of about 1.10 mils were introduced over a shirring mandrel and shirred. As the casings passed over the mandrel, the inner wall was contacted with a fine spray of the above liquids. Each casing was coated with p about 3 mg. moisture-providing liquid per inch of casing. Each shirred strand of casing contained 125 feet of casing and had from 0.0075 mg. to 0.3 mg. sorbitan B trioleate per inch of casing. The moisture content of the casing was about 18% plus or minus 2%.

The casing shirred very smoothly at the 0.5%, 1%, 1.5%, 5% and 10% levels and the casing did not jam in approximately 50,000 feet shirred. The casings performed well in the field, i.e., in stuffing, but the strands coated - 7 with the fluid at 0.25% and 10% sorbitan trioleate did not perform as well as the strand having’0.5%, 1.0%, 1.5%, and 5% level. At the 0.25% level there seem to be more pinholes in the casings and more problems in shirring, e.g., breaking. Probably this was due to llie low concentrat ion of lubricant l on the wall of the casing. I'he casing with the 10% sorbitan trioleate level processes well but there was a tendency for the shirred strand td grow.

Best shirring results were noted at the 1% to 1.5% sorbitan trioleate level. Field stuffing results were noted at the 1% to 1.5% sorbitan trioleate level. Field stuffing tests showed that at the 1% level the ]0 frequency of breakage in one plant was 1 defect for 1400 strands tested.

Another plant showed 30 defects for 200 strands tested. Based on a series of stuffing tests in the field ranging from the 1400 strands with 1 defect at one plant at the best to another plant of 200 strands tested and 30 defects the results obtained conclusively showed a reduced frequency of breakage at Ϊ5 the stuffing operation as compared to commercially available regenerated cellulose casings. t ! Although results varied within the plants, the consensus was that the casings in general performed much better than commercially available cellulose casings produced by prior art humidification techniques.

. EXAMPLE 2.

Shirked strands of casing were prepared by spraying a moistureproviding fluid Consisting of 1% sorbitan trioleate in water onto the inner wail of cellulose casing as described ih Example 1. The sorbitan trioleate was present in the proportion of about 0.1 mg per square inch of casing and the moisture conteht of the casing was raised to about 18% by weight.

Acetylated monotjlycefid and 1% polyoxyethylene 400 monostearate was added with the air spray for inflating the casing as it was shirred and was applied at a concentration from about 0.3 g per 100 feet strand of 24 mm diameter casing.

Typical routine stuffing tests with several thousand strands casing tested showed about a 0.2-0.4% breakage. Normally casing humidified by prior art techniques shows about a 2-3% average breakage under similar test conditions.

Claims (7)

1. A process for humidifying an artificial sausage casing formed from regenerated cellulose wherein a moisture-providing fluid is contacted with the inside wall of unshirred casing and the casing subsequently shirred, the moisture-providing fluid being a mixture comprising water and from 0.5 to 5% 10 by weight of a surfactant having lubricating properties which is applied to the casing in an amount to provide from 0.015 to 0.15 mg. surfactant per square inch of casing.
2. 2. A process according to Claim 1, wherein the surfactant is a partial fatty acid ester of sorbitol. 15
3. 3. A process according to Claim 2, wherein the partial fatty acid ester of sorbitol is an oleic acid ester.
4. 4. A process according to Claim 3, wherein the partial fatty acid ester of sorbitol is sorbitan trioleate.
5. 5. A process according to Claim 4, wherein the sorbitan trioleate is 20 present in the moisture-providing fluid at a concentration of from 0.8 to 1.5%.
6. 6. A process according to Claim 1, substantially as hereinbefore described in Example 1 or 2.
7. 7. Artificial sausage casing humidified by a process as claimed in any one of Claims 1 to 6.