ENCAPSULATION OF OXIDATIVELY UNSTABLE COMPOUNDS
An encapsulated material containing an oxidation-sensitive core is covered by at least a dried synthetic organelle layer and optional additional ingredients in the organelle layer or additional layers. By using microencapsulation to mimic or otherwise adapt the storage concepts used by seeds to protect triacylglycerol cores, oxidatively unstable materials may be provided with a synthetic, seed-like oxygen-resistant protective barrier and rendered less susceptible to oxidative degradation.
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This application claims priority from U.S. Provisional patent application Ser. No. 61/010,073 filed Jan. 4, 2008.
FIELDThis invention relates to encapsulation of materials that are sensitive to oxidation.
BACKGROUNDIn the past thirty years much new information on the benefits of a healthy diet has emerged. In addition to the traditional food pyramid, vitamins and minerals, a healthy diet may include components such as soluble and insoluble fiber for promoting gastrointestinal health, phytosterols for lowering cholesterol levels and promoting heart health, antioxidants for discouraging cancer and other inflammatory diseases, and omega-3 and omega-6 polyunsaturated fatty acids (PUFAs) for promoting heart and brain health. There has been considerable commercial interest in providing deliverable forms of such components even though in many cases the component may be oxidatively unstable. For example, companies which have introduced or announced PUFA-containing products or materials include BASF SE, Blue Pacific Flavors, GAT Food Essentials GmbH, Kerry Group PLC, Martek Biosciences Corp. and Ocean Nutrition Canada. Some of these products or materials are said to employ prilling, spray drying or encapsulation to limit premature PUFA oxidation.
The ability to store refined or extracted triacylglycerols (TAGs), antioxidants or natural colors such as anthocyanins in a dried powder faun is one of the biggest challenges for food processors, see e.g., Lawson, Harry, Food Oils and Fats, Technology, Utilization, and Nutrition, New York; Chapman & Hall, pp 18-22 (1995) and Gunstone, Frank D. and Padley, Fred B., Lipid Technologies and Applications, New York; Marcel Dekker, Inc., pp 169-199 (1997).
There is at present an ongoing and unmet need for improved methods and systems for packaging, storing or delivering phytosterols, PUFAs, TAGs, antioxidants, natural colors and other oxidatively unstable materials.
SUMMARY OF THE INVENTIONAlthough a variety of commercial attempts have been made to store oxidatively unstable materials, nature has already solved the problem in oil seeds. TAGs inside seeds may remain stable for years without loss of function or oxidation. By using microencapsulation to mimic or otherwise adapt the storage concepts used by seeds to protect oxidatively unstable cores, oxidatively unstable materials may be provided with a synthetic, seed-like oxygen-resistant protective barrier and rendered less susceptible to oxidative degradation. An oxidation-susceptible material (in the form, for example of a core per se or an already-encapsulated core) may be encapsulated or further encapsulated in at least a dried synthetic organelle layer to form a pseudo “oil-seed” capsule. This pseudo oil-seed capsule may be provided with additional functional or protective ingredients or shell layers to form a complex multi-component or multi-layered protective system for oxidation-sensitive cores. One such additional layer may be an oxidation barrier layer containing a “pseudo-peri-carp” or PPC layer made using a fiber-, carbohydrate- or protein-containing film-forming material. Another such additional layer may be a hydrocolloid or HC layer made using a natural or chemically-modified hydrocolloid material, e.g., an alginate.
The resulting microcapsules include an oxidatively unstable core and dried synthetic organelle shell (which may be described as an Oil Body Shell or OBS). The microcapsules may be further modified, e.g., by adding the materials for a PPC layer or HC layer (as components of the OBS or as separate layers), antioxidants, chelating agents, deodorized oils or other dissolved, suspended or dispersed ingredients to one or more of the core or shell layer(s) to provide unique structures for stable oil or powder delivery in pharmaceutical, dietary, cosmetic, agricultural and other commercial uses. The disclosed encapsulated materials and methods are especially useful for imparting improved oxidation protection to difficult to protect core materials such as unsaturated and polyunsaturated oils and acids.
The present invention accordingly provides, in one aspect, an encapsulated material comprising an oxidation-sensitive core covered by at least one shell comprising a dried synthetic organelle layer. The invention provides, in another aspect, a method for protecting an oxidatively unstable material, which method comprises providing or forming a particle or droplet of the oxidatively unstable material and forming a dried synthetic organelle layer surrounding the particle or droplet.
The disclosed encapsulated materials and methods may artificially mimic the natural method of oil storage in oil seeds to provide processed oils and other oxidatively unstable materials with enhanced oxidative stability and in an effectively dry powder faun.
Unless the context indicates otherwise the following terms shall have the following meaning and shall be applicable to the singular and plural:
The terms “a,” “an,” “the,” “at least one,” and “one or more” are used interchangeably. Thus a microcapsule that contains “a” shell may include “one or more” shells.
The term “deliverable” when used with respect to an encapsulated substance means that the substance is at least partially surrounded by an additional substance that imparts one or more altered properties to the encapsulated substance, e.g., altered transport, altered flowability, altered resistance to oxidation or moisture, altered abrasion resistance, or altered performance in a commercial application (e.g., a food application).
The term “dried” does not necessarily refer to a process of manufacture, but rather to the available water content in an article or component (e.g., a layer) thereof. The term “available water” does not include water of hydration.
The terms “encapsulated material” and “microcapsule” mean particles (often but not always spherical in shape, and often but not always having a diameter of about 10 nanometers to about 5 mm) which contain at least one liquid, gel or solid core surrounded by at least one continuous membrane or shell.
The term “ingestible” means capable of and safe for oral administration.
The term “microsphere” means a microcapsule material whose particles contain two or more cores distributed in and surrounded by at least one continuous membrane or shell.
The term “particulate” means a finely divided dry powder material.
The terms “preferred” and “preferably” refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the invention.
The term “synthetic” when used with respect to an organelle layer means that the layer is not part of a naturally encapsulated object such as a seed, but is instead part of a manufactured encapsulated object made by combining a core and the organelle layer. The organelle layer in such an encapsulated object may be formed by combining one or more oleosins and one or more phospholipids, or may be formed from extracted or otherwise isolated organelle layers obtained from seeds or other naturally encapsulated objects.
The recitation of a numerical range using endpoints includes all numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.). The recitation of sets of upper and lower endpoints (e.g., at least 1, at least 2, at least 3, and less than 10, less than 5 and less than 4) includes all ranges that may be formed from such endpoints (e.g., 1 to 10, 1 to 5, 2 to 10, 2 to 5, etc.).
The pericarp or seed coat 102 as shown in
By using microencapsulation to mimic or otherwise adapt storage concepts used by seeds to protect TAG cores, oxidatively unstable materials may be provided with a synthetic, seed-like oxygen-resistant protective barrier and rendered less susceptible to oxidative degradation. One additional factor may be considered when forming synthetic or artificial TAG encapsulation systems. Various TAGs of interest for encapsulation may not previously have been handled in a manner consistent with the TAGs in seeds. For example, prooxidants such as metals (e.g., iron and copper), TAG oxidation products (e.g., ketones, peroxides and aldehydes), oxidase enzymes, and dissolved oxygen may all affect extracted or otherwise isolated TAGs. In vivo TAGs in oil seed bodies are shielded or otherwise protected from or completely shielded from the above prooxidants, but upon extraction from oil seeds, algae, or fish the TAGs may be completely exposed to oxidase enzymes (e.g., lipase) from other parts of the plant or to dissolved metal ions from extraction and processing steps. Producing a new microcapsule that mimics a seed and organelle will be furthered improved if these issues are addressed as well.
The disclosed encapsulated materials include at least an oxidation sensitive core and at least one shell layer containing a dried synthetic organelle layer over the core. Preferably the organelle layer is immediately adjacent the core layer, but intermediate or additional shells may surround the core, the organelle layer, or both the core and organelle layer. For example, the above-mentioned HC layer may facilitate upper gastrointestinal (UGI) tract bypass when the disclosed encapsulated materials are orally administered to mammalian subjects. A particularly useful layer, especially over the organelle layer, is the above-mentioned PPC layer. A PPC layer is intended to mimic the functionality of the pericarp layer in a natural seed with respect to providing oxidation reduction or other protection for the core. Exemplary PPC layers may be formed from at least one of dietary fiber (e.g., food grade fiber), a simple carbohydrate (e.g., a monosaccharide or disaccharide such as a sugar), or a protein, and may also include at least one antioxidant. PPC layers containing one or more of fiber, carbohydrate and protein may also be referred to as fiber/carbohydrate/protein layers or FCP layers, with the “/” symbol signifying that any of fiber, carbohydrate and protein or combinations thereof may be present in the FCP shell (FCPS). If the encapsulated material is not required to be ingestible, then the outer and if desired inner layers may be ingestible or not as desired, whereas for ingestible encapsulated materials at least the outermost layer is ingestible.
