Gel composition made of gellan gum and agarose for producing soft capsules or films, use thereof and method for producing same

Abstract

The invention relates to a gel composition for producing soft capsules or films, said gel composition comprising agarose, gellan gum with a high degree of acylation, one or more fillers, one or more plasticizers and water. The invention also relates to a method for producing soft capsules, having the steps of: providing a gel composition according to the invention at a temperature between 80 and 100°C, forming a film from the gel composition by cooling to a temperature below 30°C, providing a capsule filling, producing the soft capsules by enclosing the capsule filling with the film formed from the gel composition, thereby forming the capsule shell, and drying the capsule shell to a water content of approximately 20 wt.% or less.

Description

[0001] Gel mass made from gellan and agarose for the production of soft capsules or films, their use and manufacturing process

[0002] The present invention relates to a gel mass for producing soft capsules or films, as well as a process for producing the gel mass.

[0003] The invention further relates to the use of such a gel mass for producing soft capsules or films, as well as to processes for producing soft capsules or films using such a gel mass.

[0004] Soft capsules have long been a well-known dosage form for pharmaceutical active ingredients or dietary supplements. The vast majority of soft capsules on the market have a capsule shell based on gelatin as a gel-forming hydrocolloid. These soft gelatin capsules are manufactured using the so-called Scherer process, in which the filling is encapsulated fully automatically using counter-rotating forming rollers (hence the synonymous term "rotary die process"). Two gel ribbons made of a gel mass, which typically contains about 40 to 50 wt.% gelatin, a plasticizer (e.g., glycerin), and water, are passed between the forming rollers at a temperature of about 55 to 70°C and welded around the filling. Upon cooling, the gel mass acquires its required strength through gelation (so-called cold-set gelation) and is then dried.

[0005] Due to the desire of a growing segment of the population to largely or completely avoid the use of animal products, there is a growing demand for vegan soft capsules, i.e. soft capsules in which gelatin, an animal product, has been replaced by plant or microbial biopolymers. Various biopolymers, in particular polysaccharides and proteins, are known which, as hydrocolloids, can in principle be used to produce gels that have more or less similar properties to gelatin gels. In detail, however, the rheological properties, in particular, differ from those of a gelatin-based gel mass, which are required for the reliable implementation of the Scherer process. This applies in particular to the viscosity, strength, and seam formation properties of the gel mass required for the process.

[0006] The invention is therefore based on the object of proposing a vegan gel mass from which soft capsules can be produced using the established Scherer process.

[0007] This object is achieved according to the invention in the gel mass of the type mentioned at the outset in that the gel mass comprises agarose, gellan with a high degree of acylation, one or more fillers, one or more plasticizers and water.

[0008] It has surprisingly been shown that the combination of agarose and gellan with a high degree of acylation, in particular, enables the production of a gel mass whose rheological properties are highly suitable for the production of soft capsules using the Scherer process. In particular, the gel mass according to the invention can be processed using the same equipment used to produce soft gelatin capsules. The agarose, in particular, provides the required gel strength, while the gellan with a high degree of acylation is responsible for the required elasticity of the gel mass. The respective advantageous properties of the two polymers, and in particular their gel formation, are surprisingly not negatively affected by this combination.

[0009] Agarose is a polysaccharide composed of D-galactose and 3,6-anhydro-L-galactose. Agarose is the main component of agar, in which it, along with agaropectin, makes up approximately 70% by weight. Agar is obtained from various algae species, primarily from the red algae of the genera Gelidium and Gracilara. As a component of agar, which is traditionally used as a food in Asia, agarose is completely harmless to health. This represents a significant advantage over carrageenan, a hydrocolloid also derived from algae, which, however, has been suspected for some time of causing allergy-like effects in humans. The European Food Safety Authority has set a permissible daily intake of 75 mg / kg body weight for carrageenan, whereas there are no such restrictions for agarose or agar.

[0010] Preferably, the agarose is present as a component of agar in the gel mass according to the invention. Agar is relatively inexpensive. Alternatively, pure agarose, which is obtained by removing the agaropectin from agar, can also be used for the gel mass.

[0011] Since the melting point of agar is typically around 92°C and thus higher than that of gellan (approximately 70 to 80°C), the melting point of the gel mass according to the invention is primarily determined by the agar (or agarose). Since it is advantageous in the production of soft capsules if the gel bands can be sealed at the lowest possible temperature, the use of an agar with the lowest possible melting point is preferred within the scope of the invention.

