Activable pectin-containing citrus fiber, methods for its production and use, and mixtures thereof

Abstract

Activable pectin-containing citrus fiber, characterized in that the activatable pectin-containing citrus fiber has a yield stress II (crossover) in a 2.5 wt% fiber suspension in demineralized water of 0.1 - 1.0 Pa and a dynamic Weissenberg number in a 2.5 wt% fiber suspension in demineralized water of 4.5 - 8.0, wherein the activatable pectin-containing citrus fiber is obtained by a process comprising: a. Providing a raw material containing cell wall material of an edible citrus fruit; b. Digestion of the raw material by incubation of an aqueous suspension of the raw material at an acidic pH value; c. Single- or multi-stage separation of the digested material from step (b) from the aqueous liquid; d. Washing the material separated in step (c) with an aqueous solution, wherein the aqueous solution is water, deionized water or a salt solution with an ionic strength of l < 0.2 mol / l, and separation of coarse or undigested particles; e. Separation of the washed material from step (d) from the aqueous liquid; f. Washing the separated material from step (e) at least twice with an organic solvent, with subsequent separation of the washed material from the organic solvent each time; g. Drying of the material from step (f) comprising drying at normal pressure to obtain the activatable pectin-containing citrus fiber; wherein the activatable pectin-containing citrus fiber obtained has less than 10 wt.% water-soluble pectin and a yield stress l (rotation) in a 2.5 wt.% fiber dispersion in demineralized water of 1.0 to 4.0 Pa.

Description

[0001] The present invention relates to an activatable pectin-containing citrus fiber. The invention further relates to the use of the pectin-containing citrus fiber as a thickening or structuring agent in various industrial products. The invention also relates to a mixture of the activatable pectin-containing citrus fiber with a soluble pectin. Finally, the invention relates to a food product, feed product, food supplement, beverage, cosmetic product, pharmaceutical product, or medical device produced using the pectin-containing citrus fiber according to the invention. Background of the invention

[0002] Dietary fiber consists largely of indigestible food components, mostly carbohydrates, found primarily in plant-based foods. For simplicity, dietary fiber is divided into water-soluble fiber, such as pectin, and water-insoluble fiber, such as cellulose. Dietary fiber is considered an important component of the human diet.

[0003] Dietary fiber is considered beneficial to health. The water-soluble fiber in food increases the volume of food without significantly increasing its energy content. If it hasn't already swelled sufficiently before ingestion, it absorbs further water in the stomach. The resulting increase in volume leads to a greater feeling of satiety. Furthermore, dietary fiber prolongs the transit time of food through the stomach and intestines. Water-soluble fibers like pectin bind bile acids involved in cholesterol metabolism in the intestines, thus lowering cholesterol levels.

[0004] Soluble fiber, in particular, is said to reduce glucose absorption, slow down glucose adsorption and starch processing, and control postprandial serum glucose levels. People who consume plenty of fiber have a reduced risk of numerous lifestyle diseases, especially obesity, high blood pressure, coronary heart disease (CHD), stroke, diabetes, and various gastrointestinal disorders. Accordingly, the German Nutrition Society (DGE) recommends a daily intake of at least 30 g of fiber.

[0005] The use of citrus fiber as dietary fiber in food production is gaining increasing importance. One reason for this is that citrus fiber is a mixture of insoluble fiber such as cellulose and soluble fiber such as pectin, thus ideally offering the aforementioned range of health-promoting effects. By using citrus fiber, the functional properties of food products, such as viscosity, emulsification, gel formation, shape stability, or texture, can be specifically optimized and adjusted. Citrus fiber can therefore replace other less accepted or even potentially harmful additives in food and, as substances not classified under E-numbers, lead to simpler product labeling and thus to increased product acceptance.

[0006] WO 01 / 17 376 A1 relates to a process for producing dietary fiber with high water-binding capacity and its application. It teaches a process for producing fruit fibers, such as apple fiber or citrus fiber, in which plant components are digested in an acidic environment and subsequently washed with alcohol (see claim 1, page 7, line 16 to page 8, line 5). However, the process only yields citrus fibers with a water-binding capacity of 17g of water perg of fiber (page 6, line 18).

[0007] WO 2012 / 016 190 A1 relates to a process for producing citrus fiber from citrus pomace. The process includes a homogenization step, followed by a washing step with an organic solvent and a final solvent removal and drying step (see claim 1 and examples 1 to 5 on page 14, line 13 to page 16, line 10). The necessary homogenization, which is preferably high-pressure homogenization (page 4, lines 1 to 2), necessitates a complex manufacturing process to obtain fibers with good hydration properties and viscosity (see page 2, lines 3 to 6).

