WO2001064040A1

WO2001064040A1 - Gathered tubular foodstuff wrapping based on cellulose

Info

Publication number: WO2001064040A1
Application number: PCT/EP2001/001831
Authority: WO
Inventors: Klaus-Dieter Hammer; Herbert Gord; Rainer Neeff; Klaus Berghof; Markus Eilers; Reinhard Maron
Original assignee: Kalle Gmbh & Co. Kg
Priority date: 2000-03-03
Filing date: 2001-02-19
Publication date: 2001-09-07
Also published as: RU2265336C2; US20030062649A1; EP1274313A1; AU2001233783A1; JP2003525042A; DE10009979A1

Abstract

The invention relates to a casing consisting of a tubular foodstuff wrapping based on cellulose. The wrapping is produced according to the NMMO method. The casing is particularly stable and is thus suited for fully automatic filling devices such as those used for producing cooked or boiled sausages.

Description

Ruched, tubular food casing based on cellulose

The invention relates to a gathered, tubular food casing based on cellulose. It is particularly suitable for the production of sausages.

Food casings, especially sausage casings, are often offered in a form in which about 15 to 50 m of the casing are pushed together to form sticks of about 20 to 60 cm in length. The gathering of the artificial intestine (also known as stocking) has been known for a long time and is widely described in the general specialist literature as well as in the patent literature (for example in the monograph by G. Effenberger, Wursthüllen - Kunstdarm, H. Hoizmann Verlag GmbH & Co. KG, Bad Wörishofen, 2nd ed. [1991] 58 - 60) It takes place on so-called shirring machines. Before shirring, the cover is laid flat and rolled up. It is then pulled off the roll, inflated and pulled onto the shirring mandrel of the shirring machine. The outside diameter of the shirring mandrel determines the inside diameter The caterpillar to be produced The gathering places a high load on the casing. Immediately before or during the gathering, it is therefore usually from the inside, from the outside or sprayed or wetted with water and / or oil from both sides to make them more supple. This prevents cracks from forming on the ruffles. The

Gathering tools themselves can be designed in very different ways. For example, gathering wheels are known which can be smooth or serrated on the outside, as well as surrounding belts. Once the desired number of meters has been gathered, the cover is cut off. The caterpillar produced in this way should be as stable as possible and self-supporting. For storage and transport, it is still often with a

Provide outer packaging (generally a net or a film). Finally, sleeves are also known which have been gathered on a dimensionally stable sleeve. The caterpillar is drained again when it is filled with sausage meat. Often, several caterpillars are placed in a storage container, from which individual caterpillars are then automatically removed and onto the filling tube of the high-speed filling machine be pushed. It is crucial that the caterpillar does not break, even if it has been watered. Otherwise there is a malfunction in the process, which has to be eliminated laboriously by hand.

The portioning of the sausages and the sealing or tying of the ends of the sausages, which are necessary after filling, are usually also carried out automatically. In this way, i.a. also made sausages. The sausage meat is portioned by the pump of the filling machine. Each time the conveying process is interrupted, the corresponding sausage length is generated by twisting off. The whole process runs fully automatically with high

Speed down. The chain of the sausages produced in this way is hung - likewise by machine - on a suitable frame, on which the sausages are then brought directly to the further treatment stages. In the case of these scalded sausages, the casing is used as a filling and manufacturing aid and is peeled off mechanically after boiling or scalding (possibly also smoking) and cooling the sausages before packing them in bags, glasses or cans.

To date, tubular food casings based on cellulose have mainly been produced using the viscose process. A cellulose xanthate solution (= viscose) is passed through an annular slot nozzle

Extruded print. The cellulose is then regenerated from the viscose in various precipitation and washing baths. The first precipitation bath is usually an aqueous sodium sulfate / sulfuric acid solution (the so-called Müller bath). Aqueous ammonium sulfate / sodium sulfate / sulfuric acid baths are also used for the precipitation. The tube made of regenerated cellulose is then washed, if necessary treated with a plasticizer (such as glycerol), provided on the inside and / or outside with an impregnation (for example to make it easier to peel), dried to the intended final moisture and rolled up. The roll goods can then be gathered in sections as described. The mechanical strength of non-watered and watered caterpillars made of tubular Cellulose casings which are produced by the viscose process, however, often leave something to be desired.

The object was therefore to improve the mechanical stability of shirred sticks made of tubular cellulose casings. This object was achieved in that instead of the cellulose casings produced by the viscose process, casings produced by the N-methyl-morpholine-N-oxide (NMMO) process are used for gathering.

