WO1996007328A1

WO1996007328A1 - Improvements in the production of tubular cellulosic casings for meat products, especially for sausages

Info

Publication number: WO1996007328A1
Application number: PCT/BR1995/000038
Authority: WO
Inventors: Hartmut Paul Schultze; Albert Hinrich Harm Bergoldt
Original assignee: Hoechst Do Brasil S.A.
Priority date: 1994-09-05
Filing date: 1995-09-05
Publication date: 1996-03-14
Also published as: AU3559295A; CZ65797A3; MX9701515A; BR9403440A; EP0779781A1

Abstract

The improvements are characterized in that the aqueous, acid, saline bath contains ammonium sulphate, especially being an aqueous solution containing sulphuric acid, ammonium sulphate and sodium sulphate, and/or - preferably and - in that, after the desulfurization of the cellulose hydrate tube, the latter is treated with a first amount of a plasticising material, subjected to a first drying step in the blown form, treated with the second amount of a plasticising material, internally coated with a lubricating material optionally further containing one or more materials of the group consisting of colouring, aromatizing and flavouring agents, subjected to a second drying step in the blown form, flattened, optionally wound and optionally shirred. The humidification may be carried out between the (only or second) drying and the winding or during the shirring by applying water or a portion or all of the lubricating material.

Description

"Improvements in the production of tubular cellulosic casings for meat products, especially for sausages"

The present invention relates to processes for producing a flexible tubular casing, based on regenerated cellulose, for use in the meat industry, especially in the manufacture of sausages.

Various types of materials have been proposed for sausage casings in tubular form. However, casings made of re¬ generated cellulose, employed especially in the manufacture of "frankfurters" or "vienna" sausages, are the most used.

In most of the cases the sausage casings of this type are produced in shirred form, called sticks. For instance a tube of a length of about 30 meters originates, by shirring, a stick having a length of about 30 cm. In the meat industry, in modern stuffing or filling machines (known in Brazil as "embutideiras") , most of which work automatically, these sticks are stuffed with the sausage mass, being thereby unfolded, and are twisted so as to produce the desired length. Thereafter, they are subjected to a cook- ing, scalding and/or smoking treatment; in this treatment co¬ agulation of the sausage mass takes place and the so-called "own skin" of the sausage is formed. After this treatment, the casings are separated from the coagulated sausage mass at high speed, by using a peeling device. The sausages obtained thereby can be packed in cans, jars or others containers and, as the case may be, they are sterilized and put on the market. Although this procedure is very fast and economical, it meets with great difficulties for maintenance of a constant quality of the sausage casings, particularly as regards their mechanical resistance when they are stuffed, twisted and quickly separated, as well as regarding their reliable peelability.

- Thus, for instance, the separation of the sticks and the twisting, which determines the constant length of the sausages, should take place without any damage that could lead to loss of the sausage mass and thereby to the inter¬ ruption of the producing process.

- At the first contact of the sausage casing with the meat mass which is inserted therein, the moisture of said mass will be transferred to the casing, whereby the expansion properties of the regenerated cellulose will be modified, that is, under the pressure of the sausage mass the casings will relatively easily become deformed. However, in spite of this, throughout the production they should reliably provide a filling or stuffing diameter which remains equal, as well as ensure a constant weight of the sausages and a cylindri¬ cal shape.

A complete peeling is highly desirable from the eco¬ nomical standpoint.

The peeling can often be helped advantageously by placing the set of sausages in water and/or by spraying them with water and/or by cooling them in a cold chamber or in cold channels. However, the efforts to rationalize the manufacture of small diameter sausages lead more and more to the elimi¬ nation of these auxiliary steps and also require constantly increasing peeling speeds at which the casings should be re¬ moved without leaving residues and without undergoing cracks. Here there are great challenges for the peelability, which is essentially determined by the adhesion force between the internal surface of the casing and the surface of the coag- ulated sausage mass.

From the foregoing it follows that it is highly de¬ sirable to provide a process which results in improving the mechanical resistance and the peelability of the regenerated- cellulose casings designed for use in the industry of meat- based products, especially sausages.

Another important object in the industry of meat-based products of the "stuffed" type (known in Brazil as "embutidos") , especially sausages, is to provide these pro- ducts with a coloured surface.

For the production of meat-based "stuffed" products having a coloured surface, for instance reddish, two processes are used at present:

1. DYING THE CASING AND TRANSFERRING COLOUR FROM THE COLOURED CASING TO THE "STUFFED" PRODUCT

Initially the casing is coloured, in the case of small di¬ ameter casings for sausage for instance by passing it through a bath containing both a plasticising material, for example glycerin, and a pigment, for example annatto pigment. Then the casing is stuffed with meat and the prod¬ uct is subjected to a process of cooking, scalding and/or smoking in which colour is transferred from the casing to to the meat. The coloured casing used for the transfer has an intense colour; however, the meat product coloured by it acquires a much clearer colouring similar to that of the original mass.

2. COLOURING THE "STUFFED" PRODUCT ALREADY PEELED

At present, in a considerable part of the market the use of non-toxical natural organic pigments, such as annatto, in the colouring of "stuffed" products is widespread.

