EP4519181A1

EP4519181A1 - Capsule for producing a beverage

Info

Publication number: EP4519181A1
Application number: EP23724740.8A
Authority: EP
Inventors: Violette BOURG; Nihan Dogan; Audrey Virginie MURPHY
Original assignee: Societe des Produits Nestle SA; Nestle SA
Current assignee: Societe des Produits Nestle SA; Nestle SA
Priority date: 2022-05-05
Filing date: 2023-05-03
Publication date: 2025-03-12
Also published as: KR20250005142A; WO2023213870A1; MX2024013575A; US20250326567A1; CN119156330A; AU2023263733A1; JP2025514072A

Abstract

The invention concerns a capsule for use in a beverage preparation machine, said capsule containing a soluble and/or extractable beverage ingredient, said capsule comprising : - a capsule body (2) defining a chamber (21), - a top membrane (3) closing the top opening, and adapted to be punctured for liquid injection into the capsule, and - a bottom membrane (4), provided inside the chamber (21) so as to delimit between the top membrane (3) and said bottom membrane an ingredient chamber, and - an opening device (5) provided inside the chamber and adapted to open the chamber by relative engagement of said opening device with the bottom membrane (4) under the effect of the liquid pressure increase in the ingredient chamber during injection of said liquid, wherein said opening device (5) is made of a biodegradable material, and said biodegradable material is a polymeric composition, said polymeric composition comprising : - at least one polymer selected from the group consisting of polyhydroxyalkanoates (PHA), - at least one or more nucleants, - at least one or more mineral fillers.

Description

CAPSULE FOR PRODUCING A BEVERAGE

Field of the invention

The invention relates to a capsule for use in a beverage preparation machine.

Background of the invention

Single-serve beverage capsules are known in the art. These capsules are commonly used with beverage preparation machines for on demand dispensing of beverages, like coffee or tea.

For this, usually a beverage capsule with a capsule body that encloses a beverage ingredient is inserted in a capsule receiver of a beverage preparation machine. The capsule receiver is closed and the beverage preparation is started. In the capsule receiver, a top membrane of the capsule is punctured with a needle to inject a fluid, generally water, in the capsule to interact with the beverage ingredient inside the capsule to produce the desired beverage. The fluid fills the capsule so that the pressure inside the capsule increases. When a sufficient amount of fluid fills the capsule, a self-opening mechanism in the capsule is activated and opens a bottom membrane of the capsule to release the prepared beverage at a time when the extraction of the beverage component is completed. Examples of working principles of this type of container are described in patent EP 1472156.

In the prior art, beverage containers of this type are usually made of plastic. Considering that the containers are designed for single time use only, their disposal has to be managed since reusing and recycling the materials used can be challenging. Therefore, attempts are made to replace these materials with alternatives, like cellulose or bioplastic, which allow overcoming the problems existing with disposing and/or recycling the containers after use. However, it has to be considered that these alternative materials do not have the same material characteristics and advantages as the usual plastic materials.

In particular, considering a capsule such as described in patent EP 1472156 and schematically illustrated in Figure 1 , such a type of capsule 1 comprises :

- a capsule body 2 defining a chamber 21 with a top opening 23 closed by a top membrane 3 that is adapted to be punctured for liquid injection into the capsule, and

- a bottom membrane 4, provided inside the chamber so as to delimit between the top membrane 3 and this bottom membrane 4 an ingredient chamber, and

- an opening device 5 provided inside the capsule body and below the bottom membrane and adapted to open the chamber by relative engagement of said opening device with the bottom membrane under the effect of the liquid pressure increase in the ingredient chamber during injection of liquid.

If the opening device 5 of a capsule presenting such a construction is made of a bioplastic, several drawbacks can be observed.

