WO2011094840A1

WO2011094840A1 - Preservative package comprising plant material

Info

Publication number: WO2011094840A1
Application number: PCT/CA2011/000111
Authority: WO
Inventors: James Robinson
Original assignee: Biofume Technologies Inc.
Priority date: 2010-02-03
Filing date: 2011-02-03
Publication date: 2011-08-11

Abstract

A preservative package comprising plant material comprising glucosinolates is described. The package may be used to preserve food products and a variety of other products. The plant material is preferably a mustard plant material.

Description

PRESERVATIVE PACKAGE COMPRISING PLANT MATERIAL

RELATED APPLICATION This is a Patent Cooperation Treaty Application which claims the benefit of 35

U.S.C. 1 19 based on the priority of corresponding U.S. Provisional Patent Application No. 61/300,953, filed February 3, 2010, which is incorporated herein in its entirety.

FIELD OF THE INVENTION

The invention described herein generally relates to packaging and more specifically to a gas permeable package capable of retaining a preservative agent, notably a plant product obtained from a plant comprising glucosinolates, such as mustard. The package is particularly useful for the preservation of food products.

BACKGROUND OF THE INVENTION

It is important for commercial as well as health reasons that food and other products are prepared in such a manner that these products can be preserved. An increase in shelf life of food products, beverage products, personal care products, pharmaceutical products and the like, facilitates delivery and handling of these products and permits an increase in profit margin for the producer and improved quality for the end user. In this respect synthetic additives, such as benzoate, sorbate and organic acids, have long been used to restrict microbial growth and preserve, or otherwise increase the shelf life of food and other products.

Synthetic chemical additives are subject to increasing regulation and many preservatives which once were acceptable for use in foods are now prohibited. Furthermore many chemical additives are known to significantly alter the flavor characteristics of food products, rendering such food products safe for human consumption but unacceptable from a taste standpoint. Moreover, consumer demand for natural preservatives has been increasing. Consequently there is a growing need for methods and means of safe preservation of food products which do not rely on synthetic chemical additives into food products, and which nevertheless restrict the deterioration of the quality of the food product. Notwithstanding the foregoing to date very few effective natural preservatives have been identified.

Mustard seeds have been used as a natural source for the preparation of preservatives. In this regard US Patent 7,563,434 discloses a mixture of an aliphatic isothiocyanate and an aromatic isothiocyanate obtainable from mustard seed which is useful in the preservation of food products. It is a disadvantage of the preservative system disclosed in US Patent 7,563,434 that it is mixed with the food product thus resulting in consumption of the preservative system and alteration of the flavor characteristics.

One approach to the problem of preservation of food and other products which restricts consumption of the preservative agent, relies on the use of a preservative agents and other quality retaining agents, such as dessicants, anti-oxidants and freshness retaining agents, packaged in a gas permeable package which is enclosed in the food containers. Such packages are disclosed in for example US Patents 4,657,133 and 4,856,649. Whether or not these packages are effective depends to a significant extent on the preservative composition that is used. Only preservative compositions capable of (i) vaporizing to a sufficient degree under storage conditions, (ii) transferring in vaporized form to the exterior of the package, (iii) exerting a preservative effect under storage conditions and (iv) not affecting the quality of the material to be preserved, are suitable to be used in conjunction with these packages.

There are still significant shortcomings to the preservatives known to the art. In particular there is a need for effective natural preservatives which are not mixed with the food product. SUMMARY OF THE INVENTION

The present invention provides a preservative package comprising a plant material containing glucosinolates. In a preferred embodiment the present invention provides a novel gas permeable package that is useful in the preservation of food products and other products with a limited shelf life. The gas permeable package here disclosed comprises plant material comprising glucosinolates as a preservative, which represents a food grade, non-synthetic and non-toxic material. Accordingly the present invention provides a gas permeable package for retaining a plant material comprising glucosinolates, said package comprising pores sufficiently large to permit the passage of (a) water to the interior of the package and (b) an effective amount of glucosinolate breakdown product in vapor state to the exterior of the package, but sufficiently small to retain the plant material. The package preferably comprises a material capable of attracting or absorbing water while permitting the passage of gasses. Such material may be a coating deposited on the package wherein such coating attracts or absorbs water while permitting the passage of gasses. In preferred embodiments of the invention, the plant material is from mustard plants.

Other features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those of skill in the art from the detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 depicts a series of graphs showing the bactericidal effect of a mustard plant material containing plastic package.

