Patent Description:
Citrus fibers are known to have many interesting properties making them suitable for use in a variety of products for human and animal consumption. Citrus fibers have been successfully employed, mainly as texturizing additives, in food and feed products and beverages, but also in personal care, pharmaceutical and detergent products. For the manufacturing of any of the above products, citrus fibers may be used in dry form (dry citrus fibers) or they may be dispersed in an aqueous medium. In particular the use of dry citrus fibers is advantageous due to the fibers' longer shelf life and reduced costs of shipping from a fiber production plant or storage site to a processing facility.

Dry citrus fibers and compositions containing thereof are for example known from <CIT>, <CIT>, and <CIT>. When carefully dried, these known citrus fibers may retain an optimum free surface area available for binding water upon rehydration and dispersion, which in turn provides said fibers with thickening capabilities, good stability, and the capacity to create optimum textures. Using various techniques such as the one disclosed in <CIT>, the properties of the dry citrus fibers can be further tailored to provide optimum functionalities.

Often, the ability of citrus fibers to bind and stabilize the water is considered essential for products containing a dispersion of said fibers in an aqueous medium or for those prepared from such dispersions. This ability is particularly important during products' transportation, when the products may be subjected to shocks and high gravity forces (G-forces) which in turn may cause the water to separate from the remaining components or ooze out therefrom. Such water separation may deleteriously influence the texture, rheology and visual appearance of the products and is hence highly undesired.

However, preparing citrus fibers and in particular dry citrus fibers without affecting their water binding characteristics such as water holding capacity and swelling volume, is difficult. It is known that the separation of water in products where citrus fibers are used to hold it and stabilize it, increases exponentially with the G-forces acting on said product; in other words, the water binding characteristics of the citrus fibers contained by said product decay exponentially with the G-forces acting on the product. Another important property which may be largely lost during processing is the capacity of the citrus fibers to disperse in an aqueous medium under mild and low shearing conditions. A method of providing dry fibers which are dispersible in an aqueous medium is to functionalize or derivatize the fibers, i.e. grafting various chemical moieties on the surface of the fibers. <CIT> discloses dry fibers, e.g. citrus fibers, functionalized with acidic polysaccharides retained on their surface. These fibers however, can only be dispersed in water with a high-shear mixing device of the ULTRA TURRAX type and cannot be thus considered readily dispersible.

Another method known to provide dry, dispersible fibers, involves drying the fibers in the presence of additives. <CIT> and <CIT> disclose dry compositions containing up to <NUM> wt% of a polyhydroxylated compound and dry fibers. Although citrus fibers were mentioned as being a suitable example, no experimental data using such fibers was reported therein.

It was also observed that known dry citrus fibers containing or free of additives may have undesirable characteristics such as stickiness, which in turn may cause problems during a subsequent processing thereof. Also, their water binding characteristics are less than optimum with a stronger decay of their water holding capacity with G-forces. Also, their water holding capacity at a certain G-force as well as their swelling volumes and G' values are reduced while their viscosity profiles is less than optimum.

Accordingly, there is an unmet need in the industry for dry citrus fibers, which have optimum water binding characteristics. In particular there is a need for such fibers having a reduced decay of their water binding characteristics when the G-forces acting thereupon are increasing. It is also preferred that such fibers can be readily dispersed in an aqueous medium. More in particular there is a need for such fibers having optimized water holding capacities and/or swelling volumes and which preferably upon dispersion in an aqueous medium provide said medium with an optimum rheological behavior. More in particular, there is a need for dry citrus fibers which when dispersed in an aqueous medium, show an optimized water holding capacity and/or swelling volume and provide the aqueous medium with optimum G' values and/or an optimum viscoelastic stability.

A primary object of this invention may thus be to provide dry citrus fibers having an optimized decay of their water binding characteristics with the G-forces acting thereupon. Preferably, said fibers are readily dispersed in an aqueous medium under low-shear stirring to form a dispersion having optimum rheological properties.

The invention provides dry citrus fibers having a water holding capacity (WHC) of at least <NUM> of water per gram of anhydrous (<NUM>% moisture) fibers, the WHC being determined on an aqueous medium containing <NUM> wt% (relative to the total weight of said medium) of said fibers dispersed therein after subjecting said medium to a G force of <NUM>, wherein the citrus fibers are produced by the method defined in the claims. Said fiber preferably have a swelling factor (SV), wherein when applying a gravitational force (G-force) on an aqueous medium containing <NUM> wt% of said fibers dispersed therein, the WHC varies with the G-force according to Formula <NUM>: <MAT> wherein DF is a decay factor of at least <NUM>.

In a further aspect, the invention relates to dry citrus fibers having a water holding capacity (WHC) of at least <NUM> of water per gram of anhydrous (<NUM>% moisture) fibers, the WHC being determined on an aqueous medium containing <NUM> wt% of said fibers dispersed therein after subjecting said medium to a G-force of <NUM>, wherein the citrus fibers are produced the method defined in the claims, and wherein said fibers have a storage modulus (G') of at least <NUM> Pa when measured on an aqueous medium containing an amount of <NUM> wt% citrus fibers dispersed therein under a low-shear stirring of less than <NUM> rpm.

Any feature of a particular embodiment of the present invention may be utilized in any other embodiment of the invention. The word "comprising" is intended to mean "including" but not necessarily "consisting of" or "composed of. " In other words, the listed steps or options need not be exhaustive. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Similarly, all percentages are weight/weight percentages unless otherwise indicated. Except in the examples and comparative experiments, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word "about". Unless specified otherwise, numerical ranges expressed in the format "from x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "from x to y", it is understood that all ranges combining the different endpoints are also contemplated. For the purpose of the invention ambient (or room) temperature is defined as a temperature of about <NUM> degrees Celsius.