One drawback is that, under rises of temperature and pressure, the properties of objects made of bioplastic can change. In the case of the capsule described above, this change of properties is a serious problem for the opening device made of bioplastic because when hot water is introduced in the chamber and until pressure rises and the bottom membrane is pushed to the opening device, this opening device deforms with the risk of breaking and/or not recovering its original shape after tearing of the bottom membrane and pressure decrease. The result is that beverage ingredient can be dispensed from the ingredient chamber to the drinking cup, such as roast and ground coffee particles or non-dissolved soluble powder, or that a part of the beverage is not correctly prepared. The beverage preparation is not acceptable for the consumer.

Another drawback is that the opening device presents a certain thickness in order to provide a resistance to the pressure that rises in the capsule during the beverage preparation. Consequently, when this thick piece of material ifs made of bioplastic, its disintegration as a home compostable object becomes relatively long.

An object of the invention is to address the above existing problems.

Summary of the invention

In a first aspect of the invention, there is provided a capsule for use in a beverage preparation machine, said capsule containing a soluble and/or extractable beverage ingredient, and the capsule comprises :

- a capsule body defining a chamber, and

- a top membrane closing the top opening and adapted to be punctured for liquid injection into the capsule, and

- a bottom membrane, provided inside the chamber so as to delimit between the top membrane and said bottom membrane an ingredient chamber, and

- an opening device provided inside the chamber and adapted to open the chamber by relative engagement of said opening device with the bottom membrane under the effect of the liquid pressure increase in the ingredient chamber during injection of said liquid, and wherein said opening device is a moulded piece made of a biodegradable material, and said biodegradable material is a polymeric composition, said polymeric composition comprising :

- at least one polymer selected from the group consisting of polyhydroxyalkanoates (PHA),

- at least one or more nucleants, - at least one or more mineral fillers.

This capsule comprises a capsule body defining a chamber for the beverage ingredient, a top membrane closing this chamber, a bottom membrane provided inside the chamber and an opening device adapted to open said bottom membrane.

The capsule body usually comprises :

- a side wall defining a chamber and extending axially between a top opening, and

- a circumferential flange projecting radially outward from the top opening, said flange comprising an upper surface opposite to the chamber with respect to the opening and an opposed lower surface.

Usually the bottom of the capsule body comprises an outlet through which the beverage can be dispensed.

Generally, the top membrane is attached to the upper surface of the flange of the body.

The capsule comprises a beverage ingredient that can be a soluble or extractable beverage ingredient. The ingredient is hold between the top membrane and the bottom membrane.

The opening device is positioned inside the body but outside the ingredient chamber. Accordingly, the opening device is positioned below the bottom membrane.

Usually, the opening device comprises a plate and this plate comprises opening elements rising from the upper surface of the plate, and accordingly in direction of the bottom membrane. These opening elements are designed to pierce, tear, puncture the bottom membrane under the effect of the liquid pressure increase in the ingredient chamber during injection of said liquid.

These rising opening elements can be spikes, cone- or pyramid-shaped (optionally truncated at their ends) turned upwardly towards the bottom membrane which may form protrusions and recesses against the bottom membrane facing the opening device.

Preferably, the opening elements present sharp pointed end.

Preferably, the plate of the opening device comprises beverage evacuation holes extending from the upper surface of the plate to the lower surface of the plate, and said holes being positioned between the rising opening elements.

In the state of the art, this opening device is a moulded piece of plastic such as polypropylene. In the present embodiment, the opening device is a moulded piece of a biodegradable material. This biodegradable material is a polymeric composition that comprises :

- at least one or more nucleants,

- at least one or more mineral fillers.

The opening device is manufactured by moulding from this polymeric composition.

Usually, the opening device is integrally made of this polymeric composition.

Generally, the polymeric composition comprises at least one polyhydroxyalkanoate containing repeating units of formula (I) :

-O- CHRi- (CH₂)n-CO- where :

- Ri is selected from -H, Ci- C12 alkyls, C - C16 cycloalkyls, C₂- C12 alkenyls, optionally substituted with at least one group selected from : halogen (F, Cl, Br), -CN, -OH, -COOH, - OR, -COOR (with R = C1-C4 alkyl, benzyl ),

- n is zero or an integer of from 1 to 6, preferably is 1 or 2.

