METHOD FOR WHITENING TOBACCO

Abstract

A method for preparing bleached tobacco material for use in a smokeless tobacco product, comprising (i) extracting tobacco material with an aqueous solution to provide solid tobacco material and a tobacco extract; (ii) bleaching the solid tobacco material with a solution comprising a strong base, an oxidizing agent, or a combination thereof to provide bleached tobacco material; and (iii) drying the bleached tobacco material to provide bleached tobacco material; wherein the solid tobacco material is not subjected to elevated temperature treatment with sulfur-containing reagents, organic solvents, sodium hydroxide, or an acid between extraction and bleaching.

Description

METHOD FOR WHITENING TOBACCO Field of Invention The present invention relates to products made from or derived from tobacco, or that otherwise incorporate tobacco, and are intended for human consumption. Background of the Invention Cigarettes, cigars, and pipes are popular smoking articles that employ tobacco in various forms. These smoking articles are used by heating or burning tobacco, and the smoker inhales the aerosol (e.g., smoke). Tobacco can also be enjoyed in a smokeless form. Particularly popular smokeless tobacco products are used by placing some form of processed tobacco or tobacco-containing formulation into the user's mouth. Conventional formats for such smokeless tobacco products include moist snuff, snus, and chewing tobacco, which are generally composed almost entirely of particulate, granular, or crushed tobacco, and are divided into portions by the user or presented in individual portions, such as single-use pouches or sachets. Other traditional forms of smokeless products include compressed or agglomerated forms, such as plugs, tablets, or granules. Alternative product formats are also known, such as chewing gum containing tobacco and mixtures of tobacco with other plant materials. See, for example, the types of formulations, ingredients, and processing methodologies for smokeless tobacco disclosed in U.S. Patents Nos. 1,376,586 to Schwartz; 4,513,756 to Pittman et al.; 4,528,993 to Sensabaugh, Jr. et al.; and 4,624,269 to Story et al. 4,991,599 from Tibbetts; 4,987,907 from Townsend; 5,092,352 from Sprinkle, III et al.; 5,387,416 from White et al.; 6,668,839 to Williams; 6,834,654 to Williams; 6,953,040 to Atchley et al.; 7,032,601 to Atchley et al.; and 7,694,686 to Atchley et al.; U.S. Patent Applications Nos. 2004 / 0020503 to Williams; 2005 / 0115580 to Quinter et al.; 2006 / 0191548 to Strickland et al.; 2007 / 0062549 to Holton, Jr. et al.; 2007 / 0186941 to Holton, Jr. et al.; 2007 / 0186942 to Strickland et al.; 2008 / 0029110 to Dube et al.; 2008 / 0029116 by Robinson et al; 2008 / 0173317 by Robinson et al; 2008 / 0209586 by Neilsen et al; 2009 / 0065013 by Essen et al; and 2010 / 0282267 by Atchley, as well as WO2004 / 095959 by Arnarp et al, each of which is incorporated herein by reference. More recently, smokeless tobacco product configurations have been proposed that combine tobacco material with various binders and fillers, with example product formats including lozenges, tablets, gels, extruded forms, and the like. See, for example, [details of product configurations]. FRncnn / zznz / e / YiAi For example, the types of products described in U.S. patent applications Nos. 2008 / 0196730 by Engstrom et al.; 2008 / 0305216 by Crawford et al.; 2009 / 0293889 by Kumar et al.; 2010 / 0291245 by Gao et al.; 2011 / 0139164 by Mua et al.; 2012 / 0037175 by Cantrell et al.; 2012 / 0055494 by Hunt et al.; 2012 / 0138073 by Cantrell et al.; 2012 / 0138074 by Cantrell et al.; 2013 / 0074855 by Holton, Jr.; 2013 / 0074856 by Holton, Jr.; 2013 / 0152953 by Mua et al.; 2013 / 0274296 by Jackson et al.; 2015 / 0068545 by Moldoveanu et al.; 2015 / 0101627 by Marshall et al.; and 2015 / 0230515 by Lampe et al., each of which is incorporated herein by reference. In addition, all-white snus portions are gaining popularity and offer a discreet and aesthetically pleasing alternative to traditional snus. Such modern products in white pouches may contain bleached tobacco or perhaps no tobacco at all.Over the years, various treatment methods and additives have been proposed to alter the overall character or nature of the tobacco materials used in tobacco compositions. For example, additives or treatment processes are sometimes used to alter the chemical or sensory properties of the tobacco material or, in the case of smokable tobacco materials, to alter the chemical or sensory properties of the main smoke generated by smoking articles, including the tobacco material. In some cases, a heat treatment process may be used to impart a desired color or visual character to the tobacco material, desired sensory properties to the tobacco material, or a desired physical nature or texture to the tobacco material. It would be desirable in the art to provide additional methods for altering the character and nature of tobacco (and tobacco compositions and formulations) useful in smoking articles or smokeless tobacco products. In particular, an improved tobacco bleaching process and bleached tobacco material are desirable, wherein the tobacco bleaching process does not include chemical pulping or alkaline extraction prior to the bleaching operation of the tobacco material. Summary of the Invention This description provides a method for processing tobacco material to modify its color, specifically to produce a lighter-colored (i.e., bleached) tobacco material. The bleached tobacco material can be used in smokeless tobacco products to create materials suitable for oral use with a bleached appearance. Remarkably, it has been found that a high degree of bleaching can be achieved without a harsh chemical pulping step prior to bleaching, such as an elevated-temperature treatment with sulfur-containing reagents, organic solvents, sodium hydroxide, or an acid. FRncnn / zznz / e / YiAi In various embodiments, a method for bleaching tobacco material is provided, the method comprising (i) extracting tobacco material with an extraction solution to provide solid tobacco material and a tobacco extract; (ii) bleaching the solid tobacco material with a bleaching solution comprising a strong base, an oxidizing agent, or a combination thereof to provide bleached tobacco material; and (iii) drying the bleached tobacco material to provide bleached tobacco material; wherein the solid tobacco material is not subjected to elevated temperature treatment with sulfur-containing reagents, organic solvents, sodium hydroxide, or an acid between the extraction step (i) and the bleaching step (ii). In various embodiments, the bleached tobacco material is characterized by an International Organization for Standardization (ISO) brightness of at least approximately 50%.The bleached tobacco materials provided in this document can be used in a smokeless tobacco product, for example. In various embodiments, the starting tobacco material comprises leaves, stems, or a combination thereof. In certain embodiments, the tobacco material comprises stems of Rustica. In some embodiments, the tobacco material comprises at least approximately 90% by weight of roots, stems, or a combination thereof. In some embodiments, the bleaching method further includes grinding the tobacco material prior to extraction so that the ground tobacco material can pass through a sieve with a mesh size of 18 US. In certain embodiments, the tobacco material may be ground to a size in the range of 0.2 mm to approximately 2 mm prior to extraction. In several embodiments, the extraction solution is an aqueous solution. In some embodiments, the extract solution may be acidic, basic, or neutral. The extraction solution may also include metal chelating agents and / or oxidizing agents. For example, in certain embodiments, the aqueous solution comprises one or more of EDTA and DTPA. In certain embodiments, the extraction solution is acidic with a pH of less than approximately 7 and incorporates a metal chelating agent such as ethylenediaminetetraacetic acid (EDTA). In some embodiments, the step of extracting the tobacco material is carried out at a temperature of approximately 100°C or lower. In several embodiments, the molar ratio of the extraction solution to the tobacco material in the extraction step is from approximately 4:1 to approximately 16:1. In certain embodiments, the bleaching method may further comprise mixing the solid tobacco material with wood pulp prior to bleaching. In several embodiments, the bleaching step may include treatment with a solution of a strong base and an oxidizing agent or combinations of oxidizing agents. In various embodiments, the bleaching solution comprises one or more peracetic acids, FRncnn / zznz / e / YiAi sodium hydroxide and hydrogen peroxide. In some embodiments, the bleaching solution comprises a strong base and an oxidizing agent, wherein the weight ratio of the amount of oxidizing agent to the amount of strong base is from approximately 1:1 to approximately 100:1. In certain embodiments, the weight ratio of the amount of oxidizing agent to the amount of strong base is from approximately 2.5:1 to approximately 15:1. In various embodiments, the step of bleaching the solid tobacco material is carried out at a temperature of approximately 100°C or lower. In several embodiments, the bleaching method further comprises neutralizing the bleached tobacco material to a pH in the range of approximately 5 to approximately 11 before drying. In some formulations, the bleaching solution also includes one or more stabilizers in addition to an oxidizing agent. The stabilizers can be selected from the group consisting of magnesium sulfate, sodium silicate, and combinations thereof, for example. In several embodiments, the bleaching solution used to bleach the solid tobacco material comprises a chelating agent. In certain embodiments, the chelating agent comprises one or more of EDTA and DTPA. The bleaching solution may also incorporate oxidizing stabilizers and metal chelating agents. In certain formulations, the bleaching solution comprises hydrogen peroxide, a strong base, a metal chelating agent such as ethylenediaminetetraacetic acid (EDTA), and an oxidizing stabilizer such as sodium silicate and / or magnesium salts such as magnesium sulfate. The bleached tobacco material can be dried to a moisture content of less than approximately 30 percent on a wet basis, for example. In various embodiments, the bleaching methods described herein further include dehydrating the tobacco material using at least one screw press and one basket centrifuge following step (i) (the extraction step) and / or step (i) (the bleaching step). The bleaching method may further include grinding the bleached tobacco material after drying to a size in the range of approximately 5 mm to approximately 0.1 mm. In several embodiments, the bleaching method further comprises incorporating the bleached tobacco material into a smokeless tobacco product. The smokeless tobacco product may further comprise, for example, one or more additional components selected from the group consisting of flavorings, fillers, binders, pH adjusters, buffering agents, colorants, disintegrating aids, antioxidants, humectants, and preservatives. FRncnn / zznz / e / YiAi A smokeless tobacco product is also provided, incorporating bleached tobacco material prepared according to the methods described herein. In certain embodiments, the smokeless tobacco product comprises a water-permeable pouch containing the bleached tobacco material. The smokeless tobacco product may further include, for example, one or more additional components selected from the group consisting of flavorings, fillers, binders, pH adjusters, buffering agents, colorants, disintegrating aids, antioxidants, humectants, and preservatives. Also provided herein is a method for preparing bleached tobacco material for use in a smokeless tobacco product, wherein the method essentially consists of: (i) extracting tobacco material with an extraction solution to yield solid tobacco material and a tobacco extract; (ii) separating the solid tobacco material and the tobacco extract; (iii) bleaching the solid tobacco material with a solution comprising a strong base, an oxidizing agent, or a combination thereof to yield bleached tobacco material; and (iv) drying the bleached tobacco material to yield bleached tobacco product. The method may optionally include one or more of the following process steps: (i) grinding the tobacco material so that the ground tobacco material can pass through a sieve with a sieve size of 18 US(i) dehydrating the tobacco material using at least one screw press and one basket centrifuge after the extraction and / or bleaching stage; (iii) neutralizing the bleached tobacco material to a pH in the range of about 5 to about 11 before drying; and (iv) grinding the bleached tobacco material after drying to a size in the range of about 5 mm to about 0.1 mm. In several embodiments, the extraction solution is an aqueous solution. The invention includes, without limitation, the following forms. Modality 1: A method for preparing bleached tobacco material, comprising: (i) extracting tobacco material with an extraction solution to provide solid tobacco material and a tobacco extract; (ii) bleaching the solid tobacco material with a bleaching solution comprising a strong base, an oxidizing agent, or a combination thereof to provide bleached tobacco material; and (iii) drying the bleached tobacco material to provide bleached tobacco material; wherein the solid tobacco material is not subjected to elevated temperature treatment with sulfur-containing reagents, organic solvents, sodium hydroxide, or an acid between the extraction of the tobacco material and the bleaching of the solid tobacco material. Mode 2: A method of mode 1, further comprising grinding the tobacco material to a size in the range of approximately 0.2 mm to approximately 2 mm. FRnrnn / zznz / e / YiAi Modality 3: A method of any of modalities 1-2, wherein the extraction of the tobacco material is carried out at a temperature of approximately 100°C or lower. Modality 4: A method of any of modalities 1-3, wherein the bleaching of the solid tobacco material is carried out at a temperature of approximately 100°C or lower. Mode 5: A method of any of modes 1-4, wherein the bleached tobacco material is dried to a moisture content of less than approximately 30 percent moisture on a wet basis. Mode 6: A method of any of modes 1-5, further comprising dehydrating the tobacco material using at least one screw press and one basket centrifuge after extracting the tobacco material and / or bleaching the solid tobacco materials. Mode 7: A method of any of modes 1-6, wherein the bleaching solution comprises one or more of peracetic acid, sodium hydroxide, and hydrogen peroxide. Mode 8: A method of any of modes 1-7, wherein the bleaching solution further comprises one or more stabilizers in addition to an oxidizing agent. Modality 9: A method of any of modalities 1-8, wherein the bleaching solution further comprises one or more stabilizers, and wherein the stabilizers are selected from the group consisting of magnesium sulfate, sodium silicate, and combinations thereof. Mode 10: A method of any of modes 1-9, wherein the bleaching solution comprises a strong base and an oxidizing agent, and wherein the molar ratio of the amount of oxidizing agent to the amount of strong base is from approximately 1:1 to approximately 100:1. Mode 11: A method of any of modes 1-10, wherein the bleaching solution comprises a strong base and an oxidizing agent, and wherein the weight ratio of the amount of oxidizing agent to the amount of strong base is approximately 2.5:1 to about 15:1. Mode 12: A method of any of modes 1-11, further comprising neutralizing the bleached tobacco material to a pH in the range of approximately 5 to approximately 11 before drying the bleached tobacco material. Mode 13: A method of any of modes 1-12, further comprising grinding the bleached tobacco material after drying the bleached tobacco material to a size in the range of approximately 5 mm to approximately 0.1 mm. FRnrnn / zznz / e / YiAi Mode 14: A method of any of modes 1-13, wherein the extraction solution comprises a chelating agent. Mode 15: A method of any of modes 1-14, wherein the extraction solution comprises a chelating agent, and wherein the chelating agent comprises one or more of EDTA and DTPA. Mode 16: A method of any of modes 1-15, wherein the bleaching solution used to bleach the solid tobacco material comprises a chelating