DE1570178A1 - Process for making a consumable tubular casing - Google Patents

Description

Munich, June 16, 1965 L / P

Applicant: MILEVER Ή.Ύ. , Museum Park 1, Rotterdam, Holland

Process for the production of a consumable, tubular casing

The present invention relates to edible products, particularly tubular casings.

Good quality casings for use as sausage skins (so-called natural skins) are often difficult to obtain Lot to get and are quite expensive. Various attempts have been made in the past to produce an artificial, edible sausage skin with properties that are similar to those of a good natural skin are similar and which can be produced relatively cheaply in large quantities. Different methods for doing this have already been suggested, but the skins obtained by them were either inferior in theirs Quality or, if they were of the desired quality, they were relatively expensive.

The present invention provides a method of making an artificial sausage skin by treating Collagen under highly alkaline conditions and then extruding the modified collagen into one Tube shape.

The modification of the collagen according to the invention is best carried out by treating the collagen with

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a saturated or nearly saturated solution of a salt capable of preventing the collagen from swelling, and a solution of a strong alkali, preferably at a pH of 13 or above. The salt which prevents the collagen from swelling is suitably an alkali metal salt, for example sodium sulfate, and is preferably used in a more than 90% saturated solution, based on the salt concerned. The strong alkali is one which can provide a solution with a pH of 13 or above and is preferably an alkali metal hydroxide, for example sodium hydroxide. The loading ψ treatment with alkali should be performed in the presence of the salt.

The modified collagen which is obtained in this way can be converted into gelatin more easily than unmodified Collagen, and the extent to which the treatment has modified the collagen, can be determined by the amount of collagen produced Gelatin (compared with the amount generated from unmodified collagen) can be determined when the material is used into an excess of boiling water at a neutral pH-7 / ert and under essentially ion-free conditions is introduced. A test to determine the degree of modification of the collagen is given below.

Test to determine the degree of collagen modification:

The percentage of extractable gelatin in 15 minutes at 10O ⁰ C from a 50 g sample of collagen (normally skin) in 100 ml of water is called the "gelatin conversion ¹ *. The sample is at a pH of 7-9 and below im The sample is washed in running water for at least 24 hours before the gelatin conversion is determined: The amount of gelatin formed is most conveniently determined by measuring the fractionation rate by comparing the amount thus obtained.

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ten index with a standard curve of the fraction indices, plotted against the gelatin concentration, determined.

Using this test, the material possesses which is used to produce the sausage skins, preferably a gelatin conversion value between about 10 and 22% and preferably between 10 and 17% (unmodified collagen is usually 5% or less Gelatin conversion).

After the initial treatment under highly alkaline conditions, the modified collagen is washed for Removal of excess alkali and salt. It can be acidified with an acid (but not a carboxylic acid) be to the complete removal of the alkali and. of salt to facilitate. It's cheap the modified one Acidifying collagen to a pH value between 4 and 5 at this stage of the process and washing after acidification continue until the modified collagen has a pH of about 7.

The modified collagen is preferably now subjected to a comminution, which preferably continues for so long until the suspension has a smooth, fibrous consistency with a solids content between 9 and 15 »preferably between 10 and 11? Ö.

The crushed, modified collagen is then swollen with an acid, preferably a hydroxycarboxylic acid, best to a pH value between 2.5 and. 4-.0, preferably between 2.9 and 3 »2. Also, water can are added to achieve a solids concentration between 2.5 and 10, preferably between 6 and 8%.

Sometimes it may be desirable to change the drying properties of the casing and the moisture content

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To make it more uniform, a certain amount becomes one suitable plasticizer or humectant added to the acidic swollen material. To the For example, glycerin can be the acidic swollen material be added in a final concentration of about 1%.

Ventilation is preferred after the acidification stage performed by thoroughly mixing the acidic swollen material under partial vacuum, preferably under air of 3 cm mercury pressure.

Before the modified, swollen collagen is extruded, a filtration can be carried out to remove undesired To remove lumps of material which could block the extrusion device, although that in the one according to the invention Process obtained, swollen collagen is normally extrudable without filtration.

The extrusion can be carried out in any suitable precipitation bath, preferably at a temperature of 0-37 ⁰ C.

Sodium chloride in concentrated solution is very successful as a precipitant for both eucollagen and collagen (with a solids content below about 5% other chemicals such as ammonium sulphate may be used be more suitable as a precipitant, however, the use of such substances is not as desirable as they usually require thorough washing of the casings and their presence in food often does not meet the food laws. Sodium chloride does not have to be completely washed out of the casing and does not violate any food laws). Extrusion into a saturated sodium chloride solution is then preferred Type of precipitation of the solid material in the suspension.

