AU2016213700C1 - Preparation of mild tasting and high yielding kava powder - Google Patents

Abstract

5297F-AU An ultra-fine kava powder is disclosed having a nominal particle size of less than approximately 60 pm and preferably less than approximately 30 Pm. The ultra-fine kava powder is prepared by feeding a coarse kava precursor (9) into the pulverising chamber (2) of a pulveriser. The coarse kava precursor (9) is pulverised to produce an intermediate kava powder (13). During the pulverising of the coarse kava precursor (9), air at a temperature of less than approximately 250 C is injected into the pulverising chamber (2) to prevent the temperature of the intermediate kava powder (13) exceeding approximately 600 C. The pulverisation is continued until a substantial proportion of the kava particles have a nominal size of less than approximately 60 pm and preferably less than approximately 30 pm. The ultra-fine kava powder can be formed into a granulated powder which demonstrates excellent granule dispersion.

Description

5297F-AU 2016213700 02 Nov 2016

PREPARATION OF MTTJ) TASTING AND HIGH YIELDING KAVA

POWDER

Field of the Invention

The present invention relates to kava technology and, in particular, to improving the palatability and physiological effect of beverages, foodstuffs, and other ingestible products containing extracts from the kava plant.

Background Art

Kava products have been widely used for improving human health for 3000 years in Melanesian and Polynesian societies, for which kava has become known as “the Pacific elixir”. Kava drink is a traditional Melanesian and Polynesian drink and is formed from water infused with an extract made from dried roots of the kava plant.

Kava drink, in particular, is consumed at various social and ceremonial occasions throughout most of the Pacific Islands, and is well regarded as creating feelings of wellbeing, relaxing muscles, and inducing sleepiness.

Indeed, kava products are widely recognised as having a number of beneficial effects. For example, kava products contain various pharmacologically active ingredients, including kavalactones, having activities such as analgesic activity, anxiolytic activity, muscle-relaxant activity, anti-inflammatory activity, and so on.

Kava-based products are generally considered to be unpalatable in Western culinary arts and can be difficult to commercialise in these societies. In particular, an innate bitterness in taste, a strong flavour, and an aroma all contribute to kava drink and other kava products being regarded as an acquired taste for which there is little gustative, or olfactory, incentive to acquire.

Traditionally, mastication of kava root was employed in order to liberate the active ingredients more effectively. A pulp of kava and saliva resulting from this mastication was used to prepare a kava beverage. 1

5297F-AU 2016213700 02 Nov 2016

In recent times, mechanical and/or chemical processes are used to enhance the beneficial effects of kava products, for example by enhancing the liberation, the absorption, and the bioavailability of the active ingredients per unit weight of constituent kava raw material (root, root stump, and basal stem). However, these prior art mechanical and/or chemical processes can also exacerbate undesirable qualities, in particular qualities deleterious to palatability such as bitterness, grittiness, and a harsh flavour. For example, when kava root is extracted into water, the resulting kava drink can be described as having an unpleasant peppery or pungent taste that is stronger than the taste or aroma of the constituent root material.

There have been many attempts to solve the undesirable qualities of kava products including the bitter taste and pungent flavour. Among the methods used to ameliorate these qualities and reduce the bitter taste and spicy flavour, was to add lemon, or to mix coconut milk or chocolate etc. with the kava extract. However, these methods have not afforded a satisfactory result.

The prior art mechanical and/or chemical processes used to enhance the beneficial effects of kava products can also adversely affect yield, and there can be a reduced total of the active ingredients in a resulting prior art kava product when compared with the total of the active ingredients in the constituent kava.

Kava raw material is commonly processed by pounding, grinding, or the like. A comminuted kava product can be made from the kava raw material. This material includes roots, stumps, and/or basal stems of a kava plant, either with bark included or removed. The kava raw material can be either fresh or dried prior to the comminution. Fresh kava raw material can have a water content of approximately 75% to 80% w/w. Accordingly, fresh kava raw material tends to spoil more rapidly, and requires more expensive or specialised storage, than dried kava raw material which typically has a water content of under approximately 15% w/w. Comminuted kava products usually have their own characteristic brownish hue.