agent. Mode 17: A method of any of modes 1-16, wherein the bleaching solution used to bleach the solid tobacco material comprises a chelating agent, and wherein the chelating agent comprises one or more of EDTA and DTPA. Modality 18: A method of any of modalities 1-17, wherein the molar ratio of the extraction solution to the tobacco material is from approximately 4:1 to approximately 16:1. Mode 19: A method of any of modes 1-18, wherein the extraction solution is an aqueous solution. Modality 20: A method of any of modalities 1-19, wherein the tobacco material comprises sheets, stems or a combination thereof. Modality 21: A method of any of modalities 1-20, wherein the tobacco material comprises Rustica stems. Modality 22: A method of any of modalities 1-21, wherein the tobacco material comprises at least approximately 90% by weight of roots, stems or a combination thereof. Modality 23: A method of any of modalities 1-22, wherein the bleached tobacco material is characterized by an International Organization for Standardization (ISO) brightness of at least approximately 50%. Mode 24: A method of any of modes 1-23, further comprising mixing the solid tobacco material with wood pulp before bleaching the solid tobacco material. Modality 25: A method of any of modalities 1-24, further comprising incorporating the bleached tobacco material into a product adapted for oral use, such as a smokeless tobacco product. FRnrnn / zznz / e / YiAi Mode 26: A method of any of modes 1-24, further comprising incorporating the bleached tobacco material within a product adapted for oral use, such as a smokeless tobacco product, wherein the product further comprises one or more additional components selected from the group consisting of flavorings, fillers, binders, pH adjusters, buffering agents, colorants, disintegration aids, antioxidants, humectants, and preservatives. Modality 27: A product adapted for oral use, such as a smokeless tobacco product, incorporating bleached tobacco material prepared according to a method of any of modalities 1-24. Modality 28: A product (such as a smokeless tobacco product) incorporating bleached tobacco material prepared according to the method of any of Modalities 124, comprising a water-permeable pouch containing the bleached tobacco material. Mode 29: A product (such as a smokeless tobacco product) incorporating bleached tobacco material prepared according to the method of any of modes 1-24, further comprising one or more additional components selected from the group consisting of flavorings, fillers, binders, pH adjusters, buffering agents, colorants, disintegration aids, antioxidants, humectants and preservatives. Modality 30: A method for preparing bleached tobacco material for use in a smokeless tobacco product, comprising essentially (i) extracting a tobacco material with an extraction solution to provide a solid tobacco material and a tobacco extract; (ii) separating the solid tobacco material and the tobacco extract; (iii) bleaching the solid tobacco material with a bleaching solution comprising a strong base, an oxidizing agent, or a combination thereof to provide bleached tobacco material; and (iv) drying the bleached tobacco material to provide bleached tobacco material. Mode 31: A method of mode 30, wherein the extraction solution is an aqueous solution. These and other features, aspects, and advantages of the invention will become apparent from reading the following detailed description together with the accompanying drawings, which are briefly described below. The invention includes any combination of two, three, four, or more of the aforementioned embodiments, as well as combinations of two, three, four, or more features or elements set forth in this description, regardless of whether such features or elements are expressly combined in a specific embodiment described herein. This description is intended to be read holistically, from FRnrnn / zznz / e / YiAi so that any separable feature or element of the disclosed invention, in any of its various aspects and forms, should be seen as being intended to be combinable unless the context clearly indicates otherwise. Brief Description of the Figures Having thus described the description in the above general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and in which: FIGURE 1 is a front perspective view illustrating a bagged product according to a Modality; and FIGURE 2 is a flowchart that illustrates the general steps for preparing bleached tobacco material according to a modality. Detailed Description of the Invention The aspects of the present description will now be described in more detail below. However, this invention can be carried out in many different ways and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided to make this description exhaustive and complete, and to fully convey the scope of the invention to those skilled in the art. As used in this specification and in the claims, the singular forms a, an, and the include plural referents unless the context clearly dictates otherwise. Reference to percentage of dry weight or dry weight basis refers to the weight on a dry ingredients basis (i.e., all ingredients except water). Certain embodiments will be described with reference to Figure 1 of the accompanying drawings, and these described embodiments involve snus-type products that have an outer pouch and contain bleached tobacco material. As explained in more detail below, these embodiments are provided by way of example only, and the smokeless tobacco product may include tobacco compositions in other forms. Referring to Figure 1, a first embodiment of a smokeless tobacco product 10 is shown. The tobacco product 10 includes a moisture-permeable pouch 20 containing a material 15 comprising bleached tobacco of a type described herein. The smokeless tobacco product may also optionally comprise, in certain embodiments, a plurality of dispersed microcapsules. FRnrnn / zznz / e / YiAi within the tobacco filling material 15, the microcapsules containing a component (e.g. a flavoring) as described in more detail below. Tobacco Product 10 is typically used by placing a pouch containing the tobacco formulation in the mouth of a human subject / user. During use, saliva in the user's mouth causes some of the components of the tobacco formulation to pass through the water-permeable pouch and into the user's mouth. The pouch is preferably not chewed or swallowed. The user is provided with tobacco flavor and satisfaction and is not required to spit out any portion of the tobacco formulation. After approximately 10 to 60 minutes, typically 15 to 45 minutes, of use / enjoyment, substantial amounts of the tobacco formulation and the contents of the optional microcapsules have been absorbed (either by gingival or buccal absorption) by the human subject, and the pouch can be removed from the subject's mouth for disposal.In certain modalities, the bag materials can be designed and manufactured so that, under normal conditions of use, a significant amount of the tobacco formulation content penetrates through the bag material before the moment the bag loses its physical integrity. The present invention provides a bleached tobacco composition, smokeless tobacco products incorporating such bleached tobacco compositions, and methods for preparing a bleached tobacco composition and for incorporating such compositions into smokeless tobacco products. As used herein, the term bleached refers to a composition comprising tobacco material that has been treated to remove a certain degree of color. Therefore, a “bleached” tobacco material treated according to the methods described herein has a visually lighter shade than untreated tobacco material.The bleached tobacco composition of the invention can be used as a component of a smokeless tobacco composition, such as loose wet snuff, loose dry snuff, chewing tobacco, pelleted tobacco pieces, extruded or formed tobacco strips, chunks, rods or bars, finely divided ground powders, finely divided or ground agglomerates of powdered pieces and components, flake-shaped pieces, molded processed tobacco pieces, pieces of chewing gum containing tobacco, tape-like film rolls, readily soluble or dispersible films or strips in water, or capsule-like materials. The tobaccos used in the tobacco compositions of the invention may vary. In certain embodiments, the tobaccos that may be employed include hot-air cured or Virginia tobaccos (e.g., K326), Burley, sun-cured (e.g., Indian Kurnool and Oriental tobaccos, including Katerini, Prelip, Komotini, Xanthi, and Yambol), Maryland, dark-cooked, dark-air cured tobaccos (e.g., Passanda, Cubano, Jatin, and Bezuki tobaccos). FRnrnn / zznz / e / YiAi light air-cured tobaccos (e.g., North Wisconsin and Galpao tobaccos), air-cured Indian tobaccos, Red Russian and Rustica, as well as several other rare or specialty tobaccos and various blends of any of the foregoing tobaccos. Descriptions of several types of tobacco, cultivation practices, and harvesting practices are set forth in Tobacco Production, Chemistry and Technology, Davis et al. (Eds.) (1999), which is incorporated herein by reference. Several other representative types of plants of the Nicotiana species are set forth in Goodspeed, The Genus Nicotiana, (Chonica Botánica) (1954); U.S. Patents Nos. 4,660,577 to Sensabaugh, Jr. et al.; 5,387,416 to White et al.; and 7,025,066 to Lawson et al.; U.S. Patent Applications Nos. 2006 / 0037623 by Lawrence, Jr. and 2008 / 0245377 by Marshall et al.; each of which is incorporated herein by reference. Examples of Nicotiana species include N. tabacum, N. rustica, N. alata, N. arentsii, N. excelsior, N.olvidadoiana, N. glauca, N. glutinosa, N. gossei, N. kawakamii, N. knightiana, N. langsdorffi, N. otophora, N. setchelli, N. sylvestris, N. tomentosa, N. tomentosiformis, N. undulata, N. x sanderaeca, N. de a.fricaixina N. bonariensis, N. debneyi , N. longiflora, N. maritina, N. megalosiphon, N. occidentalis, N. paniculata, N. plumbaginifolia, N. raimondii, N. rosulata, N. simulans, N. stocktonii, N. suaveolens, N. wi umbráiticaulies, N. wi umbrática N. acuminata, N. attenuata, N. benthamiana, N. cavicola, N. clevendii, N. cordifolia, N. corymbosa, N. fragrans, N. goodspeedii, N. linearis , N. miersii, N. nudicaulis, N. obtusifolia, N. obtusifolia, N.. sub.. Hersperis, N. pauciflora, N. petunioides, N. quadrivalvis, N. repanda, N. rotundifolia, N. solanifolia and N. spegazzinii. Nicotiana species can be derived using genetic modification or crossbreeding techniques (for example, tobacco plants can be genetically manipulated or crossbred to increase or decrease the production of components, characteristics, or attributes). See, for example, the types of plant genetic modifications discussed in U.S. Patents Nos. 5,539,093 to Fitzmaurice et al.; 5,668,295 to Wahab et al.; 5,705,624 to Fitzmaurice et al.; 5,844,119 to Weigl; 6,730,832 to Dominguez et al.; 7,173,170 to Liu et al.; 7,208,659 to Colliver et al.; and 7,230,160 to Benning et al.; and in U.S. Patent Application No. 2006 / 0236434 to Conkling et al. and PCT WO 2008 / 103935 of Nielsen et al. See also the types of tobacco discussed in U.S. Patents Nos. 4,660,577 of Sensabaugh, Jr. et al.; 5,387,416 of White et al.; and 6,730,832 of Dominguez et al., each of which is incorporated herein by reference.Ideally, the tobacco materials are those that have been properly cured and aged. Especially preferred techniques and conditions for curing smoke-cured tobacco are set forth in Nestor et al., Beitrage Tabakforsch. Int., 20 (2003) 467-475 and Peele's U.S. Patent No. 6,895,974, which are incorporated herein by reference. Representative techniques and conditions for curing air-cured tobacco are set forth in Roton et al., Beitrage Tabakforsch. Int., 21 (2005) 305-320 and Staaf et al., Beitrage Tabakforsch. Int., 21 (2005) 321-330. FRnrnn / zznz / e / YiAi are incorporated herein by reference. Certain unusual or rare types of tobacco may be sun-cured. The methods for improving the smoking quality of oriental tobaccos are set forth in U.S. Patent No. 7,025,066 to Lawson et al., which is incorporated herein by reference. Representative oriental tobaccos include katerini, prelip, komotini, xanthi, and yambol tobaccos. Tobacco compositions including air-cured dark tobacco are set forth in U.S. Patent Application No. 2008 / 0245377 to Marshall et al., which is incorporated herein by reference. See also, types of tobacco as set forth, for example, in U.S. Patent Application No. 2011 / 0247640 to Beeson et al., which is incorporated herein by reference. The Nicotiana species can be selected for the content of various compounds present within it. For example, plants can be selected based on their production of relatively high quantities of one or more compounds that are to be isolated. In certain cases, plants of the Nicotiana species (e.g., common tobacco) are specifically cultivated for the abundance of compounds on their leaf surface. Tobacco plants can be grown in greenhouses, growth chambers, outdoors in fields, or hydroponically. Various parts or portions of the Nicotiana plant may be used. For example, virtually the entire plant (e.g., the whole plant) may be harvested and used as is. Alternatively, various parts or pieces of the plant may be harvested or separated for later use after harvesting. For example, the flower, leaves, stem, stalk, roots, seeds, and various combinations thereof may be isolated for further use or treatment. In some forms, the tobacco material subjected to the treatments set forth herein consists of ground Rustica stems. Post-harvest processing of the plant or part thereof can vary. After harvest, the plant, or part thereof, may be used in its green form (e.g., the plant or part thereof may be used without undergoing any curing process). For example, the plant or part thereof may be used without being subjected to significant storage, handling, or processing conditions. In certain situations, it is advantageous for the plant or part thereof to be used practically immediately after harvest. Alternatively, for example, a plant or part thereof in its green form may be chilled or frozen for later use, freeze-dried, irradiated, yellowed, dried, cured (e.g., using air-drying techniques or techniques employing the application of heat), heated or cooked (e.g., roasted, fried, or boiled), or otherwise subjected to storage or treatment for later use. The harvested plant or part of it can be physically processed. The plant or part of it can be separated into individual parts or pieces (for example, the leaves are FRncnn / zznz / e / YiAi may be removed from the stems and / or the stems and leaves may be removed from the stem). The harvested plant or individual parts or pieces may be subdivided into parts or pieces (e.g., leaves may be shredded, cut, crushed, pulverized, ground, or milled into pieces or parts that may be characterized as filler pieces, granules, particles, or fine powders). The plant, or parts thereof, may be subjected to external forces or pressures (e.g., by being pressed or subjected to roller treatment). By carrying out such processing conditions, the plant or part thereof may have a moisture content that approximates its natural moisture content (e.g., its moisture content immediately after harvest), a moisture content that is achieved by adding moisture to the plant or part thereof, or a moisture content that results from drying the plant or part thereof.For example, powdered, pulverized, ground, or milled plant pieces or parts thereof may have a moisture content of less than 25 percent by weight, often less than 20 percent by weight, and frequently less than 15 percent by weight. Tobacco compositions intended for use in a smokeless form, as shown in Figure 1, may incorporate only one type of tobacco (e.g., in the so-called pure grade form). For example, the tobacco within a tobacco composition may consist solely of hot-air cured tobacco (e.g., all the tobacco may be composed of or derived from hot-air cured tobacco sheets or a mixture of hot-air cured tobacco sheets and hot-air cured tobacco stalks). In one embodiment, the tobacco comprises or consists solely of sun-cured, ground Rustica stalks (i.e., N. rustica stalks). The tobacco within a tobacco composition may also have the so-called blended form. For example, the tobacco within a tobacco composition of the present invention may include a mixture of hot-air cured tobacco parts or pieces, such as burley (e.g.,Malawi burley tobacco) and oriental tobaccos (e.g., as tobacco composed of, or derived from, tobacco foil, or a mixture of tobacco foil and tobacco stem). The