Particle containing at least a volatile substance and process for its preparation

Abstract

The invention is directed to a particle containing at least a volatile substance comprising a core comprising at least one matrix material and the at least one volatile substance and at least one coating layer, whereby a first coating layer is a non-confluent layer comprising at least a carrier material, whereby optionally the non-confluent layer contains at least one hydrophobic substance, and optionally the particle is surrounded by at least one confluent layer and/or further non-confluent layer(s) as well as to a process for producing the same.

Claims

1. A particle containing at least one volatile substance comprising: a core comprising at least one matrix material, the at least one volatile substance, and optionally at least one texturizer; and at least one coating layer; wherein the at least one matrix material is selected from the group consisting of fats, hydrogenated triglycerides and waxes that are solid or semi-solid at 20 C. and 1 atmosphere, the core contains 30% by weight to 97% by weight of matrix material based on the total mass of the core, the at least one volatile substance being contained in the core has a vapor pressure at 125 C. between 10 mm Hg and 200 mm Hg, a first coating layer is a non-confluent layer comprising at least one carrier material being attached to the core, the at least one carrier material is an inorganic material having a porous structure and a D.sub.50 of 1 to 300 m, and the core has an average surface coverage by the non-confluent layer of 1% to 50%; wherein the non-confluent layer contains at least one hydrophobic substance, and the particle is surrounded by at least one confluent layer and/or further non-confluent layer(s), and the presence of the first non-confluent layer increases the recovery of the volatile substance in the core during granulation or fluidization of the particle; wherein the at least one volatile substance being contained in the core is selected from an essential oil or a plant extract each being prepared from a plant selected from the group consisting of oregano, thyme, caraway, mint, peppermint, anise, orange, lemon, fennel, star anise, clove, cinnamon, wintergreen and garlic; or from an ingredient, component or compound of the essential oil or plant extract selected from the group consisting of trans-anethole, D-limonene, -terpinene, p-cymene, 2-carene, linalool oxide, isomenthone, camphor, linalool, terpinen-4-ol, 2-isopropyl-1-methoxy-4-methylbenzene, L-menthol, ethylamine, -terpineol, -caryophyllene, D-carvone, methyl salicylate, -caryophyllene, lavandulyl acetate, caryophyllene oxide, eugenol, thymol and carvacrol; and wherein the at least one matrix material is selected from hydrogenated palm oil, hydrogenated sunflower oil, hydrogenated corn oil, hydrogenated rapeseed oil, hydrogenated peanut oil, hydrogenated soybean oil, candelilla wax or carnauba wax.

2. The particle according to claim 1, wherein the core contains 3% by weight to 50% by weight volatile substances based on the total mass of the core.

3. The particle according to claim 1, wherein the at least one volatile substance being contained in the core has a vapor pressure at 125 C. between 30 mm Hg and 70 mm Hg.

4. The particle according to claim 1, wherein the core has a diameter between 50 m and 1000 m.

5. The particle according to claim 1, wherein the core contains 50% by weight to 85% by weight of matrix material based on the total mass of the core.

6. The particle according to claim 1, wherein the core includes the at least one texturizer and the at least one texturizer is selected from the group consisting of whey protein, corn protein, wheat protein, rape protein, pea protein, celluloses, starches, pectin, montmorillonites, stearates, sulphates and precipitated silica; wherein the at least one texturizer is up to 20% by weight of the at least one matrix material.

7. The particle according to claim 1, wherein the core has an average surface coverage by the non-confluent layer of 2% to 25%.

8. The particle according to claim 1, wherein the inorganic material has a porous structure with a D.sub.50 of 2 to 150 m.

9. The particle according to claim 1, wherein the carrier material of the non-confluent layer comprises at least one hydrophobic substance.

10. The particle according to claim 9, wherein the at least one hydrophobic substance in the non-confluent layer contains at least 100% by weight of the at least one semi-solid or liquid hydrophobic substance based on the mass of the carrier material without the at least one semi-solid or liquid hydrophobic substance.

11. The particle according to claim 9, wherein the at least one hydrophobic substance is selected from essential oils consisting of monoterpenes, -terpinene, linalool, geraniol, menthol, citronellal, carvone or menthone; sesquiterpenes consisting of farnesol, farnesene, -bisabolol or -caryophyllene; or aromatic compounds consisting of carvacrol, thymol, cinnamaldehyde, anethole or eugenol.

