IE44779B1 - A process for humidifying and shirring artificial sausage casing - Google Patents

Abstract

The disclosure describes a process for humidifying an artificial sausage casing on a shirring machine wherein a moisture-providing fluid is contacted with the inside wall of the unshirred casing and the casing is subsequently shirred. The moisture-providing fluid is a mixture of water and from about 0.5-5% of a surfactant having lubricating properties. The fluid is applied to the casing in a proportion to provide from about 0.015 to 0.15 mg. surfactant per square inch of casing. In this manner artificial sausage casings are produced with fewer defects in terms of damage on the shirring mandrel and fewer pinholes and greater elasticity to prevent breakage during stuffing.

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.

To raise the moisture content of artificial sausage casings to render 5 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 of 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 0.02-0.4% 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 - 2 It has also been suggested to humidify artificial casings after they ' ' of water have been shirred by spraying a mixture/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 vegetable fats, and to Ο^θ fatty ketene dimers in a 12% glycerin-water solution.

According to the invention there is provided a process for humidifying an artificial sausage casing (as hereinafter defined), 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 square 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 is used herein to mean a synthetic casing formed from collagen, amylose, starch, or alginates.

The moisture-providing fluid for humidifying the casing is a substantially homogeneous mixture consisting of water and a water dispersible - 3 4 4 7 7 9 - 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 10 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 their water15 insolubility or non-dispersibility, 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 20 wet-out and spreading for permitting rapid humidification of the casing but also provide for a thin, uniform coating of a lubricant 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. '25 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 . 4 ... 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 55! 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 its 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 of 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 humidification ranges from 2 0.015 to 0.15 mg/in . At this level of surfactant, the casing has outstanding physical properties. The sorbitan trioleate produces casing having fewer pinholes and a higher resistance to breaking than has been achieved in any of the commercial processes. Another benefit 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 per 50,000 to 60,000 feet of casing shirred. This is substantially lower than is achieved with casings humidified - 5 44779 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 morioglycerides and polyoxyethylene monoesters, e.g., polyoxyethylene 400 monostearate.

In the shirring of collagen casings it has been found particularly advantageous to include a partial fatty acid ester of glycerine in the humidification fluid containing the partial fatty acid ester of sorbitol.

The inclusion of the glycerine fatty acid ester in the humidification materially reduces "linker breakage when the casings are used by the meat processor.

Thus, when the casings are stuffed, twisted and linked by the meat processor, if the casings are not adequately humidified, splitting at the shoulder portion of the meat filled casing will occur during twisting to prepare sausage links. The phenomenon is referred to in the art as linker breakage and if the linker breakage exceeds 2 to 3%, the casings are unacceptable for use. - 6 By using a mixture of the partial fatty acid esters of glycerine and sorbitol, humidified artificial sausage casings derived from animal hide collagen are produced with greater elasticity to prevent linker breakage during stuffing.

The partial oleic acid esters of glycerine are particularly useful in the practice of the invention and are available commercially as mixtures of mono and diglycerides from the Glidden-Durkee Division of SCM under the trade mark GMO. GMO is composed of 55% by weight of the monoglyceride of oleic acid 35% of the diglyceride of oleic acid and the balance consisting essentially of the triglyceride of oleic acid.

When partial fatty acid esters of glycerine are used they are preferably present in the aqueous humidifying fluid at a concentration in excess of 0.1% by weight. As will hereinafter be illustrated, the incorporation of 0.1% by weight of the partial fatty acid ester of glycerine in the humidification fluid causes an undesirable increase in the linker breakage encountered during the stuffing of the collagen casing. Generally, the amount of the partial fatty acid ester of glycerine incorporated in the humidification medium should be from 0.12% to 1.0% by weight. Although concentrations of the partial fatty acid ester of glycerine in excess of 1% by weight may be incorporated in the humidification fluid such excess amounts will have little effect in improving the resistance of the collagen casing to breakage during the stuffing and linking operations performed by the meat processor. When the concentration of the partial fatty acid ester of glycerine in the humidification medium is in the range of 0.15% to 1.0% by weight, upon application to the internal walls of the casing during normal collagen strand shirring operations, this concentration range yields about 0.01 to 0.10 milligrams 2 (mg) of the glycerine ester per square inch (in )*of casing surface.

The sorbitan fatty acid ester (e.g., sorbitan trioleate) of the fatty acid ester mixture is included in the humidification fluid in a proportion of from 0.5 to about 2% by weight and preferably from 0.8 to 1.5% by weight. As a rule of thumb, as the proportion of the mixed glycerine mono-and diester is reduced toward the lower amount in the humidification fluid e.g., 0.12% by weight, the - 7 4 4779 proportion of partial fatty acid ester of sorbitan is increased toward the upper amount. Likewise, where the proportion of fatty acid ester of sorbitan, e.g., sorbitan trioleate, is reduced toward the lower amount e.g., 0.5%, the proportion of mixed glycerine ester is increased toward the upper amount, e.g. 1%. The sorbitan ester is applied to the internal casing walls at levels of from 0.04 to 0.10 mg/ιη of casing surface.

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 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 spraysystem 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. All percentages are expressed as weight percentages. t .

EXAMPLE 1.

Artificial sausage casings of 40 to 50 foot lengths of collagen casing 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.