The present invention accordingly relates to a caterpillar made of a tubular food casing based on cellulose, which is characterized in that the casing is produced by the NMMO process.

The casing (in the unracked state) preferably has a nominal caliber of 14 to 50 mm, preferably 16 to 25 mm. It is particularly suitable for use as a peel, particularly in the manufacture of sausages. A caterpillar comprises about 30 to 70 m, preferably about 40 to 60 m, of the casing.

The production of (non-gathered) tubular cellulose casings by the NMMO process is known per se (WO 97/31970). The fact is used that cellulose is soluble in oxides of tertiary amines without chemical change, ie without derivatization. N-methyl-morpholine-N-oxide (hereinafter referred to as NMMO) has proven to be a particularly suitable oxide of a tertiary amine. A major advantage of this process is that it is technically less complex and less environmentally hazardous (in particular, the carbon disulfide required in the viscose process can be dispensed with). To produce the cellulose solution, pulp (for example made of wood or cotton) is mashed at room temperature in a 60% by weight N-methyl-morpholine-N-oxide solution with stirring. With increasing temperature and reduced pressure, water is then distilled off until the residue consists practically only of cellulose and NMMO monohydrate. The solvent then consists of 87.7% by weight of NMMO and the rest of water. The cellulose is completely dissolved in it at a temperature of around 90 to 105 ° C. Water is then drawn off with stirring and heating under reduced pressure, so that the solvent for the

Cellulose consists of 90.5 to 92.5% by weight of NMMO and 9.5 to 7.5% by weight of water. The proportion of cellulose is 6 to 15% by weight, based on the total weight of the spinning solution. Another advantage of the NMMO process is that the length of the cellulose chains remains practically unchanged (an average degree of polymerization DP of 400 to 650 is usual). In contrast, the viscose process causes a noticeable chain breakdown. To adjust special properties of the shell, it may be expedient to mix the spinning solution with other components. Synthetic polymers or copolymers and sugar esters are suitable. They act primarily as permanent ("primary") plasticizers. They also reduce the tendency to crystallize

Cellulose. The proportion of these additional components can be up to 25% by weight, based on the weight of the dry cellulose. In general, however, the proportion of these components is not more than about 1 to 20% by weight.

The NMMO / cellulose solution is then extruded downward (“spun”) with the aid of an annular gap die. The temperature of the spinning solution in the annular gap nozzle is preferably approximately 85 to 105 ° C. The annular gap generally has a width of 0.1 to 2, 0 mm, preferably 0.2 to 2.0 mm, the width must be adapted to the "delay" (quotient of outflow speed and take-off speed).

Then the primary tube created during the extrusion is in the

The air gap between the annular gap nozzle and the surface of the precipitation bath is transversely stretched.

The air gap in which the blow molding takes place is preferably 1 to 50 cm, particularly preferably 2.5 to 20 cm. It also depends on the diameter (Caliber) of the tubular film after the blow molding. The blow molding can be effected by compressed air or other gases under a corresponding pressure, which get into the interior of the hose through openings in the nozzle body. The transverse strength of the hose is increased considerably by stretching in the transverse direction. After entering the spinning bath, the spinning bath solution also reaches the interior of the cellulose tube through appropriate devices in the nozzle body. As a result, the hose solidifies faster, and at the same time the inner sides of the hose are prevented from sticking together.

The spinning bath itself is an NMMO-containing aqueous solution. This solution contains about 10 to 20% by weight of NMMO. The NMMO can be recovered practically quantitatively from the precipitation bath and reused. Used aqueous NMMO solutions can be cleaned, for example, by means of ion exchange columns. The water can then be removed in vacuo until the

NMMO concentration has reached 60% by weight. This NMMO solution can be used again for the production of spinning solution.

