Electrostatic spray-dried active compound powder and method for producing same

Abstract

A method for producing an active compound powder is provided, comprising electrostatically spray drying a formulation comprising at least one active compound, an encapsulating agent, and optionally excipients, at an inlet temperature of 150° C. or less and an outlet temperature of 100° C. or less, wherein an electric charge is applied externally to droplets of the active compound formulation stock solution.

Description

Detailed Description of the Invention

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS]

[0001] This application is a continuation of U.S. Patent Application No. 18 / 129,355, filed March 31, 2023, which is a continuation-in-part of co-pending International Patent Application PCT / US2022 / 054149, filed December 28, 2022, and claims the benefit of U.S. Provisional Patent Application No. 63 / 296083, filed January 3, 2022, each of which is incorporated by reference in its entirety. This patent application also claims the benefit of U.S. Provisional Patent Application No. 63 / 325,709, filed March 31, 2022, which is incorporated by reference in its entirety.

[0002] [Background of the invention]

[0002] Encapsulated active compound powders are widely used across a variety of industries, including food, beverages, cosmetics, and dietary supplements. Encapsulation provides, for example, a barrier against oxygen, light, and free radicals (Desai et al., Journal of Microencapsulation, 22(2), pp. 179-192 (2005)).

[0003]

[0003] Active compound powders, such as oil powders, are typically produced using spray drying systems. However, such systems require high inlet and outlet temperatures that may put the active compound or other components of the powder at risk of degradation (Anwar et al., Journal of Food Engineering, 105, 367-378 (2011)). Thus, there remains a need to effectively produce active compound powders that are storage stable, have improved loading capacity, and / or have improved encapsulation efficiency.

[0004] [Summary of the Invention]

[0004] The present invention provides a method for producing an active compound powder, comprising the step of electrostatically spray drying a formulation comprising at least one active compound, an encapsulating agent, and optionally excipients, at an inlet temperature of not more than 150°C and an outlet temperature of not more than 100°C, wherein an electric charge is applied externally to droplets of the active compound formulation feedstock liquid [Claim 1].

[0005]

[0005] The present invention also provides a method for producing an oil emulsion powder, comprising the step of electrostatically spray drying an emulsion comprising at least one oil, an encapsulating agent, and optionally an emulsifier, at an inlet temperature of not more than 150°C and an outlet temperature of not more than 100°C, wherein an electric charge is applied externally to the droplets of the oil emulsion feed liquid [Claim 2]. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a vertical cross-sectional view of a schematic spray-drying system for processing an active compound-containing formulation into powder form in accordance with an embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged vertical cross-sectional view of an electrostatic spray nozzle assembly of a schematic spray drying system. [Figure 3A] FIG. 1 is a first cross-sectional view of an electrostatic spray nozzle assembly according to an illustrative example. [Figure 3B] FIG. 2 is a second cross-sectional view of an electrostatic spray nozzle assembly according to an illustrative example. [Figure 4] FIG. 4 is a detailed cross-sectional view of the nozzle head portion including the induction ring of the electrostatic spray nozzle assembly illustrated in FIGS. 3A and 3B. [Diagram 5] FIG. 4 is an exploded perspective view of the electrostatic spray nozzle assembly illustrated in FIGS. 3A and 3B. [Figure 6] FIG. 1 shows scanning electron micrographs (SEM) images at 5,000x magnification of 20%, 50%, and 80% (w / w) vegetable oil-containing powders encapsulated by electrostatic spray drying (ESD) and spray drying (SD). [Figure 7A]FIG. 1 shows SEM images at 5,000x magnification of 50% and 80% (w / w) ESD powders containing either coconut oil and medium chain triglycerides (MCT) from coconut. [Figure 7B] FIG. 1 shows SEM images of 5000x magnification of 50% and 80% (w / w) ESD powders with flaxseed oil and olive oil, respectively. [Figure 8] FIG. 1 shows SEM images at 5,000x magnification of oil encapsulated powders containing 50% and 80% (w / w) fish oil and ghee. [Figure 9] FIG. 1 shows SEM images at 5,000x magnification of oil-encapsulated powders containing either 50% (w / w) orange oil or mint oil. [Figure 10] FIG. 1 shows bacterial counts (log cfu / g, with 1% starter culture addition) for S. thermophilus (ST) and L. bulgaricus (LB) on day 0 and after 90 days of storage at 4° C. [Figure 11] FIG. 1 shows an SEM image of encapsulated oil-bacteria powder at 10,000x magnification. [Figure 12] FIG. 1 shows SEM images of 40% oil-loaded DHA oil powder prepared by conventional spray drying (CSD) and electrostatic spray drying (ESD) with different encapsulating materials: (i) maltodextrin and casein, (ii) maltodextrin and methylcellulose, and (iii) maltodextrin and saponin. [Figure 13] FIG. 1 shows the relationship between the percentage of viable bacterial cells in the dried powder versus time (days) after drying with an electrostatic spray dryer with an internal negative charging system (Run 001), the percentage of viable bacterial cells in the dried powder versus time (days) after drying with an electrostatic spray dryer with an external positive charging system (Run 032), and the percentage of viable bacterial cells in the dried powder versus time (days) after drying with conventional freeze drying.

[0007] While the invention is susceptible to various modifications and alternative forms, certain illustrative embodiments will be described in detail below. It should be understood, however, that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention.

[0008] [Detailed Description of the Invention]

[0021] The present invention is based at least in part on the surprising discovery that active compound powders spray dried using conventional high heat spray drying systems have limited loading capacity and / or encapsulation efficiency compared to low heat electrostatic spray systems. In accordance with this discovery, the present invention provides a method for producing an active compound powder, comprising electrostatically spray drying a formulation comprising at least one active compound, an encapsulating agent, and optionally excipients at an inlet temperature of 150° C. or less and an outlet temperature of 100° C. or less. The produced active compound powder has at least one advantage over the corresponding active compound powder produced by spray drying, such as high storage stability, improved loading capacity, and / or improved encapsulation efficiency, compared to an equivalent active compound powder prepared using spray drying.

[0009]

[0022] The present invention also provides a method for producing an oil emulsion powder, comprising electrostatically spray drying an emulsion comprising at least one oil, an encapsulating agent, and optionally an emulsifier, at an inlet temperature of 150°C or less and an outlet temperature of 100°C or less.

[0010]

[0023] In the present method, the inlet temperature is any suitable temperature that provides an active compound powder having the characteristics described herein. Typically, the inlet temperature is 150°C or less (e.g., about 140°C or less, about 135°C or less, about 130°C or less, about 125°C or less, about 120°C or less, about 115°C or less, about 110°C or less, about 105°C or less, about 100°C or less, about 95°C or less, or about 90°C or less). In some embodiments, the inlet temperature is about 140°C or less, about 100°C or less, about 150°C, about 140°C, or about 90°C. In comparison, conventional spray drying systems have very high inlet temperatures, typically about 140°C or more, e.g., 180-250°C.

[0011]

[0024] In this method, the outlet temperature is any suitable temperature that provides the active compound powder with the characteristics described herein.Typically, the outlet temperature is about 80°C or less (e.g., about 75°C or less, about 70°C or less, about 65°C or less, about 60°C or less, about 55°C or less, about 50°C or less, about 45°C or less, about 40°C or less, about 35°C or less).In some embodiments, the outlet temperature is about 60°C or less, about 50°C or less, about 60°C, about 50°C, or about 35°C.In comparison, conventional spray drying systems have an outlet temperature of more than 60°C, typically about 95°C.

[0012]

[0025] The atomizing temperature of electrostatic spray drying systems is also relatively low, e.g., about 100° C. or less (e.g., about 95° C. or less, about 90° C. or less, about 85° C. or less, about 80° C. or less, about 75° C. or less, about 70° C. or less, about 65° C. or less, about 60° C. or less, about 55° C. or less, about 50° C. or less, about 45° C. or less, about 40° C. or less, about 35° C. or less, or about 30° C. or less).

[0013]

[0026] The electrostatic spray drying process applies a voltage to the spray droplets, which is typically about 0.1 kV or more (e.g., about 0.5 kV or more, about 1 kV or more, about 2 kV or more, about 4 kV or more, about 5 kV or more, about 7 kV or more, about 9 kV or more, about 12 kV or more, or about 15 kV or more). The upper limit of the applied voltage is typically 30 kV, and in some cases the upper limit is 20 kV or more preferably 15 kV. Any two of the aforementioned endpoints may be used to define a closed-ended range, or a single endpoint may be used to define an open-ended range. In the drying process, the applied voltage may be continuous or modulated between two or more different voltages, known as pulse width modulation (PWM). Any two or more applied voltages in the range of between 0.1-30 kV (e.g., 0.5 kV-1 kV, 1 kV-5 kV, 1 kV-10 kV, 5 kV-15 kV) may be used for PWM to obtain the desired effect, such as, in particular, the desired aggregate size. In some embodiments of the method, the applied voltage is continuous. In other embodiments of the method, the applied voltage is modulated between two or more different voltages, such as, alternating between 1 kV and 10 kV.