The untreated collagen casing had a diameter of 21 mm, a wall thickness of about 27 mils and a moisture content of 8 to 12%. The casing strand was introduced over a shirred mandrel and shirred. As the casing passed over the mandrel, the inner wall was contacted with a water solution containing 1% sorbitan trioleate. The sorbitan trioleate was present in an amount of 0.06 to 0.07 mg/square inch of casing. The casing shirred smoothly and was determined to have a moisture content in excess of 24% EXAMPLE 2.

Artificial sausage casings extruded from collagen were humidified during the shirring process by employing the apparatus described in U.S. Patent No. 3,451,827 using a spray system for applying the fluid to the inner wall of the casing.

The humidification fluid was prepared by dispersing 1% sorbitan trioleate and 0.2% GMO in a water solution. A reel of dry, i.e., 14% water, collagen casing flat stock having a diameter of 21 mm and a wall thickness of about 1.2 to 1.4 mils was introduced over the shirring mandrel and shirred. As the casings passed over the mandrel, the inner wall of the casing was contacted with a fine spray of the aqueous dispersion at a rate of 8 cc/strand. At this application 2 rate, the inner walls of the casing had applied thereto 7.8 mg/in of the aqueous dispersion. The shirred strand of casing contained 40 feet of casing 2 and the internal walls of the casing contained 0.06 to 0.07 mg/in sorbitan 2 trioleate and 0.013 to 0.015 mg/in GMO. The moisture content of the casing was about 24%.

The casing shirred very smoothly. The casings performed well when stuffed and linked and a linker breakage of 0.94% was observed when the casings were stuffed and linked by a meat processor.

For the purposes of contrast the procedure of Example 2 was repeated, with the exception that sorbitan trioleate and GMO were not dispersed in the water spray. The shirred casing when stuffed and linked was determined to have a linker breakage of 2.20%.

EXAMPLE 3.

In another test a shirred strand of collagen casing was prepared by spraying a humidification fluid consisting of 1% sorbitan trioleate and 0.2% GMO - 9 in water onto the inner wall of the casing following the procedure of Example 1.

The sorbitan trioleate was present in a proportion of about 0.07 mg per square - 2 inch of the casing and GMO was present at about 0.014 mg/in of casing and the moisture content of the casing was raised to about 24*« by weight.

For purposes of contrast, the procedure of Example 3 was repeated in a series of runs with the exception that in one run only 1% sorbitan trioleate was incorporated in the humidifying fluid, in a second run 1% sorbitan trioleate and 0.1% GMO were incorporated in the humidifying fluid and in a third run, the adjuvants added to the humidifying fluid were 2.5% sorbitan trioleate and 1% carboxymethyl cellulose (CMC).

The linker breakage during stuffing and linking by a meat processor of the collagen strands humidified in accordance with Example 3 as well as in the contrasting runs was observed and recorded. The linker breakage of these strands is summarized in the table below’.

TABLE _ ' Test No, Adjuvant(s) added to Humidification Fluid Linker breakage % 1 1% Sorbitan Trioleate 0.09 0.2% GMO 2 1% Sorbitan Trioleate + 0.1% GMO 6.00 3 1% Sorbitan Trioleate 2.30 . 4 .- 2.5% Sorbitan Trioleate 2.40 1% CMC By reference to the table, it is immediately apparent that collagen 25 casings humidified more than 0.1% by weight of an adjuvant which is a partial fatty acid esterof glycerine give substantially less linker breakage when linked and stuffed (Test No. 1) than collagen casings humidified with aqueous dispersions containing no other adjuvants or other amounts of the said glycerine ester adjuvant (Test Nos. 2 to 4).

Claims (12)

1. A process for humidifying an artificial sausage casing (as hereinbefore defined), wherein a moisture-providing fluid is contacted with the inside wall of an unshirred casing and the casing subsequently shirred, the moisture-providing 5 fluid being a mixture comprising water and nvm 0.Ϊ» to s*. 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. A process according to Claim 1, wherein the artificial casing is formed from collagen. 10

3. A process according to Claim 1 or 2, wherein there is included in the moisture-providing fluid more than 0.1% by weight of a partial fatty acid ester of glycerine as an adjuvant.

4. A process according to Claim 3, wherein the partial fatty acid ester of glycerine is an oleic acid ester. 15

5. A process according to any one of Claims 1 to 4, wherein the surfactant is a partial fatty atid ester of sorbitol.

6. A process according to Claim 5, wherein the partial fatty acid ester of sorbitol is an oleic acid ester.

7. A process according to Claim 6, wherein the partial fatty acid ester 20 of sorbitol is sorbitan trioleate.

8. A process according to Claim 7, wherein the sorbitan trioleate is present in the moisture-providing fluid at a concentration of from 0.8 to 1.5%.

9. A process according to any one of Claims 3 to 8, wherein the glycerine ester is a mixture of mono- and di glycerides. 25

10. A process according to any one of Claims 3 to 9, wherein the glycerine ester is present in the moisture-providing fluid at a concentration of 0.12 to 1% by weight.

11. A process according to Claim 1, substantially as hereinbefore described in Example 1, 2 or 3.

12. Artificial sausage casings humidified by a process as claimed in any one of Claims 1 to Π.