The colouring process, in the case of sausages, is carried out by passing the "stuffed" product - after cooking, scalding and peeling - through tanks containing these pigments in alcoholic solutions at temperatures higher than the room temperature. ? Specifically in the sausage indus¬ try the colouring of sausages is carried out in water tanks to which the commercial pigment is added. Salt can also be added in order to improve the fixation of the pigment. The temperature of the tanks is relatively high, and the residence time is significant. Further sausage washing and drying steps are necessary prior to packing. The great dis¬ advantage of this process is the need for cleaning and maintaining the tank with pigment, as well as the great danger of contaminating the product with microorganisms. At present, the process of colouring the "stuffed" product is expensive and requires great care, such as microbiological control and control of the pigment contents in the bath.

From the foregoing it follows that there is at pres- ent a need for a process which, on the one hand, makes it pos¬ sible to colour meat-based "stuffed" products, in particular sausages, in a more effective way than the present process of transferring colour from the previously coloured casing to the "stuffed" product contained therein, and which, on the other hand, avoids the disadvantages of the process of colouring the previously peeled "stuffed" product.

From the technical literature processes are known which are intended to produce tubular casings with a small di¬ ameter having good characteristics for the use here in issue. These processes are essentially based on the classic process of spinning viscose (an alkaline solution of cellulose xanthogenate) , in which viscose is spun through annular slot tubes, under pressure, into acidic precipitation baths and is coagulated therein in a tubular gel form and then cellulose is regenerated as cellulose hydrate. After passing through vari¬ ous baths, for instance alkaline solutions, for removing ex¬ cess sulphur compounds, the tube is intensively washed with water and led to a bath containing substances - hereinafter called plasticising materials - whiι_n serve as a softening, flexibility-providing and moisture-maintaining means, such as an aqueous glycerin solution, or similar substances. Then the tube is usually treated with a lubricating material, which fa¬ cilitates the subsequent peeling and is known as "easy peel", and the tube is then dried and shirred. In another variant, after the treatment with a lubricating material, the tube is dried and, during the shirring process, its inner walls are treated with a peeling aid.

Although the known processes have often been adapted in order to meet with the requirements of the meat-processing industry, they cannot always meet with the characteristics re¬ quired by the very complex stuffing and peeling process.

The object of the present invention is to provide a flexible tubular casing, based on regenerated cellulose, for use in the meat industry and especially in the manufacture of sausages, which has a higher mechanical resistance to the stuffing, twisting and peeling processes, providing a lower number of stuffing failures and a higher peeling ratio, with a consequent economy in the production costs. Another object of the present invention is to pro¬ vide a flexible tubular casing, based on regenerated cellulose, for use in the meat industry and especially in the manufacture of sausages, which presents a higher peeling ra¬ tio. Another object of the present invention is to pro¬ vide a flexible tubular casing, based on regenerated cellulose, for use in the meat industry and especially in the manufacture of sausages, which is highly resistant to the stuffing, twisting and peeling processes, easy to peel, as well as capable of effectively transferring colour, flavour and/or aroma to the meat "stuffed" product contained therein, thus eliminating the need for passing the "stuffed" products through colouring tanks for the obtention of a desired colour and/or eliminating the need for submitting the "stuffed" prod- uct to the smoking process for the obtention of smoked odor and flavour, and drastically reducing the machinery, material and labour costs.

These objects have been achieved by the present in¬ ventors through the processes described below. Thus, the present invention provides a process for producing a flexible tubular casing based on regenerated cellulose for use in the meat industry, especially in the man¬ ufacture of sausages, this process being of the type wherein viscose manufactured by the xanthation method is spun through annular slot tubes into an aqueous, acidic, saline bath, in which the newly formed gel tube is coagulated and regenerated into cellulose hydrate, thereafter the cellulose hydrate tube is washed with water, desulfurized, treated with a plasticising material, internally coated with a lubricating material optionally further containing one or more materials of the group consisting of colouring, aromatizing and flavouring agents, dried in the blown form, flattened, op¬ tionally wound and optionally shirred, wherein, after being dried, the tube is subjected to a rehumidification carried out (i) between its drying and winding or

(ii) during its shirring by applying to the tube - via mandrel of the shirring machine - water or at least a portion of said lubricating material, said process being characterized in that said aqueous, acidic, saline bath contains ammonium sulphate. This process will be referred to as process a) hereinafter.

A specific embodiment of process a) is characterized in that said bath is an aqueous solution containing sulphuric acid, ammonium sulphate and sodium sulphate.

A more specific embodiment of process a) is charac¬ terized in that said aqueous solution contains:

- up to about 20 wt% of sulphuric acid, - up to about 30 wt% of ammonium sulphate and

- up to about 30 wt% of sodium sulphate and is used at a temperature of up to about 45°C.

In an even more specific embodiment of process a), said aqueous solution contains - about 10 to about 20 wt% of sulphuric acid,

- about 15 to about 30 wt% of ammonium sulphate, and

- about 10 to about 15 wt% of sodium sulphate.