[0012] In a preferred embodiment of the invention, the agar comprises partially hydrolyzed agar. Partial hydrolysis of the agar can reduce its melting point, e.g., to below 90°C or below 85°C. Partial hydrolysis can be achieved, in particular, by thermal hydrolysis of the agar, as described below, or by chemical or enzymatic hydrolysis.

[0013] In addition to agarose, the gel composition according to the invention contains gellan with a high degree of acylation as another gel-forming hydrocolloid. It has been shown that, in combination with agarose, this leads to significantly better rheological properties of the gel composition than gellan with a low degree of acylation.

[0014] The required proportion of agarose and gellan in the gel mass according to the invention is, as explained in detail below, significantly lower than for gelatin. Particularly against this background, the gel mass according to the invention also contains one or more fillers. The filler(s) are preferably selected from fructans, especially inulin, and from modified and / or hydrolyzed starches, especially maltodextrin. However, unmodified starch is not suitable as a filler because it prevents the agarose from gelling.

[0015] The gel mass according to the invention further contains one or more plasticizers to ensure the required flexibility of the produced soft capsules. The plasticizer(s) are preferably selected from sugar alcohols and non-reducing sugars, in particular from glycerol, sorbitol, sorbitan, mannitol, maltitol, isomalt, isomaltulose, and trehalose.

[0016] Advantageously, the gel mass further comprises one or more complexing agents for divalent metal ions. Complexing these metal ions, particularly calcium and magnesium ions, lowers the setting temperature of the gel mass. The complexing agent(s) are preferably selected from alkali metal salts of polybasic carboxylic acids, particularly sodium or potassium citrate.

[0017] As already mentioned, the gel mass according to the invention preferably comprises a significantly lower proportion of agarose and gellan with a high degree of acylation, typically about 5% by weight or less, than the gelatin content of a gel mass for soft gelatin capsules (about 40 to 50% by weight). The quantitative composition of the gel mass according to the invention is preferably as follows: about 0.7 to about 2.1% by weight of agarose or about 1.0 to about 3.0% by weight of agar, preferably about 1.5 to about 2.5% by weight of agar, about 1.0 to about 3.0% by weight, preferably about 1.5 to about 2.5% by weight of gellan with a high degree of acylation, about 10 to about 25% by weight, preferably 12 to 20% by weight, of one or more fillers, about 10 to about 30% by weight, preferably 20 to 25% by weight, of one or more plasticizers, about 0.5 to 2.0% by weight of one or more complexing agents for divalent metal ions, and about 37 to about 78% by weight of water.

[0018] According to a first preferred embodiment of the invention, the specific composition of the gel mass is as follows: about 1.5 to about 2.5 wt% agar, about 2.0 to about 3.0 wt% gellan with a high degree of acylation, about 12 to about 20 wt% maltodextrin, about 8.0 to about 15 wt% glycerol, about 2.0 to about 3.0 wt% isomalt, about 0.5 to 1.5 wt% sodium citrate dihydrate, and about 55.0 to about 74.0 wt% water.

[0019] According to a second preferred embodiment of the invention, with a dry mass tending to be higher compared to the first preferred embodiment, the concrete composition of the gel mass is as follows: about 1.5 to about 2.5 wt.% agar, about 1.5 to about 2.5 wt.% gellan with a high degree of acylation, about 12 to about 20 wt.% maltodextrin, about 12 to about 20 wt.% glycerol, about 8 to about 15 wt.% isomalt, about 0.5 to 1.5 wt.% sodium citrate dihydrate, and about 38.5 to about 64.5 wt.% water.

[0020] According to a third preferred embodiment of the invention, with a tendentially higher proportion of agar and gellan compared to the second preferred embodiment, the concrete composition of the gel mass is as follows: approx. 2 to approx. 3 wt.% agar, approx. 2 to approx. 3 wt.% gellan with a high degree of acylation, approx. 12 to approx. 20 wt.% maltodextrin, approx. 12 to approx. 20 wt.% glycerol, approx. 8 to approx. 15 wt.% isomalt, approx. 0.5 to 1.5 wt.% sodium citrate dihydrate, and approx. 37.5 to approx. 63.5 wt.% water.

[0021] A higher proportion of agar and gellan typically results in increased elasticity and strength of the soft capsules or films produced from the gel mass.

[0022] The gelling point of the gel mass according to the invention is, depending on the specific recipe, typically in the range of 50 to 70 °C.

[0023] Since the gel mass according to the invention is intended in particular for the production of vegan soft capsules, it preferably does not comprise any components obtained from animal raw materials, in particular no gelatin, collagen or collagen hydrolysate.