For further consolidation, it is expedient to pass the lay-flat hose through several NMMO-containing felling skids. If the NMMO

Content in the felling skids still about 10- 20% by weight, so it takes in the following

Get off. The temperature rises from runner to runner and reaches in the last one

Skids around 70 to 80 ° C. The felling section is usually also followed

40 to 60 ° C warm water filled runners in which the last traces of NMMO are washed out of the hose. This can be followed by a so-called plasticizer skid. It contains an aqueous solution of a plasticizer for cellulose. Particularly suitable are polyols and polyglycols, especially glycerin. The aqueous solution generally contains about 5 to

30% by weight, preferably 6 to 15% by weight, of the plasticizer or the mixture of various plasticizers. The temperature in the soft Machender skids are usually between 20 and 80 ° C, preferably between 30 and 70 ° C. The tubes are then passed through a dryer in the inflated state, hot air dryers having proven particularly suitable. It is advisable to dry at a decreasing temperature (from about 150 ° C. at the inlet to about 80 ° C. at the outlet of the dryer). When drying, the swelling value drops to 130 to 180%, preferably 140 to 170%, depending on the drying conditions and glycerol content. When drying, the tube is preferably inflated to the original caliber in order to leave the degree of transverse orientation unchanged.

After leaving the dryer, the hose is moistened again to a water content of 8 to 20% by weight, preferably 16 to 18% by weight, in each case based on the total weight of the hose. It can then be laid flat and wound up using a pair of squeeze rollers. Depending on the intended use, the casings can also be provided on the inside and / or outside with an impregnation or coating, for example liquid smoke impregnation, equipment for further increasing the caterpillar stability or an easy-peel inner preparation.

In order to improve the lubricity of the caterpillars on the filling pipe and to ensure that the casing can be removed during the later peeling process without damaging the skin formed by the sausages, it has proven to be expedient to impregnate or coat the casings on the inside to provide. This impregnation or coating can be applied via the shirring mandrel before the drying process or during shirring. For example, a coating with water-soluble cellulose ethers (US Pat. No. 3,898,348), with mixtures of lecithin and alginate, chitosan and / or casein (EP-A 502 431 = US Pat. No. 5,358,784), with mixtures of anionic and nonionic is known water soluble cellulose ether and lubricants (EP-A 180 207) or with mixtures of lecithin and polytetrafluoroethylene (EP-A 635 213).

The shell compressed into a caterpillar must already be provided with a closure at one end, so that the contents do not get onto the filling table and the following sausage chain is contaminated. The closure must be designed in such a way that it prevents the sausage meat from escaping, but not the air leakage, since otherwise the pressure equalization inside would be hindered. When using additional, separate sealing materials, such as clips or clips made of plastic or metal, there is always the risk that they will get into the sausage inside with the sausage meat. It is therefore advantageous if the closure is formed by twisting or knotting the casing material itself (DE-C 12 97 508, DE-B 15 32 029, DE-C 23 17 867; EP-A 129 100).

Often the end closure is created by pulling out a short piece of the caterpillar with special pliers and pushing it back into the interior of the caterpillar after a short rotation. Another possibility is to deform the last millimeter of the caterpillar with a specially shaped firing pin and at the same time to push it into its inner bore.

The gathering of the cellulose casings produced by the NMMO process can be carried out by processes which are known per se to the person skilled in the art. The above-described effect of the improved cohesion of the caterpillar is not dependent on a particular gathering method. Suitable methods for gathering are described, for example, in DE-B 12 68 01 1, DE-B 16 32 137, DE-C 16 32 139,

DE-A 22 31 144, DE-A 22 31 145 and DE-A 22 36 600 are described.

A closer examination has shown that the cellulose casings produced by this process differ in structure and properties from the previously known casings made from regenerated cellulose. However, it was surprising that these differences are still clearly noticeable in the shirred sticks.

In order to explain the differences in the shirred sticks, the surface structure of the casings was examined. It turned out that there is a significant difference. For example, the shells manufactured using the NMMO process have a much smoother surface than those manufactured using the viscose process. The difference is clearly visible in the images that can be obtained with a scanning force field microscope (Atomic Force Microscope, AFM).

1 shows an AFM image of the surface of a watered tube made of regenerated cellulose, which was produced by the viscose process (using a sodium sulfate / sulfuric acid precipitation bath). The X and Y axes are each divided into 20 micrometer intervals, while the Z axis is divided into 500 nanometer (= 0.5 micrometer) intervals (likewise in FIG. 2). The relief is therefore shown exaggerated. The distance between the highest and lowest points on the surface is more than 1000 nm.

2 shows an AFM image of the surface of a surface after the NMMO

Processed, watered hose made of regenerated cellulose. The surface is practically flat. Surveys are only visible in isolated cases. The distance between the highest and lowest points on the surface is significantly less than 500 nm.