In another even more specific embodiment of process a), said aqueous solution contains: - about 17 wt% of sulphuric acid,

- about 20 wt% of ammonium sulphate and

- about 10 wt% of sodium sulphate.

The present invention also provides a process for producing a flexible tubular casing, based on regenerated cellulose, for use in the meat industry, especially in the manufacture of sausages, this process being of the type wherein viscose manufactured by the xanthation process is spun through annular slot tubes into an aqueous, acidic, saline bath, in which the newly formed gel tube is coagulated and re- generated into cellulose hydrate, after which the cellulose hydrate tube is washed with water, desulfurized, treated with a plasticising material, internally coated with a lubricating material optionally further containing one of more materials of the group consisting of colouring, aromatizing and flavouring agents, dried in the blown form, flattened, op¬ tionally wound and optionally shirred, wherein, after being dried, the tube is subjected to a rehumidification carried out (i) between its drying and winding or

(ii) during its shirring by applying to the tube - via mandrel of the shirring machine - water or at least a portion of said lubricating material, said process being characterized in that, after the desulfurization of the cellulose hydrate tube, the latter is treated with a first amount of a plasticising material, sub¬ jected to a first drying step in the blown form, treated with a second amount of a plasticising material, internally coated with a lubricating material optionally further containing one or more materials of the group consisting of colouring, aromatizing and flavouring agents, subjected to a second dry¬ ing step in the blown form, flattened, optionally wound and optionally shirred, wherein, after said second drying, the tube is subjected to a rehumidification carried out

(i) between its second drying and its winding or (ii) during its shirring by applying to the tube - via mandrel of the shirring machine - water or at least a portion of said lubricating material. This process will be referred to as process b) hereinafter.

The present invention further provides a process for producing a flexible tubular casing based on regenerated cellulose for use in the meat industry, especially in the man¬ ufacture of sausages, this process being of the type wherein viscose manufactured by the xanthation process is spun through annular slot tubes into an aqueous, acidic, saline bath, in which the newly formed gel tube is coagulated and regenerated into cellulose hydrate, thereafter the cellulose hydrate tube is washed with water, desulfurized, treated with a plasticising material, internally coated with a lubricating material optionally further containing one or more materials of the group consisting of colouring, aromatizing and flavouring agents, dried in the blown form, flattened, op¬ tionally wound and optionally shirred, wherein, after being dried, the tube is subjected to a rehumidification carried out (i) between its drying and winding steps or

(ii) during its shirring by applying to the tube - via mandrel of the shirring machine - water or at least a portion of said lubricating material, said process being characterized in that the aqueous, acidic, saline bath contains ammonium sulphate, and in that, after desulfurization of the cellulose hydrate tube, the latter is treated with a first amount of a plasticising material, sub¬ jected to a first drying step in the blown form, treated with a second amount of a plasticising material, internally coated with a lubricating material optionally further containing one or more materials of the group consisting of colouring, aromatizing and flavouring agents, subjected to a second dry¬ ing step in the blown form, flattened, optionally wound and optionally shirred, wherein, after said second drying, the tube is subjected to a rehumidification carried out (i) between its second drying and its winding or

(ii) during its shirring by applying to the tube - via mandrel of the shirring machine - water or at least a portion of said lubricating material. This process will be referred to as process c) hereinafter. In a specific embodiment of process c), said bath is an aqueous solution containing sulphuric acid, ammonium sulphate and sodium sulphate.

In a more specific embodiment of process c), said aqueous solution contains: - up to about 20 wt% of sulphuric acid,

- up to about 30 wt% of ammonium sulphate and

In an even more specific embodiment of process c), said aqueous solution contains:

- from about 10 to about 20 wt% of sulphuric acid,

- from about 15 to about 30 wt% of ammonium sulphate and

- from about 10 to about 15 wt% of sodium sulphate.

In an even more specific embodiment of process c). said aqueous solution contains:

- about 17 wt% of sulphuric acid,

- about 20 wt% of ammonium sulphate and

- about 10 wt% of sodium sulphate. A particularly advantageous embodiment of process b) or c) is characterized in that, in the second treatment with a plasticising material, one works with a higher concentration of plasticiser than that employed in the first treatment with a plasticising material. In a specific embodiment of such a process, in both steps of treatment with a plasticising mate¬ rial, an aqueous hot glycerin solution is used as the plasticising material. A more specific embodiment of said process is characterized in that, after the first treatment with glycerin and drying step, there is in the tube a concen- tration of about 7 to about 13 wt%, preferably from about 9 to about 11 wt% and, after the second treatment with glycerin and drying, there is in the tube a concentration of glycerin of about 13 to about 20 wt%, preferably from about 13 to about 15 wt%. Another advantageous embodiment of process b) or c) is characterized in that said second drying step is carried out at a surface temperature higher than that of said first drying step. A specific embodiment of this process is charac¬ terized in that, at the end of said first drying step, the tube has a surface temperature of up to about 65°C, whereas at the end of said second drying step, the tube has a surface temperature of about 70 to about 110°C.

