Electrostatic spray-dried oil powder and its manufacturing method

Abstract

A method for producing an oil emulsion powder is provided, 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.

Description

2. Background of the Invention

[0001] Encapsulated oil 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)).

[0002] Oil powders are typically produced using spray drying systems. However, such systems require high inlet and outlet temperatures that may put the oil 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 oil powders that are storage stable, have improved loading capacity, and / or have improved encapsulation efficiency. Summary of the Invention

[0003] The present invention 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. [Brief description of the drawings]

[0004] [Figure 1] FIG. 1 is a vertical cross-sectional view of a schematic spray-drying system for processing an oil-containing emulsion into powder form according to one 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. [Diagram 3]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 4AB] 4A and 4B show SEM images at 5,000x magnification of 50% and 80% (w / w) ESD powders with either coconut oil and medium chain triglycerides (MCT) from coconut (FIG. 4A) or flaxseed oil and olive oil (FIG. 4B). [Diagram 5] FIG. 1 shows SEM images at 5,000x magnification of oil encapsulated powders containing 50% and 80% (w / w) fish oil and ghee. [Figure 6] FIG. 1 shows SEM images at 5,000x magnification of oil-encapsulated powders containing either 50% (w / w) orange oil or mint oil. [Figure 7] 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 8] FIG. 1 shows an SEM image of encapsulated oil-bacteria powder at 10,000x magnification. [Figure 9] 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.

[0005] 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. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0006] The present invention is based, at least in part, on the surprising discovery that oil 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 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. The oil powder produced has at least one advantage over the corresponding oil powder produced by spray drying, e.g., high storage stability, improved loading capacity, and / or improved encapsulation efficiency, compared to an equivalent oil powder prepared using spray drying.

[0007] In the present method, the inlet temperature is any suitable temperature that provides an oil 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.

[0008] In this method, the outlet temperature is any suitable temperature that provides the oil 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.

[0009] The spray 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).

[0010] 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.

[0011] 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 and / or cohesion properties of the particles. 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, typically negative electrostatic charges are applied in electrostatic spray drying processes. In some embodiments, alternating charges of the applied voltage are used when preparing oil powders.

[0012] 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.

[0013] 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.

[0014] The encapsulating agent is any agent capable of encapsulating oil. In a preferred embodiment of the present invention, the encapsulating agent is a carbohydrate, a lipid, a protein, ascorbic acid, or a combination thereof.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] In an embodiment of the method, the emulsion can further include at least one additive that is part of the oil powder product. One additive or more than one additive (e.g., 2, 3, 4, 5, etc.) can be used. Typical additives include, for example, antioxidants, vitamins, bacteria, omega oils, essential oils, flavors, pigments, dyes, and combinations thereof.

[0020] Antioxidants can be used to inhibit oxidation and help stabilize oil.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).

[0021] Examples of vitamins include vitamins A, B, C, D, E, and K, including their respective vitamers.

[0022] 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.

[0023] 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.

[0024] The essential oils as additives are as described herein.

[0025] 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.

[0026] 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.

[0027] In an embodiment of the present invention, the oil emulsion powder produced by the present method has a lower amount of surface free fat 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).

[0028] 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%).

[0029] In embodiments of the invention, the encapsulation efficiency of the oil emulsion 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).

[0030] 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%.

[0031] The moisture content of the oil powder product is low, typically about 5% or less (e.g., 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), preferably in combination with low water activity (e.g., 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). In an embodiment of the method, the moisture content of the oil powder product is about 4% or less or about 3% or less.

[0032] Referring more clearly to the drawings, Figure 1 is a schematic spray-drying system 10 for processing an oil-containing emulsion 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.

[0033] 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.

[0034] 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.

[0035] The spray nozzle assembly 16, best shown 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 quickly and efficiently drying the oil-containing emulsion 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 couple to a supply line 37 which is in communication with a supply of oil powder product to be spray dried.

[0036] 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. aand is axially supported within head 31 and in adjacent electrical contacting relationship to an electrode 48 extending downstream of liquid inlet passage 36.