Preferably, the polymeric composition comprises at least one polyhydroxyalkanoate, wherein Ri is methyl or ethyl, and n is 1 or 2.

Preferred repeating units of formula (I) can be those deriving from :

- 3-hydroxybutyrate,

- 3-hydroxyvalerate,

- 3-hydroxyhexanoate,

- 3- hydroxyoctanoate,

- 3-hydroxydodecanoate,

- 3-hydroxyundec-10- enoate,

- 4-hydroxyvalerate, or mixtures therof.

Particularly preferred polyhydroxyalkanoates are :

- poly-3-hydroxybutyrate (PHB),

- poly-3-hydroxyvalerate (PHV),

- poly-3-hydroxyhexanoate (PHH),

- poly-3-hydroxyoctanoate (PHO),

- poly-3-polyhydroxydodecanoate (PHDd)

- poly- 3-hydroxyundec-10- enoate (PHU), and their copolymers :

- poly (3-hydroxybutyrate-co-3-hydroxyvalerate ) (PHBV),

- poly (3-hydroxybutyrate-co-3-hydroxyexanoate ) (PHBH),

- poly (3-hydroxybutyrate-co-4-hydroxybutyrate ),

- poly (3-hydroxyoctanoate-co-3-hydroxyundecen-10-enoate) (PHOU),

- poly (3-hydroxybutyrate-co-3-hydroxyvalerate-co- 4-hydroxyvalerate ) (PHBW), or mixtures thereof.

In one embodiment, the polyhydroxyalkanoate can be a copolymer or terpolymer containing repeating units of formula (I) in combination with at least one repeating unit deriving from comonomers that are able to copolymerize with hydroxyalkanoates.

These comonomers can be lactones and/or lactams.

In this embodiment, usually, the repeating units of formula (I) are present in an amount equal to at least 10 % by moles with respect to the total moles of repeating units.

Preferably, the polyhydroxyalkanoate has a weight average molecular weight (M) which can range from 10⁴ to 10⁵g/mol .

Generally, the polymeric composition comprises at least one plasticizer selected from the group consisting of :

- polyethylene glycol) (PEG),

- acetyl-tri-n-butyl citrate (ATBC),

- isosorbide diester (ISE),

- sorbitol,

- glycerol,

- acetylated monoglycerides,

- epoxidized soybean oil (ESBO),

- triethyl citrate (TEC),

- tri(ethyleneglycol)bis(2-ethyl hexanoate) (TEG-EH),

- tributylcitrate (TBC),

- 1 ,3, 2, 4- dibenzylidene sorbitol,

- 1 ,3-p-methylbenzylidene-2,4-benzylidenesorbitol,

- bis (stearylureide) hexane,

- 1 ,3,2,4-di (p-methylbenzylidene) sorbitol,

- 1 ,3, 2, 4- dibenzylidenesorbitol, and mixtures thereof. The polymeric composition comprises at least one nucleant that can be selected from the group consisting of boron nitride, talc, hydroxyapatite, zinc stearate, nanocrystalline cellulose, montmorillonite nano clay, single wall carbon nanotube, wollastonite, multi wall carbon nanotube, cyanuric acid, fatty acids, fatty acid esters, fatty acid amines, fatty acid metal salts, pentaerythritol, di-pentaerythritol, urea derivatives, sorbitol-based compounds, sodium benzoate and mixtures thereof.

Preferably, the polymeric composition comprises a quantity of at least one nucleant of at least 0.1 % in weight, preferably at most 5 % in weight.

The polymeric composition comprises at least one mineral filler that can be selected from the group consisting of talc, wollastonite, mica, silica, calcium carbonate, kaolin, nano clays.

Preferably, the polymeric composition comprises a quantity of at least one mineral filler of at least 1 % in weight, preferably at most 50 % in weight.