The active ingredients of comminuted kava products are normally liberated by solvent extraction methods. A conventional example is a beverage made using coarsely- 2

5297F-AU 2016213700 02 Nov 2016 ground kava product. The coarse ground product is placed in a nylon stocking or similar water-pervious flexible bag, and kneaded by hand within a water-filled container until the kava active ingredients are liberated and infuse into the water to create a kava drink. One of the drawbacks of this method is that for good results the kneading requires some considerable skill. Moreover, significant quantities of the active ingredients can remain in the ground kava and subsequently be discarded with the infusion bag.

British Patent No. 2,464,806 discloses an aqueous extraction method wherein a kava extract is formed from kava constituents under elevated temperature conditions. An extract formed by this method can be more potent than the original kava constituents. This method is considered to be suitable for industrial-scale production, however it requires additional steps to manufacture a powdered product.

British Patent No. 2,507,270 discloses an aqueous extraction method that involves a kava/cyclodextrin/lecithin system to improve palatability of a kava extract, including by reducing bitterness. The beneficial effects of kava extracted by this method are similarly enhanced, however overall yield of the active ingredients is moderate at approximately 60%.

Other solvent-based extraction processes have been described in which the active ingredients are extracted using a non-water solvent, for example, alcohol or acetone.

Solvent-based extraction methods generally involve filtering to remove residual kava solids. Consequently, a portion of the active ingredients is lost and a lower yield is realised.

Powdered kava products that include all constituent kava material (excepting for example cell water content) if directly consumed can deliver a high yield of active ingredients. This is advantageous provided that the liberation, absorption, and bioavailability of the active ingredients are also favourable, and that the end product is palatable. 3

5297F-AU 2016213700 02 Nov 2016

Although several small enterprises in Fiji and Vanuatu manufacture powdered kava, they depend upon mechanical methods including cutting mills and/or hammer mills, that produce a coarsely ground powder having an average particle size of over approximately 500pm. In such coarse kava grinds, the beneficial effects of the active ingredients are not be fully realised.

It is difficult to manufacture a more finely powdered kava on an industrial scale. This is attributable in part to the propensity for finely ground kava to catch fire during comminution. Elevated temperatures are also thought to cause a reduced yield or a reduced overall absorption or bioavailability of the active ingredients per unit weight of kava constituent. A method to overcome problems in manufacturing finely powdered kava using a hammer mill is disclosed in US Patent No. 6,238,722. This method results in a medium powdered kava having an average nominal particle size of approximately 250 to 500pm.

The method of the US patent provides for an improvement upon more coarsely ground products; however an organic acid, flavourant, or like additive is still required to ameliorate or mask the unfavourable taste. Furthermore, both the coarse and medium kava powders described above, when consumed, can have a perceived grittiness in texture resulting from comminution, and can have a bitter taste. Also, kava powders produced in accordance with the method of the US patent are characterised by less than ideal active ingredient availability, liberation, and/or bioavailability, as well as less than ideal dispersion behaviour.

Genesis of the Invention

The genesis of the present invention is a desire to overcome or ameliorate some of the above disadvantages of the prior art.

Summary of the Invention

In accordance with a first aspect of the present invention there is disclosed a kava powder for oral consumption comprising a plurality of kava particles, characterised in that the particles are produced by comminuting dried kava raw materials selected from the class consisting of kava root, kava root stump, and kava 4

5297F-AU 2016213700 02 Nov 2016 basal stem, and that a substantial proportion of said particles have a nominal size of less than 60 pm.

In accordance with a second aspect of the present invention there is disclosed a method of manufacturing ultra-fine kava powder having a plurality of kava particles, said method comprising the steps of: a coarse kava precursor is fed into and pulverised by a pulveriser having a pulverising chamber to produce an intermediate kava powder; and said intermediate kava powder is cooled by an injection of a gas into said pulverising chamber whereby said intermediate kava powder does not undergo a substantial increase in temperature during said pulverisation; and said pulverisation is continued until a substantial proportion of said kava particles have a nominal size of less than 60 pm.