The ability of citrus fibers to bind and hold water is arguably one of the most important quality characteristics thereof. The release of water under normal and high-G conditions from products containing citrus fibers is an undesirable phenomenon and may deleteriously impact at least the product's texture, rheology and aspect. The present invention provides citrus fibers which have water binding characteristics never achieved hitherto. The inventors observed that the citrus fibers of the invention, obtained by the method as defined in the claims, (hereinafter "inventive fibers") have an optimum ability to bind and hold water even under increased G-forces. When used in the manufacturing of products where water stabilization is desired, the inventive fibers showed optimum water binding characteristics which decay with the G-forces less than in the case of known fibers. The inventive fibers may be thus providing the product with an optimum texture and rheology.

The invention provides dry citrus fibers having a water holding capacity (WHC) and a swelling factor (SV), wherein when applying a gravitational force (G-force) on an aqueous medium containing <NUM> wt% of said fibers dispersed therein, the WHC varies with the G-force according to Formula <NUM>: <MAT> wherein DF is a decay factor of at least <NUM>. With the wording "WHC varies with the G-force" is herein understood that the WHC of the fibers of the invention depends on the applied G-force.

Products containing water may be subjected to various amounts of external stresses, in particular during their handling and transportation. These stresses may cause the various ingredients thereof and also the water contained therein to displace from their location and eventually to be forced out of the product. To understand the influence of the external stresses on the products and find solutions that mitigate the unwanted effects thereof, the inventors replicated the external stresses in the laboratory by means of application of a range of G-forces on said products. It is known that when applying a G-force on a product containing water, wherein the water was stabilized by various means, e.g. with the help of citrus fibers, above a certain G-force threshold the release of water is accelerated exponentially. Having a higher threshold helps in minimizing the displacement and release of water. The inventors observed that the citrus fibers of the invention, as produced by the method as defined in the claims. (hereinafter "the inventive fibers") have an optimum decay factor (DF) which on one hand may increase the threshold for water release and on the other hand may minimize the amount of water released when strong G-forces (e.g. <NUM> to <NUM>) are applied on the product.

Preferably, DF of the inventive fibers is at least <NUM>, more preferably at least <NUM>, even more preferably at least <NUM>, yet even more preferably at least <NUM>, most preferably at least <NUM>.

The WHC of the inventive fibers decreases in accordance with Formula <NUM> when increasing the G-force applied on the aqueous medium containing <NUM> wt% (relative to the total weight of the medium) of said fibers dispersed therein. Preferably, the G-force is increased between <NUM> (i.e. <NUM> times the standard gravitational force (STG)) and <NUM>, more preferably between <NUM> and <NUM>, most preferably between <NUM> and <NUM>. The G-force may be applied on the aqueous medium using known means, e.g. by means of centrifugation. Such centrifugation means are described for example in the METHODS OF MEASUREMENT section hereinbelow.

For the purpose of this invention, STG can be calculated according to Formula <NUM> <MAT> wherein the "weight of object in Kg " is the weight of the aqueous medium containing the <NUM> wt% of dispersed inventive fibers. The variations of STG with altitude or other factors are not taken into account.

The inventive fibers have a water holding capacity (WHC) of at least <NUM> of water per gram of anhydrous (about <NUM>% moisture) fibers, the WHC being determined on an aqueous medium containing <NUM> wt% (relative to the total weight of said medium) of said fibers dispersed therein after subjecting said medium to a G-force of <NUM>, wherein the citrus fibers are produced by the method defined in the claims. Preferably, said WHC is at least <NUM> milliliters of water (mL) per gram of fibers (g), more preferably at least <NUM>/g, most preferably at least <NUM>/g.

Preferably the inventive fibers have a SV of at least <NUM>%, more preferably at least <NUM>%, most preferably at least <NUM>%, when determined on an aqueous medium containing <NUM> wt% (relative to the total weight of said medium) of said fibers dispersed therein. The protocol for determining the SV at low concentrations of fibers (e.g. about <NUM> wt%) is described in the METHODS OF MEASUREMENT section hereinbelow.

The citrus fibers of the invention, as produced by the method defined in the claims, are in dry form, which is herein understood as containing an amount of liquid, e.g. water and/or organic solvent, of less than <NUM> wt% relative to the total weight of the fibers. Preferably said fibers contain an amount of water (i.e. moisture content) relative to the total weight of the fibers of at most <NUM> wt%, more preferably at most <NUM> wt%, or most preferably at most <NUM> wt%. Such dry fibers may be more economical to transport and store while being readily dispersible in the aqueous medium.

The fibers of the invention are citrus fibers and are produced by the method defined in the claims. The term "fiber" as used herein, refers to an elongated object comprising microfibrils of cellulose, the fiber having a length (major axis) and a width (minor axis) and having length to width ratio of at least <NUM>, more preferably at least <NUM>, or most preferably at least <NUM>, as observed and measured by a high-resolution scanning electron microscope ("SEM"). The dimensions of the fibers were measured on "wet" fibers, i.e. fibers which were extracted from an aqueous dispersion (e.g. containing <NUM> wt% fibers). The length of the citrus fibers is preferably at least <NUM>, more preferably at least <NUM>. The width of the citrus fibers is preferably at most <NUM>, more preferably at most <NUM>, most preferably at most <NUM>.