12. The particle according to claim 1, wherein the particle is surrounded by at least one confluent layer.

13. A process for preparing a particle containing at least one volatile substance comprising the steps of: forming a melt of an at least one matrix material, whereas the at least one matrix material is selected from the group consisting of fats, hydrogenated triglycerides and waxes that are solid or semi-solid at 20 C. and 1 atmosphere, wherein the at least one volatile substance has a vapor pressure at 125 C. of between 10 mm Hg and 200 mm Hg, forming a melt-mixture comprising an emulsion, dispersion, solution or suspension of the at least one volatile substance in the melt mixture, by incorporating the at least one volatile substance into the melt mixture, forming discrete cores of the melt mixture, wherein each of the cores contain 30% by weight to 97% by weight of the at least one matrix material based on the total mass of the core; cooling the discrete cores, mixing the discrete cores with at least one carrier material containing at least one hydrophobic substance thereby forming a first non-confluent layer, wherein the at least one carrier material is an inorganic material having a porous structure and a D.sub.50 of 1 to 300 m, and surrounding the particle with at least one confluent layer and/or further non-confluent layer(s), wherein the presence of the first non-confluent layer increases the recovery of the at least one volatile substance in the core during granulation or fluidization of the particle.

14. The process according to claim 13, wherein in that the core is obtained by spray cooling.

15. The process according to claim 13, wherein the core material is mixed by shaking, slowly stirring or circulating in a batch container at a temperature of 20 C.5 C. with at least one coating material wherein the at least one coating material is selected from hydrogenated palm oil, sunflower oil, corn oil, rapeseed oil, peanut oil, soybean oil, candelilla wax, carnauba wax, limonene, -terpinene, linalool, geraniol, menthol, citronellal, carvone, menthone, farnesol, famesene, -bisabolol, -caryophyllene, carvacrol, thymol, cinnamaldehyde, anethole, eugenol, starch, cyclodextrin, polyethylene glycol, carrageenan, alginates, gum arabicum, wheat gluten, chlorides, nitrates, phosphates, sodium sulphate or ammonium sulphate.

16. The process according to claim 13, wherein the confluent layer is applied by fluidized bed coating.

17. The particle according to claim 8, wherein the inorganic material has a porous structure with a D.sub.50 of 5 to 30 m.

Description

DESCRIPTION OF THE DRAWINGS

(1) For further clarifying the particles as well as the process for obtaining the same the invention is described in the following by means of figures and examples.

(2) Therein:

(3) FIG. 1 consisting of FIG. 1A and FIG. 1B, wherein

(4) FIG. 1A shows the cross section through a particle obtained by example 1a having a core (A) and a non-confluent layer (B).

(5) FIG. 1B shows the cross section through a particle obtained by example 1 b having a core (A) and a non-confluent layer (B).

(6) FIG. 2 consisting of FIG. 2A and FIG. 2B, wherein

(7) FIG. 2A shows the cross section through a particle obtained by example 1a. The diameter of the core and the length of selected carrier material particles are drawn in.

(8) FIG. 2B shows the cross section through a particle obtained by example 1 b. The diameter of the core and the length of selected carrier material particles are drawn in.

(9) FIG. 3 shows the cross-section of a particles having a core (A) and a non-confluent layer (B) which is surrounded by a confluent layer (C)

DETAILED DESCRIPTION OF THE INVENTION

Example 1

(10) In example 1a-c) the production of particles consisting of a core comprising a volatile substance and a non-confluent layer is described on a laboratory scale.

Example 1a

(11) 1) Generation of the Core

(12) i) Generation of a Melt of a Matrix Material

(13) Hydrogenated sunflower oil (HSO) (CAS-No: 69002-71-1; ADM Sio; VGB5ST; MP: 33-70 C.; White flakes at 20 C.) was molten in a stainless steel vessel at a melting temperature of 85 C. 600 g of the HSO were poured into a 2 L glass bottle. The glass bottle was placed onto a magnetic stirrer and the temperature was kept at 85 C. Under stirring 100 g of a texturizer (hydrophobic precipitated silicate; SipernatD17; CAS-No: 68611-44-9; D.sub.50=10 m) were mixed to the molten HSO.
ii) Incorporation of a Volatile Substance into the Melt As soon as the hydrophobic precipitated silicate was completely dissolved 300 g of a mixture of volatile substances (1) consisting of 44% by weight synthetic carvacrol (CAS-No: 499-75-2), 47% by weight caraway oil (CAS-No: 8000-42-8) and 9% by weight oregano oil (CAS-No: 862374-92-3) were added. This addition reduced the temperature of the melt to approx. 60 C. The final melt thus contains 60% by weight hydrogenated sunflower oil (CAS-No: 69002-71-1), 10% by weight texturizer (CAS-No: 68611-44-9) and 30% by weight volatile substances.
iii) Formation of Discrete Cores from the Melt Mixture The mixture was re-heated to 80 C. and pumped through a hose to the spraying fluid connection of a spinning disc (fluid stream: 5.7 l/h). The spraying fluid is defined as the melt mixture forming the core. The spinning disc is a horizontally oriented disc with fine grooves on the surface. Liquid material (e.g. the melt) flowing over the surface of the rotating spinning disc forms fine droplets when leaving its edges. The rotation of the spinning disc (3275 rpm) forced the material mixture to leave the disc in form of fine droplets. The spinning disc is assembled within a prilling tower, which is a room (LBH; 9070200 cm) in which the spinning disc is installed.
iv) Cooling of the Discrete Cores Cooling was achieved by keeping the prilling tower at max. 30 C., a temperature at which the melt droplets hardens automatically. When the droplets reached the prilling tower bottom the droplets had hardened and a powder had formed (D.sub.50=approx. 200 m). In the following this powder is named core.
2) Generation of the Non-Confluent Layer Precipitated silicate (Sipernat22S; CAS-No: 112926-00-8; D.sub.50=13.5 m; spec. surface=190 m.sup.2/g) was used as the carrier material for the non-confluent layer.
3) Application of the Non-Confluent Layer onto the Core