FIGURE 2 depicts a series of graphs showing the bactericidal effect of a mustard plant material containing fiber package.

DETAILED DESCRIPTION OF THE INVENTION

As hereinbefore mentioned, the present invention relates to a novel gas permeable package that is useful in the preservation of food products and other products with a limited shelf life. The present inventors have found that plant material comprising glucosinolates when packaged using a gas permeable package or porous containment vessel and preferably coated in a manner that attracts or absorbs water provides a means for preservation. Surprisingly the package offers superior preservation of food and other products with respect to shelf life. The preservatives provided herein are additionally beneficial in that they are natural, organic and biodegradable.

Accordingly the present invention provides a preservative package comprising a plant material comprising glucosinolates. In a preferred embodiment the present invention provides a gas permeable package for retaining a plant material comprising glucosinolates, said package comprising pores sufficiently large to permit the passage (a) water to the interior of the package and (b) an effective amount of glucosinolate breakdown product in vapor state to the exterior of the package but sufficiently small to retain the plant material. The package preferably comprises a material capable of attracting or absorbing water while permitting the passage of gasses. Such material may be a coating deposited on the package wherein such coating absorbs water while permitting the passage of gasses. In particularly preferred embodiments, the present invention the plant material comprising glucosinolates is from a mustard plant.

The term "plant material comprising glucosinolates" as used herein denotes any plant material comprising glucosinolates, including any plant material obtained from plants belonging to the family of Brassicaceae, including any plant belonging to the genera Brassica and Sinapis, and any plant material obtained from a mustard plant. Representative examples of glucosinolate containing plants that may be used in accordance with the present invention include Brassica napus (rapeseed), Brassica juncaea (Oriental, Indian or brown mustard), Brassica carinata (Abyssinian or Ethiopian mustard), Brassica nigra (black mustard), Brassica rapa (rapeseed), Sinapis alba (white mustard), Sinapis arvensis (wild mustard), Armorica rusticana (horse radish) and any cultivars of the foregoing including the Canola cultivar of Brassica napus, and mixtures thereof.

The term "glucosinolate breakdown product" refers to products obtainable following hydrolysis of glucosinolate. Glucosinolate break down products are useful as preservatives as they can inhibit the growth of bacteria, yeasts and moulds. The general structure of glucosinolate is: β D Glucose

OS0₃ Examples of glucosinates that may be found in the plant material used in accordance with the present invention are epiprogoitrin and sinigrin. Included within the term glucosinolate breakdown products are the following three general classes of glucosinolate breakdown products:

( 1) R C N Nitrile

(2) R S— C— Thiocyanate (3) R N^~ C Z S Isothiocyanate

Further glucosinolate breakdown products include l-cyano-2-hydroxy-3-butene ( CHB") and goitrin, which are obtained following the breakdown of the glucosinolate epiprogoitrin. Still further glucosinolate breakdown products include allyl thiocyanate ("ATC"), allyl isothiocyanate ("AITC") and allyl cyanide ("AC") all of which are breakdown products of the glucosinolate sinigrin. "Effective amounts of glucosinolate breakdown products", as used herein are such amounts of glucosinolate breakdown products that increase the shelf life of a food product or other product, when compared to a product in the absence of the package of the present invention.

Plant Material

In accordance with the present invention any plant material obtainable from plants comprising glucosinolates may be used, including any plant material, or processed plant material, obtainable from the leaves, stems, roots or seeds of plants. Preferably the plant material as used herein is treated such as to produce a processed plant material. The plant material may for example be crushed or pressed to obtain a crushed or pressed plant material. Preferably the plant material or processed plant material used in accordance herewith is moistened using water and homogenized in order to promote the hydrolysis of glucosinolates. Pre-treatment of the plant material is preferred for certain plant materials, such as seed. Pre-treatment processes that may be used in accordance herewith include dehulling, cracking, grinding, flaking, pressing, extruding, pelleting and the like. When oil rich plant material is used in accordance herewith, it is preferable to remove the oil from the plant material. This may be accomplished through methods such as solvent extraction, hydraulic pressing, expeller pressing, cold pressing and other oil removal processes that will be well known to the skilled artisan. Since the hydrolysis of glucosinolates is performed by the heat labile enzyme plant enzyme myrosinase it is preferred that all pre-treatment steps are performed at temperatures below 85°C, more preferably below 70 °C, and most preferably below 60 °C.