[0014]

[0027] Instead of or in addition to PWM, the charge (positive or negative) of the applied voltage may be alternated as needed. Without wishing to be bound by any theory, it is believed that alternating electrostatic charges can change the surface composition of the particles, the cohesive properties and / or other physical properties of the particles produced. For example, applying a negative charge would allow more conductive compounds to migrate toward the surface of the particle and non-conductive compounds to remain near the core of the particle. Thus, when a charge is applied to the fluid inside the spray nozzle assembly disclosed herein, a negative electrostatic charge is typically applied in the electrostatic spray drying process. Alternatively, when a charge is applied to the fluid outside the spray nozzle assembly disclosed herein, a positive electrostatic charge is typically applied in the electrostatic spray drying process. In some embodiments, alternating charges of the applied voltage are used when preparing oil powders.

[0015]

[0028] The oil to be used in the method is any suitable oil that can undergo electrostatic spray drying process.In some embodiments, at least one oil is from plant or animal origin.In some embodiments, the oil is edible oil.The oil can be provided by any source, including commercially available sources, or sources extracted from suitable plant (including leaves, stems, roots, nuts, or seeds) or animal sources.Extraction can be by any suitable method, such as chemical solvent extraction and / or pressing.

[0016]

[0029] Examples of oils include vegetable oil, vegetable shortening, castor oil, rice bran oil, olive oil, canola oil, corn oil, palm oil, coconut oil, flaxseed oil, hemp seed oil, rapeseed oil, linseed oil, grapeseed oil, rosehip seed oil, pomegranate seed oil, watermelon seed oil, seabuckthorn berry oil, camellia seed oil (tea oil), cranberry seed oil, hemp seed oil, borage seed oil, evening primrose oil, and argan oil. , jojoba oil, marula oil, carrot oil, sesame seed oil, sunflower oil, shea nut oil, soybean oil, peanut oil, walnut oil, almond oil, hazelnut oil, kukui nut oil, pecan oil, macadamia nut oil, meadowfoam oil, avocado oil, apricot kernel oil, essential oils, silicone oils, fish oils, cocoa butter, shea butter, butter, ghee, medium chain triglycerides (MCTs), and any combination thereof. Examples of essential oils include, for example, aniseed oil, basil oil, bay oil, bergamot oil, cinnamon oil, clove oil, lavender oil, eucalyptus oil, lavender oil, ginger oil, geranium oil, rose oil, blue tansy oil, tea tree oil, moringa oil, lemon balm essential oil, lemongrass oil, thyme oil, rosemary oil, mint oil, lemon oil, orange oil, grapefruit oil, and fennel oil.

[0017]

[0030] An encapsulating agent is any agent capable of encapsulating an active compound. In a preferred embodiment of the present invention, the encapsulating agent is a carbohydrate, a lipid, a protein, ascorbic acid, or a combination thereof.

[0018]

[0031] In embodiments, the carbohydrate may be, for example, maltodextrin, sucrose, dextrose, glucose, lactose, trehalose, amylase, cyclodextrin, dextrin, galactomannan, pectin, starch (e.g., corn starch, waxy maize starch, native tapioca starch, pea starch), modified food starch (e.g., modified tapioca starch, OSA (octenylsuccinic anhydride) modified starch), inulin, gum arabic, guar gum, gellan gum, mesquite gum, xanthan gum, alginic acid, chitosan, shellac, carboxymethylcellulose, or combinations thereof. Maltodextrins are typically classified by their dextrose equivalent value (DE), which ranges from 1 to 20. Maltodextrins are commercially available with DE values ​​of 4, 6, 10, 12, 15, 19, 20, 25, 30, and 42. Sources of maltodextrin include, for example, corn, tapioca, and rice.

[0019]

[0032] In embodiments, the lipid may be, for example, a fatty acid or ester thereof, a fatty alcohol or ester thereof, a triglyceride, a phospholipid, a glycolipid, an aminolipid, a lipopeptide, a partial acylglycerol, or a combination thereof. Examples of suitable lipids include, for example, carnauba wax, candelilla wax, beeswax, solid paraffin, rice bran wax, hydrogenated soybean oil, hydrogenated palm oil, palmitic acid, stearic acid, behenic acid, lauric acid, glyceryl tripalmitate, glyceryl trimyristate, glyceryl trilaurate, cetyl alcohol, lauryl alcohol, stearyl alcohol, oleyl alcohol, and lecithin.

[0020]

[0033] In embodiments, the protein may be from a plant source or an animal source (e.g., milk). Examples of proteins include, for example, casein, caseinates (e.g., sodium caseinate, calcium caseinate, calcium caseinate phosphate), gelatin, casein, soy protein, wheat protein, whey protein, rice protein, pea protein, cocoa shell protein, or combinations thereof.

[0021]

[0034] In an embodiment of the method, the treatment conditions provide an emulsion between at least one oil and the encapsulating agent.In another embodiment, the emulsion comprises an emulsifier.The emulsifier is any suitable surfactant that allows the formation of an emulsified powder between the oil and the encapsulating agent.One or more (e.g., two, three, four, etc.) emulsifiers can be used in the composition. In some embodiments, the emulsifier is casein, caseinates (e.g., sodium caseinate, calcium caseinate, calcium caseinate phosphate), lecithin, saponin (e.g., Quillaja, glycyrrhizic acid), carrageenan, gum arabic (GA), xanthan, whey protein isolate (WPI), whey protein concentrate (WPC), stearates, glyceryl monostearate, sucrose esters, monopropylene glycol, propylene glycol esters of fatty acids, polyglycerol esters of fatty acids, mono- and diglycerols, mono- and diglycerides of fatty acids (e.g., citric acid esters of monoglycerides (CAEM), saturated distilled monoglycerides (SDM), polyglycerol fatty acid esters (PGFE), succinylated monoglycerides, or the like. At least one of the emulsifiers may be selected from the group consisting of polyoxyethylene(20)sorbitan monooleate, polyoxyethylene(20)sorbitan monostearate, polyoxyethylene(20)sorbitan monopalmitate, polyoxyethylene(20)sorbitan monolaurate, sorbitan monooleate, sorbitan tristearate, and sorbitan monopalmitate, lactylated esters (e.g., stearoyl lactylate), ethoxylated esters, succinated esters (e.g., sodium starch octenyl succinate), fruit acid esters, and carboxymethylcellulose, as well as combinations thereof. In a preferred embodiment, the emulsion comprises at least one emulsifier.

[0022]

[0035] In an embodiment of the method, the formulation comprises at least one active compound that is part of the powder product. One active compound or more than one (e.g., 2, 3, 4, 5, etc.) active compounds may be used. Exemplary active compounds include, for example, antioxidants, vitamins, bacteria, omega oils, essential oils, flavorings, pigments, dyes, and combinations thereof. In an embodiment of the invention, when the active compound is an oil, the optional excipient is an emulsifier. In an embodiment of the invention, when the active compound is other than an oil, the optional excipient is an oil.

[0023]

[0036] Antioxidants can be used to inhibit oxidation and help stabilize active compounds, especially oils.Suitable antioxidants include, for example, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), propyl gallate (PG), tert-butyl hydroquinone (TBHQ), β-carotene, ascorbic acid, tocopherol, tea extract, rosemary extract, sage extract, thyme extract, alkanine, shikonin, ascorbyl palmitate, and flavonoids (e.g., catechin, apicatechin, epicatechin gallate, epigallocatechin, and epigallocatechin gallate).

[0024]

[0037] Examples of vitamins include vitamins A, B, C, D, E, and K, including their respective vitamers.

[0025]

[0038] Bacteria include, for example, starter cultures, probiotics, and combinations thereof. Starter cultures may be, for example, from the genera lactobacillus, Streptococcus, and leuconostoc. Specific examples of starter cultures include, for example, L. bulgaricus, L. lactis, L. acidophilus, L. helveticus, L. casei, L. plantarum, L. rhamnosus, Leuconostoc citrovorum, Leuconostoc dextrinicum, and the like. dextranicum, S. lactis, S. cremoris, S. diacetylactis, S. durans, S. faecalis, S. thermophilus, propionic bacterium shermanii, and combinations thereof. Suitable probiotics include those from the genera Bifidobacteria, Lactobacillus, and Saccharomyces, preferably from the genus Bifidobacteria or Lactobacillus. Specific examples of probiotics include, for example, B. animalis, B. breve, B. lactis, B. longum, L. acidophilus, L. reuteri, S. boulardii, and combinations thereof.

[0026]

[0039] Omega oils, also known as omega-3 oils, are polyunsaturated fatty acids with a double bond three atoms away from the terminal methyl group. Examples include eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), alpha-linolenic acid (ALA), and combinations thereof.