Citrus fibers are fibers contained by and obtained from the fruits of the citrus family. The citrus family is a large and diverse family of flowering plants. The citrus fruit is considered to be a specialized type of berry, characterized by a leathery peel and a fleshy interior containing multiple sections filled with juice filled sacs. Common varieties of the citrus fruit include oranges, sweet oranges, clementines, kumquats, tangerines, tangelos, satsumas, mandarins, grapefruits, citrons, pomelos, lemons, rough lemons, limes and leech limes. The citrus fruit may be early-season, mid-season or late-season citrus fruit. Citrus fruits also contain pectin, common in fruits, but found in particularly high concentrations in the citrus fruits. Pectin is a gel-forming polysaccharide with a complex structure. It is essentially made of partly methoxylated galacturonic acid, rhamnose with side chains containing arabinose and galactose, which are linked through a glycosidic linkage. The pectin content of the citrus fruit may vary based on season, where ripe fruit may contain less pectin than unripe fruit.

Citrus fiber is to be distinguished from citrus pulp, which are whole juice sacs and are sometimes referred to as citrus vesicles, coarse pulp, floaters, citrus cells, floating pulp, juice sacs, or pulp. Citrus fiber is also to be distinguished from citrus rag, which is a material containing segment membrane and core of the citrus fruit.

The citrus fibers are typically obtained from a source of citrus fibers, e.g. citrus peel, citrus pulp, citrus rag or combinations thereof. Moreover, the citrus fibers may contain the components of the primary cell walls of the citrus fruit such as cellulose, pectin and hemicelluloses and may also contain proteins.

Preferably, the citrus fibers of the invention did not undergo any substantial chemical modification, i.e. said fibers were not subjected to chemical modification processes, such as any of esterification, derivatisation or enzymatic modification and combinations thereof. Preferably, the citrus fibers in accordance with the invention have a crystallinity of at least <NUM>%, more preferably at least <NUM>%, most preferably at least <NUM>% as measured on a dried (less than <NUM> wt% water content relative to the content of fibers) sample by X-ray diffraction method (Siegel method). Preferably, the crystallinity of said fibers is between <NUM>% and <NUM>%.

Preferably, the citrus fibers in accordance with the invention have a storage modulus (G') of at least <NUM> Pa when measured on an aqueous medium containing an amount of <NUM> wt% citrus fibers dispersed therein under a low-shear stirring of less than <NUM> rpm.

The storage modulus G' is commonly used in the food industry to analyze the rheological properties of dispersions and in particular fiber-based dispersions. In the art, by fiber-based dispersion is understood fibers or compositions containing thereof dispersed in an aqueous medium. G' is a measure of a deformation energy stored in the dispersion during the application of shear forces and provides an excellent indication of the dispersion's viscoelastic behavior. G' is measured on an aqueous medium containing an amount of <NUM> wt% of citrus fibers, i.e. relative to the total weight of the aqueous medium. When fibers are dispersed under low-shear in an aqueous medium, it is highly desirable to achieve dispersions having G' values as high as possible at concentrations of fibers as low as possible.

The present inventors noticed that the citrus fibers of the invention were able to meet the above requirements and hence, in addition to their excellent water binding characteristics, these novel fibers may impart food formulations containing thereof with optimum rheological properties. The novel citrus fibers have also an improved dispersibility in that they are readily dispersible. Moreover, since said citrus fibers may be used at lower concentrations to achieve increased G' values, food manufactures may have increased design freedom for food formulations, in that they may be able to add or remove constituents while maintaining optimum viscoelastic properties thereof.

The G' of the citrus fibers of the invention is preferably at least <NUM> Pa. More preferably, said G' is at least <NUM> Pa, even more preferably at least <NUM> Pa, yet more preferably at least <NUM> Pa, yet more preferably at least <NUM> Pa, yet more preferably at least <NUM> Pa, even more preferably at least <NUM> Pa, most preferably at least <NUM> Pa.

As used herein, "dispersibility" means the capacity of the dry fibers to largely regain their initial functionality upon dispersion in an aqueous medium, e.g. water, wherein by initial functionality is herein understood the functionality of the fibers before being dehydrated and/or dried. Properties defining the initial functionality may include the fibers' swelling capacity, viscoelasticity, water binding characteristics and stabilization power.

The term "readily dispersible" as used herein means that it is not necessary to use high-shear means, e.g. high-shear mixers or homogenizers, to disperse the fibers in an aqueous medium such as water; but rather that the dispersion of the fibers can be accomplished with low-shear stirring equipment, such as for example, magnetic stirrers or mechanical stirrers, e.g. an IKA® Eurostar mechanical stirrer equipped with an R1342 <NUM>-bladed propeller stirrer or a Silverson L4RT overhead batch mixer equipped with an Emulsor Screen (e.g. with round holes of about <NUM> diameter).

The term "aqueous medium" as used herein means a liquid medium which contains water, suitable non-limiting example thereof including pure water, a water solution and a water suspension, but also those liquid mediums contained by dairy products such as milk, yoghurt and the like; personal care products such as lotions, creams, ointments and the like; and pharmaceutical products
The inventors surprisingly observed that the citrus fibers of the invention manifest these high G' values upon being dispersed in an aqueous medium under low shear, i.e. stirring with less than <NUM> rpm. This is even more surprising since said high G' values were achieved at the low fiber concentrations, e.g. of <NUM> wt%. The aqueous medium preferably contains water in an amount of at least <NUM> wt%, more preferably at least <NUM> wt%, most preferably at least <NUM> wt%, relative to the total amount of the medium. Preferably, the stirring used to achieve the dispersion of the fibers of the invention in the aqueous medium is at most <NUM> rpm, more preferably at most <NUM> rpm, most preferably at most <NUM> rpm. Preferably, the citrus fibers of the invention contain an additive which is preferably distributed therebetween. By the term "additive distributed therebetween" is herein understood that said additive is distributed inside a volume defined by the totality of fibers and preferably also between the microfibrils forming the fibers.