(14) The product from step 1) (1000 g) was filled into the mixing chamber of a mixing device (kitchen aid). Under stirring at lowest level (40 rpm) 37.5 g of the carrier material from step 2) were admixed to the core until all visible lumps were divided and the material mixture was homogenized.

Example 1b

(15) 1) Generation of the Core: See Step 1) from Example 1a

(16) 2) Generation of the Non-Confluent Layer

(17) 37.5 g precipitated silicate (Sipernat22S; CAS-No: 112926-00-8; D.sub.50=13.5 m; spec. surface=190 m.sup.2/g) were weighed into the mixing chamber of a kitchen aid. Under stirring 75 g of a hydrophobic substance, being mint oil (CAS-No: 90063-97-1) was pipetted onto the silicate. The materials were mixed with the mixing device at 40 rpm kitchen aid at the lowest level until no humid lumps or free hydrophobic substance were visible any more. In the following, the precipitated silicate that contains at least one hydrophobic substance, e.g. an essential oil is named: loaded non-confluent layer.
3) Application of the loaded non-confluent layer onto the core The product from step 1) (1000 g) was filled into the mixing chamber of the kitchen aid. Under stirring at lowest level the loaded non-confluent layer from step 2) (112.5 g) was admixed to the core until all visible lumps were divided and the material mixture was homogenized.

Example 1c

(18) 1) Generation of the Core: See Step 1) from Example 1a

(19) 2) Generation of the Non-Confluent Layer

(20) 37.5 g precipitated silicate (Sipernat22S; CAS-No: 112926-00-8; D.sub.50=13.5 m; spec. surface=190 m.sup.2/g) were weighed into the mixing chamber of a kitchen aid. 37.5 g of a hydrophobic substance, being crystalline menthol (CAS-No: 2216-51-5) were weighed into a beaker glass and molten at moderate temperature (40-45 C.). The opening of the beaker glass was covered with aluminium foil to avoid menthol evaporation. Under stirring at the lowest level the molten menthol was poured over and mixed with the precipitated silicate until no humid lumps or free menthol was visible any more.
3) Application of the Loaded Non-Confluent Layer onto the Core The product from step 1) (1000 g) was filled into the mixing chamber of the kitchen aid. Under stirring at lowest level the loaded non-confluent layer from step 2) (75 g) was admixed to the core until all visible lumps were divided and the material mixture was homogenized.

(21) In addition to step 3) example 1a-c were investigated via scanning electron microscopy (SEM) to see whether the structure of a core surrounded by a non-confluent layer is feasible (FIGS. 1A and 1B).

(22) Alternatively, to the mixture of volatile substances (1) described in example 1a the following mixtures of volatile substances can exemplary also be used within the scope of the invention:

(23) (2): 30% by weight orange essential oil; 70% anise essential oil

(24) (3): 13% by weight oregano oil; 58% by weight thyme oil; 29% by weight caraway oil

(25) (4): 51% by weight peppermint oil; 10% by weight majoram oil; 16% by weight clove oil; 23% by weight star anise oil

(26) (5): 67% by weight mint oil; 2% wintergreen oil; 22% by weight L-carvone; 9% by weight methyl salicylate

(27) (6): 100% by weight oregano oil

(28) (7): 45% by weight cinnamon bark oil; 9% by weight trans-cinnamaldehyde; 18% by weight clove oil; 6% by weight eugenol; 2% by weight -caryophyllene; 20% by weight by orange oil

(29) (8): 17% by weight carvacrol; 78% by weight thymol; 5% by weight D-carvone

(30) (9): 17% by weight of garlic oil; 80% by weight of fennel oil; 3% by weight trans-anethole