Preferably, the polymeric composition comprises wollastonite, talc or nanoclays as a mineral filler, even more preferably in a content comprised between 5 and 40 % in weight.

It was observed that the presence of mineral fillers inside the polymeric composition of the opening device comprising a polymer selected from the group consisting of polyhydroxyalkanoates (PHA) accelerated the disintegration of this opening compared topolymeric composition devoid of these mineral fillers.

The polymeric composition can comprise at least one functional additive selected from the group consisting of :

- pentaerythrole tetrakis (3-(3, 5-di-tert-butyl-4- hydroxyphenyl)propionate),

- octadecyl 3-(3, 5-di-tert-butyl- 4-hydroxyphenyl) propionate,

- tris(2,4-di-tert- butylphenyl) phosphite,

- 1 ,3,5-trimethyl-2,4,6-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene,

- 2,4- bis[(octylthio)methyl)]- o-cresol,

- 2,2t-dihydroxy-4,4t-dimethoxy-benzophenon,

- ethylene bis(oxyethylene) bis-(3-(5- tert-butyl-4 -hydroxy-m-tolyl) propionate,

- octadecyl-[3- (3,5-di-tert-butyl-4-hydroxyfeyl)propionate,

- 2t, 3-bis[[ 3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyl]]propionohydrazide,

- beeswax,

- carnauba wax,

- candelilla wax,

- sumac wax (Japanese wax), - berry wax,

- paraffin wax,

- silicone and its derivatives,

- magnesium hydroxide,

- calcium stearate and mixtures thereof.

These functional additives can be used to improve processability, compatibility between the materials and/or accelerate biodegradation.

The polymeric composition can comprise at least one viscosity modifier and/or compatibilizer selected from the group consisting of :

- dicumyl peroxide (DCP),

- tert.butylperoxybenzoate (TBPB),

- hexamethylene diisocyanate (HMDI),

-multifunctionalized styrene-co-glycidyl methacrylate oligomer (Joncryl®),

- triglycidyl isocyanurate (TGIC),

- benzoyl peroxide (BPO),

- methylene diphenyl diisocyanate (MDI).

Preferably, the polymeric composition can comprise fibers such as fibers selected from the group consisting of : flax, corn, rice husk, hemp, bamboo, sisal, kenaf and mixtures thereof.

The advantage of integrating fibers in the polymeric composition of the opening device is that the disintegration of the opening part is accelerated compared to the neat PHA-based composition devoid of these fibers. This is particularly useful for the opening device that can be a thick piece of material and consequently that needs more time to be disintegrated thatn the other parts of the capsules.

Preferably, the polymeric composition comprises such fibers in a content comprised between 5 and 40 % in weight.

Usually, the opening device comprises a plate, said plate comprising opening elements rising from the upper surface of the plate, said opening elements being designed to pierce, tear, puncture the bottom membrane under the effect of the liquid pressure increase in the ingredient chamber during injection of said liquid.

Preferably the opening elements present sharp pointed ends, in particular when the bottom membrane is made of a material that present a certain elasticity, which can be the case when the bottom membrane is made of a biodegradable material. It can be the case when the bottom membrane is a laminated multilayer material comprising successively :

- a vegetable parchment layer, and

- an adhesive layer, and

- a non-woven material layer comprising fibres, wherein said fibres are biodegradable fibres. With such a bottom bottom membrane, usually the vegetable parchment support faces the opening device inside the capsule.

In one embodiment, it can be preferred that the plate of the opening device comprises beverage evacuation holes extending from the upper surface of the plate to the lower surface of the plate, and said holes being positioned between the rising opening elements. This is particularly preferred when the bottom membrane is a laminated multilayer material such as described above.

Preferably, the capsule body is made of biodegradable or compostable materials, such as paper based, starch, polycaprolactone (PCL), polylactic acid (PLA), polyhydroxyalcanoates (PHA), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), and/or polybutylene adipate terepthalate (PBAT), polyglycolic acid (PGA) or mixture thereof.