In an advantageous embodiment of process b) or c) the expansion percentage of the tube caused by the air blow during said first drying step is greater than that caused by the air blow during said second drying step. In a specific em¬ bodiment of such a process, during said first drying step, the tube is expanded by approximately 20 - 45%, preferably approx¬ imately 25 - 35%, of its average diameter at the time when it leaves of the first treatment with a plasticising material and, in said second drying step, the tube undergoes only an expansion of up to about 10%, preferably of up to about 2%.

A specific embodiment of process b) or c) is charac¬ terized in that, after the second treatment with a plasticising material, a metered amount of a liquid prepara¬ tion containing a lubricating material is introduced into the tube and, during said second drying step, a substantially even coating is formed on the inner surface of the tube. More spe- cifically, such a liquid preparation may essentially consist of a mixture of water, mineral oil and/or vegetable oil and an aqueous solution of cellulose ether, as well as an emulsifier. In this process one can advantageously employ, as the emulsifier, a polysaccharide or lipid or a mixture thereof. In process b) or c), the lubricating material can contain natural organic pigments such as, for example, annatto, paprika and curcuma and/or flavouring and/or aromatizing agents such as, for example, smoke aroma.

In process a) of this invention, one can employ the same materials employed in the various steps of process c) of this invention, since the essential difference between these two processes resides in that, in process a), the application of the plasticising material is carried out in a single step and there is only one drying step, whereas process c) com- prises two steps of application of the plasticising material and two drying steps.

In one of the alternatives of processes a), b) or c) either water or an aqueous composition can be applied via the mandrel of the shirring machine for rehumidifying and/or lu- bricating the tube.

Said aqueous composition may be a part of, or all, said lubricating material. So, aqueous solutions or emulsions based on carboxymethylcellulose (CMC) and/or on other compo¬ nents of said lubricating material can also be applied via said mandrel.

Carrying out said rehumidification via the shirring mandrel provides sticks which are more resistant to breaking and, therefore, more stable than those obtained by effecting the rehumidification after said drying (process a)) or second drying (process b) or c)). Moreover, if a lubricating mate¬ rial not containing CMC is applied to the tube after the ap¬ plication of the plasticising material and an aqueous solution of CMC is applied via mandrel during the shirring operation, particularly better results are obtained. - II -

With regard to the present invention the following aspects should also be observed:

1) It is believed that the aqueous, acidic, saline bath based on ammonium sulphate, disclosed by the present invention, causes a rapid and extensive dehydration of the newly formed gel tube, thus providing the tube with a stronger structure and lowering the degree of swelling of the regen¬ erated cellulose.

2) By the process of treatment with a plasticising material in two steps a greater compacting of the cellulose structure is obtained, due to the fact that in a first step only a small amount of plasticiser, for example glycerin is incor¬ porated (an about 7% glycerin aqueous solution at about 80^βC leads to a glycerin content of 10% in the casing after the first drying step). Only subsequently, by means of a second treatment with a plasticising solution with a higher percentage (for instance, a 11% glycerin solution), the necessary concentration of plasticiser is applied to the casing, for instance, a concentration of approximately 13% to 20% of glycerin, necessary for subsequent use. This process of applying a plasticiser, e.g. glycerin, by steps provides a structure having a greater thickness and smaller pores as compared to the classic one step treatment.

3) The above aspects (1) and (2) are contributions to the me- chanical resistance to the stuffing process and facilitate the impregnation with an emulsion containing, for example, pigment, aroma, etc.

4) According to the conventional technique the tube in the blown form is passed through drying channels. It has been found that the mechanical properties, the stability of the dimensions and the tear and shear strengths, which are rel¬ evant properties for the stuffing conditions, are improved when, during the first drying step, a strong transverse ex¬ pansion is exerted on the tube (by means of the correspond- ing air blow) and, at the time of the second drying step, the tube is just slightly expanded and, on the contrary, a thermal fixation is carried out with a higher temperature of the air and - as the case may be - of the tube. The in¬ verse process, that is, the distribution in equal amounts of the expansion and of the temperature in both the drying steps always provides worse results.

5) The application of a lubricating material preparation ("easy-peel" preparation) prior to the second drying step, that is to say, after the expansion of the tube, essen¬ tially when the first drying step has been completed, re¬ sults in the following:

- the required thickness of the "easy-peel" layer remains constant and its active ingredients, for example CMC, do not undergo any reduction in their amounts relative to the surface, which is favourable for a good peeling, and

- because of the thicker structure obtained according to the above aspects (1) to (4), the components of the "easy-peel" layer only migrate in minor amounts to the outside of the tube, that is to say, its effectiveness (for the subsequent peeling) is entirely maintained on the surface of the inner wall of the tube.

6) In the case of colouring, the inventors have used commer¬ cial nontoxical natural organic pigments, such as annatto, paprika, curcuma and mixtures thereof. These are pigments of vegetable origin of the carotenoid type. The emulsion containing the organic pigment can be prepared on the basis of water, oil, a surfactant and a thickener, and the pigment can be added in oily dispersions (either mineral or vegetable oil).