The various additional layer ingredients discussed above may also or instead be incorporated into the organelle layer. In some embodiments ingredients capable of forming one and optionally several layers are combined into the continuous phase of an emulsion containing droplets or particles of the core material. The emulsion may be processed (e.g., spray dried) to convert the emulsion into microcapsules having at least one dried shell layer. The various additional layer ingredients may arrange themselves into separate layers around the core droplets or particles (for example due to reasons such as stereochemistry, surface energy, oleophilicity, oleophobicity, hydrophilicity or hydrophobicity), or may form a matrix of ingredients from the continuous phase in a single shell layer surrounding the core droplets or particles.
The resulting encapsulated materials have a locked-in protective structure in the form of one or more shell layers surrounding an oxidatively-sensitive core, and may provide better protection against oxidation than that provided by the undried emulsion. The encapsulated materials may also employ a multi-tiered defensive approach involving oxygen barriers, lipophilic antioxidants and hydrophilic antioxidants.
A variety of core substances may be used in the disclosed encapsulated materials. Exemplary oxidation-sensitive core substances include liquid or solid materials, e.g., acidulants, animal products, antioxidants, carotenoids, catalysts, drugs, dyes, enzymes, flavors, fragrances, lutein, lycopene, metal complexes, natural colors, nutraceuticals, pigments, polyphenolics, processed plant materials, metabiotics, probiotics, proteins, PUFAs, squalenes, sterols including phytosterols, tocopherol, tocotrienol, TAGs, vitamins, unsaturated organic compounds (e.g., unsaturated rubbers and unsaturated oils) and mixtures thereof. Antioxidants, PUFAs, sterols and TAGS are of particular interest. Antioxidants may, for example, suppress, reduce, intercept, or eliminate destructive radicals or chemical species that promote the formation of destructive radicals which would otherwise lead to more rapid oxidative degradation of the encapsulated material or components thereof. Exemplary antioxidants include menaquinone (vitamin K2), plastoquinone, phylloquinone (vitamin K1), retinol (vitamin A), tocopherols (e.g., α, β, γ and δ-tocotrienols, ubiquinol, and ubiquione (Coenzyme Q10)); and cyclic or polycyclic compounds including acetophenones, anthroquinones, benzoquiones, biflavonoids, catechol melanins, chromones, condensed tannins, coumarins, flavonoids, hydrolyzable tannins, hydroxycinnamic acids, hydroxybenzyl compounds, isoflavonoids, lignans, naphthoquinones, neolignans, phenolic acids, phenols (including bisphenols and other sterically hindered phenols, aminophenols and thiobisphenols), phenylacetic acids, phenylpropenes, stilbenes and xanthones. Additional cyclic or polycyclic antioxidant compounds include apigenin, auresin, aureusidin, Biochanin A, capsaicin, catechin, coniferyl alcohol, coniferyl aldehyde, cyanidin, daidzein, daphnetin, delphinidin, emodin, epicatechin, eriodicytol, esculetin, ferulic acid, formononetin, gernistein, gingerol, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 3-hydroxycoumarin, juglone, kaemferol, lunularic acid, luteolin, malvidin, mangiferin, 4-methylumbelliferone, mycertin, naringenin, pelargonidin, peonidin, petunidin, phloretin, p-hydroxyacetophenone, (+)-pinoresinol, procyanidin B-2, quercetin, resorcinol, rosmaric acid, salicylic acid, scopolein, sinapic acid, sinapoyl-(S)-maleate, sinapyl aldehyde, syrginyl alcohol, telligrandin II, umbelliferone and vanillin. Antioxidants may also be obtained from plant extracts, e.g., from blackberries, blueberries, black carrots, chokecherries, cranberries, black currants, elderberries, red grapes and their juice, hibiscus, oregano, purple sweet potato, red wine, rosemary, strawberries, tea (e.g., black, green or white tea), and from various plant ingredients as ellagic acid. Additional exemplary antioxidants include carotenoids including hydrocarbons such as hexahydrolycopene, lycopersene, phtyofluene, torulene and α-zeacarotene; alcohols such as alloxanthin, cynthiaxanthin, cryptomonaxanthin, crustaxanthin, gazaniaxanthin, loroxanthin, lycoxanthin, pectenoxanthin, rhodopin, rhodopinol and saproxanthin; glycosides such as oscillaxanthin and phleixanthophyll; ethers such as rhodovibrin and spheroidene; epoxides such as citroxanthin, diadinoxanthin, foliachrome, luteoxanthin, mutatoxanthin, neochrome, trollichrome, vaucheriaxanthin and zeaxanthin; aldehydes such as rhodopinal, torularhodinaldehyde and wamingone; ketones such as canthaxanthin, capsanthin, capsorubin, cryptocapsin, flexixanthin, hydroxyspheriodenone, okenone, pectenolone, phoeniconone, phoenicopterone, phoenicoxanthin, rubixanthone and siphonaxanthin; esters such as astacein, fucoxanthin, isofucoxanthin, physalien, siphonein and zeaxanthin dipalmitate; apo carotenoids such as β-apo-2′-cartoenal, apo-2-lycopenal, apo-6′-lycopenal, azafrinaldehyde, bixin, citranaxanthin, crocetin, crocetinsemialdehyde, crocin, hopkinsiaxanthin, methyl apo-6′-lycopenoate, paracentrone and sintaxanthin; nor and seco carotenoids such as actinioerythrin, β-carotene, peridinin, pyrrhoxanthininol, semi-α-carotenone, semi-β-carotenone and triphasiaxanthin; retro and retro apo carotenoids such as eschscholtzxanthin, eschscholtzxanthone, rhodoxanthin and tangeraxanthin; higher carotenoids such as decaprenoxanthin and nonaprenoxanthin; secondary aromatic amines; alkyl and arylthioethers; phosphates and phosphonites; zinc-thiocarbamates; benzofuranone lactone-based antioxidants; nickel quenchers; metal deactivators or complexing agents; and the like. Commercially available antioxidants include butylated hydroxyanisole (BHA), 2,6-di-t-butyl cresol (BHT), 2,2′-methylene bis(6-t-butyl-4-methyl phenol) (available as VULKANOX™ BKF from Bayer Inc., Canada), 2,2′-thio bis(6-t-butyl-4-methyl phenol), tert-butyl hydroquinone, di-tert-butyl hydroquinone, di-tert-amyl hydroquinone, methyl hydroquinone, p-methoxy phenol, tetrakis[methylene-3-(3′,5′-di-tert-butyl-4′-hydroxyphenyl)propionate]methane, N-(2-aminoethyl)-3-[3,5-bis(tert-butyl)-4-hydroxyphenyl]propanamide, 5,7-di-tert-butyl-3-(3,4,-dimethylphenyl)-3H-benzofuran-2-one, dilauryl thiodipropionate, dimyristyl thiodipropionate, tris(nonylphenyl) phosphite, and the like, and mixtures thereof. The antioxidants 2,2′-methylene bis(6-t-butyl-4-methyl phenol) and N-(2-aminoethyl)-3-[3,5-bis(tert-butyl)-4-hydroxyphenyl]propanamide may be preferred for some applications, with the latter antioxidant being especially desirable because it includes a reactive amino group which may enable covalent incorporation into a suitably reactive core or shell.
Exemplary PUFAs include those found in fish and various grain products, e.g., fish oil, halibut, herring, mackerel, menhaden, salmon, algae, chia, flaxseed and soybeans.
Exemplary sterols include cholesterol, phytosterols (e.g. campesterol, stigasterol, β-sitosterol, Δ5-avenosterol, Δ7-stigasterol, Δ7-avenosterol and brassicasterol), steroidal hormones such as testosterone, vitamins such as D vitamins, eicosanoids (e.g., hydroxyeicostetraones, prostacyclins, prostaglandins and thromboxanes, leukotrienes; lipoxins, resolvins, isoprostanes and jasmonates. Exemplary TAGs include those found in algae oil, almond oil, beef tallow, butterfat, canola oil, chia oil, cocoa butter, coconut oil, cod liver oil, corn oil, cottonseed oil, flaxseed oil, grape seed oil, lard, olive oil, palm oil, peanut oil, safflower oil, sesame oil, soybean oil, sunflower oil, and walnut oil.
The core may include additional ingredients having limited or no susceptibility to oxidation, e.g., caveolins, phospholipids, micelle stabilizers, and mixtures thereof. Exemplary phospholipids include those discussed below. Exemplary micelle stabilizers (some of which are phospholipids, discussed below) include cardolipin, digalactosyldiacylglycerols, monogalactosyldiacylglycerols, phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol and sphingolipids and mixtures thereof. For core materials that normally are liquids at room temperature (25° C.), it will be desirable in some embodiments to gel the core. For example, core materials based on oils may be gelled as described in U.S. Pat. No. 6,858,666 B2 wherein an oxidation-sensitive oil or composition is heated in the presence of a suitable gelation agent to melt and dissolve the gelation agent in the continuous oil phase. The resultant solution may then be atomized and cooled to form particles. Exemplary gelled core particles may for example have particle diameters from about 0.1 to about 5,000 micrometers. The amount of gelation agent(s) may for example range from about 1 to about 90 wt. % of the core weight. Other additives including various salts, soluble or insoluble fibers, or additional oils may be added to the mixture. Additional exemplary gelled core particles based on PUFAs may be formed by combining a PUFA with a sterol, e.g., to form triglyceride-recrystallized phytosterols as in U.S. Pat. Nos. 6,638,547 B2 and 7,144,595 B2. Some antioxidants, e.g., Vitamin E, may also help convert a liquid core material to a gel.