portions of tobacco within the tobacco product may have processed forms, such as processed tobacco stalks (e.g., cut and rolled stalks, cut, rolled, and expanded stalks, or cut inflated stalks), or volume-expanded tobacco (e.g., inflated tobacco, such as dry ice expanded tobacco (DIET)). See, for example, the tobacco expansion processes disclosed in U.S. Patents Nos. 4,340,073 to de la Burde et al.; 5,259,403 to Guy et al.; 5,908,032 to Pointexter et al.; and 7,556,047 to Poindexter et al., all of which are incorporated by reference. In addition, the tobacco product may optionally incorporate tobacco that has been fermented. See also the types of tobacco processing techniques set out in PCT WO 05 / 063060 by Atchley et al., which is incorporated herein by reference. FRnrnn / zznz / e / YiAi In certain embodiments, the starting tobacco material may include tobacco stalks. As used herein, "stalk" refers to the long, slender part of a tobacco plant from which the leaves or flowers grow and may include the leaves, the blade, and / or the flowers. In some embodiments, it may be advantageous to use both stalks and / or roots of the tobacco plant. The tobacco stalks and / or roots may be separated into individual pieces (e.g., roots separated from the stalks and / or root parts separated from each other, such as the large root, the middle root, and the small root parts), or the stalks and roots may be combined. "Peduncle" means the stalk remaining after the leaf has been removed (including the stalk and the blade). The root and various specific root parts useful according to the present invention may be defined and classified as described, for example, in Mauseth, Botany: An Introduction to Plant Biology.Fourth Edition, Jones and Bartlett Publishers (2009) and Glimn-Lacy et al., Botany Illustrated, Second Edition, Springer (2006), which are incorporated herein by reference. The harvested stems and / or roots are normally cleaned, ground, and dried to produce a material that can be described as particulate (i.e., crushed, pulverized, ground, granulated, or powdered). As used herein, stems and / or roots may also refer to stems and / or roots that have undergone an extraction process to remove water-soluble materials. The cellulosic material (i.e., solid tobacco material) remaining after the stem and / or root materials have undergone an extraction process may also be useful in the present invention. Although tobacco material may comprise material from any part of a plant of the Nicotiana species, in certain embodiments, the majority of the material may comprise material obtained from the stems, stalks, and / or roots of the plant. For example, in certain embodiments, the tobacco material comprises at least about 90%, at least about 92%, at least about 95%, or at least about 97% by dry weight of at least one of the stem materials, the stalk material, and the root material of a harvested plant of the Nicotiana species. The tobacco material used in the present invention is typically provided in powder, shredded, ground, granulated, or fine particle form. As illustrated in operation 100 of Fig. 2, the tobacco bleaching process described herein may optionally include grinding a tobacco material. Most preferably, the tobacco is used in the form of pieces or parts having an average particle size smaller than that of the shredded tobacco pieces or parts used in so-called fine-cut tobacco products.Generally, very finely divided tobacco particles or pieces are sized to pass through a sieve of approximately 18 or 16 US, usually sized to pass through a sieve of approximately 20 US, often sized to pass through a sieve of approximately 50 US, frequently sized to pass through a screen of approximately 60 US, it can even be. FRncnn / zznz / e / YiAi sizing to pass through a 100 US sieve size screen, and furthermore, it can be sized to pass through a 200 US sieve size screen. Note that two scales commonly used for classifying particle sizes are the US sieve series and the Tyler equivalent. Sometimes these two scales are referred to as Tyler Mesh Size or Tyler Standard Sieve Series. In the present application, reference is made to the US sieve size. If desired, air sorting equipment can be used to ensure that small tobacco particles of the desired sizes or size range can be collected. In one embodiment, the tobacco material is sized in particle form to pass through an 18 or 16 US sieve size, but not through a 60 US sieve size. If desired, pieces of granulated tobacco of different sizes can be mixed together.Typically, the very finely divided tobacco particles or pieces suitable for snus products have a particle size larger than US sieve size -8, often US sieve size -8 to US sieve size +100, frequently US sieve size -16 to US sieve size +60. In certain forms, the tobacco is supplied with an average particle size of about 0.2 to about 2 mm, about 0.5 to about 1.5 mm, about 0.2 to about 1.0 mm, or about 0.75 to about 1.25 mm (e.g., about 1 mm). The manner in which tobacco is provided in a finely divided or powdered form may vary. Preferably, the tobacco parts or pieces are crushed, ground, or pulverized into a powder using crushing, grinding, or similar equipment and techniques. Most preferably, the tobacco is in a relatively dry form during crushing or grinding, using equipment such as hammer mills, cutterheads, air-controlled mills, or similar equipment. For example, the tobacco parts or pieces may be crushed or ground when their moisture content is less than approximately 15 percent by weight to less than approximately 5 percent by weight. The tobacco material may be processed to provide it in the desired form before and / or after undergoing the bleaching and / or clarifying processes described herein. In some embodiments, the type of tobacco material being treated (i.e., subjected to the processes described herein) is selected so that it is initially visually lighter in color than other tobacco materials to a certain degree. Accordingly, an optional step of the method described herein involves examining various tobacco materials and selecting one or more of them based on their visual appearance (i.e., their lightness or whiteness). When carried out, this screening step may, in some embodiments, comprise a visual screening in which certain tobacco materials (e.g., certain types of tobacco) that are visually lighter in shade than other tobacco materials are selected. In some embodiments, the FRncnn / zznz / e / YiAi Selection can be performed by means of an automated operation that selects certain tobacco materials based on predetermined characteristics (e.g., having a lightness above a given threshold value). For example, optical instruments (e.g., spectrophotometer / spectroreflectometer) and / or optical sorting equipment can be used for this purpose. Such equipment is available, for example, from Autoelrepho® Products, AZ Technology, Hunter Lab, X-Rite, SpecMetrix, and others. In various ways, tobacco material can be treated to extract one or more soluble components. See, for example, the bleaching methods described in U.S. Patent Application No. 16 / 227,742 filed December 20, 2018, which is incorporated herein by reference. As illustrated in Figure 2, this first treatment step may comprise solvent extraction in operation 105, which involves contacting the tobacco material with a solvent (e.g., water) for a time and at a temperature sufficient to cause the extraction of one or more components of the tobacco material into the solvent, and separating the extract from the residual solid tobacco material. Solid tobacco material, as used herein, is the solid residual tobacco material remaining after the liquid component (i.e., tobacco extract) is removed from the material in step 105.Tobacco extract, as used herein, refers to the isolated components of a tobacco material that are extracted from the solid tobacco material by means of a solvent that is brought into contact with the tobacco material in an extraction process in step 105. Various tobacco material extraction techniques can be used to provide a tobacco extract and a solid tobacco material. See, for example, the extraction processes described in U.S. Patent Application No. 2011 / 0247640 to Beeson et al., which is incorporated herein by reference. Other example techniques for extracting tobacco components are described in U.S. Patents Nos. 4,144,895 to Fiore; 4,150,677 to Osborne, Jr. et al.; 4,267,847 to Reid; 4,289,147 to Wildman et al.; 4,351,346 to Brummer et al.; 4,359,059 to Brummer et al.; 4,506,682 to Müller; 4,589,428 to Keritsis; and 4,605,016 to Soga et al. 4,716,911 from Poulose et al.; 4,727,889 from Niven, Jr. et al.; 4,887,618 from Bernasek et al.; 4,941,484 from Clapp et al.; 4,967,771 from Fagg et al.; 4,986,286 from Roberts et al.; 5,005,593 from Fagg et al.5,018,540 from Grubbs et al.; 5,060,669 from White et al.; 5,065,775 from Fagg; 5,074,319 from White et al.; 5,099,862 from White et al.; 5,121,757 from White et al.; 5,131,414 from Fagg; 5,131,415 from Muñoz et al.; 5,148,819 from Fagg; 5,197,494 from Kramer; 5,230,354 from Smith et al.; 5,234,008 from Fagg; 5,243,999 from Smith; 5,301,694 from Raymond et al.; 5,318,050 from González-Parra et al.; 5,343,879 to Teague; 5,360,022 to Newton; 5,435,325 to Clapp et al.; 5,445,169 to Brinkley et al.; 6,131,584 to Lauterbach; 6,298,859 to Kierulff et al.; 6,772,767 to Mua et al.; and 7,337,782 to Thompson, all of which are incorporated herein by reference. In certain embodiments, the solvent is added to the tobacco material and the material is soaked for a FRnrnn / zznz / e / YiAi for a determined period of time (e.g., approximately 1 hour); the extraction product is then filtered to give a solid tobacco material and the solvent and any solubles contained therein are filtered to give a tobacco extract. The solvent used for the extraction of the tobacco material can vary. For example, in some methods, the solvent is aqueous, such as distilled water and / or tap water. In some methods, hot water extraction can be used. See, for example, Li et al., Bloresources, 8(4), 2013 (URL:https: / / ojs.cnr.ncsu.edu / index.php / BioRes / article / view / BioRes_08_4_5690_Li_Extraction_Hemicellulose_Aspen) In some formulations, the solvent may contain one or more additives and may include, for example, organic and / or inorganic acids, bases, or salts, pH buffers, surfactants, or combinations thereof, and may comprise smaller quantities of one or more organic solvents (e.g., various alcohols, polyols, and / or wetting agents). The extraction step of the tobacco material may be carried out under acidic, neutral, or basic conditions. See, for example, Huang et al., Bioresources, 14(3), 2019 (URL:https: / / ojs.cnr.ncsu.edu / index.php / BioRes / article / view / BioRes_14_3_5544_Huang_Production_Dissolve_Grade_Pulp_Tobacco). In particular, p5548 suggests that a variety of extraction conditions can be effective in removing extracts from tobacco material. In one particular embodiment, the solvent comprises sodium hydroxide (NaOH) (e.g., as a 5% NaOH solution in water). In other embodiments, the solvent may comprise an organic solvent, such as an alcohol (e.g., ethanol, isopropanol, etc.), which may be used alone or in combination with an aqueous solvent. Hemicellulase, cellulose, or other enzymatic treatment may be employed in the extraction step of the tobacco material. Typically, the extraction involves adding a large excess of one or more solvents to the tobacco material to produce a suspension (comprising, for example, 50–90% by weight of the solvent), although the amount of solvent may vary. The solvent may be at room temperature or at an elevated temperature. For example, the solvent may be heated to a temperature between approximately room temperature and approximately 120°C, preferably between approximately room temperature and approximately 110°C (e.g., approximately 100°C, approximately 80°C, approximately 60°C, approximately 40°C, or about 20°C). In some preferred embodiments, the tobacco material can be combined with water to form a wet aqueous material (e.g., in the form of a suspension or slurry), and the resulting material is typically heated to effect the extraction of various compounds. The water used to form the wet material can be pure water (e.g., tap water or water FRncnn / zznz / e / YiAi deionized) or a mixture of water with suitable co-solvents, such as certain alcohols. In certain embodiments, the amount of water added to form the wet material may be at least about 50 percent by weight, or at least about 60 percent by weight, or at least about 70 percent by weight, based on the total weight of the wet material. In some cases, the amount of water may be described as at least about 80 percent by weight or at least about 90 percent by weight. In some embodiments, the ratio of the amount of water to the amount of tobacco material by weight is in the range of about 5:1 to about 15:1, or about 8:1 to about 12:1. In certain forms, the ratio of water to tobacco material by weight is approximately 9:1 (e.g., 1215 lb of water and 135 lb of tobacco material).As indicated below, tobacco material may include additional cellulosic material such as wood pulp, for example. In certain methods, the tobacco material can be extracted with water and at least one chelating agent capable of removing transition metals from the tobacco material. Chelating agents are useful for removing certain metals from the tobacco material that could cause yellowing and thus interfere with the bleaching process.Suitable chelating agents may include, but are not limited to, EDTA, EGTA, HEDTA, DTPA, NTA, calcium citrate, calcium diacetate, calcium hexametaphosphate, citric acid, gluconic acid, dipotassium phosphate, disodium phosphate, isopropyl citrate, monobasic calcium phosphate, monoisopropyl citrate, potassium citrate, sodium acid phosphate, sodium citrate, sodium gluconate, sodium hexametaphosphate, sodium metaphosphate, sodium phosphate, sodium pyrophosphate, sodium tripolyphosphate, stearyl citrate, tetrasodium pyrophosphate, disodium calcium ethylenediaminetetraacetate, glucono delta-lactone, potassium gluconate, and the like, and their analogues, homologues, and derivatives; as described in U.S. Patent No. 9,321,806 to Lo et al., which is incorporated herein by reference in its entirety. For example, tobacco material can be extracted with an aqueous solution comprising ethylenediaminetetraacetic acid (EDTA).In some embodiments, the chelating agent may comprise diethylenetriaminepentaacetic acid (DTPA). In various embodiments, the chelating agents may be present in an amount of approximately 0.01 to approximately 5.0 percent dry weight, approximately 0.1 to approximately 2.0 percent dry weight, approximately 0.5 to approximately 1.5 percent dry weight, approximately 0.1 to approximately 0.5 percent dry weight, or approximately 0.7 to approximately 1.0 percent dry weight, based on the total dry weight of the tobacco material. The amount of time the tobacco material remains in contact with the solvent can vary. For example, in some formulations, the tobacco material is in contact with the solvent for approximately thirty minutes to approximately six. FRncnn / zznz / e / YiAi hours (e.g., approximately 1 hour, approximately 2 hours, approximately 3 hours, approximately 4 hours, approximately 5 hours, or approximately 6 hours), although shorter and longer time periods can be used. The amount of time may depend, for example, on the temperature of the solvent. For instance, less time may be required to extract tobacco material using solvent at a higher temperature than is required to extract tobacco material with solvent at room temperature or cold. The extraction process yields a solid tobacco material and a tobacco extract. The number of extraction steps may vary. For example, in certain embodiments, the tobacco material is extracted one or more times, two or more times, three or more times, four or more times, or five or more times. In some embodiments, the extraction may be performed countercurrently or by washing the tobacco material. The solvent used for each extraction may vary. For example, in one particular embodiment, one or more extractions are performed with hot water; and in a final extraction, the extraction is performed using a basic solution (e.g., a 5% NaOH solution). After each extraction step, the solid tobacco material is filtered, and the solvent and solubles are removed from the solid tobacco material. In certain embodiments, the extracts obtained from each extraction may be combined and clarified, as described in U.S. Patent No. 