The additive is preferably in an amount of at least <NUM> wt% relative to the weight of the anhydrous citrus fibers, more preferably of at least <NUM> wt%, even more preferably of at least <NUM> wt%, yet even more preferably of at least <NUM> wt%, most preferably of at least <NUM> wt%. The weight of anhydrous fibers may be determined by drying <NUM> grams of the fibers without the additive at <NUM> under normal atmosphere until constant weight is obtained. The same determination can be carried out in the presence of the additive; however, in this case the amount of additive in the sample has to be subtracted therefrom. The upper limit for the additive amount can be kept within large variances since it was observed that the citrus fibers of the invention may have the ability to optimally include said additive. A preferred upper limit for the additive amount is at most <NUM> wt% relative to the weight of the fibers, more preferably at most <NUM> wt%, most preferably at most <NUM> wt%. In a preferred embodiment, the additive is in an amount of between <NUM> wt% and <NUM> wt%, more preferably between <NUM> wt% and <NUM> wt%, even more preferably between <NUM> wt% and <NUM> wt%, most preferably between <NUM> wt% and <NUM> wt%. In another preferred embodiment, the additive is in an amount of at least <NUM> wt%, more preferably at least <NUM> wt%, most preferably at least <NUM> wt%.

Preferably, the citrus fibers described in the embodiments of the invention contain an additive in an additive:fiber (A:F) ratio of between <NUM>:<NUM> and <NUM>:<NUM> by weight, more preferably between <NUM>:<NUM> and <NUM>:<NUM> by weight, most preferably between <NUM>:<NUM> and <NUM>:<NUM> by weight. The inventors observed that the inventive fibers have excellent water binding characteristics and stable rheological properties.

The additive used in accordance with the invention is preferably chosen from the group consisting of a sugar, a protein, a polysaccharide, a polyol and combinations thereof. More preferably, said additive is chosen from the group consisting of a sugar, a protein, a polysaccharide, a sugar alcohol and combinations thereof. Examples of sugars may include, without being limited thereto, monosaccharides such as fructose, mannose, galactose, glucose, talose, gulose, allose, altrose, idose, arabinose, xylose, lyxose, sorbose and ribose; and oligosaccharides such as sucrose, maltose, lactose, lactulose, and trehalose. Preferred proteins are those accepted in the food industry, e.g. gelatin, pea protein or pea protein hydrolisates. Preferred polysaccharides are those having a general formula (C<NUM>H<NUM>O<NUM>)n with n being preferably between <NUM> and <NUM>, more preferably between <NUM> and <NUM>, most preferably between <NUM> and <NUM>. Examples of polysaccharides include, without being limited thereto, dextrins such as maltodextrin, cyclodextrin, amylodextrin; and starches. Preferred sugar alcohols are those having the general formula HOCH<NUM>(CHOH)mCH<NUM>OH with m being preferably between <NUM> and <NUM>, more preferably between <NUM> and <NUM>, most preferably between <NUM> and <NUM>. Examples of sugar alcohols may include, without being limited thereto, glycerol, erythritol, threitol, arabitol, xylitol, ribitol, mannitol, sorbitol, galactitol, fucitol, iditol, inositol, volemitol, isomalt, maltitol, lactitol, maltotriitol, maltotetraitol, polyglycitol and combinations thereof.

In a preferred embodiment, the additive used in accordance with the invention is chosen from the group consisting of a sugar, a dextrin, and a sugar alcohol.

In another preferred embodiment, the additive used in accordance with the invention is a starch. The starch used in this invention may be any starch derived from any native source. A native starch as used herein, is one as it is found in nature. Also suitable are starches derived from a plant obtained by any known breeding techniques. Typical sources for the starches are cereals, tubers and roots, legumes and fruits. The native source can be any variety, including without limitation, corn, potato, sweet potato, barley, wheat, rice, sago, amaranth, tapioca (cassava), arrowroot, canna, pea, banana, oat, rye, triticale, and sorghum, as well as low amylose (waxy) and high amylose varieties thereof. Low amylose or waxy varieties is intended to mean a starch containing at most <NUM>% amylose by weight, preferably at most <NUM>%, more preferably at most <NUM>% and most preferably at most <NUM>% amylose by weight of the starch. High amylose varieties is intended to mean a starch which contains at least <NUM>% amylase, preferably at least <NUM>% amylose, more preferably at least <NUM>% amylose, even more preferably at least <NUM>% amylose, and most preferably at least <NUM>% amylose, all by weight of the starch. The starch may be physically treated by any method known in the art to mechanically alter the starch, such as by shearing or by changing the granular or crystalline nature of the starch, and as used herein is intended to include conversion and pregelatinization. Methods of physical treatment known in the art include ball-milling, homogenization, high shear blending, high shear cooking such as jet cooking or in a homogenizer, drum drying, spray-drying, spray cooking, chilsonation, roll-milling and extrusion, and thermal treatments of low (e.g. at most <NUM> wt%) and high (above <NUM> wt%) moisture containing starch. The starch may be also chemically modified by treatment with any reagent or combination of reagents known in the art. Chemical modifications are intended to include crosslinking, acetylation, organic esterification, organic etherification, hydroxyalkylation (including hydroxypropylation and hydroxyethylation), phosphorylation, inorganic esterification, ionic (cationic, anionic, nonionic, and zwitterionic) modification, succination and substituted succination of polysaccharides. Also included are oxidation and bleaching. Such modifications are known in the art, for example in <NPL>).