(31) (10): 41% by weight peppermint oil; 34% by weight clove oil; 25% by weight thymol

(32) (11): 100% by weight carvacrol

Example 2

(33) The structure of the particles comprising a core and a non-confluent layer were investigated via SEM. Therefore, the particles were spread over a plastic foil (thickness approx. 0.5 mm) and poured with a molten epoxy resin. When the resin had hardened the plastic foil covered with the particles and the resin was fixed with a clamp and put into the centre of a whole cylinder (d=approx. 2.5 cm, h=approx. 1 cm). The cylinder was completely filled with molten epoxy resin again. As soon as the resin had hardened, it was loosen from the cylinder and fixed into a grinding machine. The sample was ground until a level was reached that the particles were sliced. The cross section through the single particles was analyzed via SEM (Zeiss; Supra 35; Smart SEM V05.04). This revealed that all particles described in example 1 have a non-confluent layer at the surface of the core as exemplary shown in FIGS. 1A and 1B.

Example 3

(34) On basis of the analysis described in example 2 the average surface coverage of the cores by the non-confluent layer could be calculated. Therefore 10 to 20 particles of each sample/batch were analyzed. The circumference of each core was calculated by measuring its diameter and applying the formula U=*d, with U is the circumference, is Pi and d is the diameter of the core. The length of all carrier material particles of the non-confluent layer (I.sub.1,2,3 . . . , n) that are attached to the core were measured (see FIGS. 2A and 2B). The length of the carrier material particles is defined as the length of the contact line between the carrier material particles and the core. The surface coverage in percentage of one core (the core coverage CC) by the non-confluent layer was calculated according to the formula:

(35) ${\mathrm{CC}}_{1,2,3,\mathrm{.Math.},m}=\frac{\mathrm{SUM}\left(l1,2,3,\mathrm{.Math.},n\right)}{U}*100$

(36) The average surface coverage of the cores by the non-confluent layer was determined by measuring the CC of 10 to 20 particles of one sample and by calculating the average. Exemplarily, the calculation of the core coverage for the particle shown in FIG. 2A is shown:

(37) $d_1=118.72\mathrm{.Math.m}\mathrm{and}{l}_i=2.19\mathrm{.Math.m},l_2=3.53\mathrm{.Math.m},l_3=2.36\mathrm{.Math.m},l_4=6.45\mathrm{.Math.m}\mathrm{and}{l}_5=5.92\mathrm{.Math.m}.U=*d;U=*118.72\mathrm{.Math.m}=372.97\mathrm{.Math.m}$$\mathrm{SUM}\left(l_{1,2,3,4,5}\right)=2.19\mathrm{.Math.m}+3.53\mathrm{.Math.m}+2.36\mathrm{.Math.m}+6.45\mathrm{.Math.m}+5.92\mathrm{.Math.m}=20.45\mathrm{.Math.m}$${\mathrm{CC}}_1=\frac{\mathrm{SUM}\left(l_{1,2,3,\mathrm{.Math.},n}\right)}{U}*100=\frac{20.45\mathrm{.Math.m}}{327.97\mathrm{.Math.m}}*100=5.48\%.$

Example 4

(38) Cores were prepared as described in example 1a (in batches 5-7 the weight percentages have been changed according to table 1. The non-confluent layer for batch 1, 5 and 6 was applied as described in example 1a and all other batches as described in example 1b, however in amounts as indicated in table 1. All batches were analyzed via SEM with the method described in example 2 and the average surface coverage of each sample was calculated following example 3. The results showed that the average core coverage of a sample increases with increasing amount of the precipitated silicate loaded with a hydrophobic substance.

(39) TABLE-US-00001 TABLE 1 Composition of the particles and average core coverage of the non-confluent layer Core Non-confluent layer Matrix Volatile Hydro- Core material substance Carrier phobic coverage Batch (HSO) Texturizer mixture material substance Average No. [% wt] [% wt] (1) [% wt] [% wt] [% wt] [%] 1 57.83 9.64 28.91 3.62 9.9 2 61.55 4.73 28.40 1.77 3.55 5.9 3 52.13 10.79 26.97 3.37 6.74 9.8 4 53.07 4.08 24.49 6.12 12.24 10.4 5 95.29 2.94 1.77 1.3 6 32.86 14.08 46.94 6.12 23.7 7 44.90 4.08 32.66 6.12 12.24 20.8

Example 5

(40) The particles from example 4 comprising were fluidized for 20 minutes. Therefore 150 g of each batch were put into the process chamber of a laboratory scale fluidized bed plant (DMR, WFP-Mini) and the material was fluidized with a process air temperature of 27 C. and an air stream of 10-15 m.sup.3/h (depending on the fluidization of the cores) and a product temperature of about 28 C. As negative controls cores with the identical core composition but without the non-confluent protection layer were fluidized under the same conditions. Thus 1 control was required for batches 1-4 and 1 control for each of the batches 5-7. Recovery rates of four volatile compounds present in the volatile substance mixture (1) were analyzed (see table 2).