In a preferred embodiment of the present invention, the processed plant material used is a mustard plant material and in particularly preferred embodiment a mustard seed meal. Many processes for processing raw mustard seed into oil and meal known to the art. Illustrative processes are those taught by and Morra, M. J, 2000-2002, Subcontract Report National Renewable Energy Laboratory NREL/SR-510-3628. Typical of these processes is the receipt of mustard seed from the field by conventional transport means, for example, rail or truck, in a dirty and often wet condition. The mustard seed is then subjected to an elementary separation procedure, for example, contacted with a vibrating screen or using a grain cleaning machine, for example a grain cleaning machines manufactured by Damas A/S (Denmark), in which the mustard seed is separated from non-mustard seed material, such as rocks, sticks, dirt, leaves, weed seeds, loose hulls etc. It is preferred that following the cleaning the mustard seed is dried, using for example a grain dryer as manufactured by Vertec Industries Limited (Canada), so that the moisture content of the seed is reduced to between 4% and 8%, and preferably 6%. Following the removal of non-mustard seed contaminants and drying, the mustard seed may be stored, mixed with other mustard seed species, or processed to obtain mustard seed meal. At this point in the process the outer seed coating, which is also known as the seed husk or bran, may be removed from the seed by milling or cracking the seed or using another suitable abrasive process to obtain the seed kernel. Such removal of the bran is however optional and not of critical importance. The next step in the process is largely dependent on the oil (also known as "lipid" or "fat") content of the mustard meal that is desired. If a "full fat" meal is desired than the kernels are subjected to a process that does not result in oil extraction. If, on the other hand a "defatted" meal is desired than the kernels are subjected to a process resulting in oil extraction. In preferred embodiments of the present invention a defatted meal is prepared. Accordingly, the oil found within mustard seed or mustard kernel (in instances where the bran has been removed) is removed from the mustard seed by for example chemical extraction, using for example hexane, or mechanical extraction using for example an oil expeller or press, such as an oil press such as a Taby Press manufactured by Skeppsta Maskin AB (Sweden) or a Komet oil expeller manufactured by Monforts Oekotec GmbH (Germany). Preferably the mustard seed meal used in accordance with the present invention comprises between 2% and 50% of the available seed oil, and more preferably approximately between 10 and 15%, and most preferably 15% of the available seed oil.

In preferred embodiments of the present invention, the mustard seed meal obtained at this point in the process is ready for use as a preservative as referred to in this application. It is also noted that at this point in the process seed meals from one or more different sources may be mixed, for example Sinapis alba meal may be mixed with Brassica juncea meal and in this way a blended meal may be obtained, such a blended meal may exhibit different pesticide characteristics, for example it has been observed by the present inventor that a blend of Sinapis alba meal and Brassica juncea meal is particularly useful when a fast release formula is desired. Alternatively blends may be obtained by mixing mustard seeds of different mustard species prior to the de- oiling process, or mixing process intermediates obtained using different mustard species. In preferred embodiments cold pressed seeds or defatted meal obtained from different species are mixed.

In preferred embodiments of the present invention, following the de-oiling of the mustard seed, the defatted mustard seed meal is ground, to obtain mustard flour. In order to obtain flour the seed meal is preferably further treated using milling (e.g. using a hammer mill), grinding or pelletizing devices, such as a CPM pellet mill manufactured by CPM (USA), to obtain pellets with a preferred size between 2 mm and 6mm. Thereafter the pellets may be treated by a device capable of crumbling the pellets, using for example a roll crumbier, such as manufactured by Apollo (USA) or an Amandus KAHL roller, and separated for granular size using one or more screening devices comprising gauges which permit the separation of the crumbled pellets into fractions of various sizes, which may be vibrating or rotating screens. Using a rotary screen separator, for example such as those manufactured by a Rotex screener, manufactured by Rotex Inc. comprising multiple screens with different gauges it is possible to obtain products with a range of different granular sizes. Preferably granular size in formulations prepared in accordance with the present invention ranges between 0.01 mm and 10 mm. The concentrations of glucosinolates in the final formulated product may vary but typically ranges between 95 and 225

or between 0.6% w/w and 3.00% w/w.

As hereinbefore mentioned, the preservative effect of the plant material used in accordance with the present invention emanates from glucosinolate breakdown products obtained following hydrolysis of the glucosinolates. The concentration glucosinolate breakdown product present in the plant material prepared in accordance with the present invention may vary. Typically AITC is present in the final plant material in concentrations of between at least 1

and, more preferably at least 10 μχηο^/ξΐΆπι and 800 μηιο1ε^Γ3ηι, and more preferably between 10 and 200

or between 0.6% w/w and 3.00% w/w. Within the foregoing concentration ranges the glucosinolate breakdown products of the present invention are effective in that they provide for an effective preservative.