The core may for example represent at least about 5 wt. %, at least about 20 wt. % or at least about 30 wt. % of the disclosed encapsulated materials. Desirably the core is greater than 30 wt. % of the encapsulated material, e.g., at least about 40 wt. % or at least about 50 wt. %.
The disclosed dried synthetic organelle layer includes at least oleosin and phospholipid, and may comprise, consist of or consist essentially of oleosin and phospholipid. Either or both of the oleosin and phospholipid may be chemically modified. Oleosins may conveniently be obtained from high oil content plant parts. For example, oleosins have been found on oil bodies of seeds, tapetum cells, and pollen but not fruits. In pollen, oleosins are thought to be involved in water-uptake by pollen on stigma. Oleosins may help to pin the phospholipid in place within the organelle shell, and may make the organelle sufficiently robust to permit the organelle to be isolated using techniques such as extraction centrifugation, pressing, and the like. Oleosins may also contribute to one or more properties such as oxidation stability (viz., limiting oxygen diffusion into the core), structural stability (viz., keeping the core inside the shell), or steric stability (viz., increasing the shell strength). Oleoresins may conveniently be obtained via extraction techniques such as those described in Tzen, J. T. C. and Huang, A. H. C., Surface Structure and Properties of Plant Seed Oil Bodies, J. Cell Bio, 117; 327-335 (1992); Millichip, M., Tatham, A. S., Jackson, F., Griffiths, G., Shewry, P. R., and Stobart, A. K., Purification and Characterization of Oil-Bodies (oleosomes) and Oil-Body Boundary Proteins (oleosins) for the Developing Cotyledons of Sunflower (Helianthus annus L.), Biochem. J., 314; 333-337 (1996); Huang, A. H. C., Oleosins and Oil Bodies in Seed and Other Organs, Plant Physiol., 110; 1055-1061 (1996); and Ting, J. T. L., Balsamo, R. A., Ratnayake, C., Huang, A. H. C., Oleosin of Plant Seed Oil Bodies is Correctly Targeted to the Lipid Bodies in Transformed Yeast, J. Bio. Chem. 272; 3699-3706 (1997).
A variety of phospholipids may be used to form the disclosed organelle layer.
Exemplary phospholipids include natural or chemically modified phospholipids, e.g., alkylphosphocholines (viz., synthesized phospholipid-like molecules), cardiolipin, dipalmitoylphosphatidylcholine, glycerophospholipid, lecithin, phosphatidic acid, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol 3-phosphate, phosphatidylinositol (3,4)-bisphosphate, phosphatidylinositol (3,5)-biphosphate, phosphatidylinositol (3,4,5)-triphosphate, phosphatidylmyo-inositol mannosides, phosphatidylserine, sphingomyelin, sphingosyl phosphatide and mixtures thereof. An exemplary commercially available phospholipid is ULTRALEC F™ deoiled lecithin from Archer Daniels Midland Co. (Decatur, Ill.).
In some embodiments the organelle layer or other layers may contain one or more antioxidants. Exemplary such antioxidants include those discussed above in connection with the core. Some antioxidants may be used as core stabilizers and as shell stabilizers. Additional ingredients (e.g., phytosterols) may be employed in some embodiments to improve the physical stability or barrier properties (e.g., oxygen or water barrier properties) of the organelle layer or other layers.
The dried synthetic organelle layer may for example contain less than 8%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2% or less than 1% of available water. The desired dryness level may be reached by removing water (e.g., if the organelle layer is formed using an aqueous carrier or solvent) or by adding water (e.g., if the organelle layer is formed using an organic carrier or solvent) after or during formation of the disclosed encapsulated material.
The organelle layer may be in direct contact with a surface of the core, or may be in direct contact with an intermediate protective layer located between a surface of the core and the organelle layer. The latter configuration may however have a reduced core content or core loading for a given particle size. The organelle layer may as discussed above be covered by one or more additional layers, for example a water-dispersible oxygen-barrier layer, hydrocolloid layer, lipophilic layer or any combination thereof.
A variety of microencapsulating materials may be used in the disclosed encapsulated materials to form additional shell(s), sometimes also referred to as coatings or membranes, surrounding the core(s), or as additives in the organelle layer. Exemplary such materials may comprise, consist of or consist essentially of natural, semisynthetic (viz., chemically modified natural materials) or synthetic materials. Exemplary natural materials include gum arabic, agar agar, agarose, maltodextrins, alginic acid and salts thereof including sodium or calcium alginate, fats and fatty acids, cetyl alcohol, collagen, chitosan, lecithins, gelatin, albumin, shellac, polysaccharides including starch or dextran, polypeptides, protein hydrolyzates, sucrose and waxes. Exemplary semisynthetic materials include chemically modified celluloses including cellulose esters and ethers (for example cellulose acetate, ethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose and carboxymethyl cellulose) and chemically modified starches including starch ethers and esters (for example, CAPSUL™ modified starch from National Starch). Exemplary synthetic materials include polymers (for example, polyacrylates, polyamides, polyvinyl alcohol, polyvinyl pyrrolidone, polyureas and polyurethanes). Exemplary commercial microcapsule products (the shell materials for which are shown in parentheses) include Hallcrest Microcapsules (gelatin, gum arabic), Coletica THALASPHEREST™ (maritime collagen), Lipotec MILLICAPSELN™ (alginic acid, agar agar), Induchem UNISPHERES™ (lactose, microcrystalline cellulose, hydroxypropylmethyl cellulose), Unicerin C30 (lactose, microcrystalline cellulose, hydroxypropylmethyl cellulose), Kobo GLYCOSPHERES™ (modified starch, fatty acid esters), SOFTSPHERES™ (modified agar agar) and Kuhs Probiol NANOSPHERES™.
A variety of natural or chemically modified fiber materials may be used to make FCP layers or as additives in the core, organelle layer or other layers. Fiber or “roughage” is a component of food that remains undigested as it passes through the gastrointestinal system, and which does not necessarily have a fibrous structure. The vast majority of dietary fiber consists of complex carbohydrates (e.g., polysaccharides) of plant origin, for example the cellulosic wall that surrounds plant cells. Fibers may be further classified into insoluble fibers such as the classic cellulosic materials, and soluble fibers such as water-soluble polysaccharides that are not digested by human or carnivore digestive systems. Both types of fiber bind considerable water and, thus, have a softening effect on the stool. Soluble fiber may, depending on the precise polysaccharides involved, also be metabolized or partially metabolized directly by bacteria in the colon, and may promote growth of beneficial bacteria. Both insoluble and soluble fibers tend to increase motility within the gastrointestinal tract thus speeding transit time of wastes and lowering the risk of acute and chronic medical problems. This generally has a positive effect as the beneficial bacteria may also tend to lubricate the stool and prevent the growth of other bacteria which may release toxins (see e.g., Leon Prosky, J. of AOAC Intl 82:223-35 (1999)). Insoluble fibers may be obtained from a wide variety of sources. Exemplary insoluble fibers include almond fiber, cellulose, chia fiber, citrus fiber, coconut fiber, corn fiber, cottonseed fiber, flaxseed fiber, grape seed fiber, hemicelluloses, lignin, oat fiber, rice hulls, safflower fiber, sesame fiber, soybean fiber, sunflower fiber, and walnut fiber. Sources include whole grain foods, nuts and seeds, vegetables such as green beans, cauliflower, celery and zucchini, and the skins of some fruits (e.g. tomatoes). Soluble fibers may be obtained from a wide range of plant sources, including water-soluble plant pectins and pectic materials, galactomannans, arabanogalactans and water-soluble hemicellulose. Many plant “mucilages,” gums, and soluble polysaccharides found in grains, seeds, or stems such as psyllium, guar, oat (beta glucans), astragalus (gum traganth), gum ghatti, gum karaya (Sterculia gum); and gum acacia also provide soluble fiber. Partially hydrolyzed guar gums may also provide soluble fiber, and may for example be prepared as described in U.S. Pat. No. 5,260,279. Algal polysaccharides such as agar or carrageenan (which as discussed below may also be used in an HC layer) behave as soluble fiber as do other digestible carbohydrates, such as maltodextrins or dextrins, produced by chemical or enzymatic digestion (e.g., partial hydrolysis) of starch, gums and other carbohydrate polymers. Dextrins or maltodextrins may for example be prepared by controlled hydrolysis of vegetable starches (e.g., potato or corn) as is described in U.S. Pat. No. 5,620,873 to Ohkuma et al. Soluble cellulosic ethers and other cellulose derivatives (e.g., carboxymethyl cellulose) behave as soluble fiber as do digestible carbohydrate polymers artificially prepared using bacterial enzymes. Storage carbohydrates such as lower molecular weight grades of inulin (see for example U.S. Pat. No. 5,968,365 to Laurenzo, et al.) are also important soluble fibers. Anionic chitosan derivatives, for example carboxylation and above all succinylation products of chitosan may also be used as soluble fibers. A number of companies now provide an entire range of soluble fiber materials. For example, TIC Gums of Belcamp, Md., Novartis Nutrition of Minneapolis, Minn. and Imperial Sensus of Sugar Land, Tex. provide food grade soluble fiber compounds. Additional soluble fibers are available in the United States as BENEFIBER™ from Novartis Nutrition of Minneapolis, Minn. or in other countries as SUN-FIBER™ from Taiyo of Japan. It is peimissible and often advantageous to blend an assortment of different soluble fibers to create any particular fiber-water mixture. In fact the disclosed method may facilitate or dictate the selection of suitable fibers and their quantity or mode of delivery. Many of the various soluble fibers may have essentially identical properties when it comes to providing bulk and hydration to stools. However, selected soluble fibers may provide desirably altered solution clarity, lipid absorption, sugar absorption or other factors of interest. For example, among presently available soluble fibers, dextrins, inulins and partially hydrolyzed guar gum appear to provide aqueous solutions having the greatest degree of clarity. However, many dextrins and inulins contain a small amount of a metabolizable component and have a slight sweet taste. For some applications it will be advantageous to provide a portion of the soluble fiber in the form of hydrolyzed guar gum or some other flavorless and non-metabolizable compound, together with a second portion in the form of a metabolizable fiber such as an inulin. Even though some fibers may produce solutions having lower clarity, combinations with clear soluble fibers can yield a solution which is both high in fiber and clarity and low in sweetness or other taste. Other soluble fibers can be combined to realize the advantages of fiber mixtures.