If necessary, the precipitation salt can be removed by washing the shell before drying, or at least its con-

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centering in the envelope can be reduced. The washing can done by spraying the shell with water; preferably the spray water contains about 2.5% by weight of 880 ammonium hydroxide.

A precipitation bath containing salt, particularly sodium chloride and ammonium hydroxide, has also been used. In the sodium chloride is preferably located in such a bath in saturated solution and the content of ammonium hydroxide is not greater than N / 2, preferably N / 10.

If desired, tanning agents can be used in the precipitation or in a subsequent process stage to increase the strength of the moist shell. The product can be kept in the tubular shape by inflating it with a solution of the precipitant and / or air, which conveniently through suitable openings in the extrusion nozzle is inserted into the opening of the hose.

The casing is during and after the final drying preferably kept at a pH not lower than 5, since it has been found that the slope of the in her contained eucollagen to convert into gelatin is increased by the presence of acid. Preferably the The pH of the casing should not be less than 6. The point in time at which the pH of the casing should be adjusted depends on the respective process conditions. In general, the pH of the shell should never be below 5 when the temperature the shell is raised above the gelatinization point of the eucollagen. The pH value is therefore preferably adjusted before the temperature is increased, e.g. if the casing is by means of is dried at high temperature.

After the extrusion, the casing is generally dried, preferably with warm air. Air is preferably passed through the envelope to help it. inflate while drying, so that it retains its tubular shape.

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Optionally, after the precipitation in the salt solution, the shell can be partially or essentially completely dried (preferably by inflating with air), while it is still saturated with the salt, which is preferably sodium chloride, since it has been found so dried casings are generally stronger than those from which the salt was washed before drying. if If this is done, the shell can with water, preferably such water, which ammonium hydroxide in low concentration (about N / 10) should be washed after the moisture content of the casing has been reduced to about 20% has been. The washed casing is then again dried in "warm" air to a suitable moisture content.

The invention is illustrated by the following examples.

example 1

5 kg of limed Yiehhaut split pieces were in 20 l of water, which contained 200 ppm free chlorine, immersed for 1 hour at room temperature. The split pieces were then transferred to 20 l of a 10? fig sodium chloride solution, to which HGl was added to achieve a pH of 5.0. When the middle of a cut piece reacted acidic to phenolphthalein, the acid wash was complete and the split pieces were in water washed until the centers of the split pieces reacted neutrally.

The split pieces were then soaked in 20 l of a saturated sodium sulfate solution at 20 ^° C. for 24 hours. Sodium hydroxide was then added to make the salt solution molar with respect to sodium hydroxide, ie 4%, and the splits were gently agitated in this bath for an additional 24 hours at 20 ° C.

The gelatin conversion of the modified Collagen was determined as follows:

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Discs 3 »8 cm in diameter were made from the split pieces punched out. Some of these disks were used to dry the solids at 105 ° C in an oven determine and 50 g of the remaining slices were in 100 ml of boiling water placed. The mixture was on Heated to 100 ° C. and refluxed for 15 minutes. The resulting gelatin solution became solids freed, cooled to 40 ° C and the pH of the solution was measured to make sure it was between 7 and 9 and the concentration of. Gelatin was made using of the refractive index determined.

The gelatin conversion in% is 100 y, where

c (100 + 50 (1 - x)) y ₌ __. _t

50 χ (1 - c) P

χ the fractionated solids content, ρ the density of gelatin and collagen (1.389 g / ml) and c is the concentration of gelatin in g / ml.

A test conducted in this way indicated that the modified Collagen had a gelatin conversion of 14% and was therefore suitable for extrusion to hide.

The splits thus treated were washed with water, then dilute HCl was added, however the pH was not lowered below 3.0. The split pieces were washed again with water until the center point of a cut piece was neutral. The split pieces were then crushed by passing them through a high-speed Choppers with a plate with holes about 8 mm in diameter were sent. “Yasser was through that Machine, together with the split pieces, to the To lower the temperature and to obtain a crushed mass with a solids content of 10-11%. The crushed, modified collagen was then further crushed.

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nert by passing it through a colloid mill 3 times resulting in a paste with a smooth, fibrous consistency.

The modified collagen suspension was then thoroughly mixed in a planetary mixer while water and lactic acid were added to achieve a solids concentration of 7% and to reduce the pH value to 3 »o. The resulting mass was deaerated by placing it under vacuum in a Z-shaped mixer Propeller was mixed for 20 minutes.