9,420,825 to Beeson et al., which is incorporated herein by reference in its entirety.In other methods, some extracts are discarded, such as extracts from later stages. In such methods, for example, it may be desirable to use only the tobacco extract obtained from the first extraction of a tobacco material or to combine tobacco extracts obtained from a first and second extraction of tobacco material. After the extraction process, the solid tobacco material is generally isolated from the tobacco extract, as illustrated in operation 110 of Fig. 2, for example, by filtration or centrifugation, although these methods are not intended to be exhaustive. Alternatively, in some embodiments, the solid tobacco material can be isolated from the extract by distillation (e.g., steam distillation) of the tobacco mixture (e.g., the tobacco suspension). The filtration process may involve passing the liquid through one or more filter screens to remove selected sizes of particulate material. The screens may be, for example, stationary, vibrating, rotary, or any combination thereof. The filters may be, for example, pressure filters or flow filters. In some embodiments, the filtration method used may involve microfiltration, ultrafiltration, and / or nanofiltration.A filter aid can be used to provide effective filtration and can comprise any material commonly used for this purpose. For example, some common filter aids include cellulose fibers, perlite, bentonite, diatomaceous earth, and other siliceous materials. To remove solid components, alternative methods can also be used, such as centrifugation or decantation / sedimentation of the components. FRncnn / zznz / e / YiAi Liquid extraction by siphon. See, for example, the processes and products described in U.S. Patent Applications Nos. 2012 / 0152265 to Dube et al. and 2012 / 0192880 to Dube et al., incorporated herein by reference in their entirety. The extracted solids component can be used as starting tobacco material in various embodiments of the bleaching process described herein. The solid tobacco material obtained and isolated after the extraction stage(s) is bleached (i.e., bleached) according to any means known in the art, as shown in step 120 of Figure 2. It is noted that, in certain embodiments, the combination of solid tobacco material and wood pulp may undergo a bleaching step or any other step of the process described herein; however, for convenience, the following description refers only to the solid tobacco material. For example, bleaching methods using various bleaching or oxidizing agents and oxidation catalysts may be employed. Examples of oxidizing agents include peroxides (e.g., hydrogen peroxide), chlorite salts, chlorate salts, perchlorate salts, hypochlorite salts, ozone, ammonia, and combinations thereof.Examples of oxidation catalysts are titanium dioxide, manganese dioxide, and combinations thereof. Processes for treating tobacco with bleaching agents are discussed, for example, in U.S. patents Nos. 787,611 to Daniels, Jr.; 1,086,306 to Oelenheinz; 1,437,095 to Delling; 1,757,477 to Rosenhoch; 2,122,421 to Hawkinson; 2,148,147 to Baier; 2,170,107 to Baier; 2,274,649 to Baier; 2,770,239 to Prats et al.; 3,612,065 to Rosen; 3,851,653 to Rosen; 3,889,689 to Rosen; and 3,943,945 to Rosen. Rainer's 4,143,666; Campbell's 4,194,514; Rainer et al.'s 4,366,823, 4,366,824, and 4,388,933; Schmekel et al.'s 4,641,667; Berger's 5,713,376; and Giolvas's PCT WO 96 / 31255, all of which are incorporated herein by reference. Other bleaching methods using reagents such as ozone and potassium permanganate may also be used. See, for example, Minami's U.S. Patent No. 3,943,940, which is incorporated herein by reference. In certain embodiments of the present invention, the tobacco material is bleached using a caustic reagent and / or an oxidizing agent. In some embodiments, the tobacco solids material is bleached using both a caustic reagent and an oxidizing agent. In such embodiments, the caustic reagent and the oxidizing agent may be provided separately or in combination. The stepwise addition of a strong base and / or a bleaching agent may be used in the bleaching step. See, for example, Zhao et al., Bioresources, 5(1), 276-210, 2010. URL:https: / / pdfs.Semanticscholar.org / 8e78 / 9d93d8cc673e2f13b8daee35e3477c51b3fe.pdf; Sun, HOU, Journal Of Bioresources and Bioproducts, 3(1),35-39, 2018; URL: http: / / www.bioresources FRncnn / zznz / e / YiAi bioproducts.com / index.php / bb / article / view / 110 / 109. In certain modalities, multiple stages of oxidative bleaching can be applied after the initial extraction stage. The caustic reagent can vary and may be, for example, any strong base, including, but not limited to, an alkali metal hydroxide, an alkaline earth metal hydroxide, or a mixture thereof. In certain example embodiments, the caustic reagent is sodium hydroxide or potassium hydroxide. Alternative reagents that may be used include, but are not limited to, ammonium hydroxide, sodium carbonate, potassium carbonate, ammonia gas, and mixtures thereof. The caustic reagent is generally provided in solution (e.g., in aqueous solution), and the concentration of the caustic reagent in the solution may vary. Furthermore, the amount of caustic reagent used in the methods of the present invention may vary.For example, in certain formulations, the caustic reagent is provided in an amount of between approximately 1% and approximately 50% by dry weight (e.g., between approximately 1% and approximately 40% or between approximately 1% and approximately 30%) of the dry tobacco solid material. For example, the caustic reagent may be provided in an amount of approximately 2%, approximately 5%, approximately 7%, approximately 10%, or approximately 25% by weight of the dry tobacco solid material. It is noted that the amount of caustic reagent required may, in certain formulations, vary as a result of the strength of the caustic reagent. For example, in some formulations, a more caustic reagent may be required when the caustic reagent is a weaker base, while in other formulations, a less caustic reagent may be required when the caustic reagent is a strong base. An oxidizing agent (i.e., oxidizer or oxidant) can be any substance that readily transfers oxygen atoms and / or gains electrons in a redox (reduction / oxidation) chemical reaction. Peroxides (e.g., hydrogen peroxide, peracetic acid) are the preferred oxidizing agents; however, any oxidizing reagent, including but not limited to: other oxides (including nitrous oxide, silver oxide, chromium trioxide, chromate, dichromate, pyridinium chlorochromate, and osmium tetroxide); oxygen (O2); ozone (O3); fluorine (F2); chlorine (Cl2); and other halogens; hypochlorite, chlorite, chlorate, perchlorite, and other halogen analogues thereof; nitric acid; nitrate compounds; sulfuric acid; persulfuric acids; and hydroxyl radicals, can be oxidizing agents. manganate and permanganate compounds (for example, potassium permanganate); sodium perborate; 2,2'-dipyridyl disulfide; and combinations thereof may be used according to the invention.In the peroxide bleaching stage, peroxide activators such as TAED (tetraacetylethylenediamine) can be used, which generates peracetic acid in situ. See, for example, URL: https: / / www.tappi.org / content / events / 07recycle / presentation / hsieh.pdf, Zhao et al, Bioresources, 5(1), 276-210, 2010, FRncnn / zznz / e / YiAi https: / / pdfs .semanticscholar.org / 8e78 / 9d93d8cc673e2f13b8daee35e3477c51 b3fe.pdf. In certain preferred embodiments, the oxidizing agent used according to the invention does not contain chlorine. In certain embodiments, the oxidizing agent is provided in the form of an aqueous solution. The amount of oxidizing agent used in the methods of the present invention may vary. For example, in certain embodiments, the oxidizing agent is provided in an amount by weight of approximately 0.1 to fifty times the weight of the (dry) solid tobacco material. For example, in some embodiments, the oxidizing agent is provided in an amount by weight approximately equal to the weight of the (dry) solid tobacco material, approximately 0.25 times the weight of the (dry) solid tobacco material, approximately 0.5 times the weight of the (dry) solid tobacco material, approximately 0.7 times the weight of the (dry) solid tobacco material, approximately 1.0 times the weight of the (dry) solid tobacco material, approximately 1.25 times the weight of the dry tobacco solids material, approximately 1.5 times the weight of the dry tobacco solids material, approximately 2 times the weight of the dry tobacco solids material, or approximately 5 times the weight of the dry tobacco solids material. In some embodiments, the oxidizing agent is provided in an amount by weight in the range of approximately 0.1 to approximately 5 times the weight of the dry tobacco solids material, approximately 0.2 to approximately 2.5 times the weight of the dry tobacco solids material, approximately 0.25 to approximately 1.5 times the weight of the dry tobacco solids material, approximately 0.5 to approximately 1.0 times the weight of the dry tobacco solids material, or approximately 0.7 to approximately 0.9 times the weight of the dry tobacco solids material. Different oxidizing agents may have different application rates.In certain embodiments where the oxidizing agent comprises hydrogen peroxide, the bleaching solution may comprise hydrogen peroxide at a weight of approximately 0.25-1.5 times the weight of the dry tobacco solids material. The solids content of the oxidative bleaching stage can be adjusted. While not limited by theory, a higher solids content can be beneficial, resulting in a need for a less oxidizing bleaching agent to achieve a target whiteness (or brightness). For example, in certain formulations, the bleaching solution may contain approximately 0.7–0.9 times more oxidizing agent than the dry tobacco material (approximately 10% solids), or approximately 1.0 times more oxidizing agent than the dry tobacco material (approximately 4.5% solids). In some formulations, a solids content >25% can be beneficial. See, for example, https: / / www.valmet.com / DulD / mechanical-DulDina / bleaching / bleach-tower / : FRncnn / zznz / e / YiAi httDs: / / www.valmet.com / pulp / mechanical-Dulp¡na / bleach¡na / h¡ah-cons¡stencv-bleach¡na-phc / ). As previously stated, the percentage of solids during bleaching can vary and may impact the effectiveness of the bleaching operation. As described in the Examples below, the percentage of solids is calculated using the following formula: Solids (%) = 100 x (weight of dry tobacco) / (weight of dry tobacco + weight of water + weight of oxidizing agent) In several varieties, the percentage of solids may range from approximately 1-20%, approximately 3-15%, or approximately 3-10%. In some varieties, the percentage of solids may range from approximately 2-5% or approximately 8-12%. The percentage of solids may be, for example, at least 2%, at least 3%, at least 4%, at least 5%, or at least 10%. In several embodiments, the bleaching process may also include treatment with one or more stabilizers in addition to an oxidizing agent. For example, the stabilizer may be selected from the group consisting of magnesium sulfate, sodium silicate, and combinations thereof. In various embodiments, the stabilizers may be present in an amount of approximately 0.01 to approximately 3.0 percent dry weight, approximately 0.1 to approximately 2.5 percent dry weight, or approximately 0.5 to approximately 2.0 percent dry weight, based on the total dry weight of the solid tobacco material. In various forms, the bleaching step may also include treatment with at least one chelating agent. Suitable chelating agents may include, but are not limited to, EDTA, EGTA, HEDTA, DTPA, NTA, calcium citrate, calcium diacetate, calcium hexametaphosphate, citric acid, gluconic acid, dipotassium phosphate, disodium phosphate, isopropyl citrate, monobasic calcium phosphate, monoisopropyl citrate, potassium citrate, sodium acid phosphate, sodium citrate, sodium gluconate, sodium hexametaphosphate, sodium metaphosphate, sodium phosphate, sodium pyrophosphate, sodium tripolyphosphate, stearyl citrate, tetrasodium pyrophosphate, disodium calcium ethylenediaminetetraacetate, glucono delta-lactone, potassium gluconate, and similar products, and their analogues, homologues, and derivatives; as described in U.S. Patent No. 9,321,806 of Lo et al., which is incorporated herein by reference in its entirety. According to the invention, the solid tobacco material is brought into contact with the caustic reagent and / or the oxidizing agent for a period of time. The tobacco material can be brought into contact with the caustic reagent and the oxidizing reagent simultaneously, or it can be brought into contact with the caustic reagent and the oxidizing reagent separately. In one embodiment, the oxidizing reagent is added to the tobacco material, and then the caustic reagent is... FRnrnn / zznz / e / YiAi adds to the tobacco material so that, after addition, both reagents are in contact with the tobacco material simultaneously. In another embodiment, the caustic reagent is added to the tobacco material and then the oxidizing reagent is added to the tobacco material so that, after addition, both reagents are in contact with the tobacco material simultaneously. The weight ratio of the oxidizing agent to the caustic reagent can vary. In certain embodiments, such as when the caustic reagent is NaOH and the oxidizing agent is hydrogen peroxide, the weight ratio of hydrogen peroxide to NaOH is approximately 1:1 to approximately 100:1, preferably approximately 5:1 to approximately 50:1, and more preferably approximately 5:1 to approximately 15:1. In certain embodiments, the weight ratio of hydrogen peroxide to NaOH is between approximately 2.5:1 and approximately 13:1, or approximately 8:1 and approximately 13:1. These ratios are not limited to the ratios of NaOH and hydrogen peroxide and could also apply to other combinations of caustic reagents and oxidizing agents. The contact time between the tobacco material and the caustic reagent and / or oxidizing agent can vary. For example, in certain methods, the contact time is sufficient to produce a solid tobacco material with a lighter color compared to untreated tobacco. In some methods, the tobacco material is contacted with the caustic reagent and / or oxidizing agent overnight. Typically, this contact time is at least approximately 10 minutes, usually at least approximately 20 minutes, and more often at least approximately 30 minutes. In other methods, the contact time is no more than 10 hours, no more than 8 hours, no more than 6 hours, no more than 4 hours, no more than 2 hours, or no more than approximately 1 hour. In certain methods, the tobacco material may be heated during treatment with the caustic reagent and / or oxidizing agent. Generally, heating the tobacco material accelerates the bleaching process. When the tobacco material is heated during treatment, sufficient color lightening is usually achieved in less time than in methods where the tobacco material is not heated. The temperature and duration of the heat treatment process will vary, and in general, the duration of the heat treatment will decrease as the heat treatment temperature increases. In certain methods, the mixture of tobacco material, caustic reagent, and / or oxidizing agent may be heated to a temperature between room temperature and approximately 100°C (for example, approximately 90°C or approximately 80°C). Preferably, the mixture is heated between room temperature and approximately 75°C.The warm-up. FRncnn / zznz / e / YiAi when appropriate, can be performed using any heating method or apparatus known in the art. Heating can be carried out in a closed vessel (e.g., one that provides a controlled atmospheric environment, controlled atmospheric components, and controlled atmospheric pressure) or in a vessel that is essentially open to ambient air. The temperature can be controlled using a jacketed vessel, direct steam injection into the tobacco, bubbling hot air through the tobacco, and similar methods. In certain configurations, heating is performed in a vessel that is also capable of providing mixing of the composition, for example, by stirring or agitation. Examples of mixing vessels include mixers available from Scott Equipment Company, Littleford Day, Inc., Lódige Process Technology, and the Breddo Likwifier Division of American Ingredients Company. Examples of vessels that provide a controlled pressure environment include high-pressure