Brief Description of the Drawings

Some embodiments of the present invention will now be described with reference to the drawings, in which:

Fig. 1 is a flow chart summarising a first method for preparing an ultra-fine kava powder,

Fig. 2 is a graphical particle analysis illustrating the particle size and distribution of the ultra-fine kava powder produced by the method of Fig. 1;

Fig. 3 is a laboratory analysis of the kavalactone content of the ultra-fine powdered kava of Fig. 1;

Fig. 4 is a flow chart summarising a method for preparing granulated ultra-fine kava powder; and

Fig. 5 is an illustration of a preferred fine pulveriser used for preparing the ultra-fine kava powder of Fig 1.

Detailed Description

According to a first embodiment of the present invention, there is disclosed a method of manufacturing an ultra-fine kava powder. The method includes the following stages: A. Produce of a kava plant is subjected to a drying process; and 5

5297F-AU 2016213700 02 Nov 2016 B. The kava produce is subjected to a preliminary stage of comminution either before or after the drying process to form a coarse kava precursor; and C. The dried produce of a kava plant or the coarse kava precursor is subjected to a primary stage of comminution to form an intermediate kava powder and then an ultra-fine kava powder.

This processing of the produce of a kava plant prior to consumption increases the liberation of the active ingredients, realises a higher overall rate of absorption, and similarly realises a higher bioavailability.

As seen in Fig. 1, before drying, the kava plant material is preferably washed in step 100 to remove any soil residue, etc. Then in step 200 the kava produce is dried. In step 300 a preliminary comminution stage is carried out using a hammer mill to produce the course kava precursor.

Next in step 400 the primary comminution stage is carried out using a fine pulveriser. Finally, if required, the result of the primary stage is re-pulverised in step 500, if necessary depending upon particle size.

Preferably, the method does not substantially involve any further processing, beyond the cleaning, drying, and comminution. For example, no solvent is used.

Preferably, the kava produce includes whole kava root. Preferably the root has its bark removed to reduce bitterness. The kava produce can also include root stumps and/or basal stems of the kava plant.

The drying process is preferably continued until a dried kava material of under approximately 15% w/w water content is obtained, in order to minimise rotting of kava material. Preferably, drying is performed by the action of the sun. More preferably, drying is performed by the action of hot air having a sufficiently low humidity. Preferably, the hot air has a temperature of less than 90°C, more preferably less than 60°C. Preferably, a substantial reduction in water content of the kava material occurs before the preliminary stage, and more preferably before the primary 6

5297F-AU 2016213700 02 Nov 2016 stage, of comminution. Preferably, the drying process is continued throughout comminution.

The preliminary comminution is preferably performed with an impact grinder. Preferably, the impact grinder has a substantially low frequency of impact. Preferably, the impact grinder is a hammer mill. Preferably, the preliminary comminution results in the coarse kava precursor having an average particle size of between approximately 500 to 700pm.

Preferably, the temperature of the kava material during the preliminary comminution is less than 90°C, and more preferably less than 60°C.

The primary stage of comminution is preferably performed in a fine pulveriser. The fine pulveriser is preferably a hybrid of hammer mill and air-fluid mill designs.

The preferred hybrid pulveriser is illustrated in Fig 5, and has a feed system 1, a pulverising chamber 2, and a rotor 3 driven by a motor 4. The rotor 3 is located within the pulverising chamber 2 and divides the chamber into an intake side 5 and an outlet side 6. The rotor 3 has a first set of radially-oriented pulverising pins 7 located on the intake side 5, and a second set of radially-oriented pulverising pins 8 located on the outlet side 6 of the pulverising chamber 2. The coarse kava precursor 9 is fed into a hopper 10 and moved with the screw feeder 11 toward a gas inlet 12 where after the coarse kava precursor 9 enters the intake side 5 of the pulverising chamber 2. The rotor 3 is driven at high speed (e.g. 3500 rpm) by the motor 4 to comminute the coarse kava precursor 9 into the intermediate kava powder 13, and ultimately into the desired ultra-fine kava powder. Kava particles suspended in the airflow may leave the outlet side 6 of the pulverising chamber 2 through the gas outlet 14, and be re-circulated to the gas inlet 12 if required.