Preferably, the top membrane is made of biodegradable or compostable materials, such as paper based, starch, polycaprolactone (PCL), polylactic acid (PLA), polyhydroxyalcanoates (PHA), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), and/or polybutylene adipate terepthalate (PBAT), polyglycolic acid (PGA) or mixture thereof.

The capsule can comprise a distributor wall extending through the internal cross section of the chamber to define an inferior sub-chamber for the ingredient and a superior distribution chamber for the liquid. This distributor wall comprises small holes to distribute liquid uniformly on the ingredient.

Such a distributor can be a compostable film made of cellophane and starch, or polycaprolactone (PCL), polylactic acid (PLA), polyhydroxyalcanoates (PHA), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), and/or polybutylene adipate terephthalate (PBAT), polyglycolic acid (PGA) or mixture thereof.

Usually, the capsule is produced by separately producing the capsule body and the opening device and assembling them in a further step.

In a particular embodiment, the capsule body can comprise a bottom wall that is made integral with the opening device. Accordingly in this embodiment, the opening device is integrally molded with the capsule body. The capsule body is moulded of the same biodegradable polymeric composition as the opening device.

In the present application, technical requirements and procedures for determining biodegradability and compostability of a material are determined according to international standards, such as EU 13432 or US ASTM D6400. For example, one of the tests requires that - for a material to be considered “(industrially) compostable” - at least 90% of the material in question must be biologically degraded under controlled conditions in 6 months. Similar test schemes exist also for a certification to home compostability.

Thus, it is possible to dispose the entire capsule system after its use in compost piles so that earth can be supplied with nutrients once the material is completely biodegraded.

The above aspects of the invention may be combined in any suitable combination. Moreover, various features herein may be combined with one or more of the above aspects to provide combinations other than those specifically illustrated and described. Further objects and advantageous features of the invention will be apparent from the claims, from the detailed description, and annexed drawings.

Brief description of the drawings

Specific embodiments of the invention are now described further, by way of example, with reference to the following drawings in which :

- Figure 1 shows a schematic cross-section of a capsule according to the present invention,

- Figure 2 is a graph showing the strain of different polymeric materials.

Detailed description of exemplary embodiments

Figure 1 illustrates schematically a capsule 1 according to the present invention.

The capsule 1 comprises a capsule body 2 with one or more sidewall(s) 21 that extend axially from a bottom towards a top. The sidewall extends towards a top opening 23. At the top opening 23, the body comprises a circumferential flange 24 that extends radially outward from the sidewall.

Generally, any transversal cross section of the body capsule is circular from the bottom to the top and the flange is circular too as illustrated in the perspective view of Figure 2.

The sidewall delimits a chamber 22 for containing a soluble and/or extractable beverage ingredient.

This soluble beverage ingredient is a water soluble powder ingredient and can be selected within the list of : instant coffee powder, milk powder, cream powder, instant tea powder, cocoa powder, soup powder, fruit powder or mixture of said powders. The powders can be agglomerated or sintered.

This beverage ingredient packed in the package can also be an ingredient able to be extracted or infused like a roast and ground coffee, or tea leaves. In that embodiment water extracts the beverage ingredient.

The capsule comprises a top membrane 3 that is fixed, sealed or attached to at least a part of the upper surface of the circumferential flange and accordingly covers and closes the top opening 23.

This top membrane is adapted to be punctured for liquid injection into the capsule. Preferably, the top membrane is pierceable by an injection needle of the beverage preparation machine which is adapted to inject an extraction liquid under pressure inside or into the chamber. Preferably, the puncturing operation is made at one single place by a water injection needle such as described in W02006/082064 or W02008/107281.

The term "top membrane" should be understood as the membrane which is pierced by the injection needle of machine, as opposed to the "bottom membrane" (such as described below) which should be understood as the membrane located on the opposite side of the capsule 1.