The invention also relates to dry citrus fibers having a water holding capacity (WHC) of at least <NUM> of water per gram of anhydrous (<NUM>% moisture) fibers, the WHC being determined on an aqueous medium containing <NUM> wt% (relative to the total weight of said medium) of said fibers dispersed therein after subjecting said medium to a G-force of <NUM> wherein the citrus fibers are produced by the method defined in the claims, and wherein said fibers have preferably a storage modulus (G') of at least <NUM> Pa when measured on an aqueous medium containing an amount of <NUM> wt% citrus fibers dispersed therein under a low-shear stirring of less than <NUM> rpm. Preferably said fibers contain an additive. Preferred ranges for WHC and G' as well as preferred examples of the additive are given above and will not be repeated herein. Preferably, said fibers contain an amount of liquid, e.g. water and/or organic solvent, of less than <NUM> wt% relative to the total weight of the fibers. Preferably said fibers contain an amount of water of at most <NUM> wt%, more preferably at most <NUM> wt%, or most preferably at most <NUM> wt% relative to the total weight of the fibers.

The invention relates to dry citrus fibers having a water holding capacity (WHC) of at least <NUM> of water per gram of anhydrous (<NUM>% moisture) fibers, the WHC being determined on an aqueous medium containing <NUM> wt% (relative to the total weight of said medium) of said fibers dispersed therein after subjecting said medium to a G-force of <NUM>, wherein the citrus fibers are produced by the method defined in the claims. Preferably, said WHC is at least <NUM> of water (mL) per gram of fibers (g), more preferably at least <NUM>/g, most preferably at least <NUM>/g. Preferably, the fibers contain an additive. Preferred examples of the additive are given above and will not be repeated herein. Preferably, said fibers contain an amount of liquid, e.g. water and/or organic solvent, of less than <NUM> wt% relative to the total weight of the fibers. Preferably said fibers contain an amount of water of at most <NUM> wt%, more preferably at most <NUM> wt%, or most preferably at most <NUM> wt% relative to the total weight of the fibers.

The invention also relates to dry citrus fibers having a water holding capacity (WHC) of at least <NUM> of water per gram of fibers, as defined in the claims, said fibers containing an additive distributed therebetween. Examples of the additives were given above and will not be repeated herein. Preferably, the WHC is at least <NUM>/g, more preferably at least <NUM>/g, most preferably at least <NUM>/g. The inventive fibers have the required and preferred WHC under a gravitational force (G-force) of at <NUM>. Preferably, the dry citrus fibers contain an amount of liquid, e.g. water and/or organic solvent, of less than <NUM> wt% relative to the total weight of the fibers with the additive. Preferably said fibers contain an amount of water of at most <NUM> wt%, more preferably at most <NUM> wt%, or most preferably at most <NUM> wt% relative to the total weight of the fibers with the additive. Such dry citrus fibers may be more economical to transport and store. Preferably, said fibers have a storage modulus (G') of at least <NUM> Pa, said G' being measured on an aqueous medium obtained by dispersing an amount of said fibers therein under a low shear stirring of less than <NUM> rpm to obtain a citrus fibers' concentration of <NUM> wt% relative to the total weight of the aqueous medium. Preferably, G' is at least <NUM> Pa, more preferably at least <NUM> Pa, even more preferably at least <NUM> Pa, yet more preferably at least <NUM> Pa, yet more preferably at least <NUM> Pa, most preferably at least <NUM> Pa when said fibers are dispersed under a low shear stirring of preferably less than <NUM> rpm, more preferably less than <NUM> rpm.

The citrus fibers of the invention are produced by a method , comprising the steps of:.

It is difficult to prepare dry citrus fibers without affecting their water binding characteristics and/or dispersibility in an aqueous media. This difficulty is attributed to many factors (collectively referred to in literature as "hornification") such as the formation of hydrogen bonds and/or lactone bridges between the fibers. Hornification typically reduces the available free-surface area of the fibers and/or strengthens the linkage between the fibers, which in turn may reduce the capacity of the fibers to absorb, bind and hold liquid and to disperse. Hornified dry citrus fibers either cannot be dispersed into an aqueous medium, e.g. water, a water solution or a water suspension, or they can be dispersed only by using high or ultra-high shear mixing. The method of the invention succeeded however in producing dry citrus fibers having excellent water binding characteristics and rheological properties.

The method of the invention (the inventive method), contains a step of homogenizing an aqueous slurry of a source of citrus fibers ("source slurry"). The terms "slurry" and "dispersion" mean the same within the context of the present invention and are used interchangeably herein. The source of citrus fibers may be citrus peel, citrus pulp, citrus rag or combinations thereof. The source of citrus fibers may be a by-product obtained during the pectin extraction process. Preferably, the source of the citrus fibers is citrus peel; more preferably is de-pectinized citrus peel. Said source slurry preferably comprises a dry substance content of at least <NUM> wt%, more preferably at least <NUM> wt%, more preferably at least <NUM> wt%. Preferably said dry substance content of said source slurry is at most <NUM> wt%, more preferably at most <NUM> wt%, even more preferably at most <NUM> wt%, yet even more preferably at most <NUM> wt%, most preferably at most <NUM> wt%.

The homogenization of the source slurry may be carried out with a number of possible methods including, but not limited to, high shear treatment, pressure homogenization, cavitation, explosion, pressure increase and pressure drop treatments, colloidal milling, intensive blending, extrusion, ultrasonic treatment, and combinations thereof.