Preferred mechanisms of comminution when using the preferred hybrid pulveriser are described as follows. A first mechanism of comminution arises where kava particles impact with sides 15 of the first set of pulverising pins 7. A second mechanism of comminution arises where kava particles on the intake side 5 of the pulverising 7

5297F-AU 2016213700 02 Nov 2016 chamber 2 are sufficiently small to become partially disposed within a grinding mesh 16 located around the inner circumference 17 of the pulverising chamber 2 and are subsequently impacted by ends 18 of the first set of pulverising pins 7. A third mechanism of comminution arises where kava particles on the outlet side 6 of the pulverising chamber 2 become partially disposed within the grinding mesh 16 and are subsequently impacted by the ends of the second set of pulverising pins 8. Kava particles may also be ground between the first set 7 or the second set of pulverising pins 8, and the inner circumference 17 of the pulverising chamber 2 when those particles are not partially disposed within the grinding mesh 16. A further mechanism of comminution involves collision between kava particles suspended in an air stream within the pulverising chamber 2. In summary, a range of comminution mechanisms are involved including high speed impact, crushing, shearing, and grinding.

Preferably, the interior of the pulverising chamber 2 and the exterior of the pulverising rotor 3 and pins, 7 and 8, that are exposed to the intermediate kava powder are made of stainless steel in order to preventing any contamination of the kava powder.

The preferred hybrid pulveriser’s rotor preferably has a diameter of approximately 500mm, is preferably driven at 3500-5000 rpm, and is preferably fed with coarse kava precursor at a rate of 15kg to 20kg per hour when operated at approximately 20°C at the air inlet, and with a maximum power input of approximately 7.5 horse-power. The feed rate, power input, rotor speed, and injected air temperature can be adjusted to suit a given pulveriser design.

An injection of a cooling gas having a temperature lower than the intermediate powdered kava can be performed during the primary stage of comminution to increase production capacity while ensuring a high quality kava powder. Preferably, the cooling gas has a temperature of less than 25°C, more preferably less than 10°C. The cooling gas is preferably air. The cooling gas preferably has a temperature and/or a water content which is/are sufficiently low to cause the water content of the intermediate powdered kava to decrease during the primary comminution. Preferably, a temperature of the cooling gas in the pulverising chamber following absorption of 8

5297F-AU 2016213700 02 Nov 2016 heat from the intermediate powdered kava is less than 90°C, and most preferably less than 60°C.

In a closed circuit or partially-closed circuit air recirculation system, the cooling gas preferably originates from the outlet side of the pulverising chamber, having been passed through a heat exchanger to lower the gas temperature. Active cooling of recirculating gasses is not necessary when using the preferred hybrid pulveriser because when properly adjusted, the intermediate kava powder does not undergo a deleterious increase in temperature.

The primary comminution is continued until the ultra-fine powdered kava is formed, being powder comprised of kava particles of which a substantial proportion have a nominal particle size of less than 60 pm, and more preferably less than 30 pm. As seen from Fig. 2, preferably at least half of the particles form a fraction having a nominal size of less than 25 pm. Preferably, at least one quarter of the particles have a nominal size of less than 15 pm. Preferably, the particles have a mean nominal size of between 10 to 20 pm.

The kava particles as also seen in Fig. 2, are preferably substantially uniform in size. More preferably, a size distribution of the particles has a span of less than two; the span being calculated as the difference between particle sizes at the 90th and 10th percentiles, divided by particle size at the 50th percentile.

The hybrid-type fine pulveriser used in the method disclosed above is ordinarily used for pulverising brittle materials such as metals and ceramics. Such equipment is not designed to be used to pulverise material such as kava raw materials that include high fibre content.