[0008] WO 94 / 27451 A1 concerns the production of natural thickening agents from citrus fruit and teaches a process in which an aqueous slurry is prepared from citrus pomace, heated to a temperature of 80 to 180°C, and subsequently subjected to high-pressure homogenization (see summary). Here, too, in addition to heating, a high-pressure homogenization step is necessary to obtain fibers with advantageous rheological properties.

[0009] German patent DE 41 33 920 C1 concerns the production of low-protein, pectin-rich cell-structured materials and specifies apples, pears, white cabbage, kohlrabi, cauliflower, celery, and carrots as raw materials (see column 5, lines 4-9). According to column 3, lines 40 to 47, the removal of the plant proteins involves incubation in a weakly alkaline solution between 8.0 and 9.5 at temperatures below 60°C. The basic production process, as described in column 5, lines 31 to 44, comprises an alkaline protein extraction step, blanching, pectin deesterification under alkaline conditions, acid washing for ash removal, acid-free washing, initial drying with suitable organic solvents, and gentle thermal final drying. With these seven process steps, it is a complex procedure that also results in fruit fibers containing deesterified pectin.

[0010] EP 3 466 983 A1 relates to a process for producing an activated pectin-containing biomass composition from a pectin-containing starting biomass material such as citrus peels, an activated pectin-containing biomass composition, and a product comprising such an activated pectin-containing biomass composition (see paragraph

[0010] ). The process comprises the formation of activated pectin-containing biomass by adding an acidic activation solution to the biomass material and heating it to a temperature > 40 °C. The activated pectin-containing biomass can only be obtained by applying mechanical energy (paragraph

[0011] ).

[0011] EP 3 372 093 A1 relates to a process for obtaining citrus fibers from citrus peels, wherein the citrus peels must first be homogenized and then washed with organic solvents and subsequently dried to obtain citrus fibers (paragraph

[0006] ).

[0012] WO 2006 / 033 697 A1 relates to a process for cleaning citrus fibers in citrus vesicles, wherein the vesicles washed with organic solvents are desolventized and dried citrus fibers are obtained from them.

[0013] WO 2017 / 019 752 A1 relates to a process for producing citrus fiber from citrus pomace. The process includes a homogenization step (a), followed by a precipitation step (b) with an organic solvent to obtain a granular precipitate, a separation step (c) to obtain a semi-dry fiber cake, comminution of the fibers and addition of an additive in step (d), and a final step (e) for solvent removal and drying (see claim 9,

[00081] ,

[00085] ,

[00087] ,

[00088] ,

[00091] and

[00092] ). Due to the necessary homogenization, which is preferably high-pressure homogenization (

[00083] ), the special alcohol precipitation step and the milling with additive addition, a complex manufacturing process is required here in order to obtain fibers with good dispersibility under low shear stress (see

[0008] ).

[0014] CN 1 09 832 632 A relates to an industrial manufacturing process for highly dispersible citrus fibers, in which citrus peels are broken down under high temperature and alkaline treatment, dispersed and dehydrated by alcohol dehydration.

[0015] Therefore, there is a need for new pectin-containing citrus fibers.

[0016] The present invention is based on the objective of improving the state of the art or offering an alternative to it. Summary of the invention

[0017] According to a first aspect of the present invention, the stated problem is solved by an activatable pectin-containing citrus fiber according to claim 1.

[0018] These fibers are activatable fibers that exhibit satisfactory strength due to partial activation during the manufacturing process. However, achieving optimal rheological properties such as viscosity or texturing requires the application of additional shear forces by the user. They are therefore partially activated fibers that can be further activated.

[0019] As the inventors have discovered, the citrus fibers according to the invention exhibit good rheological properties. The fibers according to the invention can be easily rehydrated, and the advantageous rheological properties are retained even after rehydration.

[0020] Citrus fibers are largely tasteless and odorless, making them advantageous for use in the food industry. The natural flavor of the other ingredients is not masked and can therefore develop optimally.

[0021] The citrus fibers according to the invention are obtained from citrus fruits and thus represent natural ingredients with known positive properties.

[0022] Plant processing residues such as citrus pomace can be used as raw materials in the manufacturing process. These processing residues are inexpensive, available in sufficient quantities, and offer a sustainable and ecologically sound source for the citrus fibers according to the invention.

