NZ270464A - Cellulose sausage casing with annatto internal coating - Google Patents

Description

New Zealand Paient Spedficaiion for Paient Number £70464 ♦ Patents Form No 5 270 priority Date(s):.../.P..z3~.

Compete Specification Filed; Class: (6) AZ&C azuj.IJM.

Publication Date:, P.O. Journal No: 11 7.. P AT Ei'lT 0 F Fi C£ -8 FEB 1995 receive THE PATENTS ACT 1953 COMPLETE SPECIFICATION SAUSAGE CASING COATED IN ANNATTO AND A METHOD FOR COATING THE INNER SURFACE OF THE CASING We, VISCOFAN, Industria Navarra de Envolturas Celulosicas, S.A. a Spanish company of Iturrama, 23 - Entreplanta, 31007 Pamplona (Navarra), Spain, hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: -1- (following by page la) 27 0 4 - la- " SAUSAGE CASING COATED IN ANNATTO AND A METHOD FOR COATING THE INNER SURFACE OF THE CASING OBJECT OF THE INVENTION The invention relates to cellulose casings with an added colouring that are used for making skinless sausages and that transfer colour to the sausage stuffed within such casing.

BACKGROUND OF THE INVENTION Sausages are made stuffing a casing with a meat emulsion and then cooking and processing and sometimes 15 smoking the same to obtain the sausage.

Some types of sausages are inserted in regenerated cellulose casings and processed inside the casings. After the emulsion process, the casing is generally peeled off 20 and the sausages are packaged to be sold to consumers.

Sausage manufacturers need to provide sausages with an appearance that is appealing to consumers. Colour is an important feature in this overall appearance. The 25 colour of sausages depends upon the emulsion and the kind of meat used. It also depends on processing conditions, for instance whether or not an additional smoking treatment is provided.

Sausages having a substantially uniform surface colour are much to be desired. This is why a solution sausage manufacturers sometimes provide comprises colouring the outside of sausages in colouring reservoirs containing edible Colouring, inter alia annatto. 27 0 4 And yet this alternative of colouring sausages in colouring baths poses manifold disadvantages for food manufacturers. One such problem lies in the need of having suitable colouring equipment including reservoirs, conveyor belts and solutions for colouring and washing, inter alia.

Furthermore, gradual consumption of the colouring contained in the bath leads to an uneven colouring of sausages and to overcome this problem it is therefore necessary to gradually replace the colouring used up.

In addition, after colouring the sausages some kind of fixing or washing generally follows. Colouring losses in such washing baths mean that additional colouring is used up, and furthermore, the waste from such colouring baths also poses an environmental pollution problem.

Moreover, the increased time of exposure of the peeled sausages to the external environment leads to an increased risk of microbiological contamination of the sausages. cellulose casings used in manufacturing sausages are made extruding a viscous solution through an annular opening. The resulting tube is coagulated and washed in various reservoirs and is finally soaked in a plasticizing agent and dried. Cellulose casings can also be prepared with a fibrous net embedded into the wall. This fibrous net is usually made of rope paper in order for the casing to be stronger. Such casings are known as fibrous casings.

Cellulose casings have also been made soaked in various edible colourings in order for the colouring to 270 be transferred while the sausage is being processed to its surface and thus the colour will stay on the surface of the sausage when the casing is removed. Food colourings, F.D. & C. Red number 40 and F.D. & C. Yellow 5 number 6, are artificial colourings used to make casings that transfer colour to the sausages stuffed therein.

The casing can be coloured in a colouring bath or otherwise providing an inner coating upon the inner 10 casing surface.

The casing can be coloured in a bath by passing the casing through a colouring bath, usually whilst it is in a gel state, in order to soak the casing with the 15 colouring. US patent number 2,521,101 to Thor et al. describes an example of this method.