[0027]

[0040] The essential oils as active compounds are as described herein.

[0028]

[0041] The flavoring agent may be in the form of an oil, a non-aqueous solution, or an emulsion. The flavoring agent may be natural or synthetic. Suitable examples include, for example, limonene, fenchone, vanillin, thymol, menthol, isoamyl acetate, benzaldehyde, ethyl propionate, ethyl butyrate, methyl anthranilate, methyl salicylate, ethyl decadienoate, allyl hexanoate, ethyl maltol, 2,4-dithiapentane, fumaric acid, acetic acid, ascorbic acid, citric acid, lactic acid, malic acid, phosphoric acid, tartaric acid, citral, massoialactone, acetoin, manzanate, cinnamaldehyde, glutamate (e.g., mono- and / or disodium glutamate), glycine salts, guanylate salts, inosinate salts, and 5'-ribonucleotide salts.

[0029]

[0042] The pigments or dyes may be natural or synthetic and may be, for example, minerals, clays, charcoal, carbon black, ultramarine, ultramarine green shade, Tyrian red, Indian yellow, cadmium based pigments (e.g. cadmium yellow, cadmium red, cadmium green, cadmium orange), chromium based pigments (e.g. chrome yellow, chrome green), cobalt based pigments (e.g. cobalt violet, cobalt blue, cerulean blue, aureolin), copper based pigments (e.g. azurite, han purple, han blue, Egyptian blue, malachite, Paris green, phthalocyanine blue BN, phthalocyanine green G, verdigris), iron oxide based pigments (e.g. sanguine, caput mol tum, mortuum), oxide red, red ochre, yellow ochre, Venetian red, Prussian blue), lead-based pigments (e.g., white lead, red lead, Kremnitz white, Naples yellow), manganese-based pigments (e.g., manganese violet red, YInMn blue), titanium-based pigments (e.g., titanium yellow, titanium beige, titanium white, titanium black), zinc-based pigments (e.g., zinc white, zinc ferrite, zinc yellow), marine pigments (e.g., chlorophyll a, b, and c, β -carotene, phycocyanin, xanthophyll, phycoerythrin), aluminum powder, vermilion, aniline dyes (e.g., mauveine, aniline yellow), azo dyes (e.g., CI Direct Black 171, Sunset Yellow, Tartrazine, Azorubin, Ponceau, Amaranth, Allura Red), acid dyes (e.g., Indian Ink, Congo Red, Nigrosoine), naphthol (azoic) dyes, nitro dyes (e.g., Maritus Yellow), anthraquinone dyes (e.g., CI Reactive Blue 19, Indanthrone, Alizarin, 1-aminoanthraquinone), sulfur dyes (e.g., Indophenol, Sulfur Black, Sulfur Red 7), turmeric, and combinations thereof.

[0030]

[0043] In an embodiment of the present invention, the oil emulsion powder produced by the present method has a lower amount of surface free fat, i.e., oil, compared to the spray-dried powder of the same oil emulsion. For example, the oil powder product may have a surface free fat of 40% or less (e.g., 37% or less, 35% or less, 30% or less, 25% or less, 20% or less, 10% or less, 8% or less, 6% or less, 5% or less, 4% or less, 3% or less, 2% or less, 1% or less, 0.5% or less, or 0.2% or less).

[0031]

[0044] The percentage of surface free fat or oil can be determined as follows: Add 3 g of powder to a beaker. Add 30 mL of hexane. Stir for 2 minutes. Filter through No. 1 Whatman filter paper into a weighed beaker. After the solvent has evaporated for approximately 48 hours, the beaker is weighed.

number

[0032]

[0045] In an embodiment of the present invention, the oil emulsion powder has any suitable oil content (e.g., about 1 to 90%). For example, the oil content may be about 1% or more (e.g., about 5% or more, about 10% or more, about 15% or more, about 20% or more, about 25% or more, about 30% or more, about 35% or more, about 40% or more, about 45% or more, about 50% or more, about 55% or more, about 60% or more, about 65% or more, about 70% or more, about 75% or more, about 80% or more, or about 85% or more). The upper limit of the oil content is typically about 90% or less (e.g., about 85% or less, about 80% or less, about 75% or less, about 70% or less, about 65% or less, about 60% or less, about 55% or less, about 50% or less, about 45% or less, about 40% or less, about 35% or less, about 30% or less, about 25% or less, about 20% or less, about 15% or less, or about 10% or less). Any two of the aforementioned endpoints may be used to define a closed-ended range, or a single endpoint may be used to define an open-ended range. In embodiments, the oil powder produced by the claimed method has a high oil content (e.g., 20% or more, 50% or more, 60% or more, 70% or more, or 80% or more, about 90%).

[0033]

[0046] In embodiments of the invention, the encapsulation efficiency of the active compound blend powder is 50% or greater (e.g., 55% or greater, 60% or greater, 65% or greater, 70% or greater, 75% or greater, 80% or greater, 85% or greater, 90% or greater, 92% or greater, 95% or greater, 96% or greater, 97% or greater, 98% or greater, and 99% or greater).

[0034]

[0047] Active encapsulation efficiency can be determined as follows: Mix 2.5 g of powder with 18 mL of water in a beaker. The beaker is placed in an ultrasonic bath for 20 minutes. The solution in the beaker is transferred to a separatory funnel. Add 10 mL of chloroform and 20 mL of methanol. Shake by inversion 50 times. Add 10 mL of chloroform. Shake the separatory funnel for 2 minutes. Stasis is maintained for 2 hours. The upper phase is filtered through No. 1 Whatman filter paper into a tared beaker. After the solvent evaporation is complete, the beaker is weighed.

number

[0035]

[0048] In an embodiment of the present invention, the method provides improved oil content and encapsulation efficiency compared to spray-dried powders of the same oil emulsion. In particular, the oil content of the produced oil powder can be in the range of 1-60% combined with an encapsulation efficiency in the range of 90-99%. In another embodiment of the present invention, the oil content can be in the range of 61-90% combined with an encapsulation efficiency in the range of 55-90%.

[0036]

[0049] The moisture content of the active compound powder product is low, preferably in combination with low water activity (including, for example, about 0.3 or less, about 0.28 or less, about 0.25 or less, about 0.2 or less, about 0.18 or less, about 0.15 or less, or about 0.1 or less), typically about 5% or less (for example, about 4.5% or less, about 4% or less, about 3.5% or less, about 3% or less, about 2.5% or less, about 2% or less).In an embodiment of the method, the moisture content of the active compound powder product is about 4% or less or about 3% or less.

[0037]

[0050] Referring more clearly to the drawings, Figure 1 is a schematic spray drying system 10 for processing an active compound encapsulated formulation into powder form in accordance with the present invention. The basic structure and operation of the schematic spray drying system 10 is similar to that disclosed in commonly assigned U.S. Patent No. 10,286,411, the disclosure of which is incorporated herein by reference.

[0038]

[0051] The spray drying system 10 in this case includes a drying chamber 12 in the form of an upright cylindrical structure, a top closure arrangement in the form of a cover or lid 14 for the drying chamber 12 having a heated air inlet 15 and a liquid spray nozzle assembly 16, a bottom closure arrangement in the form of a powder collection cone 18 supported at the bottom of the drying chamber 12, a filter element housing 19 from which the powder collection cone 18 extends and which has a heated air discharge outlet, and a processing tower 11 including a bottom powder collection chamber 21.

[0039]

[0052] The illustrated drying chamber 12 has a "replaceable internal non-metallic" insulating liner 22 concentrically spaced from the inner wall surface 12a of the drying chamber 12 through which the electrostatically charged liquid spray particles are discharged from the spray nozzle assembly 16. The liner 100 has a diameter d that is smaller than the inner diameter d1 of the drying chamber 12, thereby providing an insulating air gap 101 with the inner wall surface 12a of the drying chamber 12. The liner 100 is preferably non-structural, made of a non-permeable flexible plastic material.

[0040]

[0053] The spray nozzle assembly 16, as best seen in Figure 2, is a pressurized air assisted electrostatic spray nozzle assembly for directing a spray of electrostatically charged particles into the dryer chamber 12 for rapidly and efficiently drying the active compound encapsulated formulation into powder form. The schematic spray nozzle assembly 16 includes a head 31 supporting a nozzle, an elongated nozzle barrel or body 32 extending downstream from the head 31, and a discharge spray tip assembly 34 at the downstream end of the elongated nozzle body 32. In this case, the head 31 is made from plastic or other non-conductive material and is formed with a radial liquid inlet passage 36 which receives and communicates with a liquid inlet fitting 38 to connect to a supply line 37 which communicates with a supply of active compound powder product to be spray dried.