In a preferred embodiment, the homogenization of the source slurry is a pressure homogenization treatment which may be carried out with a pressure homogenizer. Pressure homogenizers typically comprise a reciprocating plunger or piston-type pump together with a homogenizing valve assembly affixed to the discharge end of the homogenizer. Suitable pressure homogenizers include high pressure homogenizers manufactured by GEA Niro Soavi of Parma (Italy), such as the NS Series, or the homogenizers of the Gaulin and Rannie series manufactured by APV Corporation of Everett, Massachusetts (US). During the pressure homogenization, the source slurry is subjected to high shear rates as the result of cavitation and turbulence effects. These effects are created by the source slurry entering a homogenizing valve assembly which is part of a pump section of the homogenizer at a high pressure (and low velocity). Suitable pressures for the inventive method are from <NUM> bar to <NUM> bar, more preferably between <NUM> bar and <NUM> bar. While not being bound to any theory, it is believed that the homogenization causes disruptions of the source of citrus fibers and its disintegration into the fibrous component.

Depending on the particular pressure selected for the pressure homogenization, and the flow rate of the source slurry through the homogenizer, the source slurry may be homogenized by one pass through the homogenizer or by multiple passes. In one embodiment, the source slurry is homogenized by a single pass through the homogenizer. In a single pass homogenization, the pressure used is preferably from <NUM> bars to <NUM> bars, more preferably from <NUM> bars to <NUM> bars, even more preferably from <NUM> bars to <NUM> bars. In another preferred embodiment, the source slurry is homogenized by multiple passes through the homogenizer, preferably at least <NUM> passes, more preferably at least <NUM> passes through the homogenizer. In a multi-pass homogenization, the pressure used is typically lower compared to a single-pass homogenization and preferably from <NUM> bars to <NUM> bars, more preferably from <NUM> bars to <NUM> bars, even more preferably from <NUM> bars to <NUM> bars.

The result of the homogenization step is an aqueous slurry of citrus fibers ("fibers slurry") comprising a dry substance content of fibers in essentially the same amount as the source slurry. Said fibers slurry is then contacted with an organic solvent. Said organic solvent should preferably be polar and water-miscible to better facilitate water removal. Examples of suitable organic solvents which are polar and water-miscible include, without limitation, alcohols such as methanol, ethanol, propanol, isopropanol and butanol. Ethanol and isopropanol are preferred organic solvents; isopropanol is the most preferred organic solvent for use in the inventive method. The organic solvent can be used in its <NUM>% pure form or may be a mixture of organic solvents. The organic solvent can also be used as a mixture of the organic solvent and water, hereinafter referred to as an aqueous solvent solution. The concentration of organic solvent in said aqueous solvent solution is preferably from about <NUM> wt% to about <NUM> wt% relative to the total weight of said solution, more preferably between <NUM> wt% and <NUM> wt%, most preferably between <NUM> wt% and <NUM> wt%. In general, lower concentrations of the organic solvent are suitable to remove water and watersoluble components whereas increasing the concentration of said organic solvent also helps in removing oil and oil-soluble components if desired. In one embodiment, an organic solvent mixture containing a non-polar organic (NPO) co-solvent and the organic solvent or the aqueous solvent solution is used in the inventive method. The utilization of the organic solvent mixture may improve for example the recovery of oil-soluble components in the citrus pulp. Examples of suitable NPO co-solvents include, without limitation, ethyl acetate, methyl ethyl ketone, acetone, hexane, methyl isobutyl ketone and toluene. The NPO co-solvents are preferably added in amounts of up to <NUM>% relative to the total amount of organic solvent mixture.

The fibers slurry is contacted with the organic solvent preferably in a ratio slurry:solvent of at most <NUM>:<NUM>, more preferably at most <NUM>:<NUM>, or most preferably at most <NUM>:<NUM>. Preferably said ratio is at least <NUM>:<NUM>, more preferably at least <NUM>:<NUM>, most preferably at least <NUM>:<NUM>. Preferably, said fibers slurry is contacted with the organic solvent for at least <NUM> minutes, more preferably for at least <NUM> minutes, most preferably for at least <NUM> minutes. Preferably, said slurry is contacted with the organic solvent for at most several hours, more preferably for at most <NUM> hours, most preferably for at most <NUM> hour.

According to the invention, said fibers slurry is contacted with said organic solvent to obtain a precipitate phase and a liquid phase. The inventors observed that during contacting the organic solvent with the fibers slurry, the fibers slurry releases at least part of its water content into the organic solvent which in turn causes the citrus fibers to precipitate. By "precipitate phase" is herein understood a phase containing the majority of the citrus fibers, e.g. more than <NUM>% of the total amount of fibers, preferably more than <NUM>%, most preferably more than <NUM>% and also containing organic solvent and water. The precipitate phase usually settles due to gravity forces. The precipitate phase typically has a solid- or a gel-like appearance, i.e. it essentially maintains its shape when placed on a supporting surface. By "liquid phase" is herein understood a phase containing organic solvent and water. The liquid phase may also contain some citrus fibers which did not precipitate. According to the invention, the precipitate phase is in the form of granules, preferably, millimeter-size granules. Preferred granule sizes are between <NUM> and <NUM>, more preferably between <NUM> and <NUM>. By "the size of a granule" is herein understood the biggest dimension of said granule. The formation of the precipitate phase into granules may be achieved for example by bringing under agitation the fibers slurry into a container containing the organic solvent or by pouring said slurry in the organic solvent. The amount of agitation typically dictates the size of the formed granules. It was observed that by forming granules, the subsequent water removal from said granules is facilitated. Without being bound to any theory, it is believed that the formation of granules also aids in preserving and/or increasing the free surface area of the citrus fibers available for water binding and may also avoid a collapse of the fibers.

The precipitate phase is subsequently separated from the liquid phase to obtain a semi-dry citrus fibers cake ("fiber cake"). Said separation can be achieved using known methods such as centrifugation, filtration, evaporation and combinations thereof.