A variety of natural or chemically modified carbohydrates may be used to make FCP layers or as additives in the core, organelle layer or other layers. Exemplary such carbohydrates include monosaccharides, disaccharides, trisaccharides and oligosaccharides such as dextrose, fructose, dextrose, galactose, glucose, lactose, mannose, ribose, sucrose, trehalose and xylose, as well as sugars contained in sources such as corn products, molasses, spent sulfite liquors, sugar beets, and their respective hydrolysates. Reducing sugars and non-reducing sugars may be employed. Reducing sugars may also be used to promote a Maillard reaction with proteins as discussed in more detail below.
A variety of natural or chemically modified proteins may be used to make FCP layers or as additives in the core, organelle layer or other layers. Exemplary such proteins include dairy proteins, e.g., casein, caseinate, milk protein concentrate (MPC), whey, whey protein concentrate (WPC) and whey protein isolate (WPI); processed proteins, e.g., albumin, albumen, collagen, gelatins (e.g., beef, fish or pork gelatin), soy protein concentrate (SPC) and wheat gluten; vegetarian proteins from nuts (e.g., almonds, beechnuts, brazil nuts, chestnuts, hazelnuts or walnuts) or from seeds (e.g., amaranth, barley, beans, buckwheat, canola, chia, corn, flax, hemp, millet, oats, peanuts, peas, pumpkins, quinoa, rice, rye, sorghum, soybeans, sunflowers, wheat and wild rice; miscellaneous protein sources, e.g., algae, eggs and yeast; and animal protein sources, e.g., meat or blood portions of beef, buffalo, cephalopods, chicken, deer, ducks, eel, elk, emu, fish, geese, goat, ostrich, pork, rabbits, rodentia, sheep, shellfish, turkeys, water buffalo and yaks.
A variety of natural or chemically modified hydrocolloids may be used to make hydrocolloid shell (HCS) layers or as additives in the core, organelle layer or other layers. Exemplary hydrocolloids include alginates and other algal polysaccharides such as agar; carrageenans; gelatins; hyaluronates; modified starches; pectins; sulfated dextrans; xanthan gums; cellulose derivatives such as carboxymethyl cellulose, oxidized cellulose and microcrystalline cellulose; and mixtures thereof. Alginic acid, its salts and complete and partial neutralization products thereof may also be employed. Alginic acid is a mixture of carboxyl-containing polysaccharides with an idealized monomeric unit, and a weight average molecular weight of about 18,000 to about 120,000. Exemplary salts of alginic acid and complete and partial neutralization products thereof include alkali metal salts such as sodium alginate (“algin”), and ammonium and alkaline earth metal salts. Mixed alginates, for example sodium/magnesium or sodium/calcium alginates, may also be employed. Hydrocolloids may also be crosslinked, as discussed in more detail below.
The disclosed encapsulated materials may contain a variety of adjuvants, including chelating agents, surfactants, UV absorbers and other ingredients or additives that will be familiar to persons having ordinary skill in the microencapsulation art. Exemplary chelating agents include citric acid and ethylenediaminetetraacetic acid (EDTA). Exemplary surfactants include anionic, nonionic, cationic and amphoteric (zwitterionic) surfactants. Exemplary anionic surfactants include soaps, alkyl benzenesulfonates, alkanesulfonates, olefin sulfonates, alkylether sulfonates, glycerol ether sulfonates, α-methyl ester sulfonates, sulfofatty acids, alkyl sulfates, fatty alcohol ether sulfates, glycerol ether sulfates, fatty acid ether sulfates, hydroxy mixed ether sulfates, monolyceride (ether) sulfates, fatty acid amide (ether) sulfates, mono- and dialkyl sulfosuccinates, mono- and dialkyl sulfosuccinamates, sulfotriglycerides, amide soaps, ether carboxylic acids and salts thereof, fatty acid isethionates, fatty acid sarcosinates, fatty acid taurides, N-acylamino acids, for example acyl lactylates, acyl tartrates, acyl glutamates and acyl aspartates, alkyl oligoglucoside sulfates, protein fatty acid condensates (e.g., wheat-based vegetable products) and alkyl (ether) phosphates. Exemplary nonionic surfactants include fatty alcohol polyglycol ethers, alkylphenol polyglycol ethers, fatty acid polyglycol esters, fatty acid amide polyglycol ethers, fatty amine polyglycol ethers, alkoxylated triglycerides, mixed ethers and mixed formals, optionally partly oxidized alk(en)yl oligoglycosides or glucuronic acid derivatives, fatty acid-N-alkyl glucamides, protein hydrolyzates (e.g., wheat-based vegetable products), polyol fatty acid esters, sugar esters, sorbitan esters, polysorbates and amine oxides. Cationic or nonionic surfactants containing polyglycol ether chains may have a conventional homolog distribution, but preferably have a narrow-range homolog distribution. Exemplary cationic surfactants include quaternary ammonium compounds, for example dimethyl distearyl ammonium chloride, and esterquats, more particularly quaternized fatty acid trialkanolamine ester salts. Exemplary amphoteric or zwitterionic surfactants include alkylbetaines, alkylamidobetaines, aminopropionates, aminoglycinates, imidazolinium betaines and sulfobetaines. Further details concerning these and other exemplary surfactants may be found for example in J. Falbe (ed.), “Surfactants in Consumer Products”, Springer Verlag, Berlin, 1987, pages 54 to 124 or J. Falbe (ed.), “Katalysatoren, Tenside and Mineraloladditive (Catalysts, Surfactants and Mineral Oil Additives)”, Thieme Verlag, Stuttgart, 1978, pages 123-217.
UV absorbers act as stabilizers to protect the microcapsule by absorbing radiation in the range of about 270-500 nanometers and subsequently releasing the energy into the environment through non-destructive means. Exemplary UV absorbers include hindered amine light stabilizers (HALS), cinnamate esters, hydroxybenzophenones, benzotriazoles, substituted acrylates, salicylates, oxanilides, hydroxyphenyltriazines, nanoparticle titania, nanoparticle zinc oxide, and the like.
The disclosed encapsulated materials may also include absorbents, dehydrators, flow aids and other agents that may assist in pouring, storing or dispensing the encapsulated materials or in mixing them with other materials. The agent may in some embodiments form a coating over an outer layer, in effect representing an additional shell, and may in other embodiments be an additive included in an outer layer. The agent may change the surface energy of the encapsulated material, absorb excess oil, or serve other functions. Exemplary such agents include inorganic or organic materials such as activated carbon, alumina, aluminum phosphates, aluminium silicates, bentonite, bone phosphate, calcium aluminosilicate, calcium carbonate, calcium ferrocyanide, calcium silicate, magnesium oxides, magnesium silicates, magnesium trisilicate, oat or other fibers, Polydimethylsiloxane, potassium aluminium silicate, potassium ferrocyanide, powdered phytosterols, silicas (e.g., fumed or precipitated silicas), sodium aluminosilicate, sodium bicarbonate, silicon dioxide, sodium ferrocyanide, sodium silicate, stearic acid, talc, sodium phosphate, tricalcium phosphate, zeolites, and mixtures thereof. The agent may for example represent about 0.5 to about 5 wt. % of the encapsulated material.