Otherwise, various methods are known to apply coatings on the inner casing surface to which various 20 substances can be added for various objectives. Among such methods there is a method of spraying or soaking the inside of the casing during the folding operation described in US patent number 3,451,827 to Bridgeford and the bubble coating method described in US patent numbers 25 3,378,379 to Shiner et al. and 3,106,471 to Firth. According to this bubble coating method, a quantity of liquid is placed inside the casing and held there by action of rollers that press the casing to prevent the liquid from passing whilst the casing moves forward. By 30 acting upon the rollers a desired quantity of the internal liquid is allowed to pass, thereby coating the inner casing surface.

The coating is usually provided on the inside of the 35 casing, though it may be so provided on the outside if 2704a the inside of the casing is turned inside out before stuffing the meat.

Annatto is an edible colouring that is used in some 5 countries for colouring the surface of sausages because it has a very attractive reddish colour. In the market there are various annatto extracts with different characteristics. There are water-soluble annatto colourings containing norbixin as primary colouring 10 matter and other oil-soluble colourings containing bixin as primary colouring matter. The quantities of colouring of the extracts can vetry and their bixin and norbixin contents are spectrophotometrically determined, expressing the same as its equivalent norbixin contents.

Annatto, as aforesaid, cam be used for colouring the outer surface of sausages and for colouring sausage casings by passing the same through a bath of annatto, as described for instance in US patent number 2,521,101 to 20 Thor et al.

It is clear therefore that annatto can be used for colouring sausages and casings in baths. And yet attempts at manufacturing cellulose casings incorporating annatto 25 colouring and capable of transferring colour to the sausage have been unsuccessful. Which is why, because of the difficulties production thereof entails, there are currently no commercial cellulose casings transferring emnatto available. These difficulties can be summarised 30 as follows: - emnatto, soedced in the gel state, is difficult to remove from the casing and only a small quantity is tremsferred to the sausage; - 2704 64 it is difficult to achieve the high concentration desired of annatto in the casing because of the short time period the colouring has to be diffused into the casing, given the relative high speed of travel through 5 the bath; - emnatto solutions cemnot endure the relatively high temperatures, close to 60 *C, and persistence of the baths in the normal manufacturing process, without being noticeably impaired; emd - the high temperatures required to dry casings in the drier are also harmful for the stability of annatto.

In addition to these technical difficulties, the various characteristics of the various annatto extracts (oil- and water-soluble) that are commercially available limit their capability of being used separately, for such colourings, per se, do not provide coatings of suiterible 20 characteristics upon the cellulose casing.

In fact, oily emnatto solutions do not moisten the cellulose casing, for it is substemtially hydrophilic, and remain as drops upon the casing surface, wherefore 25 instead of providing a coating of even colour, sausages are provided having a spotted appearemce (spots on the surface).

Furthermore, the used of aqueous annatto solutions 30 provides unevenly coloured casings. These aqueous emnatto solutions stick to both sides of the casing emd when the casings are opened the colouring stays only on one of the sides, wherefore half the casing is coloured whereas the other side stays without emy colour, the sausages being 35 thus unacceptable emd unevenly coloured. 27 0 4 Cellulose casings are usually sold folded, shaped as small cylinders (sticks) containing at least 50 metres of folded casing. Oily coatings also reduce the adherence between the casing folds that are produced in the folding 5 process, thereby yielding unacceptable folded cylinders of cellulose casings, that do not retain their own shape after folding.

It would therefore be much to be desired for a 10 cellulose casing to be provided, capable of transferring annatto colouring to the sausage stuffed inside the said casing. A casing of this kind would inter alia offer the following advantages: - emnatto is a colouring that remains upon the surface of the sausage and does not migrate into the same, as do food colourings that are normally used in this kind of cellulose casings in sausages that may transfer colouring (transferable); colouring is saved, for diffusion of the colouring into the sausage requires a greater quantity of colouring matter to achieve the same colour upon the surface of the sausage; a "natural" colouring is used, as compared with "artificial" colourings that are normally used in this kind of transferable cellulose casings, which means a better acceptance among consumers; an additional advantage over colouring of finished sausages in annatto baths is that contact between the colouring and the surface of the sausage takes place during the hot processing stage which means that the 35 colouring will be fixed better to the surface of the 2704 sausage and the risk of microbial contamination will be reduced; emd yet smother advantage of this casing, for the food 5 manufacturer, lies in that the manufacturer would no longer require sausage colouring equipment.