[0023] Citrus fibers are established and accepted in the food industry, so that corresponding compositions can be used immediately and internationally without lengthy approval procedures. The invention in detail

[0024] Citrus fruits, and preferably citrus fruit processing residues, can be used as raw materials. Accordingly, citrus peel (and here albedo and / or flavedo), citrus vesicles, segment membranes, or a combination thereof can be used as raw material in the process according to the invention. Preferably, citrus pomace is used as raw material, i.e., the press residues of citrus fruits, which typically contain the pulp in addition to the peels.

[0025] Any citrus fruits known to experts can be used in this context. The following are examples, listed here without limitation: Mandarin (Citrus reticulata), Clementine (Citrus × aurantium, Clementine group, Syn.: Citrus clementina), Satsuma (Citrus × aurantium, Satsuma group, Syn.: Citrus unshiu), Mangshan (Citrus mangshanensis), Orange (Citrus × aurantium, Orange group, Syn.: Citrus sinensis), Bitter Orange (Citrus xaurantium, Bitter Orange group), Bergamot (Citrus × limon, Bergamot group, Syn.: Citrus bergamia), Pomelo (Citrus maxima), Grapefruit (Citrus xaurantium, Grapefruit group, Syn.: Citrus paradisi), Pomelo (Citrus xaurantium, Pomelo group), Lime (Citrus xaurantiifolia), Common Lime (Citrus × aurantiifolia, Syn.: Citrus latifolia), Kaffir lime (Citrus hystrix), Rangpur lime (Citrus × jambhiri), Lemon (Citrus × limon Lemon group), Citron (Citrus medica) and Kumquats (Citrus japonica, Syn.: Fortunella). The orange (Citrus × aurantium orange group, Syn.: Citrus sinensis) and the lemon (Citrus × limon lemon group) are preferred.

[0026] The acidic pulping in step (b) of the process serves to remove pectin by converting the protopectin into soluble pectin and simultaneously activating the fiber by increasing its internal surface area. Furthermore, the raw material is thermally comminuted during the pulping process. Through acidic incubation in an aqueous environment under the influence of heat, it decomposes into citrus fibers. This thermal comminution eliminates the need for a mechanical comminution step in the manufacturing process. This represents a significant advantage over conventional fiber manufacturing processes, which, in contrast, require a shearing step (such as (high-)pressure homogenization) to obtain a fiber with sufficient rheological properties.

[0027] The raw material is present as an aqueous suspension during digestion. According to the invention, a suspension is a heterogeneous mixture of a liquid and finely dispersed solids (raw material particles) within it. Since the suspension tends towards sedimentation and phase separation, the particles are suitably kept in suspension by shaking or stirring. Therefore, it is not a dispersion in which the particles are broken down by mechanical action (shearing) to such an extent that they are finely dispersed.

[0028] To achieve an acidic pH value, a specialist can use any acid or acidic buffer solution known to them. For example, an organic acid such as citric acid can be used.

[0029] Alternatively or in combination, a mineral acid can also be used. Examples include sulfuric acid, hydrochloric acid, nitric acid, or sulfurous acid. Nitric acid is preferred.

[0030] In the acidic digestion in step (b) of the process, the pH value of the suspension is between pH = 0.5 and pH = 4.0, preferably between pH = 1.0 and pH = 3.5 and particularly preferably between pH = 1.5 and pH = 3.0.

[0031] The incubation for the acidic digestion takes place at a temperature between 60°C and 95°C, preferably between 70°C and 90°C and particularly preferably between 75°C and 85°C.

[0032] Incubation takes place over a period of between 60 minutes and 8 hours, and preferably between 2 hours and 6 hours.

[0033] The aqueous suspension, when acidified, suitably has a dry mass of between 0.5 wt.% and 5 wt.%, preferably between 1 wt.% and 4 wt.%, and particularly preferably between 1.5 wt.% and 3 wt.%.

[0034] The aqueous suspension is stirred or shaken during digestion. This is preferably done continuously to keep the particles in suspension.

[0035] In step (c) of the process, the decongested material is separated from the aqueous liquid and thus recovered. This separation is carried out as a single-stage or multi-stage separation.

[0036] Advantageously, the decongested material is subjected to a multi-stage separation process. It is preferred that the separation from the aqueous liquid involves the stepwise removal of increasingly finer particles. This means, for example, that in a two-stage separation, both stages remove larger particles, with the second stage separating finer particles compared to the first, in order to achieve the most complete possible separation of the particles from the aqueous liquid. Preferably, the first separation of particles is carried out using decanters and the second separation using separators. This results in the material becoming increasingly fine-particulate with each separation step.