autoclaves available from Berghof / America Inc.from Concord, California, and high-pressure reactors available from The Parr Instrument Co. (e.g., Parr Reactor Model No. 4522 and 4552 described in U.S. Patent No. 4,882,128 to Hukvari et al.). The pressure inside the mixing vessel during the process can be atmospheric pressure or elevated pressure (e.g., from approximately 10 psig to approximately 1000 psig). In other embodiments, the heating process is carried out in a microwave oven, a convection oven, or by infrared heating. Atmospheric air, or ambient atmosphere, is the preferred atmosphere for carrying out the optional heating step of the present invention. However, heating can also take place under a controlled atmosphere, such as a generally inert atmosphere. Gases such as nitrogen, argon, and carbon dioxide can be used. Alternatively, a hydrocarbon gas (e.g., methane, ethane, or butane) or a fluorocarbon gas can also provide at least part of a controlled atmosphere in certain embodiments, depending on the choice of treatment conditions and the desired reaction products. In certain embodiments, before drying the bleached tobacco material, it may be treated with an acid to neutralize it to a pH in the range of approximately 5 to approximately 11 (as illustrated in operation 125 of Fig. 2, for example), such as approximately 6 to approximately 10. The bleached tobacco material may be treated with sulfuric acid, hydrochloric acid, citric acid, or any combination thereof. Other acids known in the art may also be used to neutralize the bleached tobacco material. After treatment with an acid, the pH of the bleached tobacco material may be approximately 7. FRnrnn / zznz / e / YiAi After treatment of the solid tobacco material with the caustic reagent and / or the oxidizing reagent, the treated tobacco material is generally filtered (i.e., isolated from the caustic and / or oxidizing reagent) and dried (as illustrated in operation 130 of Fig. 2, for example) to yield bleached tobacco material. In certain embodiments, the bleached tobacco material can be dried to a moisture level of approximately 1–30%, approximately 5–20%, or approximately 10–15% moisture on a wet basis. As is known in the art, the term wet basis refers to a measure of the water in a solid, expressed as the weight of water as a percentage of the total wet solid weight. After drying, the bleached tobacco material can optionally be ground to a size ranging from approximately 5 mm to approximately 0.1 mm, or from approximately 1 mm to approximately 0.1 mm. In certain formulations, the bleached tobacco material can be ground to a size of less than approximately 10 mm, less than approximately 5 mm, less than approximately 2 mm, or less than approximately 1 mm. In some embodiments, the bleached tobacco material thus produced can be characterized as lighter in color (e.g., bleached) compared to untreated tobacco material. Visual and / or instrumental evaluations such as those described above can be used to verify and, if desired, quantify the degree of lightening achieved by the method of the invention herein described. Evaluating the bleaching of a material generally requires comparison with another material. The extent of lightening can be quantified, for example, by spectroscopic comparison with a sample of untreated tobacco (e.g., untreated tobacco material). White colors are often defined with reference to the chromaticity diagram of the International Commission on Illumination (CIE).Bleached tobacco material can, in certain forms, be characterized as being closer to pure white on the chromaticity diagram than untreated tobacco material. In bleaching processes known in the art, the extracted solids component may undergo certain treatments intended to break down the fibers of the extracted solids material and / or remove lignin (e.g., a hydrolysis step with at least one acid, a mechanical and / or chemical pulping step, a caustic wash at high temperature, etc.). In the bleaching processes described herein, the extracted solids component is not subjected to treatment at high temperature with reagents containing sulfur, organic solvents, sodium hydroxide, or an acid between the extraction step and the bleaching step. FRnrnn / zznz / e / YiAi After drying, bleached tobacco material may have an ISO brightness of at least approximately 50%, at least approximately 55%, at least approximately 60%, at least approximately 65%, at least approximately 70%, or at least approximately 75%. In some forms, the bleached tobacco material described herein may have an ISO brightness in the range of approximately 50% to approximately 90%, approximately 55% to approximately 75%, or approximately 60% to approximately 70%. ISO brightness may be measured according to ISO 3688:1999 or ISO 2470-1:2016. The whiteness of a material can also be characterized according to the ASTM E313-73 whiteness test. The whiteness of bleached tobacco material prepared according to the methods described herein may be in the range of approximately 1-30, 5-25, 10-20, or 10-15, for example. In some embodiments, the whiteness of bleached tobacco material prepared according to the methods described herein may be at least 5, at least 10, at least 12, at least 15, at least 20, or at least 25. The bleached tobacco materials described herein can also be characterized based on the TAPPI 227OM-99 Freeness Test. Freeness levels can be indicated as a Canadian Standard Freeness (CSF) value. The freeness level is generally an indicator of the pulp drainage rate. The higher the value, the easier the pulp is to drain. Harsher bleaching processes typically used during the bleaching of tobacco materials can degrade individual fibers and undesirably reduce the degree of lightness in the bleached tobacco materials. Therefore, the bleaching methods provided herein can advantageously produce bleached tobacco materials with higher roughness values ​​compared to other bleaching methods that also include a pulping operation. The freeness level of pure tobacco pulp can range from approximately 0 to approximately 500 CSF.In some forms, the purity of the bleached tobacco materials produced here may be in the range of around 300 CSF to around 800 CSF, or around 400 CSF to around 700 CSF, or around 500 CSF to around 650 CSF. In several embodiments, wood pulp is added to the tobacco materials during the general bleaching processes described herein. It is noted that the wood pulp can be introduced into the bleaching process at any of the steps described herein. For example, in certain embodiments, the methods described herein may further comprise mixing the tobacco input material with a wood material prior to extraction, so that the wood material is also extracted. In certain embodiments, the methods described herein may FRnrnn / zznz / e / YiAi also includes mixing the solid tobacco material with wood pulp after the extraction process. In some forms, the wood pulp is bleached and can be added after the solid tobacco materials have been bleached. If unbleached wood pulp is used, an additional caustic extraction stage may be necessary, or the wood pulp can be added to the solid tobacco material before the bleaching stage. In several embodiments, the wood pulp may be commercially available wood pulp. In certain embodiments, the wood pulp may be bleached hardwood pulp. The wood pulp added to the processes described herein may be added in an amount of approximately 1 to approximately 20% by weight, or approximately 5 to approximately 15% by weight, based on the total weight of the input materials used (i.e., the total weight of tobacco material and wood pulp used). In some embodiments, the wood pulp may be added in an amount of at least approximately 1% by weight, at least approximately 5% by weight, or at least approximately 10% by weight, based on the total weight of the input materials used.In certain forms, wood pulp may be added in an amount of no more than approximately 5% by weight, no more than approximately 10% by weight, no more than approximately 15% by weight, or no more than approximately 20% by weight, based on the total weight of the input materials used. The tobacco materials discussed in the present invention may be treated and / or processed in other ways before, after, or during the process steps described above. For example, if desired, the tobacco materials may be irradiated, pasteurized, or otherwise subjected to controlled heat treatment. Such treatment processes are detailed, for example, in U.S. Patent Application No. 2009 / 0025738 to Mua et al., which is incorporated herein by reference. In certain embodiments, the tobacco materials may be treated with water and an additive capable of inhibiting the reaction of asparagine to form acrylamide upon heating the tobacco material (e.g.,an additive selected from the group consisting of lysine, glycine, histidine, alanine, methionine, glutamic acid, aspartic acid, proline, phenylalanine, valine, arginine, compositions incorporating divalent and trivalent cations, asparaginase, certain non-reducing saccharides, certain reducing agents, phenolic compounds, certain compounds having at least one free thiol group or functionality, oxidizing agents, oxidation catalysts, natural plant extracts (e.g., rosemary extract) and combinations thereof. See, for example, the types of treatment processes described in U.S. Patent Applications Nos. 2010 / 0300463 and 2011 / 0048434 to Chen et al., and U.S. Patent No. 8,991,403 to Chen et al., which are incorporated herein by reference. FRncnn / zznz / e / YiAi modalities, this type of treatment is useful when the original tobacco material is subjected to heat in the extraction and / or distillation process described above. The bleached tobacco material can be incorporated into a smokeless tobacco product according to the present invention. Depending on the type of tobacco product being processed, the tobacco product may include one or more additional components besides the bleached tobacco material as described above. For example, the bleached tobacco material can be processed, blended, formulated, combined, and / or mixed with other materials or ingredients, such as other tobacco materials or flavorings, fillers, binders, pH adjusters, buffering agents, salts, sweeteners, colorants, oral care additives, disintegrating aids, antioxidants, humectants, and preservatives.See, for example, those representative components, a combination of components, relative amounts of those components and ingredients in relation to tobacco, and ways and methods of employing those components, set forth in U.S. Patent Applications Nos. 2011 / 0315154 to Mua et al.; 2007 / 0062549 to Holton, Jr. et al.; 2012 / 0067361 to Bjorkholm et al.; 2017 / 0020183 to Bjorkholm; and 2017 / 012183 to Bjorkholm; and U.S. Patent No. 7,861,728 to Holton, Jr. et al., each of which is incorporated herein by reference. The relative amount of bleached tobacco material within the smokeless tobacco product can vary. Preferably, the amount of bleached tobacco material within the smokeless tobacco product is at least approximately 10%, at least approximately 25%, at least approximately 50%, at least approximately 60%, at least approximately 70%, at least approximately 80%, or at least approximately 90% based on the dry weight of the formulation. A typical range of tobacco material within the formulation is approximately 1% to approximately 99%, most often approximately 10% to approximately 50% by weight on a dry basis. The bleached tobacco material used for manufacturing the smokeless tobacco products of the invention is preferably provided in the form of powder, fine particles, granules, or ground tobacco. Although not strictly necessary, the bleached tobacco material may undergo processing steps that provide additional grinding for further particle size reduction. The bleaching processes of the present invention generally yield bleached tobacco material with a reduced amount of high molecular weight compounds, leading to greater interstitial space and, therefore, a higher possible water content in the smokeless tobacco materials produced therefrom compared to unbleached tobacco materials. In certain embodiments, the smokeless tobacco products produced according to the invention FRnrnn / zznz / e / YiAi provide a faster nicotine release than products produced from unbleached tobacco materials. Examples of flavorings that may be used are components, or suitable combinations of those components, that act to alter the bitterness, sweetness, acidity, or saltiness of the smokeless tobacco product, enhance the perceived dryness or moisture of the formulation, or the degree of tobacco flavor exhibited by the formulation. Flavorings may be natural or synthetic, and the character of the flavors they impart may be described, without limitation, as fresh, sweet, herbal, confectionery, floral, fruity, or spicy. Specific types of flavors include, but are not limited to, vanilla, coffee, chocolate / cocoa, cream, peppermint, spearmint, menthol, mint, wintergreen, eucalyptus, lavender, cardamom, nutmeg, cinnamon, clove, cascarilla, sandalwood, honey, jasmine, ginger, anise, sage, licorice, lemon, orange, apple, peach, lime, cherry, strawberry, and any combination thereof. See also, Leffingwell et al., Tobacco Flavoring for Smoking Products, RJReynolds Tobacco Company (1972), which is incorporated herein by reference. Flavorings may also include components that are considered wetting, cooling, or softening agents, such as eucalyptus. These flavors may be provided alone (i.e., by themselves) or in a compound (e.g., spearmint and menthol, or orange and cinnamon). Representative types of components are also set forth in U.S. Patent No. 5,387,416 to White et al.; U.S. Patent Application No. 2005 / 0244521 to Strickland et al.; and PCT Publication No. WO 05 / 041699 to Quinter et al., each of which is incorporated herein by reference. Types of flavorings include salts (e.g., sodium chloride, potassium chloride, sodium citrate, potassium citrate, sodium acetate, potassium acetate, and the like), natural sweeteners (e.g., fructose, sucrose, glucose, maltose, mannose, galactose, lactose, and the like), artificial sweeteners (e.g.e.g., sucralose, saccharin, aspartame, acesulfame K, neotame, and similar substances); and mixtures thereof. The number of flavorings used in tobacco compositions may vary, but is normally up to approximately 10 percent by dry weight, and certain varieties are characterized by a flavoring content of at least approximately 1 percent by dry weight, such as approximately 1 to approximately 10 percent by dry weight. Combinations of flavorings are often used, such as 0.1 to 2 percent by dry weight of an artificial sweetener, 0.5 to 8 percent by dry weight of a salt such as sodium chloride, and 1 to 5 percent by dry weight of an additional sweetener or flavoring. Examples of filler materials include vegetable fiber materials such as sugar beet fiber (e.g., FIBREX® brand filler available from International Fiber Corporation), oats or other cereal grains (including processed or puffed grains), bran fibers, starch or other modified or natural materials, and cellulosic materials such as microcrystalline cellulose. Additional specific examples FRnrnn / zznz / e / YiAi includes corn starch, maltodextrin, dextrose, calcium carbonate, calcium phosphate, lactose, mannitol, xylitol, and sorbitol. The amount of filler, when used in the tobacco composition, can vary, but is typically up to approximately 60 percent by dry weight, with certain varieties characterized by a filler content of up to approximately 50 percent by dry weight, up to approximately 40 percent by dry weight, or up to approximately 30 percent by dry weight. Combinations of fillers may also be used. Typical binders can be organic or inorganic, or a combination of both. Representative binders include povidone, sodium carboxymethylcellulose and other modified cellulosic materials, sodium alginate, xanthan gum, starch-based binders, gum arabic, pectin, carrageenan, pullulan, zein, and the like. The amount of binder used in tobacco compositions can vary, but is normally up to approximately 30 percent by dry weight, and certain varieties are characterized by a binder content of at least approximately 5 percent by dry weight, such as approximately 5 to approximately 30 percent by dry weight. The preferred pH adjusters or buffering agents provide and / or buffer within a pH range of approximately 6 to approximately 10, and examples of agents include metal hydroxides, metal carbonates, metal bicarbonates, and mixtures thereof. Specific example