If an aqueous ammonium sulfate / sodium sulfate / sulfuric acid precipitation bath is used in the viscose process instead of the miller bath, the roughness of the surface increases even further. Shells produced according to this process variant (available, for example, from Trificel, Brazil) result in shirred sticks with particularly low mechanical stability. The caterpillars broke if they were loaded with a weight of 340 g or more. The cellulose casings produced by the viscose process using Müllerbad as the precipitation bath gave caterpillars with a breaking strength of 600 to about 1 100 g. The caterpillars according to the invention, on the other hand, can - with the same type of gathering - be loaded with up to 1600 g, generally 1200 to 1500 g, before they break (measuring method for determining the breaking strength see under Example 1). The increased stability of the shirred caterpillars according to the invention is presumably attributable to the substantially smoother surface of the casing, which allows the pleats to stick together more strongly.

The arithmetic mean roughness R _a , determined in accordance with DIN 4768, is in the range of approximately 5 to 14 nm for the casings produced by the NMMO process, and in the range of 70 to 140 nm for the casings produced by the viscose process.

Optical micrographs also show that the shells obtained by the NMMO process have membranes made from regenerated cellulose with a much higher density. This leads to a higher strength of the casings or, with the same strength, allows a smaller wall thickness.

The smoother surface also makes the shell easier to peel off. The easy-peel preparation usually applied to the inside of the shell can therefore be reduced or even omitted entirely.

Finally, the electrokinetic potential (zeta potential) of the shell was also determined. This quantity describes the charge relationships at the interface between a membrane and a liquid phase. Conclusions can be drawn from this about the nature and properties of the surface. It also provides information on how the electrolyte and whose pH affects the surface. In aqueous media, electrical charging of the membrane surface is observed, which is caused by dissociation of functional groups of polymers on the surface of the membrane or specific adsorption of ions from electrolyte solutions. The resulting polarity of the polymer material is responsible for the formation of an electrical double layer. The potential of this electrical double layer cannot be measured directly. The zeta potential is therefore used to characterize the electrical properties. The potential builds up as soon as the surface of the membrane which is capable of dissociation and the electrolyte solution move tangentially to one another. It corresponds to the net charge density of the membrane surface. The Helmholtz-Smoluchowski equation for describing the zeta potential is:

ζ = 4 π η KE _; e ₀ D ΔP

where ζ the zeta potential [V],

E _s the flow potential [V], K the specific conductivity [Ω ^{"1 ■} cm ^{" 1} ], η the dynamic viscosity [Pa ^■ s], e ₀ the influential constant [C ^■ V ^{"1 •} cm ^{~ 1} ],

ΔP the pressure difference [Pa] and

D the dielectric constant

mean.

In the cellulose casings produced by the NMMO process, the ζ potential in the pH range from 6 to 10.5 was approximately -5 to -25 mV. In the pH range from 3.5 to 5.5, it was around + 18 to -15 mV. The shirred caterpillar according to the invention is particularly suitable for processing on high-speed filling machines. The production disruptions due to broken caterpillars described above hardly occur anymore. The caterpillars can be removed from the stuffing horn with ease and filled with sausage meat. The caterpillars according to the invention are particularly suitable for the production of

Cooked and scalded sausages, especially sausages. The casing is removed from the sausages in a known manner after brewing on automatic peeling devices.

The following examples serve to explain the invention. Percentages are

Percentages by weight, unless stated otherwise.

example 1

A cellulose gel tube of 18 mm caliber was produced using the amine oxide process and plasticized with glycerin. Immediately before drying, at the entrance to the drying tunnel, the hose was removed with a solution

1.0% carboxymethyl cellulose,

1.0% sorbitan trioleate, 0.5% mixture of mono- and diglycerides and

97.5% water

impregnated by a process known as "bubble coating". The impregnation facilitates the subsequent peeling process ("easy-peel" impregnation). Before entering the drying tunnel, there is a pair of squeeze rollers that retain the excess impregnation solution.

In the dryer, the tube was first inflated to a

Moisture from 7 to 8% dried, then brought to 16 to 18% moisture content by spraying with water and rolled up. The intermediate storage follows in a climate chamber. During the subsequent gathering, the tube was pulled off the roll and, in sections each about 50 m long, was formed into an approximately 40 cm long bead using one of the known gathering methods with the application of paraffin oil. The caterpillar withstood a load of 1,500 g.

The breaking strength was determined by storing the caterpillar horizontally in such a way that a 15 cm long section remained without support. A wire bracket (diameter of the wire about 2 mm) was then placed over the middle of this section, which was loaded with more and more weights until the caterpillar broke. The weight of the caterpillar was measured. This measurement method was also used in the following examples.