[0037] After acidic digestion and separation of the digested material, the separated material is washed with an aqueous solution. This step removes any remaining water-soluble substances, such as sugars. The removal of sugars in this step makes the citrus fiber less adhesive, thus improving its processability and application.

[0038] Within the scope of the invention, the "aqueous solution" is understood to mean the aqueous liquid used for washing. The mixture of this aqueous solution and the dissolved material is referred to as the "washing mixture".

[0039] Advantageously, the washing according to step (d) is carried out with water as an aqueous solution. The use of deionized water is particularly advantageous here.

[0040] Alternatively, a salt solution with an ionic strength of I < 0.2 mol / l can be used as an aqueous solution.

[0041] Washing according to step (d) is advantageously carried out at a temperature between 30°C and 90°C, preferably between 40°C and 80°C and particularly preferably between 50°C and 70°C.

[0042] The contact time with the aqueous solution is between 10 minutes and 2 hours, preferably between 30 minutes and one hour.

[0043] In the washing process according to step (d), the dry matter content in the washing mixture is between 0.1 wt.% and 5 wt.%, preferably between 0.5 wt.% and 3 wt.% and particularly preferably between 1 wt.% and 2 wt.%.

[0044] It is more advantageous to carry out the washing according to step (d) with mechanical agitation of the washing mixture. This is best done by stirring or shaking the washing mixture.

[0045] According to the invention, coarse or undigested particles are separated during washing according to step (d). This particle separation occurs during the separation of the washed material from the washing liquid. Separation of particles with a grain size greater than 500 µm, preferably greater than 400 µm, and most preferably greater than 350 µm, is particularly advantageous. The separation is advantageously carried out using a screening machine or a belt press. This removes both coarse particulate impurities from the raw material and insufficiently digested material.

[0046] After washing with the aqueous solution, the washed material is separated from the aqueous liquid according to step (e). This separation is advantageously carried out using a decanter or a separator.

[0047] In step (f) a further washing step is then carried out, this time using an organic solvent. This involves washing at least twice with an organic solvent.

[0048] The organic solvent is advantageously an alcohol, which may be selected from the group consisting of methanol, ethanol and isopropanol.

[0049] The washing step takes place at a temperature between 40°C and 75°C, preferably between 50°C and 70°C and particularly preferably between 60°C and 65°C.

[0050] The contact time with the organic solvent is between 60 min and 10 h, and preferably between 2 h and 8 h.

[0051] Each washing step with the organic solvent comprises contacting the material with the organic solvent for a specific duration, followed by separation of the material from the organic solvent. A decanter or press is preferably used for this separation.

[0052] When washing with the organic solvent, the dry mass in the washing solution is between 0.5 wt.% and 15 wt.%, preferably between 1.0 wt.% and 10 wt.%, and particularly preferably between 1.5 wt.% and 5.0 wt.%.

[0053] Washing with the organic solvent is preferably carried out with mechanical agitation of the washing mixture. Preferably, the washing is performed in a container equipped with an agitator.

[0054] When washing with the organic solvent, a device for homogenizing the suspension is advantageously used. This device is preferably a toothed ring disperser.

[0055] According to an advantageous embodiment, washing with the organic solvent is carried out in a countercurrent process.

[0056] In one embodiment, partial neutralization occurs during washing with the organic solvent by adding Na or K salts, NaOH or KOH.

[0057] Washing with the organic solvent can also be used to decolorize the material. This decolorization can be achieved by adding one or more oxidizing agents. Examples of such agents include chlorine dioxide and hydrogen peroxide, which can be used alone or in combination.

[0058] According to an advantageous embodiment, during at least two washing steps with an organic solvent, the final concentration of the organic solvent in the solution increases with each washing step. This incrementally increasing proportion of organic solvent reduces the water content in the fiber material in a controlled manner, so that the rheological properties of the fibers are preserved during the subsequent solvent removal and drying steps, and the partially activated fiber structure does not collapse.

[0059] Preferably, the final concentration of the organic solvent in the first washing step is between 60 and 70 vol%, in the second washing step between 70 and 85 vol%, and in an optional third washing step between 80 and 90 vol%.