Advantageously, the method described above produces the ultra-fine kava powder without causing any ignition of kava powder during comminution. Risks of ignition disclosed in the prior art at substantially larger particle sizes were described to be overcome by an injection of an inert gas such as Nitrogen. The present arrangements, on the other hand, mitigate these risks for substantially finer and more combustible 9

5297F-AU 2016213700 02 Nov 2016 particle sizes through the use of milling equipment conventionally used for e.g. metals and ceramics. Moreover, the method described above discloses air (containing combustible oxygen) as a cooling fluid thereby reducing cost.

Importantly, the method of the first embodiment provides for the manufacture of the ultra-fine kava powder without substantially reducing the total of active ingredients carried into the final product from the constituent kava material. Also, there is no substantial alteration of colour. The ultra-fine powder has a creamy colour as opposed to, for example, a blackish colour for water-extracted products. There is also no adverse effect on flavour. These benefits are believed to be attributable in part to the low temperature maintained in the intermediate kava powder during comminution.

Advantageously the ultra-fine kava powder of the first embodiment has a lower bitterness in taste than a comparative kava powder having a substantial proportion of particles with a nominal size of approximately 250 to 500pm. The ultra-fine kava powder also has an overall milder and more favourable taste than this comparative kava powder. A batch of the ultra-fine kava powder was evaluated for taste testing by a panel of ten persons, with regard given to overall acceptability (inclusive of bitterness), smoothness, and freshness in taste. The ultra-fine kava powder was evaluated against the comparative kava powder. Each tester rated the batch using a seven point scale wherein 1 indicates very bad, 3 indicates poor, 5 indicates neutral, and 7 indicates good. In addition, each tester rated the comparative kava powder. Each tester was given 4g powder / lOOmL of the ultra-fine kava powder dissolved in lOOmL of water, and 5g in 100mL of water for the comparative kava powder. The larger mass of comparative kava powder was required to produce an equivalent strength beverage to that of the ultra-fine kava powder beverage. The results of testing are reported in Table 1 below.

Table 1. Results of taste testing of the ultra-fine kava powder as compared with the comparative kava powder. 10

5297F-AU

Beverage Overall acceptability Smooth taste Fresh taste Ultra-fine kava powder 6.70 6.90 4.00 (3-4g powder / 100ml) Comparative kava powder 4.00 1.60 3.60 (5g powder / 100ml) 2016213700 02 Nov 2016

Each of the ten taste testers indicated that they could attain a comparable biological effect with the ultra-fine kava powder drink, to that of the comparative kava powder drink, notwithstanding the lower mass of kava powder per unit volume. Comparable observations were made when consuming undissolved kava powder.

The ultra-fine kava powder has a lower perceived grittiness in texture (greater smoothness) during consumption than the comparative kava powder. The lower bitterness in taste, the lower perceived grittiness in texture, and the improved physiological effects particularly become apparent as the fraction of kava particles having a nominal size below approximately 20 pm increases, and as particle size more uniformly falls below this threshold.

The beneficial effects following consumption of the ultra-fine kava powder are greater than those following consumption of the comparative kava powder. In particular, it is believed that a greater fraction of active ingredients are liberated by solvent extraction from the ultra-fine kava powder, whether into a liquid ingredient during the manufacture or preparation of a consumable product, or directly into saliva.

Laboratory analysis, the results of which are tabulated in Fig. 3, also suggests that the ultra-fine kava powder produced by this method has a yield of approximately 90-95% of the total active ingredients present in the constituent kava material.

In any case, the active ingredients of the ultra-fine kava powder are absorbed at a faster total rate into oral mucosa including the sublingual mucosa, per unit mass of constituent kava, than the comparative kava powder. Moreover the active ingredients of the ultra-fine kava powder are thought to demonstrate greater overall bioavailability based upon user experience. 11

5297F-AU 2016213700 02 Nov 2016

According to a second embodiment of the invention, there is disclosed a granulated powder formed from the ultra-fine kava powder of the first embodiment.