The capsule comprises a bottom membrane 4 that closes the bottom of the chamber 22. Accordingly, the soluble and/or extractable beverage ingredient is enclosed between the top and bottom membranes. The top and bottom membranes delimit an internal space of the chamber, the ingredient chamber 22, configured to hold the beverage ingredient for the preparation of a beverage.

In one embodiment, a distributor wall 6 can extend through the internal cross section of the chamber defining an inferior sub-chamber for the ingredient and a superior distribution chamber for the liquid. This distributor wall comprises small holes to distribute liquid uniformly on the ingredient.

The capsule comprises an opening device 5 adapted to open the chamber by relative engagement with the bottom membrane 4 under the effect of the liquid pressure increase in the chamber during injection of said liquid. The opening device 5 may comprise a rigid plate 51 comprising opening elements 52 such as spikes, cone- or pyramid-shaped - optionally truncated at their ends - on its surface turned upwardly towards the bottom membrane 4 which may form protrusions and recesses against the bottom membrane 4 facing the opening device. The opening device 5 may be generally referred to as "pyramid plate".

Holes 53 can be provided in the plate 51 to dispense beverage produced in the ingredient chamber 22 to the beverage outlet 25.

Upon liquid injection inside the chamber 4, pressure builds up, which deforms the bottom membrane 4 against the opening means 5, until the bottom membrane is pierced, giving way to the beverage prepared inside the capsule 1 respectively chamber 21 below the opening device 5. The expression "engagement" may mean that, for instance, the opening device or the second membrane, or alternatively both may be moved with respect to each other to effect opening.

Usually, the capsule body comprises a bottom beverage outlet 25, below the opening device 5. The bottom of the capsule body preferably extends below the opening means to hold said opening means and collect the beverage to this beverage outlet 25 dispensing the beverage outside of the capsule 1, e.g. into a cup.

The top membrane 3 is fixed to the flange 24 in such a way that the extraction liquid injected into the chamber 21 increases internal pressure up to the pressure necessary to obtain the piercing of the deformed bottom membrane 4 by the opening device 5. The top membrane 3 is thus fixed to the flange in such a way that it does not detach at least until a defined pressure inside of the chamber is achieved. This defined pressure may be at least 2 bars, preferably at least 3 bars or at least 6 bars. Thereby, the fixation effects that the capsule 1 does not leak via the interface between the flange and the top membrane during beverage preparation.

In the state of the art, this type of capsule is made of plastic such as polypropylene. Such a material presents properties adapted to the introduction of hot water at a temperature higher than 90°C and the rise of pressure inside the ingredient chamber 22 until the bottom membrane 4 is pierced. During the beverage preparation, the opening device 5 made of polypropylene is deformed under the force exerted by the highest pressure and slightly bends but it recovers its original shape at the end of the beverage preparation when pressure decreases. Consequently, it guarantees the functions of opening the bottom membrane and filtering the beverage.

When this opening device 5 is made of bioplastic, it has been observed that the opening device deforms itself under the effect of the temperature and pressure load exerted by hot water inside the beverage ingredient chamber. The beverage is not well prepared because :

- the high pressure that is necessary to extract roast and ground coffee or mix soluble ingredient with water is not maintained all along the beverage preparation. Alternatively, it can happen that this deformation blocks the beverage flow and creates such a high pressure that the capsule bursts or the opening device breaks. The resulting beverage does not present the expected quality.

- some beverage ingredients like coffee cake or non-dissolved soluble ingredient are not filtered and flow inside the drinking cup. Some broken parts of the deformed pyramid can be released in the cup too. These drawbacks can be avoided by selecting, as the biodegradable material of the opening device material, a polymeric composition comprising :

- at least one polymer selected from the group consisting of polyhydroxyalkanoates (PHA), and

- at least one or more nucleants, and

- at least one or more mineral fillers,

In particular, plates produced with such polymeric compositions were submitted to a load of 1.4 MPa to reflect the pressure exerted by pressurised water produced by the beverage machine water pump and introduced inside the beverage capsule. This load was exerted during 1.5 sec and then released. It was observed that :

- these plates deformed under the load with time, and

- when the load was removed, these plates came back to their original dimension or were slightly deformed only.