[0060] According to the optional step (f1), which takes place between steps (f) and (g), the solvent can be further reduced by contacting the material with steam. This is preferably carried out with a stripper in which the material is brought into contact with steam as the stripping gas in a countercurrent flow.

[0061] In an advantageous embodiment, the material is moistened with water before drying according to step (f1). This is preferably done by introducing the material into a moistening screw and spraying it with water.

[0062] In step (g), the washed material from step (f) or the stripped material from step (f1) is dried under normal pressure. Examples of suitable drying methods include fluidized bed drying, fluidized bed drying, belt dryers, drum dryers, or paddle dryers. Fluidized bed drying is particularly preferred. It has the advantage of drying the product in a loose, airy state, which simplifies the subsequent milling step. Furthermore, the precisely controllable heat input of this drying method prevents damage to the product from local overheating.

[0063] According to an advantageous embodiment, the process, after drying in step (g), additionally comprises a comminution, grinding, or sieving step. This step is advantageously designed such that, as a result, 90 wt.% of the particles have a particle size of less than 450 µm, preferably less than 350 µm, and particularly less than 250 µm. At this particle size, the fiber is readily dispersible and exhibits optimal swelling capacity.

[0064] The invention provides a pectin-containing citrus fiber obtained through the manufacturing process.

[0065] To determine the yield stress I (rotation), yield stress I (cross over), and the dynamic Weissenberg number in a 2.5 wt.% dispersion, the citrus fiber is dispersed as a 2.5 wt.% solution according to the method disclosed in the examples, and the measurement is carried out after 1 h at 20°C.

[0066] To determine the yield stress II (rotation), the yield stress II (cross over) and the dynamic Weissenberg number in a 2.5 wt.% suspension, the citrus fiber is suspended as a 2.5 wt.% solution according to the method disclosed in the examples, and the measurement is carried out after 1 h at 20°C.

[0067] According to an advantageous embodiment, the pectin-containing citrus fiber in an aqueous 4 wt. % suspension has a strength of between 60 g and 240 g, preferably between 120 g and 200 g and particularly preferably between 140 and 180 g.

[0068] Preferably, the pectin-containing citrus fiber has a viscosity of between 150 and 600 mPas, preferably between 200 and 550 mPas, and particularly preferably between 250 and 500 mPas, wherein the pectin-containing citrus fiber is dispersed in water as a 2.5 wt.% dispersion and the viscosity is changed with a shear rate of 50 s -1 measured at 20°C.

[0069] To determine the viscosity, the citrus fiber is dispersed in demineralized water as a 2.5 wt% solution using the method disclosed in the examples, and the viscosity is measured at 20°C and four shear sections (first and third section = constant profile; second and fourth section = linear ramp; evaluation each time at a shear rate of 50 s). -1 ) determined (rheometer; Physica MCR series, measuring body CC25 (corresponds to Z3 DIN), Anton Paar, Graz, Austria). A pectin-containing citrus fiber with this high viscosity has the advantage that smaller quantities of fibers are needed to thicken the final product. Furthermore, the fiber produces a creamy texture.

[0070] The pectin-containing citrus fiber advantageously has a water-binding capacity of more than 20 g / g, preferably more than 22 g / g, particularly preferably more than 24 g / g, and especially preferably between 24 and 26 g / g. Such an advantageously high water-binding capacity leads to a high viscosity and, consequently, to lower fiber consumption with a creamy texture.

[0071] According to one embodiment, the pectin-containing citrus fiber has a moisture content of less than 15 wt.%, preferably less than 10 wt.% and particularly preferably less than 8 wt.%.

[0072] It is also preferred that the pectin-containing citrus fiber in 1.0 wt% aqueous suspension has a pH of 3.1 to 4.75 and preferably of 3.4 to 4.2.

[0073] The pectin-containing citrus fiber advantageously has a particle size in which at least 90 wt.% of the particles are smaller than 450 µm, preferably smaller than 350 µm and particularly smaller than 250 µm.

[0074] According to an advantageous embodiment, the pectin-containing citrus fiber has a brightness value L* > 84, preferably L* > 86 and particularly preferably L* > 88. This means that the citrus fibers are almost colorless and do not cause any significant discoloration of the products when used in food products.

[0075] Advantageously, pectin-containing citrus fiber has a dietary fiber content of 80 to 95 wt.%.