The disclosed encapsulated materials may be prepared using a variety of encapsulation methods. For example, a solid particle of the core material may be formed and a synthetic organelle layer may be deposited and dried on the solid particle while the particle is suspended or dispersed or in a trajectory. A droplet of the core material may instead be suspended or dispersed in a fluid environment containing an organelle composition. A droplet of the core material may also be spray dried or prilled in combination with materials forming the organelle layer, optionally together with additional materials which may become incorporated into the organelle layer or may form an additional layer or layers between the core and organelle layer or surrounding the organelle layer. The materials forming the organelle layer may if desired be in fluid form at an elevated temperature (e.g., at above 30° C.) and in solid form when cooled to a lower temperature.
The various applied layers may be reacted with a variety of materials to alter some or all of the layer characteristics. This may be carried out using a variety of reaction schemes, materials and other measures. For example, a Maillard reaction between proteins and reducing sugars may be used to alter a layer containing protein or a layer containing a reducing sugar by exposing such layers to reducing sugar or protein, respectively, in the presence of sufficient heat to promote a browning reaction. Hydrocolloid (e.g., alginate layers) may be crosslinked, e.g., by inclusion of a suitable calcium salt source in the hydrocolloid layer, in an adjacent layer or in the core.
A variety of exemplary structures and methods may be used to form the disclosed encapsulated materials. When the microcapsules include additional layers other than the OBS, (e.g., a PPC layer or HC layer), the resulting encapsulated material may be referred to as a multilayer microcapsule or MLMC. An MLMC may for example be made using an oxidation-sensitive liquid core (e.g., a TAG or PUFA core) to which has been added an antioxidant (e.g., tocopherol, lycopene or tocotrienols), chelating agents, or dispersed calcium carbonate or calcium sulfate. The core may be formed by mixing or providing a portion of the active core ingredients at an appropriate temperature of, for example 70-80° C., then cooling and atomizing the mixture in a spray-drying or “prilling” column to form beads. The beads may be coated with a synthetic organelle shell or OBS which may be made from a variety of materials (e.g., lecithin or other phospholipid-containing materials and oleosins, and other optional ingredients). The thus-coated beads may be dried and a melt process may next be used to form one or more layers with antioxidant properties over the OBS, e.g. by mixing the OBS-coated cores into a film-forming composition into which antioxidants have been dissolved, dispersed or suspended. This last step may be repeated several (e.g., one to four) times. HC shell (HCS) layers may be formed, for example from an aqueous sodium alginate hydrocolloid solution to which a variety of other materials may also be added. FCPS layers may be formed, for example by adding fibers such as insoluble fiber or carboxymethyl cellulose (CMC) fibers and optional additives to a solution containing water-soluble antioxidants and reducible sugars. The resulting mixture may be formed into encapsulated materials, e.g., by adding the OBS-coated cores to the solution and spray drying to form FCP-coated particles. In a preferred process the resulting spray dried product is added to a melt for prilling or otherwise converted in order to form an outer lipophilic shell or LPS over an HC or FCP-coated core or OBS. Separation of microcapsules by centrifugation or filtration and drying to a dry state may also or instead be used to form various layers.
Using these various general processes for manufacture, a variety of different materials, layers and constructions can be used to provide a variety of encapsulated materials including OBS-coated cores, MLMCs and MLMCs including an LPS. Set out below in Table 1 are several non-limiting exemplary structural components, ingredients and functions for use in such processes. The terms “AI” and “AO” in Table 1 respectively refer to an “active ingredient” and an “antioxidant”, functions which in some cases may be performed by the same material. Typically an AI or AO will be carried and protected by the core, OBS, HCS, FCPS or other MLMC layer until such time as the AI or AO may be delivered to an intended host or site for a subsequent designed use. Other abbreviations are identified in the footnotes to Table 1. To simplify the table appearance, the first row for each new structural component (e.g., Core, OBS, etc.) includes the structural component label, and subsequent rows showing other materials for use in or as such structural component do not explicitly show the structural component label but are deemed to have been so labeled.
For encapsulated materials having a core surrounded by a single OBS layer, the core:shell weight ratio may for example range from about 10:1 to about 1:10, about 8:1 to about 1:1, or about 2:1 to about 2:3. For encapsulated materials having a core surrounded by four shell layers (e.g., an MLMC having OBS, HCS, FCPS and LPS layers), the core may for example represent about 5 to about 70, about 5 to about 60 or about 10 to about 40 wt. % of the total encapsulated material weight. Set out below in Table 2 are exemplary MLMC constructions showing core and layer amounts (expressed in parts by weight) for a variety of encapsulated materials containing OBS-coated cores, alginate shells, FCP shells and lipophilic shells, together with the approximate core weight percent.
The data in Table 2 show encapsulated materials with four shell layers containing about 5-60 wt. % core content. By varying the presence or absence of the various layer and their ingredients and relative amounts, encapsulated materials having a variety of properties can be formed. For example, if the lipophilic shell is eliminated and a fiber/carbohydrate/protein shell containing mainly a soluble fiber such as pectin or alginate is employed, a taste-masked MLMC with UGI bypass characteristics may be prepared. If a phytosterol-containing lipophilic shell is employed, a high temperature encapsulated material with an AO shell may be prepared for use in baked products and baking applications. Encapsulated materials whose cores or lipophilic shells contain organogels, and encapsulated materials with lipophilic shells containing hydrogenated oils crystallized in the beta form, may provide oxygen barrier or zero order (viz., concentration-independent) release characteristics.
Oxidative stability may be evaluated using a variety of tests. Simple but sensitive subjective tests such as olfactory tests or taste tests will suffice for many applications. A variety of objective may also be employed, including accelerated oxidative stress tests such as solid phase micro extraction (SPME) at an elevated temperature, e.g., 50° C. in an oxidizing atmosphere such as pure oxygen. Aging at 50° C. in pure oxygen represents a fairly severe test regime, and materials which provide low SPME values (or little change in the SPME value compared to the initial SPME value) when so aged may provide very good protection under less stringent (e.g., room temperature) storage conditions. The SPME value after 48 hours at 50° C. in pure oxygen may for example be less than 8,000, less than 5,000 or less than 4,000. The ratio of SPME after 48 hours at 50° C. to initial SPME may also be evaluated, and may for example be less than 8, less than 4, less than 2, less than 1.7 or less than 1.3. An SPME measurement for omega-3 oil may for example be carried out as follows:
SPME Oxidative Stress Test for Omega-3 OilOmega-3 oil samples are prepared by accurately weighing (to 0.1 mg) about 0.5 g of oil into a 5 cc serum bottle (Wheaton #223685), and adding a weighed portion of an internal standard made using 400 micrograms of dodecane per gram of mineral oil. Sufficient internal standard is normally employed to provide about 8 ppm dodecane in the sample. The bottle is sealed with a polytetrafluoroethylene-faced silicon septa and an aluminum crimp seal. For oxidative stress testing, two additional portions are sealed after flushing for 15 seconds with pure oxygen. These portions are held in an oven until evaluation (typically 24 hours or 48 hours at 50° C.). The bottle to be evaluated is thermostated for 30 minutes at 60° C. using a Pierce REACTITHERM™ heating bloc. The bottle headspace is then extracted for 30 minutes with a 50/30μ solid phase extraction fiber made from divinyl benzene/Carboxen™ fiber/polydimethylsiloxane/STABILFLEX™ fiber. The fiber is desorbed in the injection port of a gas chromatograph at 230° C. for 30 minutes. Typically, the next sample is thermostated at 60° C. during this 30 minute period. Chromatography is accomplished on a 20 meter RTX-CLP1 column with an ID of 0.18 mm and a 0.18 μm film thickness. The initial temperature is 45° C. for one minute, followed by heating at 3° C./minute to 60° C., then 2° C./minute to 140° C., and then finally 20° C./minute to 210° C. with a one minute hold at 210° C. to clear the column. The column is allowed to cool such that the total cycle time is 60 minutes. The flow rate is set to a constant velocity of 23 cm/second. A flame ionization detector (FID) set to maximum sensitivity is employed. Its response is calibrated using an SPME extraction of an approximate 25 milligram portion of a mineral oil standard containing 660 ppm 2-methyl 2-butene, 428 ppm ethyl benzene, 154 ppm hexane, 440 ppm 3-hexene-1-ol, 386 ppm 4-heptanal, 482 ppm 2,6-nonadienal and 404 ppm dodecane.
The disclosed encapsulated materials may be used in a variety of products and applications including foods, food additives, food supplements, prepared (e.g., baked, frozen or precooked) foods, neutraceuticals, medicines, catalysts, inks and coatings.
The invention is further described in the following Examples, in which all parts and percentages are by weight unless otherwise indicated.