[0041]

[0054] Further in this case, the head 31 carrying the nozzle is formed with a radial pressurized air atomizing inlet passage 39 downstream of the liquid inlet passage 36 and in communication with an air inlet fitting 40 which is connected to a suitable pressurized gas supply. The head 31 also has a radial passage 41 upstream of the liquid inlet passage 36 and which receives a fitting 42 for securing a high voltage cable 44 which is connected to a high voltage source and has an end 44 extending into the passage 41. a and is axially supported within head 31 and in adjacent electrical contacting relationship to an electrode 48 extending downstream of liquid inlet passage 36.

[0042]

[0055] To allow for liquid passage through head 31, electrode 48 is formed with an internal axial passage 49 which communicates with liquid inlet passage 36 and extends downstream through electrode 48. Electrode 48 is formed with a plurality of radial passages 50 which provide communication between liquid inlet passage 36 and internal axial passage 49.

[0043]

[0056] The elongated body 32 is in the form of an outer cylindrical body member 55 made from plastic or other suitable non-conductive material and has an upstream end 55a that is threadably fitted within a threaded bore in the head 31. A liquid supply tube 58 is disposed in electrical contact with the electrode 48 for efficiently electrically charging the liquid throughout its passage from the head 31 through the elongated nozzle body member 32 to the discharge spray tip assembly 34, in this case similar to that disclosed in U.S. Pat. No. 10,286,411.

[0044]

[0057] 2, the fluid is electrically charged within the spray nozzle assembly 16. More specifically, the fluid is electrically charged as it passes through the liquid supply tube 58 before being discharged from the spray nozzle assembly 16.

[0045]

[0058] Further embodiments of a spray nozzle assembly 130 for use in the spray drying system 10 of FIG. 1 are shown in FIGS. 3-5. As a first specific example, the spray nozzle 130 is a specially arranged nozzle assembly that exhibits certain electrical characteristics during operation that facilitate the generation of a continuous stream of electrostatically charged spray droplets. In FIG. 3A, an exemplary electrostatic spray nozzle arrangement is illustratively illustrated, in which electrostatic charging of the spray droplets is achieved by an electrical circuit arrangement including an induction ring 210 provided in the form of a conductive metal retaining cap located at the discharge aperture of the spray nozzle 130. The opening 215 of the induction ring 210 is wide enough to avoid excessive deposition of the active compound formulation that is released from the opening of the spray gas cap 220 and passes through the opening 215 in the form of droplets by means of a purge gas flow. By way of example, the opening 215 has an inner diameter on the order of less than 1 inch for an applied electric field having a voltage of 3,000 to 4,000 volts (3 to 4 kilovolts). More specifically, the opening 215 has a diameter of about 0.7 inches. However, depending on different applications involving spray drying of active compound formulations, the diameter of the opening 215 and / or the applied voltage (electric field potential between the induction ring 215 and the active compound formulation expelled from the nozzle) are modified depending on the spray pattern (wide / narrow spray field), the position of the nozzle aperture relative to the opening 215 of the induction ring 210 (linear displacement along the path of the spray field). In the illustrated example, the atomizing gas cap 220 is a non-conductive insulating material (e.g. a hard plastic material).

[0046]

[0059] A first conductive path is provided to generate an electrostatic field at the opening 215 of the induction ring 210 to electrostatically charge the droplets of the active compound formulation emitted from the atomizing gas cap. To this end, the induction ring 210 is conductively fitted physically (by complementary threading) to a conductive surface of the nozzle head 230. The first conductive path is further provided by a further physically conductive fit between the nozzle head 230 and the purge gas tube 240. By way of example, the nozzle head 230 and the purge gas tube 240 are physically conductively fitted by complementary threaded surfaces at 242. The purge gas tube 240 also comprises a conductive surface that provides a conductive path from the nozzle head 230 to an induction field (high voltage) electrode 250 from a high voltage field signal source (not shown).

[0047]

[0060] In the illustrated example, the outer surface of the conductive components (e.g., induction ring 210) is coated with an electrically insulating layer to reduce the possibility of arcing within the spray environment. Thus, only the inner surface (or a portion thereof) of the exposed face of induction ring 210 is an electrically conductive surface (as opposed to the unexposed threaded surface of induction ring 210, which is also an electrically conductive surface). Such an electrically insulating layer may be provided, for example, by a polytetrafluoroethylene (PTFE) coating.

[0048]

[0061] In a further illustrative example, all exposed surfaces of the conductive components - even the inner exposed surfaces of the induction ring 210 - are coated with a strong dielectric material (e.g., PTFE) to provide an electrical insulating barrier between the high (magnitude) voltage of the induction ring 210 and the low (magnitude) voltage of the active compound formulation, as well as any potential ground connection sources that the feedstock contacts before being discharged from the spray nozzle. Such an arrangement facilitates minimizing any current flow from the induction ring during operation of the exemplary electrostatic spray drying system.

[0049]

[0062] The second conductive path is provided to establish a complementary electrical (e.g. ground) path from the conductive supply line through which the active compound formulation passes, for example, from the active compound formulation supply tank to the atomizing gas cap 220. The second conductive path provides a source from the fluidic chip 280, which has an electrically grounded conductive surface in contact with the active compound formulation, to induce a charge (opposite to the electric field potential created at the opening 215) in the passing droplets via the electric field of the opening 215. The second conductive path continues with a physical electrical connection between the fluidic chip 280 and the fluidic tube 285, which provides the feedstock to the fluidic chip 280. The outer surfaces of the fluidic chip 280 and the fluidic tube 285, as well as the outer surface of the induction ring, are coated with an electrically insulating layer (e.g. PTFE).

[0050]

[0063] The atomizing gas tube 290 provides atomizing gas to the atomizing gas cap 220. The atomizing gas tube 290 is illustratively made from a non-conductive material (e.g., hard plastic, ceramic, etc.) and is configured to provide a hermetic fit with the atomizing gas cap 220. Alternatively, the atomizing gas tube 290 comprises a conductive material coated with an electrically insulating material. Thus, the atomizing gas tube 290 and the atomizing gas cap 220 provide an electrically insulating barrier between the first and second conductive paths described herein above. It should be noted that such electrically insulating properties may alternatively be achieved by coating the exposed surfaces with an insulating coating (e.g., PTFE).

[0051]

[0064] As shown in FIG. 3A, the nozzle body 260 is physically arranged with several receptacles / openings to maintain the physical / electrical fit between the components of the spray nozzle 130 exemplarily illustrated herein. In the illustrated example, the nozzle body 260 includes an induction field electrode receptacle 255 that holds the induction field electrode 250 and the conductive surface of the purge gas tube 240 in a conductive fit. The nozzle body 260 includes a ground electrode receptacle 270 that holds the electrical ground electrode 275 and the conductive surface of the fluid tube 285 in a conductive fit. The induction ring purge gas port 277 provides an opening for supplying purge gas that passes through the purge gas tube 240 and flows to the opening 215 in the induction ring 210. As further shown in FIG. 3B (another cross-sectional view rotated 90 degrees from the view illustrated in FIG. 3A), the nozzle body 260 further includes an atomizing gas port 295 that provides an opening for supplying atomizing gas to the atomizing gas tube 290.

[0052]

[0065] As shown in FIG. 3A, the nozzle body 260 includes a cylindrical receptacle having a threaded surface at 265 for holding in place a purge gas tube 240 having a complementary threaded outer surface.

[0053]

[0066] Turning now to Figure 4, an additional detailed view of the nozzle head portion of the spray nozzle depicted in Figures 3A and 3B is provided to facilitate a clearer display of the various physical relationships depicted in Figures 3A and 3B and the corresponding written description provided herein above. Additionally, Figure 5 provides an exploded perspective view of the electrostatic spray nozzle assembly depicted in Figures 3A and 3B to provide additional visual detail of an illustrative example electrostatic spray nozzle according to the present disclosure.

[0054]

[0067] Thus, in contrast to the spray nozzle assembly 16 of Figure 2, in which the fluid is charged internally before being discharged from the spray nozzle, the spray nozzle assembly 130 of Figures 3-5 charges the fluid (via the inductor ring 210) after it is discharged from the spray nozzle assembly in the form of droplets. This external charging configuration may provide several advantages over the internal charging arrangement of Figure 2, including, among others, the ability to use significantly lower voltages, which may lead to improved safety. Additionally, the external charging arrangement may have a cost advantage by eliminating the need for special electrically isolated components along the liquid supply path.

[0055]

[0068] As will become apparent, the electrostatic spray drying system 10 is operable to dry active compound powders into fine particles having improved properties over the prior art.

[0056]

[0069] As used herein, the term "about" typically refers to ±1% of the value, ±5% of the value, or ±10% of the value.

[0057]

[0070] The present invention is further characterized by the following features.

[0058]

[0071] (1) A method for producing an active compound powder, comprising electrostatically spray drying a formulation comprising at least one active compound, an encapsulating agent, and optionally excipients, at an inlet temperature of 150°C or less and an outlet temperature of 100°C or less, wherein an electric charge is applied externally to droplets of the active compound formulation feedstock liquid.