[0024] Furthermore, it is preferred if the gel composition according to the invention does not contain carrageenan. As already mentioned above, carrageenan is not harmless from a health perspective. To produce the gel composition according to the invention, its components can be dissolved in water at elevated temperature, in particular at approximately 100°C. The resulting homogeneous solution solidifies upon cooling below the gelling point, e.g., in the form of a film.

[0025] A particularly advantageous process for producing the gel mass according to the invention comprises the steps

[0026] Preparing a mixture of agar, glycerol and optionally water as a precursor; and

[0027] Producing the gel mass by mixing the precursor with gellan with a high degree of acylation, one or more fillers, one or more plasticizers and water.

[0028] By using such an agar / glycerin compound, the production and processing of the gel mass according to the invention can be simplified and accelerated. The agar is mixed with the required amount of glycerin to completely hydrate it, preferably at a temperature of approximately 95°C or more. Further processing, when the precursor is mixed with the remaining ingredients, may require additional glycerin addition.

[0029] During compound production at elevated temperatures, partial hydrolysis of the agar can occur simultaneously. As described above, this advantageously leads to a lower melting point, allowing not only the subsequent process step, in which the other components are added, to take place at a lower temperature, but also, in particular, the welding of the gel bands during the production of soft capsules from the gel mass.

[0030] The homogeneous agar / glycerin compound gels upon cooling and can be immediately mixed with the other components to obtain the gel mass according to the invention. Alternatively, a preferred embodiment of the process provides for the compound to be gelled, comminuted, and dried to produce a storable and transportable precursor, which is then further processed at a later time to produce the gel mass according to the invention.

[0031] For the production of such a storable precursor, it is advantageous if the agar / glycerin compound is first gelled by cooling and then formed and / or comminuted using suitable methods, e.g., extrusion or spheronization. The precursor is obtained in particle form, particularly as granules. Alternatively, the mixture of agar and glycerin can also be first "comminuted" by dripping and then gelled.

[0032] The comminuted precursor of agar and glycerin is preferably dried to a water content of less than approximately 15% by weight, more preferably less than approximately 10% by weight. Such dried granules are microbiologically stable and have good storage and transport properties.

[0033] The present invention further relates to the use of the gel mass according to the invention for the production of soft capsules, in particular by means of the rotary die process (Scherer process). As already explained, the gel mass according to the invention is particularly distinguished by the fact that, due to its rheological properties, it can be used for the production of vegan soft capsules on the same systems used for the production of gelatin soft capsules. Thus, no additional costs arise due to the necessary adaptation of the rotary die systems.

[0034] The present invention further relates to a process for producing soft capsules, comprising the steps

[0035] Providing a gel mass according to the invention at a temperature between 80 and 100 °C, forming a film from the gel mass by cooling to a temperature below 30 °C,

[0036] Providing a capsule filling,

[0037] Producing the soft capsules by enclosing the capsule filling with the film formed from the gel mass to form a capsule shell, and drying the capsule shell to a water content of approximately 20% by weight or less.

[0038] The process according to the invention corresponds in its basic features to the known rotary die process for the production of soft gelatin capsules and, as mentioned, can be carried out on the same rotary die systems.

[0039] However, one difference from the production of gelatin capsules is that the aging process required for gelatin capsules, which involves tempering the gel mass over a period of 6 to 18 hours, is not required for the agarose and gellan-based gel mass according to the invention. By eliminating the aging process, the process according to the invention offers significant time savings.

[0040] In rotary die systems, the gel mass is typically provided at a temperature between 80 and 100 °C via a so-called spreader box. From this box, the gel mass is transferred to a rotating cooling drum to form the film. Cooling to a temperature below 30 °C can be achieved either passively or by means of active cooling.

[0041] The capsule filling is preferably enclosed by welding two film strips together at a temperature of approximately 95°C or more, corresponding to the typical melting point of the gel mass. However, when using an agar with a correspondingly low melting point, welding can also be carried out at a temperature of approximately 85°C or less. Accordingly, the system typically comprises two spreader boxes, cooling drums, etc. The capsule filling is metered between the two opposing belts via a so-called wedge. The film strips are welded around the filling using a rotating forming roller, the actual rotary die, and the capsules are formed.

[0042] The present invention further relates to a soft capsule produced from a gel composition according to the invention and / or by the process according to the invention. Preferred embodiments and advantages of the soft capsules according to the invention have already been described in connection with the gel composition according to the invention.

[0043] The soft capsule according to the invention preferably comprises a capsule shell having a thickness in the range of approximately 200 to approximately 1,000 pm, these values ​​relating to the thickness of the capsule shell after drying of the soft capsule.