materials include citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate, and sodium bicarbonate. The amount of pH adjuster or buffering material used in the tobacco composition may vary, but is typically up to approximately 5 percent by dry weight, and certain formulations may be characterized by a pH adjuster / buffer content of less than approximately 0.5 percent by dry weight, such as approximately 0.05 to approximately 0.2 percent by dry weight.Particularly in forms comprising a distillation-clarified extract, the pH can be reduced by adding one or more pH adjusters (e.g., citric acid). A colorant may be used in sufficient quantities to provide the desired physical attributes to the tobacco formulation. Example colorants include various dyes and pigments, such as caramel coloring and titanium dioxide. The amount of colorant used in the tobacco composition may vary, but it is typically up to approximately 3 percent by dry weight, and certain formulations are characterized by a colorant content of at least approximately 0.1 percent by dry weight, such as approximately 0.5 to approximately 3 percent by dry weight. Examples of humectants include glycerin and propylene glycol. The amount of humectant used in tobacco composition can vary, but is typically up to FRncnn / zznz / e / YiAi approximately 5 percent by dry weight, and certain forms may be characterized by a humectant content of at least approximately 1 percent by dry weight, such as approximately 2 to approximately 5 percent by dry weight. Other ingredients such as preservatives (e.g., potassium sorbate), disintegrating agents (e.g., microcrystalline cellulose, croscarmellose sodium, crospovidone, sodium starch glycolate, pregelatinized corn starch, and the like), and / or antioxidants may also be used. Typically, such ingredients, when used, are used in amounts up to about 10 percent by dry weight and normally at least about 0.1 percent by dry weight, such as about 0.5 to about 10 percent by dry weight. A disintegrating agent is generally employed in a sufficient quantity to provide control of the desired physical attributes of the tobacco formulation, such as by providing loss of physical integrity and dispersion of the various component materials upon contact of the formulation with water (e.g., by swelling upon contact with water). As noted, in some embodiments, any of the components described above may be added in encapsulated form (e.g., in the form of microcapsules). The encapsulation forms a wall or barrier structure that defines an internal region and isolates this region, either permanently or temporarily, from the tobacco composition. The internal region includes a payload of an additive adapted to enhance one or more sensory characteristics of the smokeless tobacco product, such as flavor, mouthfeel, moisture, coolness / warmth, and / or fragrance, or adapted to add an additional functional quality to the smokeless tobacco product, such as the addition of an antioxidant or an immune-enhancing function. See, for example, the subject matter of U.S. Patent Application No. 2009 / 0025738 to Mua et al., which is incorporated herein by reference. Representative tobacco formulations may incorporate approximately 5% to 95% bleached tobacco material, approximately 5% to 60% filler, approximately 0.1% to 5% artificial sweetener, approximately 0.5% to 2% salt, approximately 1% to 5% flavoring, approximately 1% to approximately 5% humectants (e.g., propylene glycol), and up to approximately 10% pH adjuster or buffering agent (e.g., sodium bicarbonate or citric acid), based on the total dry weight of the tobacco formulation. Specific percentages and ingredient choices will vary depending on desired flavor, texture, and other characteristics. Descriptions of various components of snus product types and their constituent parts are also set forth in U.S. Patent Application No. 2004 / 0118422 to Lundin et al., which is incorporated herein by reference. See also, for example, U.S. Patents Nos. 4,607,479 to Linden; 4,631,899 to Nielsen; FRncnn / zznz / e / YiAi 5,346,734 by Wydick et al.; and 6,162,516 by Derr, and U.S. Patent Application No. 2005 / 0061339 by Hansson et al.; each of which is incorporated herein by reference. The components of the tobacco composition may be mixed using any mixing technique or equipment known in the art. The optional components mentioned above, which may be in liquid or dry solid form, may be mixed with the bleached tobacco material in a pretreatment step before mixing with any remaining components of the composition, or they may simply be mixed with the bleached tobacco material along with all the other liquid or dry ingredients. Any mixing method that brings the ingredients of the tobacco composition into intimate contact may be used. A mixing apparatus featuring an impeller or other agitating structure is typically used.The example mixing equipment includes coating drums, conditioning cylinders or drums, liquid spraying apparatus, conical-type mixers, ribbon mixers, mixers available as FKM130, FKM600, FKM1200, FKM2000, and FKM3000 from Littleford Day, Inc., Plough Share-type mixing cylinders, and the like. As such, the overall blending of various components with the bleached tobacco material can be relatively uniform. See also, for example, the types of methodologies set forth in U.S. Patents Nos. 4,148,325 to Solomon et al.; 6,510,855 to Korte et al.; and 6,834,654 to Williams, each of which is incorporated herein by reference. The forms and methods for formulating snus-type tobacco formulations will be evident to those skilled in the art of producing snus tobacco products. The moisture content of a smokeless tobacco product before use by a consumer can vary. Typically, the moisture content of the product, as it is present inside the pouch before insertion into the user's mouth, is less than 55 percent by weight, generally less than 50 percent by weight, and often less than 45 percent by weight. For certain tobacco products, such as those incorporating snus-type tobacco compositions, the moisture content may exceed 20 percent by weight and frequently exceeds 30 percent by weight. For example, a representative snus-type product may have a tobacco composition exhibiting a moisture content of approximately 20 percent to approximately 50 percent by weight, preferably approximately 20 percent to approximately 40 percent by weight. The way in which the moisture content of the formulation is controlled can vary. For example, the formulation can be subjected to thermal or convective heating. As a specific example, the formulation can be oven-dried or hot-air dried at temperatures of around 40°C to around 95°C, with a preferred temperature range of around 60°C to around 80°C, for a period of time appropriate to achieve the desired moisture content. FRncnn / zznz / e / YiAi desired moisture. Alternatively, tobacco formulations can be moistened using wrapping drums, conditioning cylinders or drums, liquid spraying apparatus, ribbon mixers, or blenders. Most preferably, moist tobacco formulations, such as the types of tobacco formulations employed within snus products, are subjected to pasteurization or fermentation. The techniques for pasteurizing / heat-treating and / or fermenting snus tobacco products will be evident to those skilled in the art of snus product design and manufacture. The acidity or alkalinity of a tobacco formulation, often characterized in terms of pH, can vary. Typically, the pH of such a formulation is at least around 6.5, and preferably at least around 7.5. In some forms, the pH of the formulation will not exceed approximately 11, or approximately 9, and frequently will not exceed approximately 8.5. A representative tobacco formulation has a pH of approximately 6.8 to approximately 8.2 (e.g., approximately 7.8). A representative technique for determining the pH of a tobacco formulation involves dispersing 5 g of the formulation in 100 mL of water for high-performance liquid chromatography and measuring the pH of the resulting suspension / solution (e.g., with a pH meter). In certain formulations, bleached tobacco material and any other components mentioned above are combined within a moisture-permeable packet or pouch that acts as a container for tobacco use. The composition / construction of such packets or pouches, such as the container pouch 20 in the formulation illustrated in Figure 1, may vary. Suitable packets, pouches, or containers of the type used for the manufacture of smokeless tobacco products are available under the trade names CatchDry, Ettan, General, Granit, Goteborgs Rape, Grovsnus White, Metropol Kaktus, Mocea Anís, Mocea Mint, Mocea Wintergreen, Kicks, Probe, Prince, Skruf, Epok, and TreAnkrare. The tobacco formulation may be contained in pouches and packaged in a manner and using the types of components used for the manufacture of conventional snus products.The pouch provides a liquid-permeable container similar to the mesh-like material used in tea bags. The loose, granular tobacco components diffuse easily through the pouch and into the user's mouth. Non-limiting examples of suitable types of bags are set forth, for example, in U.S. Patents Nos. 5,167,244 to Kjerstad and 8,931,493 to Sebastian et al.; as well as U.S. Patent Applications Nos. 2016 / 0000140 to Sebastian et al.; 2016 / 0073689 to Sebastian et al.; 2016 / 0157515 to Chapman et al.; and 2016 / 0192703 to Sebastian et al., each of which is incorporated herein by reference. The bags may be provided as single bags, or a plurality of bags (e.g., 2, 4, 5, 10, 12, 15, 20, FRncnn / zznz / e / YiAi or 30 bags) can be connected or linked together (e.g., end to end), -final way) in such a way that a single bag or individual portion can be easily removed for use from a strand or array of one-piece bags. A pouch, for example, can be manufactured from materials in such a way that, during use by the user, the pouch undergoes controlled dispersion or dissolution. Such pouch materials can be in the form of mesh, screen, perforated paper, permeable fabric, or similar materials. For example, pouch material made from mesh-like rice paper or perforated rice paper can dissolve in the user's mouth. As a result, the pouch and the tobacco formulation can undergo complete dispersion within the user's mouth under normal conditions of use, and thus the pouch and tobacco formulation can be ingested by the user. The amount of material contained within each product unit, for example, a pouch, may vary. In some embodiments, the weight of the material within each pouch is at least approximately 50 mg, for example, from approximately 50 mg to approximately 1 gram, from approximately 100 to 800 mg, or from approximately 200 to approximately 700 mg. In some smaller embodiments, the weight of the material within each pouch may be from approximately 100 to approximately 300 mg. For a larger embodiment, the weight of the material within each pouch may be from approximately 300 mg to approximately 700 mg. If desired, other components may be contained within each pouch. For example, at least one flavored strip, piece, or sheet of flavored water-soluble or water-dispersible material (e.g., a type of edible breath-freshening film) may be discarded within each pouch, with or without at least one capsule.These strips or sheets can be folded or crumpled for easy insertion into the bag. See, for example, the types of materials and technologies discussed in U.S. Patent Nos. 6,887,307 to Scott et al. and 6,923,981 to Leung et al.; and The EFSA Journal (2004) 85, 1-32; which are incorporated herein by reference. The smokeless tobacco product may be packaged within any suitable inner packaging material and / or outer container. See also, for example, the various types of containers for types of smokeless products disclosed in U.S. Patents Nos. 7,014,039 to Henson et al.; 7,537,110 to Kutsch et al.; 7,584,843 to Kutsch et al.; D592,956 to Thiellier; D594,154 to Patel et al.; and D625,178 to Bailey et al.; in U.S. Patent Applications Nos. 2008 / 0173317 to Robinson et al.; 2009 / 0014343 to Clark et al.; 2009 / 0014450 to Bjorkholm; 2009 / 0250360 to Bellamah et al.; 2009 / 0266837 by Gelardi et al.; 2009 / 0223989 to Gelardi; 2009 / 0230003 to Thiellier; 2010 / 0084424 to Gelardi; and 2010 / 0133140 by Bailey et al.; 2010 / 0264157 by Bailey et al.; 2011 / 0168712 by Bailey et al.; and 2011 / 0204074 by Gelardi et al., which are incorporated herein by reference. FRnrnn / zznz / e / YiAi The products described herein may be packaged and stored in a manner very similar to that of conventional types of smokeless tobacco products. For example, a plurality of packets or pouches may be contained in a container used for smokeless tobacco products, such as a cylindrical container sometimes referred to as a disc. The container may be of any shape and is not limited to cylindrical containers. Such containers may be made of any suitable material, such as metal, molded plastic, fiberboard, combinations thereof, etc. If desired, moist tobacco products (e.g., products having a moisture content above 20 percent by weight) may be refrigerated (e.g., to a temperature below about 10°C, often below about 8°C, and sometimes below about 5°C). Alternatively, relatively dry tobacco products (e.g.Products that have a moisture content of less than approximately 15 percent by weight can often be stored in a relatively wide range of temperatures. Several smokeless tobacco products described in this document are advantageous because they offer a composition that does not stain, or stains less than products made solely of unbleached tobacco materials. Therefore, these products are desirable for reducing staining of teeth and clothing that may come into contact with them. It is noted that even the spent (used) product is lighter in color than traditional spent (used) oral tobacco products. Furthermore, the products may have enhanced visual appeal due to their bleached color. The following examples are provided to further illustrate the modalities of this description, but should not be interpreted as limiting its scope. Unless otherwise stated, all parts and percentages are by weight. EXPERIMENTAL The methods of disclosure in this report are more fully illustrated by the following examples, which are provided to illustrate aspects of this report and should not be interpreted as limiting it. In the following examples, g means gram, L means liter, mL means milliliter, and Da means dalton. All weight percentages are expressed on a dry basis, meaning they exclude water content, unless otherwise stated. FRncnn / zznz / e / YiAi Comparative Example 1 A comparator bleached tobacco material designated C1 was produced by a process involving extraction of tobacco material, caustic extraction (i.e., reduction to chemical pulp) and then bleaching with hydrogen peroxide. Approximately 125 pounds of ground Rustica stem were mixed with approximately 1125 pounds of water and 0.7 pounds of EDTA. The slurry was stirred for approximately 1 hour at a temperature of 180°F. Approximately 1 pound of sodium hydroxide was added to the slurry. The slurry was discharged, and the tobacco material was drained using a basket centrifuge. The resulting tobacco material was caustically extracted: the tobacco material was mixed with 1000 lbs. of water, approximately 58 lbs. of sodium hydroxide, and 7.5 lbs. of cellulose. The suspension was stirred for approximately 1 hour at a temperature of 200°F. After mixing, approximately 77.5 lbs. of citric acid was added to the suspension. The suspension was drained using a basket centrifuge. Approximately 150 lbs. of water was used to rinse the caustically extracted tobacco material. The caustically extracted tobacco material was subjected to a peroxide bleaching process: the tobacco material was mixed with approximately 550 lbs. of water, 41 lbs. of sodium hydroxide, 12.5 lbs. of 40% sodium silicate solution, 218 lbs. of 30% hydrogen peroxide, and about 0.4 lbs. of Xiameter AFE-0100 antifoam. The slurry was stirred for approximately 1 hour at a temperature of 165°F. The slurry was drained using a basket centrifuge. About 150 lbs. of water was used to rinse the tobacco material, yielding the bleached tobacco solid. The bleached tobacco solid was dried to a moisture content of approximately 10–15%, resulting in the C1 comparison bleached tobacco material. Table 1 below gives the whiteness and brightness values ​​for bleached dry tobacco material C1.Whiteness (ASTM E313-73) and brightness (ISO) values ​​were determined using a Konica Minolta CM-700d spectrophotometer and Spectramagic NX software. The