The Package

The package of the present invention may comprise a variety of different materials. In preferred embodiments, the package is a gas permeable or porous package. The material used to make the package must be sturdy enough to retain the mustard plant material. In addition the material must be porous enough to permit passage of ambient water or moisture in liquid or vapor state to the interior of the package, and the passage of an effective amount of glucosinolate breakdown product in the vapor state to the exterior of the porous package. At the same time the pores also must be of a sufficiently fine porosity to retain the plant material. Thus, in the first instance the porosity of the material will depend on the granular size of the plant material which may vary as hereinbefore described. Relatively coarse plant material may be packaged using a material that is very porous, while fine plant material is packaged using material having a fine pore size. The present inventors have determined that porous packages having pore sizes ranging from 0.01 micron to 2000 microns are suitable for the present invention. In preferred embodiments, the pore sizes range from 2 microns to 800 microns, and in particularly preferred embodiments the pore size ranges from 2 microns to 125 microns. The present inventors have discovered that packages with a pore size in the range from 2 microns to 125 microns, and mustard plant material with a granular size somewhat larger than the selected pore size, preferably 10 % -100% larger than the selected pore size, or more preferably 15% - 25% larger than the selected pore size are preferred. For example where a pore size of 100 microns is selected the granularity of the mustard plant material preferably varies from 1 10 microns to 200 microns, and more preferably from about 1 15 microns to 125 microns. Thus selecting the foregoing pore sizes and granularity permits containment of the mustard plant material, and efficient transfer of water to in interior of the package, and transfer of an effective amount of glucosinolate breakdown product in vapor state to the exterior of the package, providing superior preservation characteristics. Packages constructed to comprise pore sizes in the aforementioned size range, will readily permit the passage of water in liquid or vapor state, ambiently present in the package of the product to be preserved, from the exterior of the package, and, concomitantly, the passage of glucosinolate breakdown products in vapor state from the interior of the package. The passage of water to the interior of the package permits hydrolysis of glucosinolates present in the mustard plant material resulting in the generation of glucosinolate breakdown products in vapor state. Vapor pressure differential between the interior and the exterior of the package promotes transmission of the glucosinolate breakdown products to the exterior of the package. Upon the transmission of an effective amount of glucosinolate breakdown products in vapor state from the package, the glucosinolate breakdown products will exert their preserving effect.

The package may be fabricated from a wide range of porous materials such as a plastic, paper or woven or non-woven fabrics, or it may be constructed from film forming polymers, such as cellulose. Preferably the material used comprises a material that readily attracts and retains ambient moisture thus effecting and facilitating the generation of glucosinolate breakdown products. Materials for fabricating the package that may be used in accordance with the present invention include for example paper or woven materials of controlled porosity, such as paper/ woven bags used to contain tea leaves, including for example corn starch derived materials such as soilon, and coffee filter paper. Furthermore softwood or hardwood pulp based materials comprising lignin, cellulose and hemi cellulose may be used to prepare the package of the present invention, as may be the fibrous materials obtained from fiber generating crops, such as hemp and abaca, which may be used in their natural form or chemically modified to prepare for example cellophane or viscose. Yet other materials that may be used to fabricate the package in accordance with the present invention are silk, which may be used to weave fabric, and muslin. The foregoing materials are deemed particularly suitable since they are natural. In other embodiments of the present invention synthetic materials may be used to fabricate the package, such as polyamide based polymers (nylon) and ethane based polymers such as polyethelene. It will be understood that the shape of the package is arbitrary, and may for example be spherical or a cylinder any other shape.

Coating of the Package

In preferred embodiments, the package comprises a substrate having a conformal coating. As used herein "conformal coating" is a coating having the general topology of the package, although it is understood that the coating can vary somewhat in thickness and need not to reproduce the adjacent geometry precisely, provided it does not significantly occlude the pores. The conformal coating may be deposited on the exterior or the interior of the package, and it must permit the passage of water from the exterior of the package and the passage of glucosinolate breakdown products in vapor state from the interior of the package. In particularly preferred embodiments the conformal coating comprises a hydrophilic material, capable of enhancing the transfer of water, present to the interior of the package, thereby enhancing the hydrolysis of glucosinolates present in the mustard plant material. Examples of hydrophyilic materials that may be used in accordance with the present invention include: ionic and non-ionic hydrophilic surfactants. A particularly useful hydrophilic material used for coating and capable of attracting water is starch.