The pigment in the aqueous phase can be present in amounts of from 0.2 to 8%, and in the oily dispersions in amounts of 0.5 - 6%. The water/oil ratio used in the tests was ca. 2 : 1, surfactants and thickeners having been employed in concentrations in the order of 1 - 3% of the total weight of the solution.

In the application of the emulsion, the inner surface of the casing comes into contact with the emulsion containing organic pigment in such a way that the casing is coated with the desired amount of pigment.

For the analysis of the pigmentation contents in the artifical casing a process of extraction with acetone was used, followed by the reading of the absorbancy at 485 nm. The colouring of the "stuffed" product with the artificial coloured casing takes place uniformly, and the casing can be normally peeled. The packing of the product can be made immediately.

7) By employing small amounts of from 0.1% up to 0,5% of polysaccharides (Satiaxane CX-91-Br of Rousselot), with or without the addition of lecithin-type phospholipids as ad¬ ditives for the traditional CMC-based "easy-peel" composi¬ tion, a substantial improvement of the industrial peelability including under critical peeling conditions (lack of cooling or reduced cooling of the sausage material by means of water or cooled air).

8) By adding aromatizing and flavouring agents, the inner sur¬ face of the casing is impregnated in such a manner that the finished product has the property of transferring smell and flavour to the stuffed mass.

9) The processes according to the invention will now be de¬ scribed in greater detail, by means of several examples and an illustration (figure 1).

DESCRIPTION OF FIG. 1 Figure 1 shows a specific scheme for carrying out process b) provided by the present invention. Thus, viscose manufactured by the xanthation method is spun through annular slot tubes into an aqueous, acidic, saline bath, (1) in which the newly formed gel tube is coagulated and regenerated into cellulose hydrate, thereafter the cellulose hydrate tube is washed with water and desulfurized (2), passes through a first bath of a plasticising material (3), in the blown form - main¬ tained closed with the help of squeezing cylinders (4a) and (4b) - is subjected to a first drying step in a first drier (4), passes through a second bath of plasticising material (5), receives application (6) of a lubricating material con¬ taining a pigment, in the blown form - maintained closed with the help of squeezing cylinders (7a) and (7b) - is subjected to a second drying step in a second drier (7), is humidified in a humidifier (8), is flattened by the squeezing cylinders (7b), is wound (9) and is shirred (10) into sticks.

Examples are given below which illustrate the in¬ vention (examples 1 to 11) and the closest prior art (example 12). The examples according to the invention are merely in- tended to illustrate it rather than to restrict it.

EXAMPLES

Example 1 (according to the invention)

In a usual manner, by the steeping process one produces an alkaline cellulose with 19% caustic soda from cot¬ ton linters pulp in the form of sheet, which in the ground state is changed by means of carbon bisulphide into sodium cellulose xanthogenate. After dissolution in 3% caustic soda, mechanical homogenization and filtration carried out in vari- ous steps, a spinnable viscose is obtained with the following characteristics:

- Cellulose contents: 7.5%

- NaOH contents: 5.9%

- Sulphur contents: 2.4% - Viscosity (drop of spheres): 98 seconds

- Temperature: 32^βC.

In order to manufacture sausage casings in the form of a tube based on regenerated cellulose, viscose is pressed (extruded) into a spinning bath by means of geared pumps through a ring tube with a ring-shaped slot having a diameter of 20 mm and a slot width of 0.25 mm. This spinning bath con¬ sists of an aqueous solution of:

- 17 wt% of sulphuric acid,

- 20 wt% of ammonium sulphate and - 10 wt% of sodium sulphate

- and has a temperature of 41°C.

The tube obtained is drawn with a velocity of up to 45 m/min. Then the tube is desulfurized by means of alkali and is intensively washed with water. Finally, the tube is dipped into a bath containing a 7% glycerin solution at 80°C.

The inside of the tube is filled with a liquid prep¬ aration consisting of a homogeneous mixture of:

- 1.0 wt% of carboxymethylcellulose,

- 44.3 wt% of water, - 22.2 wt% of mineral oil,

- 29.4 wt% of propyleneglycol,

- 1.9 wt% of "Aline 800 K" (etoxylated sorbitan monooleate supplied by Oxiteno Indύstria e Comercio S/A) ,

- 1.2 wt% of "Aerosol OT" (sodium dioctyl sulphosuccinate at - 15 -

75%, supplied by Cyanamid Quimica do Brasil Ltda.).

In the following passage, the excess preparation is eliminated from the inner wall of the tube through squeezing cylinders which are closed to a great extend. The tube thus prepared passes through a hot-air drier and is blown with air so that its plane width, measured at the time of a later wind¬ ing, is 31.5 mm. With a temperature in the drier of 140°C, the tube is dried to a moisture content of 6%, which is raised up to 16% in a conditioning chamber, which contains a fine water cloud. The ready tube contains 16% of glycerin as a plasticiser and is wound into coils.