(41) After 20 minutes fluidization a sample of a few grams was taken and the material was analyzed for its residual volatile substance content via gas chromatography (GC). Therefore 0.10 to 0.11 g of the fluidized particles were weighed into a 2 mL plastic tube. The exact sample weight was determined using an analytical balance (accuracy 0.0001 g) and noted. 1.5 mL ethyl acetate (EtOAc) were added to the particles and the plastic tubes were closed. The material was shaken for 10 minutes and afterwards centrifuged for ten minutes at 12500 rpm. The supernatant was collected in a 15 mL plastic tube. To release all the volatile material from the particles this extraction step with EtOAc was performed three times and the supernatants were collected together in the same plastic tube. Additionally 100 L of the internal standard (Dicyclohexylmethanol, CAS-No: 4453-82-1, approx. 0.5 g/L) were added and the plastic tube was made up to a volume of 5 mL with EtOAc.

(42) For the quantitative measurement of the content of the volatile substances after 20 minutes fluidization the volatile substances a Shimadzu gas chromatograph equipped with a SSL-inlet and a FID detector (Shimadzu GC-2010 plus) was used. The liner was straight with glass wool on top, the inlet maintained at 250 C. Injection volume was 1 l at a split ratio of 10. The carrier gas was helium (AlphaGaz 1, purity 99,999%) and the gas flow was 1.6 ml in constant flow mode. The separation column was a polar WAX column with length 30 m, inner diameter 0.25 mm and a film thickness of 0.25 m (Zebron ZB-WAXplus, Phenomenex). The oven program started with 60 C. for 1 min and ramped with 5 C./min to 90 C., 7 C./min to 200 C., 30 C./min to 260 C. which was then kept for 7 min. The FID detector sampling rate was of 20 Hz, hydrogen flow was 40 ml/min, zero air flow 400 ml/min and makeup gas (He) flow was 30 ml/min and it was maintained at 280 C. Therefore 1 mL of the solution described above were filled into a GC vial. The vial was closed using the respective screw lid and put into the auto sampler tray. The analysis were started using the Labsolution software. The data analysis was performed with the MassHunter Quantitative Analysis program.

(43) The volatile substance content of each product after 20 minutes fluidization (VSC.sub.20min) was compared with the volatile substance content of the original sample (VSC.sub.orig.) that has not been fluidized. The recovery was calculated by the following formula:

(44) $\mathrm{Recovery}\left[\%\right]=\frac{{\mathrm{VSC}}_{20\min }}{{\mathrm{VSC}}_{\mathrm{orig}.}}*100$
e.g. for if:
VSC.sub.orig.=8.3 mg/g and VSC.sub.20min=8.0 mg/g

(45) The recovery is:

(46) $\mathrm{Recovery}=\frac{{\mathrm{VSC}}_{20\min }}{{\mathrm{VSC}}_{\mathrm{orig}.}}*100=\frac{8.0\frac{\mathrm{mg}}{g}}{8.3\frac{\mathrm{mg}}{g}}*100=96\%$

(47) TABLE-US-00002 TABLE 2 Volatile substance recovery after 20 minutes [%] Batch No. Linalool Carvone Thymol Carvacrol 1-4 - Control 75 82 81 83 1 97 100 100 100 2 100 100 100 100 3 100 96 100 100 4 95 91 89 94 5 - Control 74 75 77 79 5 95 90 95 94 6 - Control 73 77 80 79 6 99 96 100 99 7 - Control 71 80 78 79 7 97 98 100 100

Example 6

(48) Five batches of particles consisting of a core comprising a volatile substance and a non-confluent layer were produced. All cores were produced following example 1a, however the amount of texturizer and HSO was adapted according to table 3.

(49) TABLE-US-00003 TABLE 3 Composition of the core Volatile substance Matrix material in core (HSO) Texturizer Batch No. [% wt] [% wt] [% wt] 1 30 58 12 2 30 65 5 3 30 68 2 4 30 69 1 5 30 70

(50) The cores were furnished with a non-confluent layer following example 1b. All batches were fluidized for 20 minutes under the same conditions as described in example 5 and the recovery rates of the volatile substance in the core were determined via GC as described in example 5. In parallel cores with the same compositions as shown in table 3 without the non-confluent layer protecting the volatile substances in the core were fluidized and used as negative control batches. Table 4 shows the recoveries of single compounds of the volatile substances.