Now therefore, an object of the present invention is a cellulose casing transferring a red-orange colour to 10 the sausage stuffed into the said casing with a substantially homogenous appearance, emd containing an emnatto colouring that overcomes the disadvantages aforesaid and provides the advantages listed above.

Another object of the present invention is a coating composition for a cellulose sausage coating.

An additional object of the present invention is a method for coating the inner surface of a cellulose 20 sausage casing with a coating composition. m And yet another object of the present invention is a process for fixing the colouring to the casing. other additional objects of this invention will follow clearly from the following description emd the attached claims.

SUMMARY OF THE INVENTION The invention provides a cellulose casing transferring a substantially uniform red-orange colour to the sausage stuffed inside the said casing.

The cellulose casing of this invention contains an 2704 internal coating containing at least two components: i) a water-soluble emnatto colouring, emd ii) one or more oily substances.

DETAILED DESCRIPTION OF THE INVENTION The invention provides a cellulose casing that transmits colour to sausages while they are being 10 processed, containing a macroscopically homogenous internal coating comprising at least two components, one of which is a water-soluble annatto colouring emd the other comprises one or more oily substemces.

The sausage casings that may preferably be coated with colouring in accordance with the present invention are cellulose casings, sold in the form of folded sticks of variable length, indeed of up to 50 metres or more of casing, each stick being some 30 cm long.

The said casings sure used as a mould for making the sausage by stuffing the contents. Once sausage processing is over, at the final cooking emd in many cases smoking stage, the casing is removed from the sausage by peeling.

Cellulose casings to be coated in accordance with this invention cem be casings having a fibrous net on their wall or otherwise, and may be memufactured by any of the known methods aforesaid, for instemce as described 30 in US patent numbers 2,999,757 to Shiner et al. emd 2,983,949 to Matecki.

As set out e&ove, it has now been found that the addition of em internal coating containing at least two 35 components, one of which is a water-soluble annatto - 9 2704 colouring and the other comprising one or more oil-soluble substances, onto a cellulose casing, provides casings that are able to add colour onto the sausage surface. The coating obtained for the sausage has optimal 5 features to be used in markets seeking an orange-like shade in the sausage coatings.

The market offers various annatto extracts with different characteristics. In fact, there cure water-10 soluble annatto colourings and other oil-soluble colourings, with differing amounts of bixin and norbixin, the main colouring substances. Both forms can be easily interconverted into the other form, and their concentration can be expressed approximately as the 15 equivalent concentration of amy of the two colouring forms.

The market currently offers aqueous water-soluble emnatto solutions with contents ranging approximately 20 between 0.2% and 5% of colouring matter expressed as norbixin, and water-soluble powder forms containing up to 15% of colouring matter, expressed as norbixin.

Furthermore, oil-soluble emnatto forms can also be 25 found containing approximately between 0.1% emd 5% of colouring matter expressed as bixin. Though these forms are usually referred to as oily solutions, they can comprise true solutions, suspensions or emulsions. This distinction is not a key factor in using this invention.

As set out above in the Background of the Invention, the water- or oil-soluble annatto colouring is not pet se stifficient to obtain coatings on the cellulose casing of suitable characteristics. 27 The oil-soluble annatto colouring does not stick to the essentially hydrophilic and easily removable cellulose casing surface emd hence no even wear-resisting colour is provided on the surface of the sausage.

Aqueous annatto solutions stick to both sides of the casing and when the casings are opened the colouring remains on one side only. Therefore, half the casing is coloured whilst the other half has no colour, whence the 10 sausages provided are unacceptable, since unevenly coloured.