[0037] 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.

[0038] 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.

[0039] As will become apparent, the electrostatic spray drying system 10 is operable to dry oil powders into fine particles having improved properties over the prior art.

[0040] As used herein, the term "about" typically refers to ±1% of the value, ±5% of the value, or ±10% of the value.

[0041] The present invention is further characterized by the following features.

[0042] (1) 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.

[0043] (2) The method according to feature 1, wherein the spray temperature is about 100° C. or less.

[0044] (3) The method according to any one of the preceding claims, wherein the applied voltage is about 0.1 kV or more.

[0045] (4) The method according to any one of features 1 to 3, wherein the applied voltage is continuous.

[0046] (5) The method according to any one of features 1 to 4, wherein the applied voltage is modulated between two or more different voltages.

[0047] (6) The method according to any one of features 1 to 4, wherein the applied voltage alternates between charges.

[0048] (7) The method according to any one of Features 1 to 6, wherein the oil emulsion powder has a reduced amount of surface free fat compared to a spray-dried powder of the same oil emulsion.

[0049] (8) The method according to any one of features 1 to 7, wherein the encapsulation efficiency of the oil emulsion powder is 50% or more.

[0050] (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%.

[0051] (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%.

[0052] (11) The method according to any one of features 1 to 10, wherein at least one oil is of plant or animal origin.

[0053] (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.

[0054] (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.

[0055] 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.

[0056] (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.

[0057] (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.

[0058] (17) The method according to any one of features 1 to 16, wherein the emulsion comprises an emulsifier.

[0059] (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.

[0060] (19) The method according to any one of features 1 to 18, wherein the emulsion further comprises at least one additive.

[0061] 20. The method of claim 19, wherein the at least one additive is an antioxidant, a vitamin, a bacteria, an omega oil, an essential oil, a flavoring, a pigment, a dye, or a combination thereof.

[0062] The following examples further illustrate the invention but, of course, should not be construed as in any way limiting its scope. Example 1

[0063] This example demonstrates low temperature electrostatic spray drying of an oil powder product in one embodiment of the present invention.

[0064] 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.

[0065] [Table 1] Example 2

[0066] This example demonstrates low temperature electrostatic spray drying of a vegetable oil powder product in one embodiment of the present invention.

[0067] 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 in all powders.

[0068] [Table 2]

[0069] 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)).

[0070] 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.

[0071] 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).

[0072] 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%).

[0073] Peroxide values ​​were low in all powders (below 1.8 meqO2 / kg oil).

[0074] [Table 3]

[0075] Figure 3 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. Example 3

[0076] This example demonstrates low temperature electrostatic spray drying of a vegetable based oil powder product in one embodiment of the present invention.

[0077] 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.

[0078] 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.

[0079] [Table 4]

[0080] Table 5 shows the oil loading, surface free fat, encapsulation efficiency and peroxide value for coconut, MCT, flaxseed and olive oil powders. At 50% oil loading the surface free fat was approximately 1-1.2%, which increased to 16-20% at 80% oil loading for all powders. The encapsulation efficiency was over 97% at 50% oil loading and 74-79% for powders containing 80% oil.

[0081] The peroxide value in coconut oil powder was the lowest regardless of oil loading (0.05-0.15 meq O2 / kg oil) likely 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).

[0082] [Table 5]

[0083] Figures 4A and 4B show SEM images of different oil powders with 50% and 80% oil content. Figure 4A 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. Example 4

[0084] This example demonstrates low temperature electrostatic spray drying of an animal-based oil powder product in one embodiment of the present invention.

[0085] 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.

[0086] 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.

[0087] [Table 6]

[0088] 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.

[0089] Peroxide values ​​in ghee powder were the lowest irrespective of oil loading (0.14-0.31 meq O2 / kg oil) likely due to the high content of saturated fats (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).

[0090] [Table 7]

[0091] Figure 5 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 the primary particles in the 80% oil powder showing a clear spherical appearance. Example 5

[0092] This example demonstrates low temperature electrostatic spray drying of an essential oil powder product in one embodiment of the present invention.