The package may be readily fabricated utilizing packaging techniques known to a person of ordinary skill in the art. The porous or gas permeable material may be laminated, or adhesively bonded to form a packet. It may be advantageous in some instances to include a material to provide additional support. The secondary material must be permeable to water from the exterior of the package and glucosinolate breakdown products in the vapor state from the inside of the package, and is preferably placed on the inside of the package to prevent clogging of the pores with oils or other liquids. Secondary materials may be fabricated from polymeric materials or comprise paper, or woven or non- woven fabrics.

Use of the Package

The preservative packaging material of the present invention may be used to preserve products for human use, such as food products and personal care products, as well as other products with a limited shelf life. In preferred embodiments, the package of the present invention may be placed inside storage containers comprising for example fresh produce, meat and other food products for human consumption, thereby increasing the shelf life of these products and permitting storage for significant periods of time. In accordance with the present invention spoilage of food and other products resulting form bacteria, fungi, and the like is retarded and/or prevented, thereby preserving these products and increasing food safety. The present invention is particularly useful to inhibit the growth of pathogenic foodborne bacterial contaminants such as those resulting from contamination by Escherichia, Pseudomonas and Listeria species. As further detailed in Examples 2 and 3 herein, use of the package of the present invention results in a reduction of growth of the aforementioned bacterial species by at least one order of magnitude. The concentration of mustard plant material used may be varied. In preferred embodiments, the concentration of mustard plant material ranges from 0.1 g per liter of storage container volume to 100 g per liter of container volume. In most preferred embodiments of the present invention, the concentration of mustard plant material is between O. lg and 10 g per liter of storage container. It should be noted that the package of the present invention may be used at a range of different temperatures. In preferred embodiments of the present invention, the package is used at temperatures typically used for the storage of food products, e.g. at approximately room temperature (approximately 20°C) and for refrigerated storage, typically at approximately 4°C.

The present invention is further described by reference to the following Examples which are illustrative only and not limiting the invention. Example 1. Preparation of mustard plant material with a range of different granular sizes

A total of approximately 1,402,000 Lbs of mustard seed Brassica Juncea and approximately 28,000 Lbs of Sinapis alba seed was purchased from Viterra Inc. and dried using a Vertec grain dryer, model VT5000 set at a temperature of 62°C, to achieve a moisture content of 6.5%. The two dried mustard seed portions were subsequently blended using a standard hopper (resulting in a Brassica juncea/ Sinapis alba blend of 98/2 % (w/w)) and cleaned using a Damas screen Model 640 ana. The cleaned, blended mustard seed was then subjected to a de-oiling process using a Komet oil expeller. The de-oiling process was carried out maintaining a temperature below 70°C, and provided seed meal yielding approximately 1 ,401 ,400 Lbs of defatted mustard seed meal (having an oil content of between about 10% and 15%) and approximately 429,000 Lbs of crude mustard seed oil. The defatted seed meal fraction was then crushed using a KAHL crushing roller mill at a temperature which was maintained below 70°C, yielding a mustard flour. The performance of this crushing process did not result in any substantial yield loss. The crushed material was then screened using a standard fertilizer screening unit (ROTEX Screeners - Rotex Inc). The screener yielded three separate mustard flour fractions: (1) a fraction with granular size of 0.01 - 0.25 mm; (2) a fraction with a granular size of 0.25 mm - 0.75 mm; and (3) a fraction with a granular size of 2 mm - 6mm. Each fraction represents a formulated mustard plant material formulation which may be used to as active for packaging in the preservative package or can be recycled into the system to obtain the desired size with minimal waste.