Comparative Examples 1-3Three samples of omega-3 oil (from Hormel Foods Corp.) containing 2,000 ppm tocopherols were evaluated for oxidative stability using SPME. An average SPME value of 28,663 was obtained after 48 hours at 50° C. (see Table 3).
Comparative Example 4A starch solution was prepared by blending together 150 g of M200 maltodextrin (from Grain Processing Corp.), 30 g of CAPSUL™ modified starch (from National Starch) and 20 g of sucrose (from Rainbow Foods) and then adding the resulting blended powder mixture to 300 g of 80° C. deionized (DI) water. The solution was agitated as the temperature was increased to 85° C., then cooled in an ice bath before refrigerating overnight. The following day the solution was allowed to reach room temperature (about 25° C.) before adding an oil phase made from 50 g of omega-3 oil (from Hormel Foods Corp.) containing 2,000 ppm tocopherol. The oil was emulsified into the starch solution using a SILVERSON™ L2R high shear mixer (from Silverson Machines) operated at maximum speed for 3 minutes to create an oil-in-water emulsion. The emulsion was spray dried using a NIRO™ Mobile Minor lab dryer (from Niro Equipment Corp.) operated using an inlet temperature of 225° C. and an outlet temperature of 75° C. The product had an SPME value of 43,765 after 48 hours at 50° C. (see Table 3).
Comparative Example 5An encapsulated product was prepared using the method of Comparative Example 4 but employing a starch solution made from 130 g of M100 maltodextrin (from Grain Processing Corp.), 30 g of CAPSUL modified starch and 40 g of sucrose (from Rainbow Foods) and then adding the resulting blended powder mixture to 300 g of 80° C. deionized (DI) water. The product had an SPME value of 39,985 after 48 hours at 50° C. (see Table 3).
Comparative Example 6An encapsulated product was prepared using the method of Comparative Example 4 but employing a starch solution made from 110 g of M100 maltodextrin, 15 g of CAPSUL modified starch, 75 g of sucrose and 300 g of DI water, and an oil phase made from 50 g of omega-3 oil containing 2,000 ppm tocopherol. The resulting encapsulated product had an SPME value of 38,840 after 48 hours at 50° C. (see Table 3).
Comparative Example 7A starch solution was prepared by blending together 600 g of M200 maltodextrin, 120 g of CAPSUL modified starch, 4.0 g of ascorbic acid and 80 g of sucrose and then adding the resulting blended powder mixture to 1,200 g of 80° C. DI water. The solution was agitated as the temperature was increased to 85° C., then cooled in an ice bath before refrigerating overnight. The following day 40.0 g of ULTRALEC F™ lecithin (from Archer Daniels Midland Co.) was added to 796 g of omega-3 oil (from Hormel Foods Corp.) containing 2,000 ppm tocopherol. The oil phase was heated to approximately 80° C. and allowed to cool, then emulsified into the starch solution using a SILVERSON L2R high shear mixer operated at maximum speed for 20 minutes followed by a single pass through a MICROFLUIDICS™ M110Y microfluidizer (from MFIC Corp.) operated at 103 MPa. The resulting emulsion was spray dried using a NIRO Mobile Minor lab dryer operated using an inlet temperature of 225° C. and an outlet temperature of 75° C. The total yield of product collected in bottles from the cyclone was 784 g. An additional 508 g of product was scraped from the spray drier after it cooled to room temperature. The product had an SPME value of 10,355 after 48 hours at 50° C. (see Table 3).
Example 1Corn oil and corn oil bodies were extracted by adding 500 g of methylene chloride to 250 g of corn germ. The corn germ in methylene chloride was refrigerated and allowed to soak overnight in a sealed glass container before blending on low speed for 30 seconds using a WARING™ 2 quart lab blender (from Hamilton Beach Brands, Inc.). After soaking while refrigerated overnight, the blend was poured into a sheet of four layers of cheesecloth and squeezed in order to remove most of the liquid. The permeate was placed in a shallow glass pan and the methylene chloride was allowed to evaporate in a fume hood for over 24 hours. The resulting oil-solids mixture weighed 40 g and had an apparent corn-like odor. The solids contained phospholipids and the proteins (including oleosins) associated with oil bodies in addition to other solids. An aqueous phase was prepared by first adding 1.20 g of sodium alginate to 1184 g of DI water, next adding 1.20 g of calcium chloride to 296 g of DI water, combining the two solutions with stirring, and then adding 40.0 g of ULTRALEC F deoiled lecithin, 720 g of CAPSUL modified starch, 80 g of trehalose (from Hayashibara, Co.), 4.0 g of ascorbic acid and 8.0 g of citric acid. The resulting aqueous phase was cooled in an ice bath and refrigerated overnight, followed by addition of 40 g of the oil-solids mixture. An oil phase was prepared by adding 23.9 g of ARBORIS™ AS-2 phytosterol (from Arboris, LLC) to 756 g of omega-3 oil containing 2,000 ppm tocopherol and heating to 50° C. The warm oil phase was poured into the cooled aqueous phase and emulsified using a SILVERSON LT-1 high shear mixer (from Silverson Machines) operated at maximum speed for 15 minutes, thereby providing a coarse emulsion. An ice bath was used to cool the emulsion to approximately 30° C. before passing it through a MICROFLUIDICS M110Y microfluidizer operated at 110 MPa. The emulsion was spray dried using a NIRO Mobile Minor lab dryer operated using an inlet temperature of 225° C. and an outlet temperature of 90° C. The total yield of product collected in bottles from the cyclone was 588 g. An additional 398 g of product was scraped from the dryer. The product had an SPME value of 3,345 after 48 hours at 50° C. (see Table 3), thus demonstrating improved oxidative stability over the Comparative Examples.
Example 2An encapsulated product was prepared using the method of Example 1 but employing 103 g (rather than 40 g) of the oil-solids mixture in the aqueous phase. The total yield of product collected in bottles from the cyclone was 791 g. An additional 488 g of product was scraped from the dryer. The product had an SPME value of 3,562 after 48 hours at 50° C. (see Table 3), thus demonstrating improved oxidative stability over the Comparative Examples.
Example 3Corn oil and corn oil bodies were extracted from dried corn germ. First, 262.7 g of dried, cold corn germ were removed from a −28° C. freezer, placed in a WARING 2 quart lab blender and ground on the low setting for 1.25 minutes, with a halt each 15 seconds to scrape down the sides. The ground corn germ was then placed in a 0.95 L bottle to which 500 g of water was added. The bottle was placed on a lab shaker for 60 minutes on low speed, stored at room temperature overnight, returned to the lab shaker for 5 hours on low speed and then stored in a refrigerator for 4 days. The mixture was centrifuged in 45 ml portions at 6000 rpm for 30 minutes. All of the liquid and floating material from the centrifuge tubes was collected and combined and then 15 ml of water was added to the tubes to float any remaining oil containing material. A total of 448 g of corn homogenate was collected. Next, 27 g of CaCl2 was dissolved in 50 g of water and cooled to room temperature. The Ca solution was added to the bottle of corn homogenate. The bottle was placed on a lab shaker for 1 hour on low speed. The bottle contents were transferred to a separatory funnel and stored in a refrigerator overnight. The funnel contents separated and the CaCl2/water layer was removed. A 519 g portion of water was added to the separatory funnel and the separatory funnel was shaken gently and returned to the refrigerator for 2 hours. The water layer was removed by separation and the water washing and separation steps were repeated 3 more times. A corn oil body layer weighing 133.7 g was collected.
A 450 g portion of dry calcium chloride was added to 1350 g of ROUNDY'S™ canola oil (from Creative Products, Inc. of Rossville) and lightly ground using a Silverson LT-1 high shear mixer operated at maximum speed for 20 minutes. The resulting calcium chloride dispersion was transferred to a BUHLER™ PML2 laboratory media mill (from Buhler Technology Group) and kept gently suspended, then bead milled for 150 minutes using 0.4 mm YTZ (yttria-stabilized zirconia) media, a rotor speed of 3,500 rpm and a 40% recirculating pump rate. This reduced the size of the calcium chloride particles to about 1.16 μm and provided a 25 wt. % calcium chloride suspension in canola oil. The aqueous phase was made by heating 1480 g of DI water to 40° C. and then adding 40.0 g of ULTRALEC F lecithin with stirring. After twenty minutes of stirring the temperature was increased to 80° C. and then 720 g of CAPSUL modified starch, 80 g of trehalose, 4.0 g of ascorbic acid, 8.0 g of citric acid, 1.2 g MANUGEL™ LBA sodium alginate (from Nutrasweet Kelco), and 15.0 g oat fiber were added. The solution was cooled via an ice bath before refrigerating overnight. The following day, 133.7 g of the corn oil bodies were added directly to the aqueous phase. For the oil phase, 2.0 g of the 25 wt. % suspension of calcium chloride in canola oil was added to 662.3 g of omega-3 oil containing 2,000 ppm tocopherol and heated to 50° C., followed by the dissolution of 23.9 ARBORIS AS-2 phytosterol in the 50° C. oil phase and cooling to room temperature. The cooled oil phase was poured into the aqueous phase and emulsified and spray dried as in Example 1 but without use of the microfluidizer. The total yield of product collected in bottles from the cyclone was 983 g. An additional 371 g of product was scraped from the dryer. The product had an SPME value of 2,720 after 48 hours at 50° C. (see Table 3), thus demonstrating improved oxidative stability over the Comparative Examples.