As seen in Fig. 4, a mixture of alcohol and the ultra-fine kava powder are homogenised in a mixer prior to granulation. Preferably, 60-95% w/w alcohol solution is used, and is added to the ultra-fine kava powder in step 41 until a suitable paste-like rheology is obtained. The mixture is then added in step 42 to a granulator, and the process run to completion. The dried granulate is preferably graded at step 43 to 400-700 mesh. The resultant granulate is dried at step 44 at 50°C for four hours.

However, the granulate can alternatively be graded prior to drying. That is, steps 43 and 44 can be carried out in the reverse order.

The ultra-fine kava powder of the first embodiment has demonstrated greater particle dispersion when mixed in water than the prior art powder. However, the granulated powder of the second embodiment has demonstrated excellent granule dispersion.

This has been shown to improve particle dispersion in turn, and thereby further increasing liberation rates and the user friendliness of the product.

Moreover, the ultra-fine kava powder of the first embodiment suffers from the disadvantage that it can bind to equipment used in the manufacture of capsules and tablets. However, the granulated form of the second embodiment overcomes these issues, and is particularly advantageous for manufacturing soft capsules.

The ultra-fine powdered kava and the granulated ultra-fine powdered kava can be used for making beverages, foodstuffs, and other ingestible products including at least some of those cited in the prior art. For example, the kava foodstuffs disclosed in British Patent No. 2,507,270 can be made by substituting the kava powder as disclosed therein with the ultra-fine kava powder disclosed in this specification.

The advantages of the ultra-fine kava powder disclosed herein were conferred to the beverage and the chewing gum, particularly when compared with comparable beverages and gums made in accordance with the prior art. 12

5297F-AU 2016213700 02 Nov 2016

Example 1 lOOOg of raw kava material, primarily consisting of whole kava root with bark removed, was sun-dried to approximately 15% w/w water content and then crushed by a hammer mill until an average particle size of approximately 500pm was obtained. The dried crushed raw kava material was then fed over approximately 4 minutes (approximately 15kg per hour) into a Duksan model DSCH-1500 fine pulveriser (preferred hybrid hammer-mill and air-fluid mill type; configured for air rerecirculation), and comminuted at 3500rpm (7.5 horse-power) until an average particle size of approximately 20pm was obtained. Air having a temperature of about 20°C was injected into the pulveriser throughout comminution so as to maintain the temperature of the kava material at approximately 50°C. The resulting ultra-fine powdered kava had a yield of approximately 90%, and was confirmed to have the advantages of the ultra-fine kava powder as discussed above.

Example 2 250g of the ultra-fine kava powder of Example 1 was added to 50mL of 85% ethanol alcohol, thoroughly combined, and then fed into a granulator. The resulting granulate was taken from the granulator and dried at 60 °C for 3-4 hours until dry. The dry granulate was graded to 400-700 mesh using a sieve. The graded dry granulate was then encapsulated using a soft pill press to form ingestible kava pills.

Example 3 lOOOg of ultra-fine kava powder produced in the manner of Example 1 was mechanically mixed with l%-6% w/w beta cyclodextrin and l%-6% w/w gamma cyclodextrin in a V-shaped mixer for 30 minutes. The mixture was then fed into a fine pulveriser, being substantially as described above, in order to mechanically combine the cyclodextrin with the kava particles. It is thought that the cyclodextrin and the ultra-fine kava powder underwent further comminution in this process. A substantially uniform mixture of ultra-fine kava powder and cyclodextrin was obtained. It was found that the ultra-fine kava powder had been mechanically compounded with the cyclodextrin. 13

5297F-AU 2016213700 02 Nov 2016 A second batch of the mechanically combined cyclodextrin-kava powder was prepared in accordance with the above process, except that 5%-10% w/w lecithin was added prior to mixing all three ingredients in the V-shaped mixer.

Both the mechanically combined cyclodextrin-kava powder, and the mechanically combined lecithin-cyclodextrin-kava powder, when incorporated into a water-based beverage demonstrated increased absorption, further reduced bitterness, and an overall milder taste, as compared with the ultra-fine kava powder, in the manner indicated by Table 1.