[0044] By adjusting the thickness of the film strips formed from the gel mass in the rotary die process, the resulting thickness of the capsule shell can be varied over a relatively wide range. Depending on the composition of the gel mass and the specific application of the soft capsules, thinner or thicker capsule shells may be preferred, for example, in the range of approximately 200 to approximately 400 μm, approximately 400 to approximately 700 μm, or approximately 700 to approximately 1,000 μm.

[0045] In addition to the production of soft capsules, the gel mass according to the invention is in principle also suitable for other applications, e.g. in the food sector or for technical applications.

[0046] The invention therefore also relates to the use of a gel mass according to the invention for producing a film, as well as to a film produced from a gel mass according to the invention. Such films can be used, for example, for the production of foodstuffs or as a biodegradable film (e.g., as packaging material).

[0047] The film according to the invention preferably has a thickness in the range from approximately 200 to approximately 1,000 μm. To produce the film, the gel mass according to the invention can be applied to a carrier, in particular with an appropriate thickness, e.g., by means of a doctor blade, and then cooled and dried to gel. As in the case of the capsule shell, the thickness of the film according to the invention can be varied over a relatively wide range, in particular depending on the intended use. For example, the film can have a thickness in the range from approximately 200 to approximately 400 μm, in the range from approximately 400 to approximately 700 μm, or in the range from approximately 700 to approximately 1,000 μm.

[0048] A special feature of the film according to the invention is that it is transparent after drying, unlike comparable films based on other hydrocolloids. The transparency of the film represents a significant advantage for many applications.

[0049] These and other advantages of the invention are explained in more detail using the following embodiments with reference to the figures.

[0050] They show in detail:

[0051] Fig. 1: photographic image of a film produced from the gel mass according to the invention in a rotary die system; and

[0052] Fig. 2: Photographic image of a film according to the invention after drying.

[0053] 1. Production of gel masses according to the invention

[0054] The components used for the production of gel masses according to the invention are listed in Table 1 below. Table 1

[0055] To prepare the gel mass, the agar and sodium citrate are first boiled in water while stirring until a clear solution is obtained. Then, the filler maltodextrin and the plasticizer isomalt are mixed and added to the solution while stirring until a clear solution is obtained. The highly acylated gellan is mixed with the plasticizer glycerin and gradually added to the hot solution. The mixture is stirred at 95 °C until a homogeneous gel mass is obtained.

[0056] In this procedure, crystallization of the isomalt can be prevented by mixing the isomalt with the maltodextrin before adding it to the solution.

[0057] The gel masses according to Examples 1 to 3 have a gel point of approximately 57 °C, approximately 62 °C and approximately 66 °C, respectively.

[0058] 2. Production of inventive films

[0059] A film was produced from the gel mass according to Example 1 by pouring the gel mass from the spreader box of a rotary die machine onto the cooling drum at approximately 80 °C. The cooled and gelled film exhibits sufficient stability and tensile strength to be transported over the deflection rollers of the rotary die machine without tearing. Figure 1 shows a photographic image of the film 18 running over several deflection rollers 10, 12, 14, and 16.

[0060] Before drying, the film has a thickness of approximately 1,000 μm. After drying to a water content of approximately 16 wt.%, the thickness of the film according to the invention is approximately 850 μm.

[0061] The dried film is transparent.

[0062] 3. Production and welding of films

[0063] A gel composition according to the invention was prepared according to Example 1.1 above and knife-coated onto a plastic carrier film with a thickness of approximately 1,000 μm. After cooling and drying, the film according to the invention had a thickness of approximately 700 μm.

[0064] Figure 2 shows a photographic image of the dried film 20 on the carrier foil 22, which in turn lies on a metal plate 24. The film 20 is transparent, which can be seen by the clearly translucent colored dots 26 on the metal plate 24.

[0065] Two films produced in this way were welded together using a sealing machine to simulate the seam formation during the production of soft capsules.

[0066] The sealing machine is equipped with a heating plate that is lowered onto the films to perform the welding process. The two films are placed on top of each other, with the first film being formed into a hollow, creating a cavity between them. By pressing the heating plate at a temperature of approximately 96-98 °C, the films briefly melt at the contact point and bond together. In this way, the films according to the invention could be joined together via a stable and permanent seam.

Claims

Patent claims 1. Gel mass for the production of soft capsules or films, characterized in that the gel mass comprises agarose, gellan with a high degree of acylation, one or more fillers, one or more plasticizers and water.

2. Gel mass according to claim 1, wherein the agarose is contained in the gel mass as a component of agar.

3. Gel mass according to claim 2, wherein the agar comprises a partially hydrolyzed agar.

4. Gel mass according to one of the preceding claims, wherein the filler(s) are selected from fructans, in particular inulin, and from modified and / or hydrolyzed starches, in particular maltodextrin.