Opening devices 5 made from these polymeric compositions were used to manufacture beverage capsules such as illustrated in Figure 1 . The beverage ingredient was roast and ground coffee. Coffee was prepared from the different capsules with the beverage machine commercialised under the trademark Nescafe Dolce Gusto and coffee was properly prepared therefrom.

Although the invention has been described with reference to the above illustrated embodiments, it will be appreciated that the invention as claimed is not limited in any way by these illustrated embodiments.

Variations and modifications may be made without departing from the scope of the invention as defined in the claims. Furthermore, where known equivalents exist to specific features, such equivalents are incorporated as if specifically referred in this specification.

As used in this specification, the words "comprises", "comprising", and similar words, are not to be interpreted in an exclusive or exhaustive sense. In other words, they are intended to mean "including, but not limited to".

List of references in the drawings : capsule 1 capsule body 2 chamber 20 sidewall 21 ingredient chamber 22 top opening 23 flange 24 bottom outlet 25 top membrane 3 bottom membrane 4 opening device 5 rigid plate 51 opening elements 52 holes 53 distributor wall 6

Claims

1. A capsule (1) for use in a beverage preparation machine, said capsule containing a soluble and/or extractable beverage ingredient, said capsule comprising :

- a capsule body (2) defining a chamber (21),

- a top membrane (3) closing the top opening, and adapted to be punctured for liquid injection into the capsule, and

- a bottom membrane (4), provided inside the chamber (21) so as to delimit between the top membrane (3) and said bottom membrane an ingredient chamber, and

- an opening device (5) provided inside the chamber and adapted to open the chamber by relative engagement of said opening device with the bottom membrane (4) under the effect of the liquid pressure increase in the ingredient chamber during injection of said liquid, wherein said opening device (5) is a moulded piece made of a biodegradable material, and said biodegradable material is a polymeric composition, said polymeric composition comprising :

- at least one or more nucleants,

- at least one or more mineral fillers.

2. A capsule according to Claim 1, wherein the polymeric composition comprises at least one polyhydroxyalkanoate containing repeating units of formula (I) :

-O- CHRi- (CH₂)n-CO- where :

- Ri is selected from -H, Ci- C12 alkyls, C - C16 cycloalkyls, C₂- ci2 alkenyls, optionally substituted with at least one group selected from : halogen (F, Cl, Br), -CN, -OH, -COOH, - OR, -COOR (with R = C1-C4 alkyl, benzyl ),

- n is zero or an integer of from 1 to 6, preferably is 1 or 2.

3. A capsule according to Claim 2, wherein the polymeric composition comprises at least one polyhydroxyalkanoate, wherein Ri is methyl or ethyl, and n is 1 or 2.

4. A capsule according to Claim 2 or 3, wherein the polyhydroxyalkanoate is a copolymer or terpolymer containing repeating units of formula (I) in combination with at least one repeating unit deriving from comonomers that are able to copolymerize with hydroxyalkanoates.

5. A capsule according to any one of the preceding claims, wherein the polymeric composition comprises at least one plasticizer selected from the group consisting of :

- polyethylene glycol) (PEG),

- acetyl-tri-n-butyl citrate (ATBC),

- isosorbide diester (ISE),

- sorbitol,

- glycerol,

- acetylated monoglycerides,

- epoxidized soybean oil (ESBO),

- triethyl citrate (TEC),

- tri(ethyleneglycol)bis(2-ethyl hexanoate) (TEG-EH),

- tributylcitrate (TBC),

- 1 ,3, 2, 4- dibenzylidene sorbitol,

- 1 ,3-p-methylbenzylidene-2, -benzylidenesorbitol,

- bis (stearylureide) hexane,

- 1 ,3,2,4-di (p-methylbenzylidene) sorbitol,

- 1 ,3, 2, - dibenzylidenesorbitol, and mixtures thereof.