[0093] 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.

[0094] The water activity of the resulting powders is shown in Table 8. All powders had a water activity between 0.1 and 0.23.

[0095] [Table 8]

[0096] Figure 6 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. Example 6

[0097] This example demonstrates low temperature electrostatic spray drying of an encapsulated oil-bacteria powder product in one embodiment of the present invention.

[0098] 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.

[0099] 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.

[0100] [Table 9]

[0101] 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).

[0102] 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).

[0103] [Table 10]

[0104] 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 10 6 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.

[0105] [Table 11]

[0106] Figure 7 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).

[0107] SEM images of the encapsulated oil-bacteria powders are shown in Figure 8. The primary particles were similar in appearance regardless of the amount of starter bacteria. Example 7

[0108] This example demonstrates low temperature electrostatic spray drying of docosahexaenoic acid (DHA) oil powder product from microalgae in one embodiment of the present invention.

[0109] 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 with a negative voltage of 8 kV, or freeze drying (FD).

[0110] 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)).

[0111] [Table 12]

[0112] The encapsulation efficiency ranged between 19% and 100%. Formulation influenced the encapsulation efficiency.

[0113] Peroxide values ​​ranged from 143 meq O2 / kg oil to 1550 meq O2 / kg oil after 2 months in the dark at 40°C.

[0114] FIG. 9 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 an elastic form is reached more quickly during drying (see, e.g., Sadek et al., Food Hydrocolloids, 48, 8-16 (2015)).

[0115] 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.

[0116] 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 such possible variations is encompassed by the present invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

1. 1. 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.

2. The method of claim 1 , wherein the spray temperature is about 100° C. or less.

3. 3. The method of claim 1 or 2, wherein the applied voltage is about 0.1 kV or more.

4. The method of any one of claims 1 to 3, wherein the applied voltage is continuous.

5. A method according to any one of claims 1 to 4, wherein the applied voltage is modulated between two or more different voltages.

6. The method of any one of claims 1 to 4, wherein the applied voltage alternates between charges.

7. 7. The method of any one of claims 1 to 6, wherein the oil emulsion powder has a reduced amount of surface free fat compared to a spray-dried powder of the same oil emulsion.

8. The method according to any one of claims 1 to 7, wherein the encapsulation efficiency of the oil emulsion powder is 50% or more.

9. 9. The method of claim 8, wherein the oil content is in the range of 1-60% and the encapsulation efficiency is in the range of 90-99%.

10. 9. The method of claim 8, wherein the oil content is in the range of 61-90% and the encapsulation efficiency is in the range of 55-90%.

11. The method according to any one of claims 1 to 10, wherein the at least one oil is of vegetable or animal origin.

12. The at least one oil may be 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 jojoba seed oil.

12. The method of claim 11, wherein the oil is selected from the group consisting of behenyl alcohol, glyceryl stearate, sorbitol, sorbitol glycol, sorbitol glycol esters ...

13. The method of any one of claims 1 to 12, wherein the encapsulating agent is a carbohydrate, a lipid, a protein, ascorbic acid, or a combination thereof.

14. 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.

15. 15. The method of claim 13 or 14, wherein the lipid is 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.

16. 16. The method of any one of claims 13 to 15, 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.

17. The method of any one of claims 1 to 16, wherein the emulsion comprises an emulsifier.

18. 18. The method of claim 17, wherein the emulsifier is at least one selected from casein, caseinate, lecithin, saponin, carrageenan, gum arabic, xanthan, whey protein isolate, stearates, glyceryl monostearate, sucrose esters, monopropylene glycol, propylene glycol esters of fatty acids, polyglycerol esters of fatty acids, mono- and diglycerol, 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.

19. The method of any one of claims 1 to 18, wherein the emulsion further comprises at least one additive.

20. 20. The method of claim 19, wherein the at least one additive is an antioxidant, a vitamin, a bacteria, an omega oil, an essential oil, a flavoring, a pigment, a dye, or a combination thereof.

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