Example 2. Bactericidal effect using porous plastic package containing mustard plant material. A mustard plant material having a granular size of approximately 200 microns was prepared as described in Example 1. The mustard plant material was packaged into a porous package constructed of a polyethelene plastic film having a pore size of 75 microns Three different strains of bacteria {Escherichia coli, pseudomonas fluorescens and Listeria innocua) known to cause food spoilage, were used to inoculate filter paper with 10⁵ - 10⁷ colony forming units/ml. Upon inoculation the filter paper was placed inside a hermetically sealed container together with a mustard plant material containing porous package and the container was stored for 4 days at 20°C. Varying amounts of mustard plant material (0.1 , 1.0, 10 and 100 g/ per liter of container volume) were compared. Bacterial growth was examined by performing cell counts during a 4 day period. As a control a hermetically sealed container comprising an empty porous package was used. As shown in Figure 1, over the time course of the experiment bacterial counts increased in the control. By contrast, at concentrations of 0.1, 1.0 and 10 g per liter of container volume, bacterial counts for all tested bacterial species decreased substantially to approximately 10³ -10⁴ colony forming units/ml. At lOOg per liter no further reduction in bacterial count was observed (results not shown in Figure

1)· Example 3. Bactericidal effect using porous fiber package containing mustard plant material.

Mustard plant material having a granular size of approximately 200 microns was prepared as described in Example 1. The mustard plant material was packaged into a porous package fabricated from abaca fiber pulped and processed to obtain a paper material, having a pore size of 75 microns. Three different strains of bacteria (Escherichia coli, pseudomonas fluorescens and Listeria innocua) known to cause food spoilage, were used to inoculate filter paper with 10⁵ - 10⁷ colony forming units/ml. Upon inoculation the filter paper was placed inside a hermetically sealed container together with a mustard plant material containing porous package and the container was stored for 4 days at 4°C. Varying amounts of mustard plant material (0.1, 1.0, 10 and 100 g/ per liter of container volume) were compared. Bacterial growth was examined by performing cell counts during a 4 day period. As a control a hermetically sealed container comprising an empty porous package was used. As shown in Figure 2, over the time course of the experiment bacterial counts remained unchanged in the control. By contrast, at concentrations of 0.1, 1.0 and 10 g per liter of container volume, bacterial counts for all tested bacterial species decreased. Use of a concentration of lOg per liter container resulted in the most significant bactericidal effect at 4°C. It was noted that at 1 OOg per liter no further reduction in bacterial count was observed (results not shown in Figure 1).

Claims

WHAT I CLAIM IS:

A preservative package comprising a plant material comprising glucosinolates.

The package according to claim 1 wherein the plant material is from Brassica napus (rapeseed), Brassica juncaea (Oriental, Indian or brown mustard), Brassica carinata (Abyssinian or Ethiopian mustard), Brassica nigra (black mustard), Brassica rapa (rapeseed), Sinapis alba (white mustard), or Sinapis arvensis (wild mustard), Armorica rusticana (horse radish) or mixtures thereof.

The package according to claim 1 wherein the package is a gas permeable package for retaining the plant material and comprising pores sufficiently large to permit the passage of (a) water to the interior of the package and (b) an effective amount of glucosinolate breakdown product in vapor state to the exterior of the package, but sufficiently small to retain the plant material.

The package according to claim 3 comprising a material capable of attracting or absorbing water while permitting the passage of gases.

The package according to claim 4 wherein the material capable of attracting or absorbing water while permitting the passage of gases is a coating deposited on the package wherein such coating attracts absorbs water while permitting the passage of gasses.

The package according to claims 3, 4 or 5 wherein the package comprises a natural material.

The package according to claims 3, 4 or 5 wherein the package comprises a synthetic material.

The package according to claims 6 wherein the natural material is a fiber obtained from wood, hemp or abaca.

The package according to claim 6 wherein the natural material is soilon, muslin or silk.

The package according to claim 7 wherein the synthetic material is nylon or polyethelene.

1 1. The package according to claims 3, 4 or 5 wherein the package comprises pores in the range of 0.01 micron to 2000 microns.

12. The package according to claims 3, 4 or 5 wherein the package comprises pores in a size range from 2 microns to 800 microns, and wherein the mustard plant material has a granularity between 10% and 100% larger than the pore size.

13. The package according to claim 5 wherein the coating comprises a hydrophilic material.

14. The package according to claims 3, 4 or 5 wherein the plant material is a seed meal.

15. The package according to claims 3, 4 or 5 wherein the plant material is a defatted/de-oiled seed meal.

16. The package according to claim 14 or 15 wherein the meal has an AITC content of between 1 and 800 μmoles/gram.

17. The package according to claim 14 wherein the seed meal is from Brassica napus (rapeseed), Brassica juncaea (Oriental, Indian or brown mustard), Brassica carinata (Abyssinian or Ethiopian mustard), Brassica nigra (black mustard), Brassica rapa (rapeseed), Sinapis alba (white mustard), Sinapis arvensis (wild mustard) or Armorica rusticana (horseradish).