6. A capsule according to any one of the preceding claims, wherein the polymeric composition comprises at least one nucleant selected from the group consisting of boron nitride, talc, hydroxyapatite, zinc stearate, nanocrystalline cellulose, montmorillonite nano clay, single wall carbon nanotube, multi wall carbon nanotube, cyanuric acid, fatty acids, fatty acid esters, fatty acid amines, fatty acid metal salts, pentaerythritol, di-pentaerythritol, urea derivatives, sorbitol-based compounds, sodium benzoate and mixtures thereof.

7. A capsule according to the preceding claim, wherein the polymeric composition comprises a quantity of nucleants of at least 0.1 % in weight, preferably at most 5 % in weight.

8. A capsule according to any one of the preceding claims, wherein the polymeric composition comprises at least one mineral filler selected from the group consisting of talc, wollastonite, mica, silica, calcium carbonate, kaolin, nano clays.

9 capsule according to the preceding claim, wherein the polymeric composition comprises a quantity of mineral fillers of at least 5 % in weight, preferably at most 40 % in weight.

10. A capsule according to any one of the preceding claims, wherein the polymeric composition comprises at least one functional additive selected from the group consisting of :

- pentaerythrole tetrakis (3-(3, 5-di-tert-butyl-4- hydroxyphenyl)propionate),

- octadecyl 3-(3, 5-di-tert-butyl- 4-hydroxyphenyl) propionate,

- tris(2,4-di-tert- butylphenyl) phosphite,

- 1 ,3,5-trimethyl-2,4,6-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene,

- 2,4- bis[(octylthio)methyl)]- o-cresol,

- 2,2t-dihydroxy-4,4t-dimethoxy-benzophenon,

- octadecyl-[3- (3,5-di-tert-butyl-4-hydroxyfeyl)propionate,

- beeswax,

- carnauba wax,

- candelilla wax,

- sumac wax (Japanese wax),

- berry wax,

- paraffin wax,

- silicone and its derivatives,

- magnesium hydroxide,

- calcium stearate and mixtures thereof.

11. A capsule according to any one of the preceding claims, wherein the polymeric composition comprises at least one viscosity modifier and/or compatibilizer selected from the group consisting of :

- dicumyl peroxide (DCP),

- tert. butylperoxybenzoate (TBPB),

- hexamethylene diisocyanate (HMDI),

-multifunctionalized styrene-co-glycidyl methacrylate oligomer (Joncryl®),

- triglycidyl isocyanurate (TGIC),

- benzoyl peroxide (BPO),

- methylene diphenyl diisocyanate (MDI).

12. A capsule according to any one of the preceding claims, wherein the opening device (5) comprises a plate (51), said plate comprising opening elements (52) rising from the upper surface (511) of the plate, said opening elements (52) being designed to pierce, tear, puncture the bottom membrane (4) under the effect of the liquid pressure increase in the ingredient chamber during injection of said liquid.

13. A capsule according to the preceding claim, wherein the opening elements (52) present sharp pointed ends.

14. A capsule according to Claim 12 or 13, wherein the plate (51) of the opening device (5) comprises beverage evacuation holes (53) extending from the upper surface (511) of the plate to the lower surface (512) of the plate, and said holes being positioned between the rising opening elements (52).

15. A capsule according to any one of the preceding claims, wherein the bottom membrane (4) is a laminated multilayer material comprising successively :

- a vegetable parchment layer, and

- an adhesive layer, and

- a non-woven material layer comprising fibres, wherein said fibres are biodegradable fibres, and wherein the vegetable parchment support faces the opening device (5).

16. A capsule according to any one of the preceding claims, wherein the capsule body (2) comprises a bottom wall and said bottom wall is made integral with the opening device (5).