It has now surprisingly been found that the mixture of both (water- and oil-soluble) annatto colourings 15 provides a coating that: - is not easily removable by surface wear, - is essentially even, and - prevents the casing faces from sticking.

Without setting down a binding theory, it seems that the mixture of the two improves the evenness of the oil-soluble colouring, that is far greater them with the oil-soluble colouring on its own, emd decreases the excessive 25 adherence of the water-soluble colouring on the cellulose casing.

Now therefore, a cellulose casing is provided that treuismits colour to sausages whilst they are being 30 processed, containing ein internally macroscopically homogenous coating, comprising at least two components, one of which is a water-soluble emnatto and the other comprising one or various oily substemces.

The contents of the colouring substance, expressed 27 -ll- as norbixin, in the internal coating ranges between 0.2 and 9 mg/dm2 of casing surface, preferably between 1 emd 2.5 mg/dm2 of casing surface.

The contents of the oily substance in the internal coating comprises between 1 emd 25 mg/dm2 of casing surface, preferably between 3 emd 15 mg/dm3 of casing surface. The reference to casing surface should be taken as a reference to the internal casing surface.

It has also been found that the addition of another oily compound, for instance animal oil, vegetable oil, mineral oil, silicone oil, synthetic oils emd glycerides, has a similar effect, whence these products cem replace 15 the oily annatto solution, as desired. Consequently, the internal coating need not contain em oily emnatto solution emd may instead contain one such oily compound or a mixture of two or more of such products. This mixture may optionally contain em oily annatto solution.

The quemtity of oily component may be provided at a rate of between 0.5% emd 25% of the coating weight, preferably between 3% and 15% of the coating weight.

In a preferred embodiment, the oily component of the coating is em oily bixin solution, dispersion or emulsion containing between 0.1% emd 5% of colouring matter expressed as bixin on the aggregate. The water-soluble annatto colouring used may be any commercially availe&le 30 one, such as for instemce A-5000-WS-P (CHR. Hansen's). The oil-soluble colouring used may be emy commercially available one, such as A-4OOO-OSS (CHR. Hansen's), or commercially available products of similar characteristics. 4 (M l\ ti ^ £ ■ ; 270 The quantity of colouring can vary according to the extent of colour that is to be obtained on the sausage, though the final colour will also depend to a certain extent on the meat exaulsion used and processing thereof.

This quantity of colouring, expressed as norbixin, can vary between 0.2 emd 9 mg/dm1 of casing surface, preferably between 1 emd 2.5 mg/dm2 of casing surface.

Different additives may be optionally added to the colouring coating solution. Thus, for instance, thinners such as water, edible oils; plasticizers such as polyols, for instance glycerine or propyleneglycol; emulsifiers, such as lecithin, ethylene oxide adducts emd a partial fatty acid ester and polysorbates, for instemce Tween 80; peeling or peeling enhancing substances or mixtures such as cellulose ethers, for instemce carboxymethylcellulose and other additives used habitually in making sausages can be added.

This invention also provides a suitable composition for internally coating a cellulose sausage casing, comprising at least two components, one of which is a water-soluble annatto colouring, emd the other comprises one or more oily substances, the emnatto colouring being provided at a concentration lying between 0.2% emd 10%, emd the oily substance between 0.5% emd 25%, preferably between 3% emd 15% of the coating liquid.

The water-soluble annatto colouring used can be any commercially available one, such as for instance A-4000-WS-P (CHR. Hansen's).

The second component of this coating composition comprises one or more oily substances. The oily 27 04 substances used can be commercially available oily solutions, dispersions emd emulsions of an oil-soluble emnatto colouring, such as A-4000-OSS (CHR. Hansen's) or commercially available products of like characteristics. Other oily compounds cem also be added, for instemce animal oil, vegete&le oil, mineral oil, silicone oil, synthetic oils emd glyceridas, that may replace the oily annatto solution, as appropriate, or a mixture of two or more of such compounds with or without em oily emnatto • solution can be prepared.