The tube is shirred in a known shirring machine at a velocity of 170 m/min, on a mandrel with 13.8 mm of diameter, with a proportional fold structure in the length direction, thereby obtaining a 29 m long tube length, a 375 mm long firm stick and an outer diameter of 22.5 mm. This stick is closed at one of its ends with a piece of the tube itself and can be employed for tests of stuffing and peeling.

50 sticks of this type (in a total of 1450 m of tube) are filled with a fine mass of scalded sausage, with a diameter of 21.9 - 22.1 mm, in a high performance machine, "Frank-a-matic DB 2" model, equipped with a filling tube with a diameter of 9.5 mm and a "Chuck" 21, and are automatically divided into small, 130 mm long sausages weighing 50 g. During this process, approximately 7 tear of the casings of the tube are observed, that is to say, 4.8 filling failures take place per 1,000 m:

Q 1000 = 4.8

In a cooking chamber, controlled by means of an "atmos" model, the small diameter sausages are scalded at the appropriate places during 30 min., at 70°C and cooled during 10 minutes under a water shower.

Then the casings are removed in a peeling machine model "Apollo Ranger Peeler", at a velocity of 200 m/min and the skinless sausages are gathered.

From the 11,100 sausages produced still 4,500 retain the original cellulose casing, in whole or in part. Therefore, the peeling ratio is 60%. Example 2 One proceeds as in example 1 except that the raising of the moisture content from 6% to 15% is not carried out in the conditioning chamber but rather in the shirring machine by applying water via its mandrel. The results obtained are sub- stantially the same as in example 1 except that the stick ob¬ tained is more resistant to breaking and, therefore, more stable.

Example 3 (according to the invention) The procedure is the same as in Example 1. However, a different type of glycerin treatment and drying of the tubes is chosen.

A glycerin concentration of 3% at 80^βC is employed in the bath, whereby the tube, after drying, in the blown con¬ dition, at 110^βC, presents a glycerin content of 6%. Then the tube is subjected to a second bath, which has a glycerin con¬ centration of 13% at 80^βC. After the treatment with the above mentioned peeling emulsion, the tube is led through a second drying unit, equally at 110^βC, and blown with air, so that a tube with a plane width of 31.5 mm is obtained. The tube has a glycerin content of 15% and is collected as mentioned previ¬ ously.

The results of filling and peeling under the condi¬ tions of Example 1 are the following: Q 1000 = 4.1 Peeling Ratio = 63%

Example 4 (according to the invention)

Example 3 is repeated, but the concentrations of both of the glycerin baths are changed as follows: The first and second baths respectively contain 7% and 11% glycerin. Thus, after the first drying step, the tube reaches a glycerin content of 10% and, after the second drying step, a glycerin content of 15% as in the preceding examples. It is collected as explained previously and presents the following filling and peeling results: Q 1000 = 3.5

Peeling Ratio = 65% Example 5 (according to the invention)

Example 4 is repeated, but the drying conditions are changed: the first drier has a temperature of 90°C whereas the second drier has a temperature of 120^βC. In the respective outlets of the driers, a surface temperature of the tube of 65°C (first drier) and 110°C (second drier) is measured.

After processing the tube as indicated the following filling and peeling results are obtained:

Q 1000 = 2.8

Peeling Ratio = 70% Example 6 (according to the invention)

Example 5 is repeated, but the place and degree of tube expansion by means of air blowing in the driers are changed so that, at the time of winding, a plane surface of 31.5 mm is obtained, as mentioned, and equally a moisture con¬ tent of 15% and a glycerin content of 15% are obtained.

EXPANSION IN DRIER 1 DRIER 2

VARIANT 6a 100% 0%

Variant 6b 50% 50%

Variant 6c 0% 100%

After the collection, the following filling and peeling results are obtained:

Q 1000 Peeling Ratio

VARIANT 6a 0.7 98% Variant 6b 2.8 75%

Variant 6c 2.8 70%

The above results show the superiority of alterna¬ tive 6a which is preferred in accordance with the invention. Example 7 (according to the invention) The procedure is the same as in Example 6 by Variant

6a, but the lubricating preparation given in Example 1 is changed by means of, among others, the addition of a polysaccharide (Satiaxane CX-91 BR) (xanthan gum supplied by Sanofi do Brasil Indύstria e Comercio Ltda.) and a phospholipid (lecithin), so that the following lubricating mixture is used: a) 70.0 wt% of water b) 26.0 wt% of soybean oil c) 1.0 wt% of carboxymethylcellulose d) 0.2 wt% of polysaccharide e) 1.0 wt% of lecithin f) 1.5 wt% of "Aline ES 800" g) 0.3 wt% of Aerosol OT.

The following filling and peeling results are ob¬ tained:

Q 1000 = 0.7 Peeling Ratio = 100%

Depending on the conditions provided by the shirring machine, carboxymethylcellulose and/or other components of the above lubricating mixture can also be totally or in part ap¬ plied to the tube in the shirring machine via mandrel in the form of an aqueous solution or suspension. E.g. instead of applying - as in the present example 7 - a lubricating mixture containing 1.0 wt.-% carboxymethylcellulose, a lubricating mixture only containing 0.60 wt.-% carboxymethylcellulose can be applied to the tube, with the remainder of the carboxymethylcellulose being applied in the form of an aqueous solution via mandrel in the shirring machine. Such partial or total application of the component(s) of the lubricating com¬ position ("easy peel") via mandrel in the shirring machine does not substantially affect the results obtained by the precedent alternative but the sticks obtained have a higher resistance to breaking.