brightness standard is listed as ISO 2470. FRncnn / zznz / e / YiAi Table 1 Compensation Material Whiteness Gloss C1 15 52 Comparative Example 2 A comparison bleached tobacco material designated C2 was produced using the process described in Comparative Example 1 above. C2 had a whiteness of 24 and a brightness of 58. The freeness value of C2 was measured using TAPPI 227OM-99 and was found to be 448. It is believed that C2 showed improved bleaching compared to C1 due to more efficient mixing during the treatment steps. Example 1 The bleached tobacco materials were prepared in accordance with the bleaching procedures described in this document. Approximately 125 pounds of ground Rustica stalk was mixed with approximately 1125 pounds of water and 0.7 pounds of EDTA. The slurry was stirred for approximately 1 hour at a temperature of 180°F. Approximately 1 pound of sodium hydroxide was added to the slurry. The slurry was discharged, and the tobacco material was drained using a basket centrifuge. The collected dehydrated tobacco material was designated Q tobacco material. Sample A1 was prepared by washing approximately 923 grams of tobacco material Q with five 2.5-liter portions of water. The washed tobacco material Q was dehydrated on a 300-micron mesh screen. The washed tobacco material Q was bleached with hydrogen peroxide: approximately 257 grams of wet washed tobacco material Q with a moisture content of approximately 82% was mixed with approximately 235 g of water, 14 g of 20% NaOH solution, 30.97 g of 30% hydrogen peroxide, 1.88 g of 10% sodium silicate solution, and 1.87 g of 25% EDTA solution. The suspension was placed in a polyethylene bag heated in a hot water bath for 75 minutes, reaching a temperature of approximately 80°C. The suspension was kneaded every 15 minutes. The peroxide-bleached tobacco material was added to 1 liter of water and dehydrated through a 300-micron mesh screen, then washed with 2 liters of water at room temperature.The bleached tobacco material was dried in a convection oven at 85SC for approximately 12 hours. Sample A2 was prepared by washing approximately 1100 grams of tobacco material Q with six 2.5-liter portions of water. The washed tobacco material Q was dehydrated on a 300-micron mesh screen. The washed tobacco material Q was bleached with hydrogen peroxide: approximately 308 grams of wet washed tobacco material Q with a moisture content of approximately 84% was mixed with approximately 140 g of water, 15 g of 20% NaOH solution, 125 g of 30% hydrogen peroxide, 2.03 g of 10% NaOH solution, 2.03 g of sodium silicate solution, and 2.03 g of 25% EDTA solution. The suspension was placed in a polyethylene bag heated in a hot water bath for 75 minutes, reaching a temperature of approximately 80°C. The suspension was kneaded every 15 minutes. The peroxide bleached tobacco material was added to 1 liter of water and dehydrated on a 300 mesh screen and then washed with 2 liters of water at 50°C.The bleached tobacco material was dried in a convection oven at 85°C for approximately 12 hours. FRnrnn / zznz / e / YiAi Approximately 125 pounds of ground Rustica stalk was mixed with approximately 1125 pounds of water and 0.7 pounds of EDTA. The slurry was stirred for approximately 1 hour at 180°F. Approximately 1 pound of sodium hydroxide was added to the slurry. The slurry was discharged, and the tobacco material was drained using a basket centrifuge. The tobacco material was washed by directing 1500 pounds of water through the tobacco material in the basket centrifuge. The collected dehydrated tobacco material was designated QW tobacco material. Sample A3 was prepared by bleaching QW tobacco material with hydrogen peroxide: approximately 228 grams of QW tobacco material with a moisture content of approximately 76% were mixed with approximately 1450 g of water, 28 g of 20% NaOH solution, 164 g of 30% hydrogen peroxide, 2.19 g of 10% NaOH solution, sodium silicate solution, and 2.19 g of 25% EDTA solution. The slurry was stirred with an overhead mixer and heated to a temperature of approximately 80°C for 75 minutes. The peroxide-bleached tobacco material was dehydrated on a 300-micron mesh and then washed with 3 liters of water at 50°C. The bleached tobacco material was dried in a convection oven at 85°C for approximately 12 hours. Approximately 125 pounds of ground Rustica stalk were mixed with approximately 1125 pounds of water and 0.7 pounds of EDTA. The slurry was stirred for approximately 1 hour at 180°F. Approximately 1 pound of sodium hydroxide was added to the slurry. The slurry was discharged, and the tobacco material was drained using a basket centrifuge. The collected dehydrated tobacco material was designated Q2 tobacco material. Sample A4 was prepared by bleaching tobacco material Q2 with hydrogen peroxide: approximately 199 grams of tobacco material Q2 with a moisture content of approximately 72% were mixed with approximately 1250 g of water, 22 g of 20% NaOH solution, 174 g of 30% hydrogen peroxide, 2.30 g of 10% NaOH solution, sodium silicate solution, and 2.28 g of 25% EDTA solution. The slurry was stirred with an overhead mixer and heated to a temperature of approximately 80 °C for 75 minutes. The peroxide-bleached tobacco material was dehydrated on a 300-micrometer mesh and then washed with 0.4 liters of room temperature water. The bleached tobacco material was dried in a convection oven at 85 °C for approximately 12 hours. Table 2 lists the inventive samples A1, A2, A3, and A4 prepared by the tobacco bleaching process described herein (i.e., without a caustic extraction step between the aqueous extraction and bleaching steps). The tobacco bleaching process as described herein achieves whiteness and brightness values ​​comparable to those of comparison materials C1 and C2 (the comparison material process employing caustic extraction as described above). FRncnn / zznz / e / YiAi Table 2 Inventive Sample Hydrogen Peroxide* NaOH** Hydrogen Peroxide ZNaOH (¢^) Solids Initial pH Final pH Whiteness Gloss Al 20 6 3.3 9.6 10.73 8.77 1 51 A2 74.8 6 12.5 10.0 9.82 8.23 ​​14 57 A3 90 10.1 8.9 3.0 9.63 9.48 17 58 A4 94.7 8 11.8 3.5 9.33 7.96 20 60 * = 100 x 0.3 xg 30% hydrogen peroxide / g of dry tobacco ** = 100 xg sodium hydroxide / g of dry tobacco Hydrogen peroxide / NaOH = 0.30 x g 30% hydrogen peroxide / g sodium hydroxide Solids (%) = 100 x (g dry tobacco) / (g dry tobacco + g water + g hydrogen peroxide) Initial pH = pH of the suspension at the beginning of the hydrogen peroxide bleaching step Final pH = pH of the sludge at the end of the hydrogen peroxide beach step before dewatering FRncnn / zznz / e / YiAi It is noted that the Whiteness (ASTM E313-73) and Brightness (ISO) values ​​for samples A1-A4, samples B1-B4 in Example 2 below, and sample D1 in Example 3 below were determined using a Konica-Minolta CM-700d spectrophotometer and Spectramagic NX software. The brightness standard is listed as ISO 2470. Example 2 The bleached tobacco materials were prepared in accordance with the bleaching procedures described in this document. Sample B1 was produced using the inventive process involving the extraction of tobacco material and subsequent bleaching with hydrogen peroxide. Approximately 135 lbs. of ground Rustica stalk was mixed with approximately 1217 lbs. of water and 0.74 lbs. of EDTA. The suspension was stirred for approximately 1 hour at a temperature of 180°F. Approximately 1.08 lbs. of NaOH was added to the suspension. The suspension was discharged, and the tobacco material was drained using a basket centrifuge. The resulting tobacco material was subjected to a peroxide bleaching process: the tobacco material was mixed with approximately 1177 lbs. of water, 4.6 lbs. of sodium hydroxide, 0.49 lbs. of 40% sodium silicate solution, 0.49 lbs. of EDTA, 179 lbs. of 30% hydrogen peroxide, and about 0.16 lbs. of Xiameter AFE-0100 antifoam. The slurry was stirred for approximately 1 hour at a temperature of 185°F. The slurry was drained using a basket centrifuge. About 300 lbs. of water was used to rinse the tobacco material, yielding the bleached tobacco solid. The bleached tobacco solid was dried to a moisture content of approximately 10–15%, providing the comparison bleached tobacco material B1. Sample B2 was produced using the inventive process involving the extraction of tobacco material and subsequent bleaching with hydrogen peroxide. Approximately 135 lbs. of ground Rustica stalk was mixed with approximately 1216 lbs. of water and 0.74 lb. of EDTA. The suspension was stirred for approximately 1 hour at a temperature of 180°F. Approximately 1.08 lb. of NaOH was added to the suspension. The suspension was discharged, and the tobacco material was drained using a basket centrifuge. The resulting tobacco material was subjected to a peroxide bleaching process: the tobacco material was mixed with approximately 1238 lbs. of water, 6.70 lbs. of sodium hydroxide, 0.51 lbs. of 40% sodium silicate solution, 0.51 lbs. of EDTA, and 280 lbs. of 30% hydrogen peroxide. The slurry was stirred for approximately 1 hour at a temperature of 185°F. During stirring, approximately 0.03 lbs. of Xiameter AFE-0100 antifoam was added. The slurry was drained using a basket centrifuge. Approximately 300 lbs. of water at a temperature of approximately 140°F was used to rinse the tobacco material, yielding the bleached tobacco solid. The bleached tobacco solid was dried to a moisture content of approximately 10-15%, providing the comparison material B2 of bleached tobacco. Sample B3 was produced using the inventive process involving the extraction of tobacco material and subsequent bleaching with hydrogen peroxide. Approximately 127.5 lbs. of ground Rustica stem and approximately 7.5 lbs. of cellulose (unbleached softwood raft material) were mixed with approximately 1216 lbs. of water and 0.74 lbs. of EDTA. The slurry was stirred for approximately 1 hour at a temperature of 180°F. Approximately 1.08 lbs. of NaOH was added to the slurry. The slurry was discharged, and the tobacco material was drained using a basket centrifuge. Approximately 150 lbs. of room temperature water was used to rinse the tobacco material in the basket centrifuge. The resulting tobacco material was subjected to a peroxide bleaching process: the tobacco material was mixed with approximately 1182 lbs. of water, 7.10 lbs. of sodium hydroxide, 0.70 lbs. of 40% sodium silicate solution, 0.70 lbs. of EDTA, and 246 lbs. of 30% hydrogen peroxide. The slurry was stirred for approximately 1 hour at 185°F. The slurry was drained using a basket centrifuge. Approximately 300 lbs. of room temperature water was used to rinse the tobacco material, yielding the bleached tobacco solid. The bleached tobacco solid was dried to a moisture content of approximately 10–15%, resulting in the comparison bleached tobacco material B3. The fiber freeness was measured as 611 CSF. The freeness value of B3 (and B4 below) was measured using TAPPI 227OM-99. Sample B4 was produced using the inventive process involving the extraction of tobacco material and then bleaching it with hydrogen peroxide. Approximately 135 pounds. FRnrnn / zznz / e / YiAi Ground Rustica stem was mixed with approximately 1216 lbs. of water and 0.74 lb. of EDTA. The suspension was stirred for approximately 1 hour at a temperature of 180°F. Approximately 1.08 lb. of NaOH was added to the suspension. The suspension was discharged, and the tobacco material was drained using a basket centrifuge. Approximately 150 lbs. of water at a temperature of 140°F was used to rinse the tobacco material in the basket centrifuge. The resulting tobacco material was subjected to a peroxide bleaching process: the tobacco material was mixed with approximately 1177 lbs. of water, 5.0 lbs. of sodium hydroxide, 0.50 lbs. of 40% sodium silicate solution, 0.49 lbs. of EDTA, and 178 lbs. of 30% hydrogen peroxide. The slurry was stirred for approximately 1 hour at 185°F. The slurry was drained using a basket centrifuge. Approximately 300 lbs. of water at 140°F was used to rinse the tobacco material, yielding the bleached tobacco solid. The bleached tobacco solid was dried to a moisture content of approximately 10–15%, providing the comparison bleached tobacco material B4. The fiber freeness was measured as 532 CSF. Table 3 lists the inventive samples B1, B2, B3, and B4, which were prepared by the tobacco bleaching process described herein without a caustic extraction step. The tobacco bleaching process as described herein achieves whiteness and brightness values ​​comparable to those of the comparison materials C1 and C2 (the comparison material process employing caustic extraction as described above). Table 3 FRncnn / zznz / e / YiAi Inventíve Sample Hydroges Peí oxytle / NaOH Solids (%) Start pH £od pH Whtteness Bríghtuess B1 11.7 3.2 9.07 7.99 12 57 B2 12.6 3.1 9.44 8.66 14 56 B3 10.4 4.5 9.§8 8.78 13 54 B4 10.7 4.0 9.25 8.00 10 55 Hydrogen peroxide / NaOH = 0.30 x lbs. 30% hydrogen peroxide / lb. sodium hydroxide Solids (%) = 100 x (Lbs. dry tobacco) / (Lbs. dry tobacco + Lbs. water + Lbs. hydrogen peroxide) Initial pH = pH of the suspension at the beginning of the hydrogen peroxide bleaching step Final pH = pH of the sludge at the end of the hydrogen peroxide beach step before dewatering Example 3 A bleached tobacco material was prepared in accordance with the bleaching procedures described in this document. Sample D1 was produced using an inventive process involving the extraction of tobacco material followed by bleaching with hydrogen peroxide. Approximately 125 pounds of ground Rustica stalk was mixed with approximately 1125 pounds of water and 0.7 pounds of EDTA. The slurry was stirred for approximately 1 hour at 180°F. Approximately 1 pound of sodium hydroxide was added to the slurry. The slurry was discharged, and the tobacco material was drained using a basket centrifuge. Approximately 1566 grams of the tobacco material, with a moisture content of approximately 74%, were washed with five portions of 4 liters of water at room temperature over a 300-micron mesh sieve and the resulting fiber was named QW2 tobacco material. The QW2 tobacco material was bleached with hydrogen peroxide: In a polyethylene bag, approximately 418 grams of QW2 tobacco material with a moisture content of approximately 88% were mixed with approximately 85 g of water, 30 g of 10% NaOH solution, 25 g of 30% hydrogen peroxide, 2.0 g of 10% NaOH solution, 2.0 g of sodium silicate solution, and 2.0 g of 25% EDTA solution. The slurry was heated to a temperature of approximately 76°C for 60 minutes. The peroxide-bleached tobacco material was mixed with 1000 ml of water, the pH was adjusted to 6.68 with citric acid, the slurry was then dehydrated through a 300-micron mesh screen, and subsequently washed with 1500 ml of water at room temperature. The bleached tobacco material was designated QP. The QP tobacco material was bleached with hydrogen peroxide: In a polyethylene bag, approximately 304 grams of QP tobacco material with a moisture content of approximately 90% were mixed with approximately 1.6 g of water, 4.5 g of 20% NaOH solution, 26 g of 30% hydrogen peroxide, 1.2 g of 10% sodium silicate solution, and 1.2 g of 25% EDTA solution. The slurry was heated to a temperature of approximately 75°C for 45 minutes. The peroxide-bleached tobacco material was mixed with 1000 ml of water, the pH was adjusted to 6.99 with citric acid, the slurry was then dehydrated through a 300-micron mesh screen, and subsequently washed with 1500 ml of water at room temperature. The bleached tobacco material was designated QPP. The bleached tobacco material QPP was dried in a convection oven at 85eC for approximately 12 hours giving the inventive example D1. Table 4 lists the inventive sample D1 prepared by the tobacco material bleaching process described herein (i.e., without a caustic extraction step between the aqueous extraction step and the bleaching step). The tobacco bleaching process as described herein achieves whiteness and brightness values ​​that are comparable to those of comparison materials C1 and C2 (the comparison material process employing caustic extraction as described above). FRncnn / zznz / e / YiAi Table 4 Comparison Material Whiteness Gloss DI 25 64 FRnrnn / zznz / e / YiAi Many modifications and other embodiments will occur to a person skilled in the art to which this description relates, who has benefited from the teachings presented in the preceding description. It should therefore be understood that disclosure is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used only in a generic and descriptive sense and not for the purpose of limitation.