Additionally emd optionally, the coating composition can be supplemented with various additives that eure used heibitually in making sausages, for instemce thinners, plasticizers, emulsifiers, peeling or peeling enhancing substances or mixtures emd other habitual additives cem be added.

The present invention also provides a method of coating the internal surface of a cellulose sausage coating with a coating composition. The said method of coating the inner surface of the cellulose casings > comprises a stage at which the inner wall of the said casings is placed in contact with a coating liquid or composition comprising at least two components, one of which is a water-soluble emnatto colouring, emd the other comprising one or more oily substances, wherein the water-soluble annatto colouring is provided at a concentration lying between 0.2% emd 10%, emd the oily substance between 0.5% emd 25%, preferably between 3% emd 15% of the coating liquid.

The water-soluble emnatto colouring used cem be any commercially availe&le one, for instance A-4000-WS-P (CHR. Hemsen's). 27046 The second component: of the coating liquid comprises one or more oily substances. The oily substances used cem be commercially available oily solutions, dispersions emd emulsions of an oil-soluble annatto colouring, such as A-4000-OSS (CHR. Hansen's) or commercially available products of like characteristics, other oily compounds can also be added, for instance animal oil, vegetable oil, mineral oil, silicone oil, synthetic oils and glycerides, that may replace the oily annatto solution, as appropriate, or a mixture of two or more of such compounds with or without an oily annatto solution can be prepared.

In a preferred embodiment the oily component of the coating liquid is an oily bixin solution, dispersion or emulsion.

Additionally and optionally the coating liquid cem contain various additives that are used habitually in making sausages, for instance thinners, plasticizers (between 5% and 60% of the aggregate weight of the coating liquid), emulsifiers, peeling or peeling enhancing substances or mixtures and other habitual additives.

The various methods for soaking the internal surface of the casings, inter alia as described in US patent numbers 3,106,471 to Firth emd 3,451,827 to Bridgeford, can be used, within limits, in putting the present invention into effect.

An additional application of the present invention allows coloured casings to be obtained, manufactured using a cellulose casing, provided by this invention, transmitting colour to such sausage while it is being 2704 processed, and containing a macroscopically homogenous internal coating comprising at least two components, one of which is a water-soluble emnatto colouring and the other comprises one or more oily substances.

Yet another application of the present invention provides a method for colouring sausages obtained by stuffing the meat mass into a cellulose casing as provided by this invention, which transmits colour to 10 such sausage while it is being processed, and contains a macroscopically homogenous internal coating comprising at least two components, one of which is a water-soluble annatto colouring and the other comprises one or more oilj substances.

EXAMPLES The following examples are only meant to illustrate this invention emd should not be talcen to limit the same.

EXAMPLE 1 This example illustrates the treating of a casing with a mixture of annatto colourings that provides a 25 suitable casing to transmit a substantially even red-orange colour to the food products with which the said casing is stuffed.

The components listed hereinafter are mixed in the amounts given, using a high-power mixer to disperse the same: C<?OT?«?n<?ntg A—4000—OSS AN-14 WP ml 21.4 g 27046' Propyleneglycol 25 ml Glycerine 20 ml Tween 80 1.62 g Carboxymethylcellulose (sodivun salt) (Walocel) 0.64 g Water 45 ml A—4000—OSS Is an oil-soluble annatto colouring with a colouring content of approximately 4%, and manufactured by the firm CHR. Hansen's.

AN-14 WP is a water-soluble powder annatto colouring with a colouring content of approximately 14%, and manufactured by the firm Xantoflor.

Tween 80 is a sorbitan polyoxyethylene and fatty acid ester.

The mixture is evenly applied to the inner surface of the cellulose casing by the so-called bubble method 20 (comprising applying the coating slowly, constantly and firmly) with a content of 0.04 ml/dm2 of casing surface, which is equivalent to 1.1 mg/dm2 of colouring.