Example 4

Three batches of kava ingredient were selected one from each of (a) the ultra-fine powdered kava, (b) the mechanically combined cyclodextrin-kava powder of Example 3, and (c) the mechanically combined lecithin-cyclodextrin-kava powder of Example 3. A corresponding batch of kava-coconut milk was made from each kava ingredient batch as follows.

The kava ingredient was added to low fat coconut milk, being milk that had been filtered, de-aerated, homogenized, and sterilized by a UHT process. The kava ingredient was added at a quantity of 2% w/w of coconut milk. The kava-milk combination was then blended in a mixing tank to form a kava-coconut drink.

The kava-coconut drink demonstrated a milder and reduced bitterness taste when compared with a comparable drink made with kava powders from the prior art. The active ingredients were also absorbed at a faster total rate when compared with the comparable drink.

The beverage disclosed in Example 2 of British Patent No. 2,507,270, and the chewing gum disclosed in Example 3 of British Patent No. 2,507,270, are expressly incorporated in their entirety by cross-reference, excepting that the kava CD-Complex Powder of those cross-referenced Examples is substituted for either the mechanically combined cyclodextrin-kava powder, or the mechanically combined lecithin-cyclodextrin-kava powder, of Example 3 above. 14

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According to a third embodiment of the present invention, a ‘nano’-sized kava powder having a particle size on the order of lOOOnm is prepared by the method of the first embodiment described above, excepting that during the primary stage of comminution, the cooling gas has a temperature of less than 0°C and more preferably about -20°C. The cooling gas of the second embodiment is preferably recirculated through a closed circuit having an integral freezing unit for the removal of heat produced during comminution.

In the second embodiment, the coarse kava precursor is preferably frozen prior to feeding into the pulveriser. The primary stage is adjusted such that kava particles remain frozen throughout the primary stage so as to increase their susceptibility to comminution, for example through increased particle brittleness or reduced particle flexibility.

The foregoing describes only some embodiments of the present invention and modifications obvious to those skilled in kava technology may be made

For example, the comminution can be carried out using a jet mill or air fluid mill. 15

Claims (33)

1. A kava powder for oral consumption comprising a plurality of kava particles, characterised in that the particles are produced by comminuting dried kava raw materials selected from the class consisting of kava root, kava root stump, and kava basal stem, and that a substantial proportion of said particles have a nominal size of less than 60 pm and at least half of said particles have a nominal size of less than 25 pm.

2. The kava powder according to claim 1 characterised in that at least one quarter of the particles have a nominal size of less than 15 pm.

3. The kava powder according to claim 1 or 2 characterised in that a size distribution of the particles has a span of less than two; said span being calculated as a difference between particle sizes at the 90th and 10th percentiles, divided by particle size at the 50th percentile.

4. The kava powder according to any one of claims 1 to 3 characterised in that said particles are manufactured using kava root having the bark substantially removed.

5. The kava powder according to any one of claims 1 to 4 characterised in that said dried kava raw material has a water content of less than approximately 15% w/w.

6. The kava powder according to any one of claims 1 to 5 characterised in that said particles have not been subjected to a temperature above 60°C during manufacture.

7. The kava powder according to any one of claims 1 to 6 having a lower bitterness in taste than a comparative kava powder having a substantial proportion of particles with a nominal size of approximately 250-500 pm.

8. The kava powder according to any one of claims 1 to 7 having a lower perceived grittiness in texture than a comparative kava powder having a substantial proportion of particles with a nominal size of approximately 250-500 pm.

9. The kava powder according to any one of claims 1 to 8 having more active ingredients liberated per unit mass of constituent kava, than a comparative kava powder having a substantial proportion of particles with a nominal size of approximately 250-500 pm.

10. The kava powder according to claim 9 characterised in that the liberation substantially occurs during preparation of a product for oral consumption having a liquid precursor, said product including said kava powder.