Claims

1. A method for preparing bleached tobacco material, comprising: (i) extracting tobacco material with an extraction solution to provide solid tobacco material and a tobacco extract; (ii) bleaching the solid tobacco material with a bleaching solution comprising a strong base, an oxidizing agent, or a combination thereof to provide bleached tobacco material; and (iii) drying the bleached tobacco material to provide bleached tobacco material; wherein the solid tobacco material is not subjected to elevated temperature treatment with sulfur-containing reagents, organic solvents, sodium hydroxide, or an acid between the extraction of the tobacco material and the bleaching of the solid tobacco material.

2. The method of claim 1, further comprising grinding the tobacco material to a size in the range of approximately 0.2 mm to approximately 2 mm.

3. The method of claim 1, wherein the extraction of the tobacco material is carried out at a temperature of approximately 100°C or lower.

4. The method of claim 1, wherein the bleaching of the solid tobacco material is carried out at a temperature of approximately 100°C or lower.

5. The method of claim 1, wherein the bleached tobacco material is dried to a moisture content of less than approximately 30 percent moisture on a wet basis.

6. The method of claim 1, further comprising dehydrating the tobacco material using at least one screw press and one basket centrifuge after extracting the tobacco material and / or bleaching the solid tobacco material.

7. The method of claim 1, wherein the bleaching solution comprises one or more of peracetic acid, sodium hydroxide, and hydrogen peroxide.

8. The method of claim 1, wherein the bleaching solution further comprises one or more stabilizers in addition to an oxidizing agent.

9. The method of claim 8, wherein the stabilizers are selected from the group consisting of magnesium sulfate, sodium silicate, and combinations thereof. FRncnn / zznz / e / YiAi 10. The method of claim 1, wherein the bleaching solution comprises a strong base and an oxidizing agent, and wherein the molar ratio of the amount of oxidizing agent to the amount of strong base is from approximately 1:1 to approximately 100:

1.

11. The method of claim 10, wherein the weight ratio of the amount of oxidizing agent to the amount of strong base is from approximately 2.5:1 to approximately 15:

1.

12. The method of claim 1 further comprises neutralizing the bleached tobacco material to a pH in the range of approximately 5 to approximately 11 before drying the bleached tobacco material.

13. The method of claim 1, further comprising grinding the bleached tobacco material after drying the bleached tobacco material to a size in the range of approximately 5 mm to approximately 0.1 mm.

14. The method of claim 1, wherein the extraction solution comprises a chelating agent.

15. The method of claim 14, wherein the chelating agent comprises one or more of EDTA and DTPA.

16. The method of claim 1, wherein the bleaching solution used to bleach the solid tobacco material comprises a chelating agent.

17. The method of claim 16, wherein the chelating agent comprises one or more of EDTA and DTPA.

18. The method of claim 1, wherein the molar ratio of the extraction solution to the tobacco material is from approximately 4:1 to approximately 16:

1.

19. The method of claim 1, wherein the extraction solution is an aqueous solution.

20. The method of claim 1, wherein the tobacco material comprises sheets, stems or a combination thereof.

21. The method of claim 1, wherein the tobacco material comprises Rustica stems.

22. The method of claim 1, wherein the tobacco material comprises at least approximately 90% by weight of roots, stems, or a combination thereof. FRncnn / zznz / e / YiAi 23. The method of claim 1, wherein the bleached tobacco material is characterized by an International Organization for Standardization (ISO) brightness of at least approximately 50%.

24. The method of claim 1, further comprising mixing the solid tobacco material with wood pulp before bleaching the solid tobacco material.

25. The method of any of claims 1-24, further comprising incorporating the bleached tobacco material into a product adapted for oral use.

26. The method of claim 25, wherein the product further comprises one or more additional components selected from the group consisting of flavorings, fillers, binders, pH adjusters, buffering agents, colorants, disintegrating aids, antioxidants, humectants, and preservatives.

27. A product adapted for oral use incorporating bleached tobacco material prepared according to the method of any of claims 1-24.

28. The product of claim 27 comprises a water-permeable bag containing the bleached tobacco material.

29. The product of claim 28 further comprises one or more additional components selected from the group consisting of flavorings, fillers, binders, pH adjusters, buffering agents, colorants, disintegrating aids, antioxidants, humectants, and preservatives.

30. A method for preparing bleached tobacco material for use in a smokeless tobacco product, comprising essentially: (i) extracting a tobacco material with an extraction solution to provide a solid tobacco material and a tobacco extract; (ii) separating the solid tobacco material and the tobacco extract; (iii) bleaching the solid tobacco material with a bleaching solution comprising a strong base, an oxidizing agent, or a combination thereof to provide bleached tobacco material; and (iv) drying the bleached tobacco material to provide bleached tobacco material.

31. The method of claim 30, wherein the extraction solution is an aqueous FRnrnn / zznz / e / YiAi solution.