[0059]

[0072] (2) A method for producing an oil emulsion powder, comprising electrostatically spray drying an emulsion comprising at least one oil, an encapsulating agent, and optionally an emulsifier, at an inlet temperature of 150°C or less and an outlet temperature of 100°C or less, wherein an electric charge is applied externally to the droplets of the oil emulsion feed liquid.

[0060]

[0073] (3) The method according to any one of features 1 to 2, wherein the spray temperature is about 100° C. or less.

[0061]

[0074] (4) The method according to any one of features 1 to 3, wherein the applied voltage is about 0.1 kV or more.

[0062]

[0075] (5) The method according to any one of features 1 to 4, wherein the applied voltage is continuous.

[0063]

[0076] (6) The method according to any one of features 1 to 5, wherein the applied voltage is modulated between two or more different voltages.

[0064]

[0077] (7) The method according to any one of Features 2 to 6, wherein the oil emulsion powder has a lower amount of surface free fat compared to a spray-dried powder of the same oil emulsion.

[0065]

[0078] (8) The method according to any one of features 2 to 7, wherein the encapsulation efficiency of the oil emulsion powder is 50% or more.

[0066]

[0079] (9) The method according to feature 8, wherein the oil content is in the range of 1 to 60% and the encapsulation efficiency is in the range of 90 to 99%.

[0067]

[0080] (10) The method according to feature 8, wherein the oil content is in the range of 61 to 90% and the encapsulation efficiency is in the range of 55 to 90%.

[0068]

[0081] (11) The method according to any one of features 1 to 10, wherein at least one oil is of plant or animal origin.

[0069]

[0082] (12) At least one oil is selected from the group consisting of vegetable oil, vegetable shortening, castor oil, rice bran oil, olive oil, canola oil, corn oil, palm oil, coconut oil, flaxseed oil, hemp seed oil, rapeseed oil, linseed oil, grapeseed oil, rosehip seed oil, pomegranate seed oil, watermelon seed oil, seabuckthorn berry oil, camellia seed oil (tea oil), cranberry seed oil, hemp seed oil, borage seed oil, evening primrose oil, argan oil, and ho 12. The method of claim 11, wherein the oil is jojoba oil, marula oil, carrot oil, sesame seed oil, sunflower oil, shea nut oil, soybean oil, peanut oil, walnut oil, almond oil, hazelnut oil, kukui nut oil, pecan oil, macadamia nut oil, meadowfoam oil, avocado oil, apricot kernel oil, essential oil, silicone oil, fish oil, cocoa butter, shea butter, butter, ghee, medium chain triglycerides (MCT), or any combination thereof.

[0070]

[0083] (13) The method according to any one of features 1 to 12, wherein the encapsulating agent is a carbohydrate, a lipid, a protein, ascorbic acid, or a combination thereof.

[0071]

[0084] 14. The method of claim 13, wherein the carbohydrate is maltodextrin, sucrose, dextrose, glucose, lactose, trehalose, amylase, cyclodextrin, dextrin, galactomannan, pectin, starch, modified food starch, inulin, gum arabic, guar gum, gellan gum, mesquite gum, xanthan gum, alginic acid, chitosan, shellac, carboxymethylcellulose, or a combination thereof.

[0072]

[0085] (15) The method according to any one of claims 13 to 14, wherein the lipid is a fatty acid or an ester thereof, a fatty alcohol or an ester thereof, a triglyceride, a phospholipid, a glycolipid, an aminolipid, a lipopeptide, a partial acylglycerol, or a combination thereof.

[0073]

[0086] (16) The method according to any one of features 13 to 15, wherein the protein is casein, caseinate, gelatin, soy protein, wheat protein, whey protein, rice protein, pea protein, cocoa shell protein, or a combination thereof.

[0074]

[0087] (17) The method according to any one of features 2 to 16, wherein the emulsion comprises an emulsifier.

[0075]

[0088] (18) The method according to feature 17, wherein the emulsifier is at least one selected from casein, caseinate, lecithin, saponin, carrageenan, gum arabic, xanthan, whey protein isolate, stearate, glyceryl monostearate, sucrose esters, monopropylene glycol, propylene glycol esters of fatty acids, polyglycerol esters of fatty acids, mono- and diglycerols, mono- and diglycerides of fatty acids, distilled monoglycerides, polyglycerol polyricinoleate, polysorbate 80, sorbitan esters, lactylated esters, ethoxylated esters, succinylated esters, fruit acid esters, carboxymethylcellulose, and combinations thereof.

[0076]

[0089] (19) The method according to any one of features 2 to 18, wherein the emulsion further comprises at least one active compound.

[0077]

[0090] (20) The method of any one of features 1 to 19, wherein the at least one active compound is an antioxidant, a vitamin, a bacteria, an omega oil, an essential oil, a flavoring agent, a pigment, a dye, or a combination thereof.

[0078]

[0091] (21) The method according to claim 20, wherein the optional excipient is an emulsifier when the active compound is an oil, and the optional excipient is an oil when the active compound is other than an oil.

[0079]

[0092] The following examples further illustrate the invention but, of course, should not be construed as in any way limiting its scope.

[0080] Example 1

[0093] This example demonstrates low temperature electrostatic spray drying of an oil powder product in one embodiment of the present invention.

[0081]

[0094] Oil emulsion powders were made by electrostatic spray drying (ESD) at inlet temperatures of 90°C, 140°C, and 150°C, although the inlet drying temperature can be reduced to 80°C. The spray temperature was generally kept below 80°C and the outlet temperature below 60°C. In this example, the spray temperature was set at 35°C, 50°C, and 80°C, resulting in outlet temperatures of 35°C, 50°C, and 60°C, respectively. In these examples, a negative pulse width modulation (PWM) alternating between 10 kV and 1 kV was used, but the electrostatic charge can be positive, and it can be as low as 0.1 kV or as high as 20 kV, with or without PWM. The atomizing gas pressure can range from 30 to 552 kPa. For comparison, oil emulsion powders were also spray dried by conventional high heat spray drying at inlet 180°C and outlet 90°C. Processing parameters are shown in Table 1.

[0082] [Table 1]

[0083] Example 2

[0095] This example demonstrates low temperature electrostatic spray drying of a vegetable oil powder product in one embodiment of the present invention.

[0084]

[0096] Vegetable oil emulsions were formulated to contain 20%-90% (w / w) vegetable oil, encapsulated with maltodextrin and stabilized with sodium caseinate. The oil emulsions were spray dried (SD) at 180°C and electrostatically spray dried (ESD) at 90°C and 140°C at 10 kV PWM. Table 2 shows the moisture content and water activity of the resulting vegetable oil powders. The moisture content was below 3% and the water activity was below 0.22 for all powders.

[0085] [Table 2]

[0086]

[0097] Table 3 shows the oil content, surface free fat, encapsulation efficiency, and peroxide value of the vegetable oil powders. The peroxide value (in all of the examples except Example 7) was measured immediately after the preparation of the powders using the International Dairy Federation (IDF) spectrophotometric standard method (see, for example, Rahmani-Manglano et al., Foods, 9, 545, 21 (2020)). Alternative methods for measuring the peroxide value include, for example, the titration method of the International Fragrance Association (IFRA) and American Oil Chemists' Society (AOCS) official method Cd 8b-90 (see, for example, Selim et al., Molecules, 26, 6109, 17 (2021) and Shantha et al., Journal of AOAC International, 77(2), 421-424 (1994)).

[0087]

[0098] Electrostatic spray drying produced powders with higher encapsulation efficiency than spray drying at oil contents of 20%, 50%, and 80%. Overall, encapsulation efficiency decreased as oil content increased. At 20% oil content, encapsulation efficiency was greater than 99% in the ESD powder and less than 97% in the spray-dried powder. At 50% oil content, encapsulation efficiency was greater than 97% in the ESD powder compared to less than 90% in the spray-dried powder. At 80% oil content, the ESD powder had an encapsulation efficiency of 73% compared to 53% with spray drying.

[0088]

[0099] Conventional high heat spray drying has been used to produce oil emulsion powders with oil contents up to 67%, with significantly lower encapsulation efficiencies than the ESD method of the present invention. See, for example, Alpizar-Reyes et al., International Journal of Biological Macromolecules, 2020, 145, 207-215; Benito-Roman et al., Heliyon, 2020, 6(4), e03615-e03615; da Silva James et al., Brazilian Journal of Development, 2019, 5(7), 8082-95; and Domian et al., Journal of Food Engineering, 2014, 125(1), 34-43. Comparable encapsulation efficiencies have been reported in powders with lower oil contents up to 22% (Benito-Roman et al., 2020).