To increase the dry substance content, steps b) and c) of the inventive method can be repeated at least one time, preferably before carrying out step d). The fiber cake can also be subjected to an extraction step. A preferred extraction method is pressing, e.g. with a normal press, a screw press or an extruder. A more preferred extraction method is pressure filtration using a volume chamber filter press or a membrane filter press; pressure filters being sold for example by BHS Sonthofen, DE. Two-sided liquid removal is recommended for the pressure filtration since more filtering area is available per volume of the fiber cake.

The fiber cake is semi-dry, i.e. it has a dry substance content of preferably at least <NUM> wt%, more preferably of at least <NUM> wt%, or most preferably of at least <NUM> wt% relative to the mass of said cake. Preferably, said cake has a liquid-content of at most <NUM> wt%, more preferably at most <NUM> wt%, most preferably at most <NUM> wt% relative to the total mass of said cake. The liquid typically contains organic solvent and water.

In accordance with the invention, the fiber cake is comminuted to obtain grains containing citrus fibers ("fiber grains"), said grains preferably having a diameter of at most <NUM>, more preferably at most <NUM>, even more preferably at most <NUM>, yet even more preferably at most <NUM>, yet even more preferably at most <NUM>, most preferably at most <NUM>. With "grain diameter" is herein understood the largest dimension of the grain. The diameter may be determined using a microscope equipped with graticule. Cutters may be used to cut the fiber cake into grains. Alternatively, the fiber cake can subjected to milling and/or grinding in order to form it into grains. Examples of suitable means to comminute the fiber cake include without limitation a cutter mill, a hammer mill, a pin mill, a jet mill and the like.

The fiber grains are mixed with an additive to obtain semi-dry citrus fibers comprising the additive. Examples of suitable additives as well as preferred choices are given above and will not be repeated herein. Mixing the fiber grains with the additive can be effected with known means in the art, examples thereof including without limitation a malaxer, a transport screw, an air-stream agitation mixer, a paddle mixer, a Z-mixer, a tumble mixer, a high speed paddle mixer, a power blender and the like. The additive may be provided in a solid form or in solution. Preferably, the additive is provided in a solid form, more preferably as a powder, even more preferably as a powder having an average particle size ("APS") of between <NUM> and <NUM>, more preferably between <NUM> and <NUM>; the APS can be determined by ASTM C136-<NUM>.

The semi-dry citrus fibers are subjected to a desolventizing and/or dehydrating step wherein the organic solvent and/or the water are extracted from said semi-dry citrus fibers. Preferably, the inventive method contains both steps of desolventizing and dehydration. It was surprisingly observed that during the organic solvent and/or water extraction, the hornification of citrus fibers was largely prevented. Without being bound to any theory, the inventors attributed the reduced hornification to the careful pre-processing of the citrus fibers prior to said extraction as detailed in steps a) to d) of the inventive method.

Desolventisation and dehydration of said semi-dry citrus fibers can be carried out with a desolventizer which removes organic solvent and/or water from the fibers and may also enable the organic solvent to be reclaimed for future use. Desolventizing also ensures that the obtained dry citrus fibers are safe for milling and commercial use. The desolventizer can employ indirect heat to remove the organic solvent from the semi-dry citrus fibers; the advantage of using said indirect heat is that significant amounts of organic solvents can be extracted. Also, direct heat can be provided for drying, e.g. by providing hot air from flash dryers or fluidized bed dryers. Direct steam may be employed, if desired, to remove any trace amounts of organic solvent remaining in the fibers. Vapors from the desolventizer preferably are recovered and fed to a still to reclaim at least a portion of the organic solvent.

Retention times for the desolventizing and/or dehydrating step may vary over a wide range but can be about <NUM> minutes or less. Suitable temperatures at which said desolventizing and dehydrating step is carried out depend on such factors as the type of organic solvent and most often ranges from about <NUM> to about <NUM> at atmospheric pressure. Temperatures can be appropriately increased or decreased for operation under supra- or sub-atmospheric pressures. Optionally, techniques such as ultrasound are used for enhancing efficiency of the desolventizing and dehydrating. By maintaining a closed system, solvent losses can be minimized. Preferably, at least about <NUM> wt% of the organic solvent is recovered and reused.

Dehydration can be effected with known means in the art, examples thereof including without limitation paddle driers, fluidized bed driers, stirred vacuum driers, drum driers, plate driers, belt driers, microwave driers and the like. Preferably, the dehydration temperature is at most <NUM>, more preferably at most <NUM>, most preferably at most <NUM>. Preferably, the dehydration temperature is at least <NUM>, more preferably at least <NUM>, most preferably at least <NUM>.

The desolventizing and/or dehydrating step are carried out to obtain dry citrus fibers comprising the additive, said dry citrus fibers having a moisture content of at most <NUM> wt% relative to the total weight of the fibers with the additive, preferably at most <NUM> wt%, more preferably at most <NUM> wt%, even more preferably at most <NUM> wt%, most preferably at most <NUM> wt%.

Optionally, the method of the invention further comprises a step of removing said additive and/or classifying the dry citrus fibers with or without the additive to obtain the desired particle size and/or packing the dry citrus fibers.

In a preferred embodiment, the inventive method comprises a classification step of the dry citrus fibers which may improve the homogeneity of the powder, narrow particle size distribution and improve degree of rehydration. Classification may be carried out using either a static or dynamic classifier. The inventive method may further comprise a packaging step of the dry fibers.