(51) TABLE-US-00004 TABLE 4 Volatile substance recovery [%] Batch No. Linalool Carvone Thymol Carvacrol 1 - Control 70 69 78 81 1 100 100 98 100 2 - Control 72 78 72 82 2 100 100 100 100 3 - Control 71 78 77 85 3 100 100 100 100 4 - Control 78 75 79 84 4 100 100 100 100 5 - Control 77 78 82 87 5 92 98 100 95

Example 7

(52) Particles consisting of a core and a non-confluent layer were produced. All cores were produced following example 1a, however with different matrix materials (see batch 2-3 of table 5). To evaluate whether the protective effect of the non-confluent layer is influenced by the type of the matrix material hydrogenated rapeseed oil (CAS-No: 84681-71-0, ADM Sio; VGB6; MP: 68-74 C.; White flakes at 20 C.) and hydrogenated soybean oil (CAS-No: 8016-70-4, ADM Sio; VGB4; MP: 68-71 C.; White flakes at 20 C.) have been used.

(53) TABLE-US-00005 TABLE 5 Composition of the core in % wt Volatile Batch No. substance Matrix material Texturizer 1 30 60 10 Hydrogenated sunflower oil (HSO) 2 30 60 10 Hydrogenated rapeseed oil 3 30 60 10 Hydrogenated soybean oil

(54) The cores were furnished with a non-confluent layer following the performance described in example 1b. All batches were fluidized under the same conditions as described in example 5 and the recovery of the volatile core substance was determined via GC as described in example 5. Table 6 shows the recovery of selected single compounds of the volatile substance mixture.

(55) TABLE-US-00006 TABLE 6 Volatile substance recovery [%] Batch No. Linalool Carvone Thymol Carvacrol 1 100 96 100 100 2 91 98 100 98 3 88 98 96 94

Example 8Core Composition

(56) Four batches of particles consisting of a core comprising a volatile substance and a non-confluent layer were produced. All cores were produced following example 1b and furnished with a non-confluent layer following the performance described in example 1b. To see whether the concentration of the core substance has an influence on the inventive protective effect, for each batch another concentration of the volatile core substance was used. The compositions of the different cores are listed in table 7.

(57) TABLE-US-00007 TABLE 7 Composition of the core in % wt Volatile substance Matrix material in core (HSO) Texturizer Batch No. [% wt] [% wt] [% wt] 1 5 85 10 2 10 80 10 3 20 70 10 4 40 50 10

(58) All four batches were fluidized for 20 minutes under the same conditions as described in example 5 and the recovery of the volatile core substance was determined via GC as described in example 5. Table 8 shows the recovery of selected single compounds of the volatile substance mixture. The protective effect of the non-confluent layer increases with increased volatile substance concentration in the core.

(59) TABLE-US-00008 TABLE 8 Volatile substance recovery [%] Batch No. Linalool Carvone Thymol Carvacrol 1 - Control 65 71 83 88 1 92 88 100 98 2 - Control 68 75 81 85 2 95 89 100 100 3 - Control 61 69 80 82 3 100 100 100 100 4 - Control 69 74 78 87 4 100 100 100 100

Example 9Volatility of Volatile Core Substances

(60) Cores and non-confluent layers thereto were prepared as describes for batches 1-4 and control 1-4 in examples 4. All batches were fluidized for 20 minutes under the same conditions as described in example 5 and the recovery of the volatile core substance was determined via GC as described in example 5.

(61) The recoveries of 13 selected compounds with vapor pressures between 11.3 mm Hg and 185.8 mm Hg at 125 C. were analyzed and listed in table 9.

(62) The comparison of control to batch 1 shows that the application of the (non-loaded) carrier as non-confluent layer already has a protective effect on the volatile substances present in the core. The batches 2-4 reveal that the loaded carrier material has an even better protection towards the volatile substance embedded in the core.

(63) TABLE-US-00009 TABLE 9 Volatile substance recovery [%] Volatile substance recovery after 20 minutes fluidization [%] Calculated vapor Con- Batch Batch Batch Batch pressure [mm Hg trol 1 2 3 4 @ 125 C.] D-Limonene 5 11 16 16 24 185.8028 -Terpinene 0 6 9 12 17 156.6294 p-Cymene 1 6 12 12 23 170.1698 Camphor 66 83 89 97 90 67.8680 Linalool 52 88 87 100 88 .sup.a73.1145 Terpinen-4-ol 61 78 87 98 98 -Terpineol 55 88 89 100 96 36.7883 -Caryophyllene 55 74 93 96 87 D-Carvone 66 80 85 100 94 .sup.a29.0791 -Caryophyllene 50 71 76 90 90 Eugenol 81 87 99 99 98 11.2903 Thymol 81 89 98 98 93 19.2101 Carvacrol 99 98 100 100 100 16.2002

(64) The vapor pressures were calculated using the Antoine equation, which describe the relation between the vapor pressure and temperature for pure compounds.