Example 8 (according to the invention).

The procedure is the same as in Example 7 and the pigment "Annato Powder MCC-A-20.000-WSS-P" (20% of bixin (monomethyl norbixin ester); microencapsulated; supplied by Chr. Hansen's Laboratorium A/S, Denmark) is added to the lu¬ bricating preparation. The emulsion has a contents of 1% on the basis of bixin.

After application and peeling, the colouring of the "stuffed" product showed uniformity, and the peeling process was acceptable.

Q 1000 = 0.7

Peeling Ratio = 90%

Colour = red Colour Homogeneity = 100% Example 9 (according to the invention)

The emulsion is prepared in the same way as in Exam¬ ple 7 and the pigment annatto is added in the form of an oil suspension (Ha-la do Brasil). The emulsion has, as the compo¬ nent b)", 26.0% of A-4000-OSS (annatto oil suspension, at 3.9 % of bixin, supplied by Ha-la do Brasil). Q 1000 = 0.7 Peeling Ratio = 98% Colour = red

Colour Homogeneity = 100% Example 10 (according to the invention)

The preparation is made in the same way as in Exam¬ ple 7, and the pigment Annatto is added in aqueous form (Ha-la do Brasil). The mixture has, as the component a)", 70.0% of SA 750 (aqueous suspension of annatto, at 2.5% of norbixin (^C24^H28°4) ' supplied by Chr. Hansen, Denmark).

Q 1000 = 0.7 Peeling Ratio = 85% Colour = red

Homogeneity = 100% Example 11 (according to the invention)

One works with an emulsion as in Example 6 contain¬ ing "smoke aroma" in the following concentration: As the component a)", 70.0% of SMK 5996 (liquid smoke, "pure Hickory"; supplier: Baltimore Spice, Inc.; repre¬ sentative in Brazil: Fuchs Gewύrze do Brasil Ltda.). Q 1000 = 0.7 Peeling Ratio = 98% Colour = slightly reddish

Smoke flavour and odour = strong

It is observed that the use of said "smoke aroma" not only resulted in the obtention of flavour and odour of smoked sausage, but also, additionally, in a commercially at- tractive, slightly reddish colour.

Example 12 (according to the prior art)

Example 1 is repeated but as a substitute for the spinning bath containing ammonium sulphate an aqueous bath is used which does not contain such a sulphate and contains - 13 wt% of sulphuric acid and

- 14 wt% of sodium sulphate.

The results obtained are the following: Q 1000 = 9.7 Peeling Ratio = 51%

This example 12 according to the prior art shows a number of filling failures (Q 1000) which is greater and, therefore, worse than all the examples of the invention (Exam¬ ples 1 through 10) and a peeling ratio which is lower and, therefore, worse than all the examples of the invention.

Claims

1. A process for producing a flexible tubular casing based on regenerated cellulose for use in the meat industry, especially in the manufacture of sausages, this process being of the type wherein viscose manufactured by the xanthation method is spun through annular slot tubes into an aqueous, acidic, saline bath, in which the newly formed gel tube is co¬ agulated and regenerated into cellulose hydrate, thereafter the cellulose hydrate tube is washed with water, desulfurized, treated with a plasticising material, internally coated with a lubricating material optionally further containing one or more materials of the group consisting of colouring, aromatizing and flavouring agents, dried in the blown form, flattened, op¬ tionally wound and optionally shirred, wherein, after being dried, the tube is subjected to a rehumidification carried out (i) between its drying and winding steps or

(ii) during its shirring by applying to the tube - via mandrel of the shirring machine - water or at least a portion of said lubricating material, said process being characterized in that said aqueous, acidic, saline bath contains ammonium sulphate.

2. A process according to claim 1, characterized in that said bath is an aqueous solution containing sulphuric acid, ammonium sulphate and sodium sulphate.

3. A process according to claim 2, characterized in that said bath is an aqueous solution containing

- up to about 20 wt% of sulphuric acid,

- up to about 30 wt% of ammonium sulphate and - up to about 30 wt% of sodium sulphate and is used at a temperature of up to about 45°C.

4. A process according to claim 3, characterized in that said bath is an aqueous solution containing

- about 10 to about 20 wt% of sulphuric acid, - about 15 to about 30 wt% of ammonium sulphate and

- about 10 to about 15 wt% of sodium sulphate.

5. A process according to claim 4, characterized in that said aqueous solution contains

- about 17 wt% of sulphuric acid

- about 20 wt% of ammonium sulphate and - about 10 wt% of sodium sulphate.