5. Gel mass according to one of the preceding claims, wherein the plasticizer(s) are selected from sugar alcohols and non-reducing sugars, in particular from glycerol, sorbitol, sorbitan, mannitol, maltitol, isomalt, isomaltulose and trehalose.

6. Gel mass according to one of the preceding claims, further comprising one or more complexing agents for divalent metal ions, which are preferably selected from alkali metal salts of polybasic carboxylic acids, in particular sodium or potassium citrate.

7. Gel mass according to one of the preceding claims, comprising about 0.7 to about 2.1 wt.% agarose or about 1.0 to about 3.0 wt.% agar, preferably about 1.5 to about 2.5 wt.% agar, about 1.0 to about 3.0 wt.%, preferably about 1.5 to about 2.5 wt.%, gellan with a high degree of acylation, about 10 to about 25% by weight, preferably 12 to 20% by weight, of one or more fillers, about 10 to about 30% by weight, preferably 20 to 25% by weight, of one or more plasticizers, about 0.5 to 2.0% by weight of one or more complexing agents for divalent metal ions, and about 37 to about 78% by weight of water.

8. The gel composition of claim 7 comprising about 1.5 to about 2.5 wt% agar, about 2.0 to about 3.0 wt% high acylated gellan, about 12 to about 20 wt% maltodextrin, about 8.0 to about 15 wt% glycerol, about 2.0 to about 3.0 wt% isomalt, about 0.5 to 1.5 wt% sodium citrate dihydrate, and about 55.0 to about 74.0 wt% water.

9. The gel composition of claim 7 comprising about 1.5 to about 2.5 wt% agar, about 1.5 to about 2.5 wt% high acylated gellan, about 12 to about 20 wt% maltodextrin, about 12 to about 20 wt% glycerol, about 8 to about 15 wt% isomalt, about 0.5 to 1.5 wt% sodium citrate dihydrate, and about 38.5 to about 64.5 wt% water.

10. Gel mass according to claim 8, comprising about 2 to about 3 wt.% agar, about 2 to about 3 wt.% gellan with a high degree of acylation, about 12 to about 20 wt.% maltodextrin, about 12 to about 20 wt.% glycerol, about 8 to about 15 wt.% isomalt, about 0.5 to 1.5 wt.% sodium citrate dihydrate, and approx. 37.5 to approx. 63.5 wt% water.

11. Gel mass according to one of the preceding claims, wherein the gel mass does not comprise any components obtained from animal raw materials, in particular no gelatin, collagen or collagen hydrolysate.

12. Gel mass according to one of the preceding claims, wherein the gel mass does not contain carrageenan.

13. A process for producing a gel mass according to any one of the preceding claims, comprising the steps Preparing a mixture of agar, glycerol and optionally water as a precursor; and Producing the gel mass by mixing the precursor with gellan with a high degree of acylation, one or more fillers, one or more plasticizers and water.

14. The method according to claim 13, wherein the precursor product of agar and glycerin is gelled, comminuted and dried, preferably to a water content of less than about 15% by weight, more preferably less than about 10% by weight.

15. Use of a gel mass according to one of the preceding claims for the production of soft capsules, in particular by means of the rotary die process.

16. A process for the preparation of soft capsules, comprising the steps Providing a gel mass according to any one of claims 1 to 12 at a temperature between 80 and 100 °C, Formation of a film from the gel mass by cooling to a temperature below 30 °C, Providing a capsule filling, Producing the soft capsules by enclosing the capsule filling with the film formed from the gel mass to form the capsule shell, and Drying the capsule shell to a water content of approximately 20% by weight or less.

17. The method according to claim 16, wherein the enclosing of the capsule filling is carried out by welding two bands of the film at a temperature of approximately 95°C or more.

18. A soft capsule produced from a gel mass according to any one of claims 1 to 12 and / or according to the process according to claim 16 or 17.

19. Soft capsule according to claim 18, comprising a capsule shell having a thickness in the range from about 200 to about 1,000 pm, preferably in the range from about 200 to about 400 pm, in the range from about 400 to about 700 pm or in the range from about 700 to about 1,000 pm.

20. Use of a gel composition according to any one of claims 1 to 12 for producing a film.

21. A film made from a gel composition according to any one of claims 1 to 12.

22. The film of claim 21, wherein the film has a thickness in the range of about 200 to about 1,000 pm, preferably in the range of about 200 to about 400 pm, in the range of about 400 to about 700 pm, or in the range of about 700 to about 1,000 pm.

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