(65) Antoine Equation:

(66) ${\log }_{10}p=A-\frac{B}{C+T}$
Where:
pvapor pressure of the component, mmHg
Ttemperature, C.
A, B, Ccomponent specific Antoine constants.
e.g.: Calculation of the vapor pressure of D-limonene at 125 C. with

(67) $A=7.06744,B=1691.1486,C=227.441$${\log }_{10}p=7.06744-\frac{1691.1486}{227.441+125}$${\log }_{10}p=2.269052185$$p={10}^{2.269052185}=185.8028$

(68) The Antoine constants can be obtained from different literature sources. It is preferred to obtain them from Yaws, C. L. & Satyro, M. A., Chapter 1Vapor PressureOrganic Compounds, in The Yaws Handbook of Vapor Pressure (Second Edition) Antoine Coefficients, Elsevier B. V. (2015) pp 1-314. ISBN: 978-0-12-802999-2. An alternative source may be Dykyj, J., Svoboda, J., Wilhoit, R. C., Frenkel, M. & Hall, K. R., Chapter 2 Organic Compounds, C1 to C57 Part 2, in Vapor Pressure and Antoine Constants for Oxygen Containing Organic Compounds, Springer Materials (2000) pp 111-205. ISBN: 978-3-540-49810-0 (a) from which the constants have been obtained for calculating the vapor pressure from linalool and carvone (see table 9). For all other substances, the constants from Yaws & Satyro have been used.

(69) In case different the vapor pressure calculations result in contradictory results it is herein preferred that the vapor pressure of the at least one volatile substance is in the range from the vapor pressure of D-Limonene to the vapor pressure of eugenol, preferred in the range from the vapor pressure of linalool to the vapor pressure of D-carvone.

Example 10Confluent Layer

(70) Particles consisting of a core comprising a volatile substance and a non-confluent layer and a confluent coating layer were produced. 1) Generation of the core: See 1) from example 1a 2) Generation of the non-confluent layer: See 2) from example 1b 3) Application of the non-confluent onto the core: See 3) from example 1b 4) Surrounding the particles consisting of a core comprising a volatile substance and a non-confluent layer with a confluent layer 4a)

(71) 200 g of the particles consisting of a core comprising a volatile substance and a non-confluent layer (see example 1b, step 2)) were put into the process chamber of a laboratory scale fluidized bed plant (DMR; WFP-Mini). The particles were fluidized at an air volume stream of 10 m.sup.3/h. The inlet air temperature was slightly heated to 25 C. The product temperature was 29 C. throughout the whole process. After 5 minutes fluidization the coating process was started, therefore the spray nozzle was used in the bottom spray position (spray air pressure: 1 bar; nozzle cleaning air 0.3 bar). As confluent layer material pure hydrogenated sunflower oil (CAS-No: 68002-71-1) (70 g) was used. The confluent layer material was sucked in without controlling the spray rate. 4b)

(72) 325 g of the particles consisting of a core comprising a volatile substance and a non-confluent layer (see example 1c, step 2)) were put into the process chamber of a laboratory scale fluidized bed plant (DMR; WFP-Mini). The particles were fluidized at an air volume stream of 10 m.sup.3/h. The inlet air temperature was not heated. The product temperature was around 23 C. throughout the whole process. After 5 minutes fluidization the coating process was started, therefore the spray nozzle was used in the bottom spray position (spray air pressure: 0.5 bar; nozzle cleaning air: 0.2 bar). The confluent layer material was generated by mixing the coating material (hydrogenated sunflower oil (CAS-No: 68002-71-1, 116.82 g) with the active ingredient (crystalline menthol (CAS-No: 2216-51-5, 11.2 5 g). The confluent layer material was pumped into the system. Therefore the peristaltic pump (Watson Marlow 323) was set to the value 12. When the addition of the confluent layer material was finished the product was fluidized without being coated for further 3 minutes.

(73) Control)

(74) In parallel cores prepared as described in example 1a (cores without the non-confluent layer) were surrounded with a confluent layer. Therefore, 200 g of the cores were put into the process chamber of a laboratory scale fluidized bed plant (DMR; WFP-Mini). The particles could be fluidized at an air volume stream of 15 m.sup.3/h. The inlet air temperature was slightly heated to 25 C. The product temperature was 29 C. throughout the whole process. After 5 minutes fluidization the coating process was started, therefore the spray nozzle was used in the bottom spray position (spray air pressure: 1 bar; nozzle cleaning air: 0.3 bar). As confluent layer coating material pure hydrogenated sunflower oil (CAS-No: 68002-71-1) (70 g) was used. The confluent layer material was sucked in without controlling the spray rate.