[0089]

[0100] Without being bound by any theory, it is believed that the difference in encapsulation efficiency is due to the difference in surface free fat, which is approximately one-third lower at 20% and 50% oil content in the ESD powder (<0.2% vs. 0.6% at 20% oil; <1.5% vs. 5% at 50% oil content). At 80% oil content, the difference between ESD and SD is almost doubled (ESD 21.53% vs. SD 37.41%).

[0090]

[0101] Peroxide values ​​were low in all powders (below 1.8 meqO2 / kg oil).

[0091] [Table 3]

[0092]

[0102] Figure 6 shows scanning electron microscope (SEM) images at 5,000x magnification of 20%, 50%, and 80% (w / w) vegetable oil-containing powders encapsulated by electrostatic spray drying (ESD) and spray drying (SD). The primary particles in the SD powders were generally larger than the ESD powders. At 20% and 50% oil content, little change in appearance was observed, but at 80% oil content, the physical appearance changed. The ESD powders showed increased swelling of the primary particles, while the SD powders showed significant particle fusion.

[0093] Example 3

[0103] This example demonstrates low temperature electrostatic spray drying of a vegetable based oil powder product in one embodiment of the present invention.

[0094]

[0104] Coconut oil, medium chain triglycerides (MCT) from coconut, flaxseed oil and olive oil emulsions were formulated containing 50% and 80% (w / w) oil, encapsulated with maltodextrin and stabilized with sodium caseinate. The emulsions were then dried using an electrostatic spray dryer with an inlet temperature of 90°C and an outlet temperature of 35°C.

[0095]

[0105] Table 4 shows the moisture content and water activity of the resulting powders. All powders had a moisture content below 4% and a water activity below 0.28. Moisture and water activity were higher in powders with higher oil content.

[0096] [Table 4]

[0097]

[0106] Table 5 shows the oil content, surface free fat, encapsulation efficiency and peroxide value for coconut, MCT, flaxseed and olive oil powders. At 50% oil content the surface free fat was approximately 1-1.2%, which increased to 16-20% at 80% oil content for all powders. Encapsulation efficiency was greater than 97% at 50% oil content and 74-79% for powders with 80% oil.

[0098]

[0107] The peroxide value in coconut oil powder was the lowest regardless of oil content (0.05-0.15 meq O2 / kg oil) possibly due to the high content of saturated fat (Hee et al., The Journal of Supercritical Fluids, 2017, 130, 118-124). Flaxseed oil and olive oil are rich in unsaturated fatty acids (Bakry et al., Comprehensive Reviews in Food Science and Food Safety, 2008, 15(1), 143-182; Koutsopoulos et al., Meat Science, 2008, 79(1), 188-197) and had high peroxide values ​​(1.19-1.68 meq O2 / kg oil).

[0099] [Table 5]

[0100]

[0108] Figures 7A and 7B show SEM images of different oil powders with 50% and 80% oil content. Figure 7A shows coconut oil and MCT particles, and Figure 4B shows flaxseed oil and olive oil particles. Primary particles were similar in appearance for all oil types at equal oil content. Differences were observed between 50% and 80% oil-containing powders, with primary particles in 80% oil powder showing a clear spherical appearance.

[0101] Example 4

[0109] This example demonstrates low temperature electrostatic spray drying of an animal-based oil powder product in one embodiment of the present invention.

[0102]

[0110] Fish oil and ghee emulsions were formulated to contain 50% and 80% (w / w) oil, encapsulated with maltodextrin and stabilized with sodium caseinate. The emulsions were then dried using an electrostatic spray dryer with an inlet temperature of 90° C. and an outlet temperature of 35° C. A negative pulse width modulation (PWM) alternating between 10 kV and 1 kV was used in these examples.

[0103]

[0111] The moisture content and water activity of the resulting powders are shown in Table 6. All powders had a moisture content below 3% and a water activity below 0.2 at 50% oil content and less than 0.25 at 80% oil content.

[0104] [Table 6]

[0105]

[0112] Table 7 shows the oil content, surface free fat, encapsulation efficiency and peroxide value of fish oil and ghee powders. At 50% oil content, surface free fat was approximately 1.1-1.3% which increased to 17-20% at 80% oil content for all powders. Encapsulation efficiency was above 97% at 50% oil content and 74-78% for powders containing 80% oil.

[0106]

[0113] Peroxide values ​​in ghee powder were the lowest irrespective of oil content (0.14-0.31 meq O2 / kg oil) likely due to the high content of saturated fat (Duhan et al., Journal of Food Processing and Preservation, 2021, 45(6), e15537; Gupta et al., Journal of Chemical and Pharmaceutical Research, 2015, 7(1), pp. 568-572). Fish oil is rich in polyunsaturated fatty acids, in this case omega 18 / 12 (containing 18% eicosapentaenoic acid and 12% docosahexaenoic acid) (Hashim et al., Materials Today: Proceedings, 2021, 42, 222-228; Jeyakumari et al., Journal of Food Science and Technology, 2016, 53(1), 856-863), and therefore had high peroxide values ​​(1.75 and 3.67 meq O2 / kg oil at 50% and 80% oil contents, respectively).

[0107] [Table 7]

[0108]

[0114] Figure 8 shows SEM images of fish oil and ghee powders with 50% and 80% oil content. Primary particles were similar in appearance for both oil types at equal oil content. Differences were observed between 50% and 80% oil containing powders, with primary particles in 80% oil powder showing a clear spherical appearance.

[0109] Example 5

[0115] This example demonstrates low temperature electrostatic spray drying of an essential oil powder product in one embodiment of the present invention.

[0110]

[0116] Orange and mint oil emulsions were formulated to contain 50% (w / w) oil, encapsulated with maltodextrin, and stabilized with sodium caseinate. The emulsions were then dried using an electrostatic spray dryer with inlet and outlet temperatures of 90 / 35° C. and 150 / 60° C., respectively. Negative pulse width modulation (PWM) alternating between 10 kV and 1 kV was used in these examples.

[0111]

[0117] The water activity of the resulting powders is shown in Table 8. All powders had a water activity between 0.1 and 0.23.

[0112] [Table 8]

[0113]

[0118] Figure 9 shows SEM images of orange and mint powders with 50% oil content at two drying temperatures. Primary particles were similar in appearance for both oil types. Differences were observed between orange and mint oil powders, with the primary particles in the mint oil powder showing a more obvious porous surface.

[0114] Example 6

[0119] This example demonstrates low temperature electrostatic spray drying of an encapsulated oil-bacteria powder product in one embodiment of the present invention.

[0115]

[0120] Vegetable oil emulsions were formulated to contain 50% (w / w) oil and 1%, 10% or 20% (w / w) starter culture (S. thermophilus and L. bulgaricus mixture). Maltodextrin was the encapsulant and the emulsions were stabilized with sodium caseinate. The emulsions were dried using an electrostatic spray dryer with an inlet at 90°C and an outlet at 35°C. Negative pulse width modulation (PWM) alternating between 10 kV and 1 kV was used in these examples.

[0116]

[0121] Table 9 shows the moisture content and water activity of the resulting powders. All powders had a moisture content below 4% and a water activity below 0.25 with 1% and 10% starter culture added. When 20% culture was added, the water activity increased to 0.3.

[0117] [Table 9]

[0118]

[0122] Table 10 shows the oil content, surface free fat, encapsulation efficiency, and peroxide value for the oil-bacteria powder. With 1%, 10%, and 20% culture addition, the surface free fat was less than 1% and the encapsulation efficiency was greater than 98%. The peroxide value was low (less than 0.2 meq O2 / kg oil).

[0119]

[0123] A similar study by Eratte et al. (Journal of Functional Foods, 2015, 19, 882-892) encapsulated 50% tuna oil with 16% (w / w) L. casei using whey protein isolate (WPI) and gum arabic as encapsulants. The emulsion was spray-dried (SD) and freeze-dried (FD) at 180C / 80°C. In the Eratte et al. study, surface free fat was higher than recorded for electrostatic spray drying (3.3% for spray drying and 11.3% for freeze drying), and encapsulation efficiency was lower (93% and 76% for SD and FD, respectively).

[0120] [Table 10]

[0121]

[0124] Bacterial counts (cfu / g) for S. thermophilus (ST) and L. bulgaricus (LB) at 1-20% (w / w) starter addition (10 8 In a study by Eratte et al. (2015) with the addition of 16% (w / w) L. casei, the survival rate was 106 After freeze-drying, it is less than 10 8 The viability data obtained by electrostatic spray drying were similar to freeze drying for S. thermophilus and L. bulgaricus at low spikes (1-10% here compared to 16% in Eratte et al., 2015). At a spike of 20% starter culture, the viabilities for S. thermophilus and L. bulgaricus were 1.82E+07 and 1.04E+09, respectively.

[0122] [Table 11]

[0123]

[0125] Figure 10 shows bacterial counts (log cfu / g, with 1% starter culture addition) for S. thermophilus (ST) and L. bulgaricus (LB) on day 0 and after 90 days of storage at 4° C. Viability of S. thermophilus and L. bulgaricus remained high even after 90 days of storage (>7 log cfu / g for ST and >6 log cfu / g for LB).