The water content of the casing is adjusted to 14% 25 and after folding the casing is stuffed with meat, and the sausage is then processed and peeled.

The sausages obtained had a substantially even red-orange colour.

EXAMPLE 2 This example illustrates the use of a water-soluble form of annatto that yields em uneven sausage colour. 2704 6 A The components listed hereinafter are mixed in the amounts given, using a high-power mixer to disperse the same: Components AN-14 WP 28.6 g Propyleneglycol 15 ml Glycerine 9 ml Carboxymethylcellulose (sodium salt) (Walocel) 0.64 g Water 76 ml The mixture is evenly applied to the inner surface of the cellulose casing by the bubble method, with a content of 0.04 ml/dm1 of casing surface, which is equivalent to 1.1 mg/dm2 of colouring.

The water content of the casing is adjusted to 14% and after folding the casing is stuffed with a meat emulsion, and the sausage is then processed and peeled. Folding was poor due to self-adhesion of the casing faces.

The sausages obtained had an irregular appearance covered in spots (mosaic appearance).

EXAMPLE 3 This example illustrates the use of an oil-soluble form of annatto that yields an unsuitable sausage colour.

The components listed hereinafter are mixed in the amounts given, using a high-power mixer to disperse the same: 27 '4 Components A—4000—OSS 10 ml Propyleneglycol 25 ml Glycerine 20 ml Lecithin 1.8 g carboxymethylcellulose (sodium salt) (Walocel) 0.64 g Water 45 ml The mixture is evenly applied to the inner surface of the cellulose casing by the bubble method, with a content of 0.025 ml/dm* of casing surface, which is equivalent to 0.1 mg/dm* of colouring.

The water content of the casing is adjusted to 14% and after folding the casing is stuffed with a meat emulsion, emd the sausage is then processed and peeled.

The sausages obtained bad a spotted appearance, with 20 a non-homogenous pale reddish colour that was easily removable by surface wear.

EXAMPLE 4 This example illustrates the use of a commercial annatto solution that yields an unsuitable sausage colour.

The components listed hereinafter sure mixed in the amounts given, using a high-power mixer to disperse the same: Components A-720-OWS Tween 80 98 ml 2 ml 27 A—720-OWS is an oil- and water-soluble annatto colouring with a colouring content of approximately 2.5%, of the firm CHR. Hansen's.

@ / V <■- The mixture is evenly applied to the inner surface of the cellulose casing by the bubble method, with a content of 0.04 ml/dm2 of casing surface, which is equivalent to 1.1 mg/dm1 of colouring.

The water content of the casing is adjusted to 14%.

Folding is difficult.

After folding, the casing is stuffed with a meat 15 emulsion, and the sausages are then processed and peeled.

The sausages obtained had a non-homogenous appearance emd the surface colour was easily removeible by surface wear.

EXAMPLE 5 This example illustrates the use of a casing with another mixture of annatto colouring that provides a 25 suitable casing to transmit a substantially even red-orange colour to the food products stuffed in such casing.

The components listed hereinafter are mixed in the amounts given, using a high-power mixer to disperse the same: Components A—4000—OSS A—4000—WS—P ml 21.4 g 27 Glycerine 45 ml Tween 80 1 g Water 49 ml A-4000-WS-P is a water-soluble powder annatto colouring with a colouring content of approximately 14%, of the firm CHR. Hansen's.

The mixture is evenly applied to the inner surface of the cellulose casing by the bubble method, with a content of 0.03 ml/dma of casing surface, which is equivalent to 0.90 mg/dm* of colouring.

The water content of the casing is adjusted to 14% and after folding the casing is stuffed with a meat emulsion, and the sausages are then processed and peeled.

The sausages obtained had a substantially even red-orange colour.