Example 4To a 98.00 g portion of the spray dried encapsulated powder from Example 3 was added 2.00 g of SYLOPOL™ 952 precipitated silica gel (from Grace Davison) in a 0.95 L bottle and then shaken by hand for about 10 minutes to obtain a uniform mixture. The product had an SPME value of 2,047 after 48 hours at 50° C. (see Table 3), thus demonstrating improved oxidative stability over the Comparative Examples.
Example 5To a 95.00 g portion of the spray dried encapsulated powder from Example 3 was added 5.00 g of finely ground oat fiber in a 0.95 L bottle and then shaken by hand for about 10 minutes to obtain a uniform mixture. The product had an SPME value of 2,651 after 48 hours at 50° C. (see Table 3), thus demonstrating improved oxidative stability over the Comparative Examples.
The 48 Hour SPME results mentioned above are shown below in Table 3, along with the calculated oil load, initial SPME value, ratio of the 48 hour SPME value to initial SPME value, and a subjective evaluation of the odor for the unencapsulated oil or dry powder after 48 hours at 50° C. The encapsulated materials in Examples 1 and 2 exhibited significantly improved oxidative stability over the Comparative Examples.
A 2.1 g portion of MEG-3™ omega-3 fish oil coated with fish gelatin (from Ocean Nutrition) was mixed with 11 g of TANG™ drink mix powder (from Kraft Foods, Inc.) and then added to 237 cm3 of water. The coated omega-3 oil did not disperse to form a uniform drink. Instead, the coated omega-3 oil formed clumps which settled to the bottom of the drink.
Examples 6 and 7A 2.51 g portion of the spray dried encapsulated material from Example 1 was mixed with 11 g of TANG powder and then added to 237 cm3 of water. The encapsulated material and TANG powder dispersed to form a uniform drink (Example 6). Similar results were obtained when a 4.11 g portion of the spray dried encapsulated material from Example 3 was mixed with 16.79 g of TANG powder and then added to 355 cm3 of water. The encapsulated material and TANG powder dispersed to form a uniform drink (Example 7).
Example 8A 0.85 g portion of the spray dried encapsulated material from Example 1 was mixed into a 1.9 L container of TROPICANA™ Pure Premium orange juice (from Tropicana Manufacturing Company, Inc.). The encapsulated material dispersed in the orange juice to form a uniform drink (Example 8).
Examples 9 and 10A 2.51 g portion of the spray dried encapsulated material from Example 1 was mixed with 454 g of BETTY CROCKER® Pound Cake Mix (from General Mills Sales, Inc.) followed by the addition of 177 ml of water and 2 eggs. The ingredients were mixed at low speed using a KITCHENAID™ mixer (from KitchenAid, U.S.A.) for 30 seconds, followed by mixing at medium speed for 3 minutes. The mixture was poured into a 23 cm×13 cm loaf pan, placed in a preheated 177° C. oven and baked for 50 minutes until a toothpick inserted in the center of cake came out clean. The cake was cooled for 10 minutes in the pan, then removed and cooled to room temperature on a wire rack. The encapsulated material appeared to be well dispersed in the pound cake and baked without any apparent fishy smell during baking. There was no fishy smell or taste in the finished pound cake (Example 9). Similar results were obtained when a 4.01 g portion of the spray dried encapsulated material from Example 15 was mixed with 454 g of Pound Cake Mix, 177 ml of water and 2 eggs and baked as described above. The encapsulated product appeared to be well dispersed in the pound cake and baked without any apparent fishy smell during baking. There was no fishy smell or taste in the finished pound cake (Example 10).
Preparation 1 Oil Body IsolationUsing techniques adapted from Wang, L., Properties of Soybean Oil Bodies and Oleosin Proteins as Edible Films and Coatings, Ph.D. Thesis, Purdue University, UMI Microfilm 3150845, oil bodies may be physically isolated from a total homogenate of mature soybean seeds using flotation and centrifugation. Soy seeds may be soaked in cold mM Tris-HCl buffer, pH 8.6, overnight at 4° C., or 6 hr at ambient temperature. Soaked beans (100 g) may be homogenized in 200 mL Buffer A (3 mM MgCl2 and 100 mM tris(hydroxymethyl)aminomethane whose pH is adjusted to 8.6 using HCl (Tris-HCl)) using a commercial Waring blender for 20 sec on low and then 40 sec on high. The soybeans may be further homogenized with a Virtishear homogenizer at 10,000 rpm for 1 min at 20 sec intervals. The homogenate may be filtered though 4 layers of cheesecloth and centrifuged at 100,000×g for 20 min or 20,000×g for 45 min. Oil pads may be collected and resuspended in Buffer A by vortexing briefly and centrifuged again. The recovered oil pads may be resuspended in Buffer B (Buffer A containing 0.5 M NaCl) and centrifuged again. The thus-recovered oil pads may be resuspended in Buffer C (0.1 M Na2CO3) and incubated on ice for 30 min before centrifuging. This step may be repeated until no visual material is spun out. The recovered oil pads may be washed twice in Buffer D (3 mM MgCl2, 100 mM KCl, and 2 mM N-2-Hydroxyethylpiperazine-N′-2-ethanesulfonic acid (HEPES), pH7.5) to lower the pH of the oil body suspension to pH 8. A final wash may be done in Buffer E (Buffer D containing 2 mM dithiothreitol (DTT)). The resulting oil body suspension may be stored at 4° C. for up to 2 weeks or at −80° C. for long term. Typical yields would be approximately 3-3.5 g (wet weight) of purified oil bodies from 35 g of dry seeds.
Preparation 2 Oleosin Isolation from Oil BodiesOleosin proteins may be purified from the Preparation 1 oil bodies by solvent extraction. Oil bodies stored at −80° C. may be thawed on ice and then centrifuged at 100,000×g at 4° C. for 20 min to recover the oil pad. The oil pad may be resuspended in cold acetone, mixed by vortexing and incubated at −20° C. overnight. A precipitated oleosin and phospholipids membrane may be recovered by centrifugation. The solid centrifugate may be extracted with diethyl ether and the phospholipid may be extracted with 30 mL water:methanol:chloroform (1:2:2 v/v/v).
Preparation 3 Organelle PreparationUsing techniques adapted from Tzen, J. T. C. and Huang, A. H. C., Surface Structure and Properties of Plant Seed Oil Bodies, J. Cell Bio, 117; 327-335 (1992)), a synthetic organelle solution may be made from oleosins and phospholipids. A suspension may be prepared by placing 135 pig phospholipid (PL) dissolved in chloroform at the bottom of a 1.5 mL Eppendorf tube, and allowing the chloroform to evaporate under nitrogen. A 16 μL (15 mg) quantity of TAG may be added to the tube, followed by addition of a sonicated suspension containing 210 μg of the Preparation 2 oleosin proteins in 100 μL water. Finally, 0.25 M sucrose, 50 mM Bis-Tris, pH 7.2 and sufficient water may be added to make a final volume of 1 mL. The mixture may be vortexed, and then sonicated with a 4 mm-diameter probe in a Braun-Sonic 2000 ultrasonic generator at a digital meter reading of 50 for 20 sec. The sample may be cooled in an ice bucket for 5 min, then sonicated at a digital meter reading of 200 for 20 sec.
Preparations 4 and 5 Oil CoresA nitrogen blanket over freshly distilled oil can result in appreciable oxidation of the oil if even as little as 1% oxygen is present in the nitrogen blanket. All handling of oil to be encapsulated desirably would be done using purified nitrogen. Also, to insure metallic prooxidants would be minimized, glass lined vessels may be used after distillation. Oil Cores may be made by a number of methods including emulsification and organogel particle formation. One such example could employ 500 grams of refined fish oil mixed with 5 grams of ground calcium carbonate (particle size less than 5 micrometers), 50 grams of phytosterols such as a mixture of campesterol and sitosterol, and at least one antioxidant such as 0.5 g of α-tocopherol. The mixture may be heated in the absence of oxygen to melt and dissolve the phytosterols (140-170° C.) and the resulting solution may be atomized in a cold chamber to produce solid particles of the mixture (Preparation 4).