The air-free mass, which has a viscosity of about 50 poise possessed, was fed to a counter-rotating extrusion nozzle with an annular opening of 0.5 mm. The displayed Extrusion pressure for a mass with 6% collagen was 8 kg / cm at an extrusion speed of 4- m / minute. The shell thus formed was turned up into a Saturated sodium chloride solution extruded, the envelope being inflated with air and saturated sodium chloride solution circulated inside the envelope. The inflated envelope was dried in hot air while still wet from the saturated saline solution until the moisture content was reached was below 30%, was then washed with water for removal of the salt, again dried in hot air and placed in an atmosphere of 80 #> relative humidity equilibrated for 24 hours.

Example 2

30 kg of fresh, limed split pieces were gently stirred for 18 hours in a vat containing 150 l of a saturated sodium sulfate solution. The temperature of the vat was ^{kept at 20 °} C. throughout the process and a small excess of sodium sulfate was added to maintain saturation. Sufficient sodium hydroxide was added to make the concentration 1N

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and this alkali treatment was continued for 24 hours.

The hides treated in this way were placed in running water during Washed for 30 minutes and then treated with dilute hydrochloric acid at pH 4- until the skins are essentially were neutral. 10% sodium chloride, based on the wet weight of the skin, was added to the hydrochloric acid solution, to prevent the skins from swelling. All. Traces of acid and salt were then removed by washing in water.

The hides treated in this way were ground twice through an 8 mm plate, with water or ice being added to keep the temperature below 25 ° G and the desired Achieve solids content of 10-11%. The crushed skins were passed through a colloid mill three times Making a smooth, fibrous paste.

The fibrous paste became vigorous with water and lactic acid mixed to obtain a viscous mass with a pH of 3 and a solids content of 7 »0%. This mass was deaerated by mixing in a mixer with a Z-shaped propeller for 20 minutes at a pressure of 3 cm of mercury.

The deaerated material was extruded through a counter-rotating nozzle into a precipitation bath of saturated sodium chloride solution to which ammonium hydroxide was added to achieve a concentration of N / 10. The casing was dried in a stream of warm air and the courtship was removed by spraying it with N / 10 ^ immonium hydroxide solution. The washed casing was dried in warm air to a moisture content of 30%.

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Claims (16)

Claims 1.) Process for the production of a tubular casing, characterized in that collagen is treated under strongly alkaline conditions and thereafter so chemically modified collagen extruded into tubular form will. 2.) The method according to claim 1, characterized in that the collagen with strong alkali in the presence k of a salt which prevents the collagen from swelling "is treated. 3.) Method according to claim 2, characterized in that the strong alkali is an alkali metal hydroxide, which provides a solution with a pH of 13 or above, e.g., sodium hydroxide. 4.) Method according to claim 2 or 3> characterized in that the salt capable of preventing swelling is an alkali metal salt, e.g. Sodium sulfate, is. 5.) Method according to one of the preceding claims, da- ) characterized in that the modified collagen which is extruded has a gelatin conversion (determined as described) of 10-22, preferably 10-1770. 6.) Method according to one of the preceding claims, characterized in that the modified collagen is swollen with a carboxylic acid prior to extrusion. 7.) Method according to one of the preceding claims, characterized in that the suspension of modified Collagen that is extruded, 2.5-10 wt%, 009810/1591 -2- -4f- preferably contains 6-8 wt% total solids. 8.) Method according to one of the preceding claims, characterized in that the extruded material ^{v is passed} into a precipitation bath which contains a salt that precipitates collagen. 9) Method according to claim 8, characterized in that that the salt is sodium chloride. 10.) Method for drying collagen or a modified collagen product, which is treated with a precipitating salt, e.g. sodium chloride, has been precipitated, characterized in that the product is partially or is completely dried without the precipitating salt being washed out beforehand. 11.) The method according to claim 10, characterized in that the salt is washed out of the product after drying will. 12.) Method according to one of claims 1-%, characterized in that that the precipitation bath contains a tanning agent. 13 ·) Method according to one of claims 1-9 or 12, characterized characterized in that the precipitation bath contains ammonium hydroxide. 14-.) Method according to one of the preceding claims, characterized characterized in that after the precipitation, the casing is washed with water, which is a small amount Contains ammonium hydroxide. 15.) The method according to any one of the preceding claims, characterized in that after the extrusion Casing is air dried. 16.) The method according to claim 15, characterized in that that the casing is kept at a pH not below 5 during and after drying. 009810/1591 ORIGINAL INSPECTED