(75) GC analysis was performed as described in example 5 and revealed a recovery rate of selected volatile substances of at least 80%.

(76) TABLE-US-00010 TABLE 10 Volatile substance recovery [%] Batch No. Linalool Carvone Thymol Carvacrol Control 66 78 83 82 4a 82 91 92 100 4b 80 93 92 96

Example 11

(77) Cores were produced applying the same process as described in example 1a, however with a different volatile substance mixture being 10% by weight synthetic carvacrol (CAS-No: 499-75-2), 19% by weight synthetic thymol (CAS-No: 89-83-8), 68% by weight synthetic D-carvone (CAS-No: 2244-16-8) and 3.0% by weight synthetic methyl salicylate (CAS-No: 119-36-8). The calculated vapor pressure of methyl salicylate according to example 9 is 31.7730 mm Hg at 125 C.

(78) The D.sub.50 of the cores was 540 m. The D.sub.50 is defined as the particle size below which 50% of the particles of a sample are. The cores were furnished with a non-confluent layer comprising 100% by weight crystalline menthol as described in example 1c. The particles were surrounded by a confluent layer as described in example 10-4a.

(79) As control, cores with a D.sub.50 of 200 m were produced. The process was the same as described in example 1a. The cores were also furnished with a non-confluent layer comprising 100% by weight crystalline menthol as described in example 1c and additionally surrounded by a confluent layer as described in example 10-4a.

(80) The results shown in table 11 show that even with bigger cores and different essential oil mixtures imbedded in the core the maximum loss of the volatile substances in the core is 11%.

(81) TABLE-US-00011 TABLE 11 Volatile substance recovery after applying a confluent layer [%] D.sub.50 of the core Methyl [m] Carvone Salicylate Thymol Carvacrol 200 100 91 94 100 540 100 89 93 100

Example 12

(82) Particles consisting of a core comprising a volatile substance and a non-confluent layer were produced following example 1b, however different carrier materials were used for the non-confluent layer. The cores were divided in various batches. Each of the batches was furnished with a non-confluent layer consisting of different carrier materials (see batches 1-8, table 12). Each carrier material was loaded with the maximum amount of the hydrophobic substance. In this case the maximum amount is defined as the maximum concentration of the hydrophobic substance that can be loaded onto the carrier material without moist sticky lumps being formed. The difference between various carrier materials is their medium particle size (D.sub.50). With all carrier materials that have been tested the recovery of all volatile substance was higher than 80% (see table 13).

(83) The absorption capacity in % by weight given in table 12 was determined visually. Therefore 20 g of each carrier material were weighed into a bowl. Under homogeneous stirring with a spoon the hydrophobic substance was added dropwise. The maximum absorption capacity was defined as the point at which the material mixture began to form moist lumps. The exact weight of the hydrophobic substance that had been added until then was noted.

(84) All batches were fluidized for 20 minutes under the same conditions as described in example 5 and the recovery of the volatile core substance was determined via GC as described in example 5. Table 13 shows the recovery of selected single compounds of the volatile substance mixture.

(85) TABLE-US-00012 TABLE 12 Carrier materials used in batches 1-8 D.sub.50 inert Spec. Bulk SiO.sub.2 Absorption Batch Product carrier surface density content capacity No. name [m] [m.sup.2/g] [g/l] [wt %] [wt %] 1 Cab-O-Sil 192 30-150 >99.9 391 MF5 2 Syloid 61.4 320 275 99.9 232 XDP 3050 3 Perkasil 12.9 164 70-80 98 292 GT 3000 PD 4 Zeofree 13 160 110 100 236 5162 5 Hubersorb 6.7 226 600 6 Perkasil 19.5 178 96.6 222 SM 660 7 Tixosil 5-20 100-250 >96 205 38AB 8 Tixosil 43 10 97.5 206

(86) TABLE-US-00013 TABLE 13 Volatile substance recovery after applying a confluent layer [%] Batch No. Carvone Thymol Carvacrol Linalool Menthol 1 96 97 97 90 94 2 100 100 100 95 100 3 100 100 100 94 99 4 100 100 109 100 100 5 95 86 100 82 91 6 100 100 100 95 100 7 98 100 100 93 96 8 97 100 98 92 97

Example 13

(87) The particles generated in example 10-4b were analyzed via SEM in the same way as described in example 2. The picture of the cross-section through one of the particles shows the three main parts of the particles, the core (A), the non-confluent coating layer attached to the surface of the core (B) and the confluent coating layer (C) (FIG. 3).