Oil cores or droplets may also be made by emulsification methods wherein the same components as described in Preparation 4 would be mixed and added to 1000 grams of water. The two non-miscible liquids may be vigorously mixed with ultrasonic mixers, high pressure homogenizers, or high speed mixers. The resultant mixtures would include a plurality of oil droplets or cores. One such example could employ 500 grams of refined fish oil mixed with 5 grams of ground calcium carbonate (particle size less than 5 micrometers), 50 grams of phytosterol such as a mixture of campesterol and sitosterol, and at least one antioxidant such as 0.5 g of α-tocopherol. This oil phase would be mixed into 1000 grams of water in a nitrogen-purged vessel equipped with a high shear Cowles mixing blade. The mixer would be turned on to its maximum rpm setting to produce oil droplets or cores suspended in a continuous water matrix (Preparation 5).
Preparations 6 and 7 Organelle Structure FormationStabilization of the oil cores prepared in Preparations 4 or 5 may be done through the formation of an organelle structure which includes an oil core with a stabilizing layer of phospholipid and oleosin protein. A suspension of 15 L water containing 0.25 M sucrose, 50 mM Bis-Tris, pH7.2 and the oil cores from either Preparation 4 or 5 may be prepared in a stirred nitrogen-purged 50 L vessel. To this mixture may be added 18 L of an aqueous solution containing 0.25 M sucrose, 50 mM Tris, pH7.2, 4.5 g PL and 7 g oleosin protein. The mixture may be stirred for 3 hours to form the organelle structures (Preparations 6 and 7).
Preparation 8 Organelle Structure FormationOil cores may also be prepared in situ with formation of an organelle structure. One such example for direct preparation of the organelle could employ a 33 L suspension containing 0.25 M sucrose, 50 mM Bis-Tris, pH7.2, and a refined fish oil dispersion containing 500 g fish oil, 5 grams of ground calcium carbonate (particle size less than 5 micrometers), 50 grams of phytosterol such as a mixture of campesterol and sitosterol, and at least one antioxidant such as 0.5 g of α-tocopherol, phospholipid (PL) (4.5 g) and oleosin proteins (7 g) in a 50 L nitrogen purged vessel. The mixture could be mixed with a high speed Cowles dissolver (Preparation 8).
Preparations 9 through 13 Hydrocolloid LayerThe hydrocolloid layer may include a variety of crosslinkable solidifiable hydrocolloids such as alginates, pectates, carageenates, pectin, gelatin/acacia, and others. This layer will provide an added layer of stability for the organelle, the ability to add fiber for a hard shell coating and oxidation protection, and the ability to add water-soluble antioxidants to help protect the oxidatively unstable oil core. One such example could be made by slowly adding to any of the slurries prepared in Preparations 4 through 8, with stirring, 5 L of 5 wt % sodium alginate aqueous solution. The alginate solution may contain other additives such as insoluble cellulosic fiber, soluble fiber such as inulin, or antioxidants. For example, in addition to the sodium alginate, the alginate solution may contain 100 grams of dispersed ethyl cellulose and 5 grams of anthocyanin antioxidant. The mixture may be allowed to stir for 3 hours to complete the reaction of the calcium ions from the dispersed calcium carbonate in the oil phase with the alginate in solution to form an alginate/fiber/antioxidant layer (Preparations 9 through 13).
Preparations 14 through 29 Fiber/Carbohydrate/Protein LayerTo form a stable, dry powder the materials from Preparations 4 through 13 may be spray dried as follows: The solutions described above may be fed to a Niro Lab Dryer at 10 mL/min with the inlet temperature of the dryer set at 120° C. The organelle structure may be dried to a particle size of 5-100 micrometers with a moisture content of 3-8 wt % (Preparations 14 through 21). Alternatively, to any of the solutions described in Preparations 4 through 13 an aqueous solution may be added containing 50 grams of sodium caseinate, 50 grams of trehalose, 50 grams of citrus fiber (from Fiberstar) and 500 g water, and fed to a Niro Mobile Minor lab dryer as in Example 1. The resulting MLMC structure may be dried to a particle size of 5-100 micrometers with a moisture content of 3-8 wt % (Preparations 22 through 29).
Preparations 30 through 46 Fat (Lipid) LayerThe Preparation 14 through 29 dry powders may be added to melted waxes or phytosterols and prilled as described in U.S. Pat. No. 7,237,679 B1 to form fat or lipid encapsulated particles. One such example could employ 500 grams of the Preparation 14 powder in 700 grams of molten DRITEX™ C-41V hydrogenated vegetable oil (from ACH Food & Nutrition) at 75° C. The molten melt would be prilled or atomized to form particles with a particle size of 300-600 micrometers.
Although specific examples, compositions, ingredients, temperatures and proportions have been disclosed in various aspects of the present invention, those disclosures are intended to be exemplary of species within a generic invention.
Claims
1. An encapsulated material comprising an oxidation-sensitive core covered by at least one shell comprising a dried synthetic organelle layer.
2. The encapsulated material of claim 1 wherein the core is a gel or solid at room temperature.
3. The encapsulated material of claim 1 wherein the core is a liquid at room temperature.
4. The encapsulated material of claim 1 wherein the core comprises an antioxidant, polyunsaturated fatty acid, sterol or triacylglycerol.
5. The encapsulated material of claim 1 wherein the core comprises an omega-3 or omega-6 polyunsaturated fatty acid
6-8. (canceled)
9. The encapsulated material of claim 1 wherein the core comprises an acidulant, animal product, carotenoid, catalyst, drug, dye, enzyme, flavor, fragrance, lutein, lycopene, metal complex, natural color, nutraceutical, pigment, polyphenolic, processed plant material, metabiotic, probiotic, protein, squalene, tocopherol, tocotrienol, vitamin, unsaturated organic compound, or mixture thereof.
10. (canceled)
11. The encapsulated material of claim 1 wherein the core is greater than 30 wt.
12. The encapsulated material of claim 1 wherein the organelle layer contains 8 wt. % or less of available water.
13. The encapsulated material of claim 1 wherein the organelle layer comprises lecithin or chemically modified lecithin.
14. The encapsulated material of claim 1 wherein the organelle layer comprises natural or chemically modified phospholipid, natural or chemically modified oleosin and natural or chemically modified starch.
15. The encapsulated material of claim 14 wherein the oleosin is contained in plant oil bodies or extracted plant oil bodies or a mixture thereof.
16. The encapsulated material of claim 15 wherein the plant oil bodies or extracted plant oil bodies are from corn or soybeans.
17. The encapsulated material of claim 1 wherein the organelle layer comprises natural or chemically modified phospholipid, natural or chemically modified oleosin, natural or chemically modified starch and at least one further carbohydrate.
18. The encapsulated material of claim 17 wherein the further carbohydrate comprises natural or chemically modified maltodextrin, natural or chemically modified sucrose, or natural or chemically modified trehalose.
19. The encapsulated material of claim 1 comprising a layer containing natural or chemically modified carbohydrate, natural or chemically modified starch, natural or chemically modified alginate, insoluble or soluble fiber, protein or a lipid.
20-23. (canceled)
24. The encapsulated material of claim 19 wherein the protein comprises gelatin.
25. (canceled)
26. The encapsulated material of claim 1 comprising a layer containing a phytosterol.
27. The encapsulated material of claim 1 comprising a hydrocolloid-containing layer which is crosslinked by a calcium salt source in the core or in an adjacent layer.
28. (canceled)
29. The encapsulated material of claim 1 having a solid phase micro extraction value after 48 hours at 50° C. that is less than 8,000, and a ratio of solid phase micro extraction value after 48 hours at 50° C. to initial solid phase micro extraction value that is less than 8.
30-32. (canceled)
33. A food product comprising the encapsulated material of claim 1.
34. The food product of claim 33 wherein the food is a baked food product, dry juice drink or liquid juice drink.
35-36. (canceled)
37. A method for protecting an oxidatively unstable material, which method comprises providing or forming a particle or droplet of the oxidatively unstable material and forming a dried synthetic organelle layer surrounding the particle or droplet.
38-41. (canceled)
42. The method of claim 37 wherein forming the dried synthetic organelle layer surrounding the oxidatively unstable material produces solid particle seed capsules and further comprising forming at least one additional protective layer on the solid particle seed capsules.
43. The method of claim 42 comprising forming at least one additional protective layer selected from a water-dispersible oxygen barrier layer, a hydrocolloid layer and a lipophilic layer.
44. The method of claim 37 wherein the oxidatively unstable material comprises an antioxidant, polyunsaturated fatty acid, sterol or triacylglycerol.
45-65. (canceled)
Type: Application
Filed: Jan 2, 2009
Publication Date: Mar 10, 2011
Applicant:
Inventors: William A. Hendrickson (Woodbury, MN), John M. Finney (Eden Prairie, MN), Olaf C. Moberg (New Brighton, MN), Christopher J. Rueb (St. Paul, MN), Robert G. Bowman (Woodbury, MN), Chetan S. Rao (Austin, MN), Nita M. Bentley (Austin, MN)
Application Number: 12/811,459
International Classification: A61K 9/48 (20060101); A61K 31/355 (20060101); A61K 31/201 (20060101); A61P 39/06 (20060101); A61Q 13/00 (20060101); C12N 11/00 (20060101); A23L 2/02 (20060101); A23L 1/22 (20060101);