In another preferred embodiment, the additive is extracted from the dried and/or classified citrus fibers as obtained at steps f) and/or g), respectively to obtain dry citrus fibers without the additive. To aid in the extraction of the additive, preferably, an additive is used that has a boiling point of less than the degradation temperature of the citrus fibers. The extraction may be performed by washing the additive with a suitable solvent other than water. The extraction is preferably performed by subjecting said dry citrus fibers comprising the additive to an extraction temperature between the boiling point of the additive and the degradation temperature of the citrus fibers and allowing the additive to evaporate; preferably the evaporation is carried out under vacuum. Preferably, said additive has a boiling point of at most <NUM>, more preferably at most <NUM>, most preferably at most <NUM>. The boiling points of various materials are listed in the CRC Handbook of Chemistry and Physics or alternatively, ASTM D1120 may be used to determine said boiling point. Preferably the extraction temperature is between <NUM> and <NUM>, more preferably between <NUM> and <NUM>, most preferably between <NUM> and <NUM>. Examples of additives having such reduced boiling points include low molecular weight polyols, e.g. polyether polyols, ethylene glycols, and the like. By low molecular weight is herein understood an Mw of between <NUM> and <NUM>. The use of such extractable additives enables the manufacturing of the inventive fibers. Alternatively, dry citrus fibers without the additive may be obtained with the inventive method by skipping in step d) the addition of the additive by mixing. Dry cellulose fibers may also be obtained with the method of the invention by choosing an appropriate source of cellulose fibers to be processed.

The dry citrus fibers comprising the additive are preferably milled and/or classified to obtain a powder having an average particle size of preferably at least <NUM>, more preferably at least <NUM>, most preferably at least <NUM>. Preferably said average particle size is at most <NUM>, more preferably at most <NUM>, most preferably at most <NUM>. Said average particle size may be determined by ASTM C136-<NUM>.

The invention relates to citrus fibers in dry form obtainable by the method of the present invention.

It was observed that the inventive fibers have optimal water binding characteristics and/or rheological properties. These properties may lead to optimal quality of various products containing thereof, e.g., food, feed, personal care and pharmaceutical products.

The inventive fibers are suitably used in the production of a large variety of food compositions. The food compositions of the invention are defined in the claims. Examples of food compositions comprising thereof, to which the disclosure relates, include: luxury drinks, such as coffee, black tea, powdered green tea, cocoa, adzuki-bean soup, juice, soya-bean juice, etc.; milk component-containing drinks, such as raw milk, processed milk, lactic acid beverages, etc.; a variety of drinks including nutrition-enriched drinks, such as calcium-fortified drinks and the like and dietary fiber-containing drinks, etc.; dairy products, such as butter, cheese, yogurt, coffee whitener, whipping cream, custard cream, custard pudding, etc.; iced products such as ice cream, soft cream, lacto-ice, ice milk, sherbet, frozen yogurt, etc.; processed fat food products, such as mayonnaise, margarine, spread, shortening, etc.; soups; stews; seasonings such as sauce, TARE, (seasoning sauce), dressings, etc.; a variety of paste condiments represented by kneaded mustard; a variety of fillings typified by jam and flour paste; a variety or gel or paste-like food products including red bean-jam, jelly, and foods for swallowing impaired people; food products containing cereals as the main component, such as bread, noodles, pasta, pizza pie, corn flake, etc.; Japanese, US and European cakes, such as candy, cookie, biscuit, hot cake, chocolate, rice cake, etc.; kneaded marine products represented by a boiled fish cake, a fish cake, etc.; live-stock products represented by ham, sausage, hamburger steak, etc.; daily dishes such as cream croquette, paste for Chinese foods, gratin, dumpling, etc.; foods of delicate flavor, such as salted fish guts, a vegetable pickled in sake lee, etc.; liquid diets such as tube feeding liquid food, etc.; supplements; and pet foods. These food products are all encompassed within the present disclosure, regardless of any difference in their forms and processing operation at the time of preparation, as seen in retort foods, frozen foods, microwave foods, etc..

The invention will now be described with the help of the following examples and comparative experiments, without being however limited thereto. Any examples falling outside the scope of the claims are provided for comparative purposes.

Dry citrus fibers were manufactured as follows:.

The properties of the obtained fibers are presented in Tables <NUM> and <NUM>.

Dry citrus fibers were manufactured as follows: Example <NUM> was repeated with the difference that at step (<NUM>) the comminuted semi-dry cake was mixed with various additives at various ratios as indicated in Table <NUM>. The properties of the fibers are presented in Tables <NUM> and <NUM>.

Various commercial samples (CS. <NUM> to CS. <NUM>) were also investigated
The properties of the obtained fibers and those of the commercial samples are presented in Tables <NUM> and <NUM>.

To determine how WHC varies with the G-force, the method described above in the METHODS OF MEASUREMENT section was used. Data is reported in Table <NUM>. The data was fitted using Formula <NUM> and the DF was identified.

Claim 1:
Citrus fibers in dry form having a water holding capacity (WHC) of at least <NUM> of water per gram of anhydrous (<NUM>% moisture) fibers, the WHC being determined on an aqueous medium containing <NUM> wt% (relative to the total weight of said medium) of said fibers dispersed therein after subjecting said medium to a G force of <NUM>, wherein the citrus fibers are produced by:
a) providing an aqueous slurry of a source of citrus fibers, said slurry having a pH of between <NUM> and <NUM>;
b) homogenizing the aqueous slurry of a source of citrus fibers to obtain an aqueous slurry of citrus fibers;
c) contacting the aqueous slurry of citrus fibers with an organic solvent to obtain a precipitate phase and a liquid phase; wherein the precipitate is in the form of granules;
d) separating said precipitate phase from the liquid phase to obtain a semi-dry citrus fiber cake having a dry substance-content of at least <NUM> wt% relative to the mass of said cake;
e) comminuting said cake to obtain grains containing citrus fibers; and
f) desolventizing and/or dehydrating said semi-dry citrus fibers to obtain dry citrus fibers having a moisture content of preferably below <NUM> wt% relative to the total weight of the fibers.