EXAMPLE 6 This example illustrates the treatment of a casing with a mixture of an oily substance with a water-soluble annatto colouring that provides a suitable casing for transmitting a substantially even red-orange colour to the food products stuffed in such casing.

The components listed hereinafter are mixed in the amounts given, using a high-power mixer to disperse the same: Components Delios V 20 ml AN-14 WP 25 g - 270406 Glycerine 45 ml Tween 80 2.5 g Carboxymethylcellulose (sodium salt) (Walocel) 0.64 g Water 35 ml Dellos V is a vegetable oil of the firm Henkel.

The mixture is evenly applied to the Inner surface of the cellulose casing by the bubble method, with a content of 0.066 ml/dm2 of casing surface, which is equivalent to 2.3 mg/dm2 of colouring.

The water content of the casing is adjusted to 14% and after folding the casing is stuffed with a meat emulsion, and the sausages are then processed and peeled.

The sausages obtained had a substantially even red-orange colour.

EXAMPLE 7 A number of casing samples were prepared using the processes described in the examples, and sausages were made with such casings.

The colour of the sausages was recorded using a Dr LANGE Micro Colour colorimeter. The colour is expressed in L*a*b* values. The L* values stand for the clearness of the sample; the a* values stand for the redness or red quality of the sample and the b* values stand for the yellowness or yellow quality of the sample.

The results are shown in the following table: 2704 Examole iL * 3_ TsL Remarks 1 45 .2 36.3 43.9 Correct 2 47 .5 29.2 45.8 Casing faces stuck 3 59 .4 .4 17.6 Little colour 4 49 .3 34.3 45.3 Uneven. Folding poor 49 .9 31.4 46.6 Correct 6 44 .9 34 46.9 Correct Control sausage not coloured 62 .4 6.2 11.6 Commercial coloured sausage 46 .1 34.1 40.5 The colour of the sausages made using the present invention was much like that of commercial sausages coloured using the conventional bath process.

Some preferred aspects of the invention have been described by way of example, but it will be appreciated that other variations and modifications to the invention can take place without departing from the scope of the appended claims. 4 2 7 0 4 6 4

Claims (38)

WHAT WE CLAIM IS:

1. A cellulose casing transmitting colour to sausages while they are processed, characterised by having a macroscopically homogenous internal coating comprising at least two components, one of which is a water-soluble annatto colouring and the other comprising one or more oily substances.

2. A casing as claimed in claim 1, wherein the oily component of the coating is an oily bixin solution, dispersion or emulsion.

3. A casing as claimed in claim 2, wherein the oily bixin solution has a bixin concentration lying between 0.1% and 5%.

4. A casing as claimed in claim 1, wherein the oily component of the coating is an animal oil.

5. A casing as claimed in claim 1, wherein the oily component of the coating is a vegetable oil.

6. A casing as claimed in claim 1, wherein the oily component of the coating is a mineral oil.

7. A casing as claimed in claim 1, wherein the oily component of the coating is a silicone oil.

8. A casing as claimed in claim 1, wherein the oily component of the coating is a synthetic oil.

9. A casing as claimed in claim 1, wherein the oily component of the coating is a mixture or combination of two or more oils as specified in claims 2 to 8.

10. A casing as claimed in any one of claims 1, 2 and 4 to 8, characterised in that the internal coating, the colouring substance, expressed as norbixin, is 27 0 4 6 4 -24- in a quantity ranging between 0.2 and 9 mg/dm2 of casing surface and the oily substance between 1 and 25 mg/dm* of casing surface.

11. A casing as claimed in claim 10, wherein the oily substance content lies between 3 and 15 mg/dm2 of casing surface.

12. A casing as claimed in claims 10 or 11, wherein the colouring content, expressed as norbixin, ranges between 1 and 2.5 mg/dm2 of casing surface.

13. A casing as claimed in any one of claims 1 to 12, charactersied in that the internal coating, besides a first water-soluble annatto colouring component, and a second oily component, contains at least a peeling substance or mixture.