6. A process for producing a flexible tubular cas¬ ing, based on regenerated cellulose, for use in the meat in¬ dustry, especially in the manufacture of sausages, this process being of the type wherein viscose manufactured by the xanthation process is spun through annular slot tubes into an aqueous, acidic, saline bath, in which the newly formed gel tube is coagulated and regenerated into cellulose hydrate, af¬ ter which the cellulose hydrate tube is washed with water, desulfurized, treated with a plasticising material, internally coated with a lubricating material optionally further contain¬ ing one of more materials of the group consisting of colouring, aromatizing and flavouring agents, dried in the blown form, flattened, optionally wound and optionally shirred, wherein, after being dried, the tube is subjected to a rehumidification carried out (i) between its drying and winding steps or

(i) between its second drying and its winding or

(ii) during its shirring by applying to the tube - via mandrel of the shirring machine - water or at least a portion of said lubricating material.

7. A process for producing a flexible tubular casing based on regenerated cellulose for use in the meat industry, especially in the manufacture of sausages, this process being of the type wherein viscose manufactured by the xanthation process is spun through annular slot tubes into an aqueous, acidic, saline bath, in which the newly formed gel tube is co¬ agulated and regenerated into cellulose hydrate, thereafter the cellulose hydrate tube is washed with water, desulfurized, treated with a plasticising material, internally coated with a lubricating material optionally further containing one or more materials of the group consisting of colouring, aromatizing and flavouring agents, dried in the blown form, flattened, op- tionally wound and optionally shirred, wherein, after being dried, the tube is subjected to a rehumidification carried out

(i) between its drying and winding steps or

8. A process according to claim 7, characterized in that said bath is an aqueous solution containing sulphuric acid, ammonium sulphate and sodium sulphate.

9. A process according to claim 8, characterized in that said bath is an aqueous solution containing - up to about 20 wt% of sulphuric acid,

- up to about 30 wt% of ammonium sulphate and

- up to about 30 wt% of sodium sulphate,

- and is used at a temperature of up to about 45°C.

10. A process according to claim 9, characterized in that said bath is an aqueous solution containing

- about 10 to about 20 wt% of sulphuric acid,

- about 15 to about 30 wt% of ammonium sulphate and

- about 10 - 15 wt% of sodium sulphate.

11. A process according to claim 10, characterized in that said aqueous solution contains

- about 17 wt% of sulphuric acid,

- about 20 wt% of ammonium sulphate and

- about 10 wt% of sodium sulphate.

12. A process according to any of claims 6 to 11, characterized in that, in the second treatment with a plasticising material, one works with a higher concentration of plasticiser than that employed in the first treatment with a plasticising material.

13. A process according to claim 12, characterized in that, in both the steps of treatment with a plasticising material, a hot aqueous glycerin solution is used as the plasticising material,

14. A process according to claim 13, characterized in that, after the first treatment with glycerin and the first drying step, there is in the tube a glycerin concentration of from about 7 to about 13 wt%, preferably from about 9 to about 11 wt% and, after the second treatment with glycerin and the second drying step, there is in the tube a glycerin concen¬ tration of from about 13 to about 20 wt%, preferably from about 13 to about 15 wt%.

15. A process according to any of claims 6 to 14, characterized in that the second drying step is carried out at a tube surface temperature higher than that of the first dry¬ ing step.

16. A process according to claim 15, characterized in that at the end of the first drying step the tube has a surface temperature of up to about 65°C whereas at the end of the second drying step the tube has a surface temperature of about 70 to about 110°C.

17. A process according to any of claims 6 to 16, characterized in that the percentage of expansion of the tube caused by air blowing during the first drying step is higher than that caused by air blowing during the second drying step.

18. A process according to claim 17, characterized in that during the first drying step the tube is expanded by approximately 20 - 45%, preferably by approximately 25 - 35%, of its diameter measured at the time when it leaves the first treatment with a plasticising material and in that in the sec- ond drying step the tube undergoes only an expansion of up to about 10%, preferably of up to 2%.

19. A process according to any of claims 6 - 18, characterized in that after the second treatment with a plasticising material a metered amount of liquid preparation containing a lubricating material is introduced into the tube and during the second drying step a substantially uniform coating is formed on the inner wall of the tube.

20. A process according to claim 19, characterized in that said liquid preparation essentially consists of a mix- ture of water, mineral and/or vegetable oil and an aqueous solution of cellulose ether as well as an emulsifier.

21. A process according to claim 20, characterized in that a polysaccharide or lipid or a mixture thereof is em¬ ployed as the emulsifier.

22. A process according to any of claims 6 - 21, characterized in that the lubricating material contains na¬ tural organic pigments such as, for example, annatto, paprika and curcuma.

23. A process according to any of claims 6 - 22, characterized in that the lubricating material contains a flavouring agent, for example a smoke aroma.

24. A process according to any of claims 1 - 23, characterized in that the lubricating material or a portion thereof is applied via mandrel in the shirring machine.

25. A process according to any of claims 1 - 23, characterized in that the tube is humidified by applying thereto, via mandrel of the shirring machine, an aqueous sol¬ ution of carboxymethylcellulose.

26. A process according to any of claims 1 - 23, characterized in that the tube is humidified by application of water thereto via mandrel of the shirring machine.