In a subsequent step, the caterpillar was then terminated. For this purpose, the caterpillars were pushed individually into a correspondingly shaped device and the last pleats were pressed into the caterpillar bore under mechanical deformation. The caterpillars were then wrapped in foil and placed in a box. The film was shaped so that the caterpillars can be removed from the consumer without risk of breakage and transferred to the magazine of the automatic filling machine.

Example 2

Example 1 was repeated with the difference that instead of the easy-peel solution described there, a liquid smoke preparation was used

38% acidic liquid smoke (®Enviro 24 P from Red Arrow,

Manitowoc, Wisconsin), 1% lecithin,

1% chromium fatty acid complex (®Montacell), 10% glycerin and 50% water

was used. The impregnation thus produced ensured easy peelability and at the same time caused the smell of smoke to pass onto the surface of the sausage meat. The caterpillar broke with a load

1,420 g.

Example 3

A cellulose gel tube was produced according to Example 1, but this time without an internal preparation. The casing was dried to 8 to 10% residual moisture.

After temporary storage in a climatic chamber, the hose was pulled off the roll and gathered. An aqueous solution was removed from the shirring mandrel

10.0% lecithin,

33.0% propane-1,2-diol,

0.4% polyoxyethylene sorbitan monooleate (®Tween 80),

0.2% polyethylene glycol monoalkyl ether (®Genapol X 80)

(HO- [CH ₂ -CH ₂ -0] _n - [CH ₂ ] _m -CH ₃ , where on average n = 8 and m = 12),

12.5% silicone oil dispersion,

3.0% wheat protein (®Amypro SWP),

2.5% polytetrafluoroethylene dispersion and

38.4% water

sprayed on the inside of the shell. The composition was chosen so that the caterpillar assumed a moisture content of 16 to 18% at the desired surface concentration of the active ingredients. The subsequent steps, end closure and packaging were carried out as in Example 1. The caterpillar withstood a load of 1,350 g. Example 4

Example 3 was repeated with the difference that instead of the aqueous composition described therein, a solution was used

37.7% liquid smoke ( ^® Zesti Smoke Code 10),

4.3% NaOH,

1.8% aginate,

10.1% lecithin,

3.0% ^® Genapol and

43.1% water

was sprayed on. In addition to the easy peel effect, the impregnation also brought out a smell flavor. The caterpillar was loadable with 1,250 g.

Claims

claims

1. caterpillar from a tubular food casing based on cellulose, characterized in that the casing is produced by the NMMO process.

2. caterpillar according to claim 1, characterized in that the casing has been transversely stretched in the air gap between the annular gap nozzle and the surface of the spinning bath by blow molding.

3. caterpillar according to claim 1 or 2, characterized in that the cellulose has an average degree of polymerization DP of 300 to 700, preferably 400 to 650.

4. caterpillar according to one or more of claims 1 to 3, characterized in that the casing contains up to 25 wt .-%, based on the weight of the cellulose, of other high molecular weight, less polar compounds.

5. caterpillar according to claim 4, characterized in that the further high molecular weight, less polar compound is a synthetic polymer or copolymer.

6. caterpillar according to one or more of claims 1 to 5, characterized in that the casing has a nominal caliber of 14 to 50 mm, preferably 16 to 25 mm.

7. caterpillar according to one or more of claims 1 to 6, characterized in that it comprises about 30 to 70 m, preferably about 40 to 60 m, the casing.

8. caterpillar according to one or more of claims 1 to 7, characterized in that the casing contains 8 to 20 wt .-%, preferably 16 to 18 wt .-%, of water.

9. caterpillar according to one or more of claims 1 to 8, characterized in that the casing contains a plasticizer, preferably Glyce n.

10. caterpillar according to one or more of claims 1 to 9, characterized in that the casing is provided on the outside and / or on the inside with an impregnation or coating.

1 1. caterpillar according to one or more of claims 1 to 10, characterized in that it is provided with an end closure.

12. caterpillar according to one or more of claims 1 to 1 1, characterized in that the ζ potential in the pH range from 6 to 10.5 at about -5 to -25 mV, in the pH range from 3.5 to 5.5 is around + 18 to -15 mV.

13. Use of the caterpillar according to one or more of claims 1 to 12 on a filling device in the manufacture of cooked or scalded sausages, preferably in the manufacture of sausages.