[0124]

[0126] SEM images of the encapsulated oil-bacteria powders are shown in Figure 11. The primary particles were similar in appearance regardless of the amount of starter bacteria.

[0125] Example 7

[0127] This example demonstrates low temperature electrostatic spray drying of docosahexaenoic acid (DHA) oil powder product from microalgae in one embodiment of the present invention.

[0126]

[0128] DHA emulsions contained 40% (w / w) oil and were formulated to be encapsulated using four different formulations: (i) modified starch, (ii) maltodextrin and casein, (iii) maltodextrin and methylcellulose, and (iv) maltodextrin and saponin (Quillaja). The emulsions were dried using either conventional spray drying (CSD) at an inlet temperature of 120°C, electrostatic spray drying (ESD) at an inlet temperature of 120°C using a negative voltage of 8 kV, or freeze drying (FD).

[0127]

[0129] Table 12 shows the water activity and encapsulation efficiency. All powders had a water activity below 0.52, while the ESD powder had a water activity below 0.23. In addition, the peroxide value of the resulting powders was measured after 2 months of storage in an oven at 40°C using a titration method established by the International Fragrance Association (IFRA) (see, e.g., IFRA Analytical Method, "Determination of the Peroxide Value," September 10, 20219; and Kaya et al., Food Science and Technology, 141, 110872 (2021)).

[0128] [Table 12]

[0129]

[0130] The encapsulation efficiency ranged between 19% and 100%. Formulation influenced the encapsulation efficiency.

[0130]

[0131] Peroxide values ​​ranged from 143 meq O2 / kg oil to 1550 meq O2 / kg oil after 2 months in the dark at 40°C.

[0131]

[0132] FIG. 12 shows SEM images of DHA oil CSD and ESD powders with 40% oil content with different formulations. Primary particles were similar in appearance and of the same size for all formulations. Differences were observed between ESD and CSD powders, with the deflated balloon shape being more evident for ESD than for CSD. Deflated balloons are characterized by lower air inlet and outlet temperatures. This shape may also be due to the fact that the elastic region is reached more quickly during drying (see, e.g., Sadek et al., Food Hydrocolloids, 48, 8-16 (2015)).

[0132] Example 8

[0133] This example compares a powder product for encapsulating oils using an electrostatic spray drying (ESD) system where the charge is applied externally to an embodiment of the present invention where the charge is applied internally.

[0133]

[0134] For oil encapsulation applications, the core material may comprise 5% to 90% by weight of the feed solution and the wall material may comprise 10% to 95% by weight of the feed solution, based on the total dry weight of the core material and wall material combined. The viscosity of the feed solution may be from 1 mPa·s to 10,000 mPa·s, preferably 50 to 250 mPa·s, and the solids content may be between 2% and 75%.

[0134]

[0135] Table 13 shows the formulation of the oil encapsulation feedstock used in this example.

[0135] [Table 13]

[0136]

[0136] Capsul TA is a modified food starch derived from tapioca (Ingredion, Westchester, IL, USA) used as an encapsulating agent instead of maltodextrin. Capsul TA and water were mixed for 12 hours before being added to the oil, and the entire mixture was then homogenized at 3600 RPM for 30 minutes.

[0137]

[0137] Table 14 shows the settings for the Fluid Air PolarDry® System Model 032 Electrostatic Spray Dryer (Spraying Systems, Naperville, Ill., USA) used in this example.

[0138] [Table 14]

[0139] In encapsulating oils using an externally applied charge ESD system, the system parameters are generally similar to those used for ESD systems with internal charging, except that a lower voltage may be applied. For example, a constant charge between 0.1 kV and 0.5 kV or an alternating pulse charge between 0 kV and 5 kV may be used with the nebulizing gas to generate droplets in an inert drying gas. The charge may be positive or negative. The nebulizing gas pressure may be between 0.2 bar and 6 bar. The inlet drying gas temperature may be between 40° C. and 150° C. The inert gas flow rate may be 2 Nm. 3 / hour~20,000Nm 3 / hours.

[0140]

[0139] Table 15 shows the operating parameters of the ESD used in this example.

[0141] [Table 15]

[0142]

[0140] Table 16 shows the size distribution of particles produced in runs 1a (internal charging) and 1b (external charging), as determined using a Malvern Panalytical MasterSizer 3000 instrument equipped with an Aero S or Hydro EV accessory (Spectrisplc, London, UK).

[0143] [Table 16]

[0144] Run 1b resulted in greater particle agglomeration than run 1a at all points along the particle size distribution. Generally, the greater the agglomeration of the powder, the higher the wettability of the powder, due in part to the reduction in surface area caused by the reduction in the proportion of oil at the surface. Wettability (i.e. the ability of a powder particle to absorb water present on its surface) may be measured by any suitable method, such as IDF (1979) ("Determination of the dispersibility and wettability of instant dried milk." IDF Standard No. 87. International Dairy Federation, Brussels) and GEA Niro Method No. A 6 a (revised 2005).

[0145] Table 17 shows the moisture content of the powders produced in Runs 1a and 1b, determined at a temperature of 110° C. using a thermobalance (Sartorius MA37, Sartorius AG, Göttingen, Germany) on 1-2 g sample powder.

[0146] [Table 17]

[0147] For oil encapsulation, the moisture content of the final powder should be below 5%. For run 1a with a 50% solids content feedstock, the maximum feed rate that results in a moisture content below 5% is 56-60 LPH, i.e., 56-60 kg / hr. No significant difference was observed between the moisture content of samples prepared with internal charging and those prepared with external charging, e.g., at a flow rate of 40 LPH, the moisture content of run 1a was 2.8 and that of run 1b was 2.23.

[0148]

[0144] Table 18 shows the surface oil content and oil encapsulation efficiency of powders produced with an ESD spray dryer system having either an internally or externally charged nozzle compared to values ​​for powders produced with a conventional high temperature spray dryer, a Buchi B290 (Buchi, Switzerland).

[0149] [Table 18]

[0150]

[0145] The surface oil content of the samples prepared with the ESD system was substantially the same for both the internally and externally charged nozzles, and both values ​​were greater than those for the comparative Buchi spray dryer. However, the oil encapsulation efficiency was substantially improved in the ESD system of the present invention, and the oil encapsulation efficiency was essentially 100% for the ESD system using the nozzle with the externally applied charge.

[0151] Example 9

[0146] In this example, an encapsulated bacterial powder product prepared using an electrostatic spray drying (ESD) system in which the charge is applied externally is compared to one in which the charge is applied internally, in an embodiment of the invention.

[0152]

[0147] Table 19 shows the formulation of the bacterial encapsulation feedstock used in this example.

[0153] [Table 19]

[0154] In this example, Lactobacillus Rhamnosus (LGG) from CHR Hanssen was used. For the laboratory scale experiments, 1.4 g of LGG was added to a solution of maltodextrin DE19 (20% dry weight) (Glucidex® 19, Roquette). 400 g of the solution was dried at laboratory scale to obtain SD, FD and ESD. At industrial scale, the feed amount was adjusted in terms of the evaporation capacity and expected yield of each technology.

[0155]

[0149] Table 20 shows the settings for the Fluid Air Polar Dry® System Models 001 and 032 electrostatic spray dryers used in this example, where Model 001 is a laboratory scale spray dryer system while Model 032 is a large scale pilot scale system.

[0156] [Table 20]

[0157] Table 21 shows the operating conditions for the Model 001 and 032 electrostatic spray dryers used in this example.

[0158] [Table 21]

[0159]

[0151] Table 22 shows the operating conditions for the Cryotec Pilote bench model (Saint-Gely-du-Fesc, France) freeze dryer used in this example.

[0160] [Table 22]

[0161]

[0152] Table 23 shows the water activity of the dry powders as determined using a Rotronic device.

[0162] [Table 23]

[0163]

[0153] All powders had a water activity below 0.28.

[0164]

[0154] The bacterial powder was analyzed for viable cell content using the following method: 1 g of powder was resuspended in 10 mL of TS buffer, appropriate serial dilutions were made, and 1 mL of each final solution was plated on an MRS agar plate. The cell viability percentage was defined as the ratio between the log(CFU / g) of viable cells before drying and the log(CFU / g) of viable cells after drying. To assess the stability over time, the same measurements were performed at different times over a period of two months.

[0165]

[0155] Figure 13 shows a graph illustrating the relationship between the percentage of viable bacterial cells in the dried powder over time (days) after electrostatic spray drying with an internal negative charging system (Run Model 001), the percentage of viable bacterial cells in the dried powder over time (days) after electrostatic spray drying with an external positive charging system (Run Model 032), and the percentage of viable bacterial cells in the dried powder over time (days) after conventional freeze drying. The results showed that the electrostatic spray-dried powder showed similar stability to the freeze-dried powder and could be more stable after a long time, i.e., after approximately 2 months. Compared to the conditions for spray drying with internal charging in the Model 001 system, the outlet temperature during spray drying with external charging in the Model 032 system was 10°C higher, but the oil-bacteria powder showed similar stability over time.