11. The kava powder according to any one of claims 1 to 10 having active ingredients which are absorbed at a faster total rate, per unit mass of kava constituents, than a comparative kava powder having a substantial proportion of particles with a nominal size of approximately 250-500 pm.

12. The kava powder according to claim 11 characterised in that the absorption occurs through oral mucosa including sublingual mucosa.

13. The kava powder according to any one of claims 1 to 12 having active ingredients which have a greater bioavailability, per unit mass of kava constituents, than a comparative kava powder having a substantial proportion of particles with a nominal size of approximately 250-500 pm.

14. A method of manufacturing ultra-fine kava powder having a plurality of kava particles, said method being characterised by the steps of: a coarse kava precursor is fed into, and pulverised by, a pulveriser having a pulverising chamber to produce an intermediate kava powder; and said intermediate kava powder is cooled by an injection of a gas into said pulverising chamber whereby said intermediate kava powder does not undergo a substantial increase in temperature during said pulverisation; and said pulverisation is continued until a substantial proportion of said kava particles have a nominal size of less than 60 pm.

15. The method according to claim 14, characterised in that the pulverisation is continued until a substantial proportion of the kava particles have a nominal size of less than 30 pm.

16. The method according to claim 14 or 15, characterised in that the pulveriser is a hybrid of hammer-mill and air-fluid mill designs and has a rotor located inside the pulverising chamber, said rotor being driven by a motor, said rotor having at least one set of pulverising pins or blades, and said pins or blades causing comminution of kava material by mechanisms selected from the class consisting of impact, crushing, shearing, and grinding.

17. The method according to claim 16, characterised in that the rotor is rotated at approximately 3500-5000 rpm,, the coarse kava precursor is fed into the pulverising chamber at a rate of about 15 to 20kg/hour, and the motor has a maximum power of about 7.5 horsepower.

18. The method according to any one of claims 14 to 17, characterised in that said pulverising chamber has an interior temperature to which the intermediate kava powder is substantially exposed, said interior temperature being below approximately 60°C.

19. The method according to any one of claims 14 to 18, characterised in that said gas has a temperature of less than 25°C.

20. The method according to any one of claims 14 to 19, characterised in that said gas has a temperature and/or a water content which is/are sufficiently low to cause water content of the intermediate kava powder to decrease during the pulverisation.

21. The method according to any one of claims 14 to 20, characterised in that said gas is air.

22. The method according to any one of claims 14 to 21, characterised in that the coarse kava precursor is made from raw kava materials selected from the class consisting of kava root, kava root stump, kava basal stem, and barks thereof.

23. The method according to any one of claims 14 to 22, characterised in that prior to the pulverisation, the coarse kava precursor is dried.

24. The method according to claim 23, characterised in that the dried coarse kava precursor has a water content of less than approximately 15% w/w.

25. The method according to any one of claims 14 to 24, characterised in that the coarse kava precursor is comminuted prior to the pulverisation.

26. The method according to claim 25, characterised in that the comminution includes grinding the coarse kava precursor.

27. The method according to claim 26, characterised in that said grinding is performed by an impact grinder, preferably a hammer mill.

28. The method according to any one of claims 25 to 27, characterised in that the comminuted kava precursor is substantially comprised of particles having an average particle diameter of between approximately 500-700 pm.

29. The method according to any one of claims 14 to 28 characterised in that said ultra-fine kava powder has a greater total of available active ingredients, per unit mass of constituent kava, than a comparative kava powder having a substantial proportion of particles with a nominal size of approximately 250-500 pm.

30. The method according to any one of claims 14 to 29 characterised in that the coarse kava precursor has organic fibres which are pulverised to substantially have a nominal size of less than approximately 60 pm and preferably less than approximately 25 pm.

31. The method according to any one of claims 14 to 30 characterised in that said ultra-fine kava powder has a flavour which is substantially equivalent to the coarse kava precursor.

32. The method according to any one of claims 14 to 31 characterised in that said kava powder has a colour which is substantially equivalent to the coarse kava precursor.

33. The method as claimed in any one of claims 14 to 32 characterised in that said ultra-fine kava powder is formed into granules.