14. A casing as claimed in claim 13, characterised in that the peeling substance or mixture contains at least a cellulose ether.

15. A casing as claimed in claim 13, characterised in that the peeling substance or mixture contains at least carboxymethylcellulose.

16. A casing as claimed in any one of claims 1 to 12, characterised in that the internal coating, besides a first water-soluble annatto colouring component, and a second oily component, contains at least an emulsifier.

17. A casing as claimed in any one of claims 13 to 15, characterised in that the internal coating, besides a first water-soluble annatto colouring component, a second oily component, and a third peeling substance or mixture component, contains at least an emulsifier.

18. A casing as claimed in claims 16 or 17, wher^m 2 7 0 4 6 4 -25- the emulsifier is lecithin.

19. A casing as claimed in claims 16 or 17, wherein the emulsifier is an ethylene oxide adduct and a partial fatty acid ester or a partial fatty acid and sorbite derivative anhydrides ester.

20. A cellulose casing as claimed in any one of claims 1 to 19, characterised in that the said casing has a fibrous net embedded in its wall.

21. A method for coating the internal surface of the regenerated cellulose casings as claimed in any one of claims 1 to 20, characterised in that the internal wall of such casings is made to contact with a coating liquid comprising at least two components, one of which is a water-soluble annatto colouring and the second component being one or more oily substances, wherein the water-soluble colouring, expressed as norbixin, is found at a concentration ranging between 0.2% and 10%, and the oily substance between 0.5% and 25%.

22. A coating method as claimed in claim 21, wherein the oily substance content is found at a concentration ranging between 3% and 15% of the coating liquid.

23. A coating method as claimed in claim 21, wherein the oily component of the coating liquid is a bixin solution, dispersion or emulsion.

24. A coating method as claimed in claim 21, characterised in that the internal coating liquid, besides a first water-soluble annatto colouring component, and an oily component, contains at least a peeling substance or mixture.

25. A coating method as claimed in claim 2 characterised in that the peeling substance or mi // <*■ 2 7 0 4 6 4 -26- contains at least a cellulose ether.

26. A coating method as claimed in claim 25, characterised in that the peeling substance or mixture contains at least carboxymethylcellulose.

27. A coating method as claimed in claim 21, characterised in that the internal coating, besides a first water-soluble annatto colouring component, and an oi^y component, contains at least an emulsifier.

28. A coating method as claimed in claim 27, wherein the emulsifier is lecithin.

29. A coating method as claimed in claim 27, wherein the emulsifier is an ethylene oxide adduct and a partial fatty acid ester or a partial fatty acid and sorbite derivative anhydrides ester.

30. A coating method as claimed in claim 21, characterised in that the internal coating liquid, besides a first water-soluble annatto colouring component, and an oily component, contains at least a plasticizer at a rate lying between 5% and 60% of the aggregate weight of the coating liquid.

31. A coating method as claimed in claim 30, wherein the plasticizer is glycerine.

32. A coating method as claimed in claim 30, wherein the plasticizer is propyleneglycol.

33. A coloured sausage manufactured using a casing as claimed in any one of claims 1 to 20.

34. A method for coating sausages obtained by stuffing the meat mass in a casing as claimed in any one of c 1 to 20. 2 7 0 4 6 4 -27-

35. A cellulose casing transmitting colour to sausages and like meat products, substantially, as hereinbefore described (but with exclusion of the prior art products referred to).

36. A method of coating the internal surfaces of casings for sausages forming and for imparting colour thereto, substantially as hereinbefore described (but with exclusion of the prior art methods referred to).

37. A sausage product when formed with the casing according to claim 35.

38. A sausage product when formed with the coating by the method according to any one of claims 21 to 32 inclusive, or claim 36. VISCOFAN, Industria Navarra de Envolturas Celulosicas, S.A. By their Authorised Attorneys JOHN A REMMINGTON & ASSOCIATES T o, V ,v^ $