[0166] Example 10

[0156] This example compares the effects of external application of charge versus internal application of charge and different inlet temperatures on the encapsulation efficiency of a volatile oil (peppermint oil) in an embodiment of the present invention.

[0167]

[0157] Table 24 shows the formulation of the peppermint oil encapsulation feedstock used in this example.

[0168] [Table 24]

[0169]

[0158] Capsul TA was hydrated overnight and then combined with peppermint oil and homogenized for 30 minutes.

[0170]

[0159] Table 25 shows the settings of the Fluid Air PolarDry® Systems Model 032 electrostatic spray dryer (Spraying Systems, Naperville, IL, USA) used in all runs in the examples.

[0171] [Table 25]

[0172]

[0160] Table 26 shows the operating conditions for the Model 032 electrostatic spray dryer used in this example.

[0173] [Table 26]

[0174]

[0161] Table 27 shows the water activity of the dried bacterial powder as determined using the Rotronic device.

[0175] [Table 27]

[0176]

[0162] The water activity of all powders was very low, below 0.094, ensuring the viability of the encapsulated bacteria.

[0177] Table 28 shows the oil encapsulation efficiency of volatile oil powders produced at relatively high (140° C.) and low (90° C.) inlet temperatures on an ESD spray dryer system with either an internally or externally charged nozzle. To determine the encapsulation efficiency, 1 g of powder was added to 9 g of water and the solution was evaporated in an oven at 130° C. for 60 hours. Calculations of the percentage of oil in the powder were performed assuming a moisture content of 5% and were calculated as follows:

number

[0178] [Table 28]

[0164] The data showed that at both low and high inlet temperatures, the encapsulation efficiency of the ESD system with external charging at low voltage (3 V) was the same as the ESD system with internal charging and high voltage (15 V). However, the data also showed that the low inlet temperature (Runs 2 and 4) resulted in a higher encapsulation efficiency than the high inlet temperature (Runs 1 and 3).

[0179]

[0165] The use of the terms "a" and "an" and "the" and "at least one" and similar referents in the context of the present invention (particularly in the context of the claims below) should be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term "at least one" followed by a list of one or more items (e.g., "at least one of A and B") should be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" should be construed as open-ended terms (i.e., meaning "including, but not limited to"), unless otherwise noted. The recitation of ranges of values ​​herein is intended merely to serve as a shorthand method of individually referring to each individual value falling within the range, unless otherwise indicated herein, and each individual value is to be incorporated herein as if it were individually recited herein. All methods described herein may be performed in any suitable order, unless otherwise indicated herein or otherwise clearly contradicted by context. Any and all examples provided herein, or the use of exemplary language (e.g., "for example"), are intended merely to better illuminate the invention, and do not limit the scope of the invention unless otherwise claimed. No language in this specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0180]

[0166] Preferred embodiments of the present invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of these preferred embodiments will become apparent to those skilled in the art upon reading the foregoing description. The inventors expect that those skilled in the art will employ such variations at their option, and the inventors intend for the invention to be carried out otherwise than as specifically described herein. Accordingly, the present invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all these possible variations is encompassed by the present invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

1. A method for producing an active compound powder, comprising the step of electrostatically spray-drying a formulation containing at least one active compound and an encapsulating agent at an inlet temperature of 150°C or less and an outlet temperature of 100°C or less, wherein an electric charge is externally applied to droplets of the liquid raw material of the active compound formulation.

2. The method according to claim 1, wherein the electrostatic spray drying is performed at a spray temperature of 100°C or lower.

3. The method according to claim 1, wherein the charge is applied by a voltage of 0.1 kV or more.

4. The method according to claim 1, wherein the charge is applied by a continuous voltage.

5. The method according to claim 1, wherein the charge is applied by a voltage modulated between two or more different voltages.

6. The method according to claim 1, wherein the electrostatic spray drying further comprises an excipient.

7. The method according to claim 1, wherein the encapsulating agent is a carbohydrate, a lipid, a protein, ascorbic acid, or a combination thereof.

8. The method according to claim 7, wherein the carbohydrate is maltodextrin, sucrose, dextrose, glucose, lactose, trehalose, amylase, cyclodextrin, dextrin, galactomannan, pectin, starch, processed food starch, inulin, gum arabic, guar gum, gellan gum, mesquite gum, xanthan gum, alginic acid, chitosan, shellac, carboxymethylcellulose, or a combination thereof.

9. The method according to claim 7, wherein the lipid is a fatty acid or an ester thereof, a fatty alcohol or an ester thereof, a triglyceride, a phospholipid, a glycolipid, an aminolipid, a lipopeptide, a partial acylglycerol, or a combination thereof.

10. The method according to claim 7, wherein the protein is casein, caseinate, gelatin, casein, soy protein, wheat protein, whey protein, rice protein, pea protein, cocoa shell protein, or a combination thereof.

11. The method according to claim 1, wherein the at least one active compound is an antioxidant, a vitamin, a bacterium, an omega oil, an essential oil, a flavoring agent, a pigment, a dye, or a combination thereof.

12. The method according to claim 1, wherein if the active compound is an oil, the optional excipient is an emulsifier, and if the active compound is not an oil, the optional excipient is an oil.

13. The method according to any one of claims 1 to 12, wherein the two or more different voltages include a positive voltage and a negative voltage.

14. A method for producing an oil emulsion powder, comprising the step of electrostatically spray-drying an emulsion containing at least one oil and an encapsulating agent, and optionally an emulsifier, at an inlet temperature of 150°C or less and an outlet temperature of 100°C or less, wherein an electric charge is externally applied to droplets of the supply raw material liquid of the oil emulsion.

15. The method according to claim 14, wherein the electrostatic spray drying is performed at a spray temperature of 100°C or lower.

16. The method according to claim 14, wherein the charge is applied by a voltage of 0.1 kV or more.

17. The method according to claim 14, wherein the charge is applied by a continuous voltage.

18. The method according to claim 14, wherein the encapsulating agent is a carbohydrate, a lipid, a protein, ascorbic acid, or a combination thereof.

19. The method according to claim 14, wherein the oil emulsion powder further comprises an emulsifier.

20. The method according to claim 14, wherein the oil emulsion powder has a lower amount of surface free fat compared to a spray-dried oil emulsion powder.

21. The method according to claim 14, wherein the encapsulation efficiency of the oil emulsion powder is 50% or more.

22. The method according to claim 21, wherein the oil content is in the range of 1 to 60% and the encapsulation efficiency is in the range of 90 to 99%.

23. The method according to claim 21, wherein the oil content is in the range of 61 to 90% and the encapsulation efficiency is in the range of 55 to 90%.

24. The method according to claim 14, wherein at least one of the oils is of plant or animal origin.

25. The above at least one type of oil is vegetable oil, vegetable shortening, castor oil, rice bran oil, olive oil, canola oil, corn oil, palm oil, coconut oil, flaxseed oil, hemp seed oil, rapeseed oil, linseed oil, grapeseed oil, rosehip seed oil, pomegranate seed oil, watermelon seed oil, sea buckthorn berry oil, camellia seed oil (tea oil), cranberry seed oil, hemp seed oil, borage seed oil, evening primrose oil, argan oil, joho The method according to claim 24, wherein the oil is barley oil, marula oil, carrot oil, sesame seed oil, sunflower oil, shea nut oil, soybean oil, peanut oil, walnut oil, almond oil, hazelnut oil, kukui nut oil, pecan oil, macadamia nut oil, meadowfoam oil, avocado oil, apricot kernel oil, essential oils, silicone oil, fish oil, cocoa butter, shea butter, butter, ghee, medium-chain triglycerides (MCT), or any combination thereof.

26. The method according to claim 14, wherein the emulsion contains an emulsifier.

27. The method according to claim 26, wherein the emulsifier is at least one selected from casein, caseinate, lecithin, saponin, carrageenan, gum arabic, xanthan gum, whey protein isolate, stearate, glyceryl monostearate, sucrose ester, monopropylene glycol, propylene glycol ester of fatty acids, polyglycerol ester of fatty acids, mono and diglycerol, mono and diglycerides of fatty acids, distilled monoglycerides, polyglycerol polyricinolate, polysorbate 80, sorbitan ester, lactyl ester, ethoxylated ester, succinyl ester, fruit acid ester, carboxymethylcellulose, and combinations thereof.

28. The method according to claim 14, wherein the emulsion further comprises at least one active compound.

29. The method according to any one of claims 14 to 28, wherein the two or more different voltages include a positive voltage and a negative voltage.

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