[0076] Due to the acidic extraction step, the pectin content of the citrus fiber is significantly reduced, so that, according to the invention, the pectin-containing citrus fiber has less than 10 wt.%, preferably less than 8 wt.%, and particularly preferably less than 6 wt.% of water-soluble pectin. This residual pectin is highly esterified pectin. According to the invention, highly esterified pectin is defined as a pectin with a degree of esterification of more than 50%. The degree of esterification describes the percentage of carboxyl groups in the galacturonic acid units of the pectin that are present in esterified form, e.g., as methyl esters. The degree of esterification can be determined using the method according to JECFA (Monograph 19-2016, Joint FAO / WHO Expert Committee on Food Additives).

[0077] In another aspect, the invention relates to the use of the pectin-containing citrus fiber according to the invention as a thickening agent or structuring agent in a food product, a feed product, a beverage or food supplement or in a cosmetic product.

[0078] In another aspect, the invention relates to a mixture comprising the pectin-containing citrus fiber according to the invention and a soluble pectin, which may be either a low-esterified or a high-esterified or low-esterified amidated pectin or mixtures thereof.

[0079] In another aspect, the invention relates to a food product, a feed product or a beverage that has been produced using the pectin-containing citrus fiber according to the invention. Definitions

[0080] A citrus fiber, as described in the application, is a component consisting primarily of fibers, isolated from the non-lignified plant cell wall of a citrus fruit and consisting mainly of cellulose. The term "fiber" is somewhat misleading because citrus fibers do not appear macroscopically as fibers but rather as a powdery product. Other components of citrus fiber include hemicellulose and pectin.

[0081] A pectin according to the application is defined as a plant polysaccharide consisting essentially of α-1,4-glycosidically linked D-galacturonic acid units as a polyuronide. The galacturonic acid units are partially esterified with methanol. The degree of esterification describes the percentage of carboxyl groups in the galacturonic acid units of the pectin that are present in esterified form, e.g., as methyl esters.

[0082] According to the invention, a highly esterified pectin is defined as a pectin with a degree of esterification greater than 50%. A low-esterified pectin, on the other hand, has a degree of esterification less than 50%. The degree of esterification describes the percentage of carboxyl groups in the galacturonic acid units of the pectin that are present in esterified form, e.g., as methyl esters. The degree of esterification can be determined using the method according to JECFA (Monograph 19-2016, Joint FAO / WHO Expert Committee on Food Additives).

[0083] It should be explicitly noted at this point that features of the solutions described above or in the claims and / or figures can also be combined, if necessary, in order to implement or achieve the explained features, effects and advantages in a cumulative manner.

[0084] All features disclosed in the application documents are claimed to be essential to the invention, provided that they are novel individually or in combination with each other compared to the prior art.

[0085] It should be expressly noted that, within the context of this patent application, indefinite articles and numerical indications such as "one", "two", etc., are generally to be understood as "at least" indications, i.e., as "at least one...", "at least two...", etc., unless it is expressly clear from the respective context or it is obvious or technically necessary for the person skilled in the art that only "exactly one...", "exactly two...", etc., can be meant.

[0086] Further advantages, special features and expedient further developments of the invention will become apparent from the dependent claims and the following presentation of preferred embodiments with reference to the illustrations. Examples of implementation

[0087] The embodiments shown here are merely examples of the present invention and should therefore not be interpreted as limiting. Alternative embodiments considered by a person skilled in the art are likewise covered by the scope of protection of the present invention. 1. Description of the manufacturing process using a rough flow diagram

[0088] In Fig.Figure 1 schematically depicts a process for producing citrus fiber as a flow diagram. Starting with citrus pomace 10, the pomace is broken down by hydrolysis 20 through incubation in an acidic solution at 70° to 80°C. This is followed by two separate steps 30a (decanter) and 30b (separator) to separate all particles from the liquid phase as completely as possible. In step 35, the separated material is washed with an aqueous solution, and coarse or undigested particles are removed from the resulting washing mixture by wet sieving. In step 40, the solid is then separated from the liquid phase. Subsequently, two alcohol washing steps 50 and 70 are carried out, each followed by solid-liquid separation using decanters 60 and 80. Finally, in step 100, the fibers are gently dried using fluidized bed drying to obtain the citrus fibers 110 according to the invention. 2. Test method for determining the yield strength (rotational measurement) Measuring principle:

[0089] This yield strength provides information about the structural strength and is determined in the rotational test by increasing the shear stress acting on the sample over time until the sample begins to flow.

[0090] Shear stresses below the yield strength cause only elastic deformation, which only leads to yielding at shear stresses above the yield strength. In this determination, this is measured by exceeding a defined minimum shear rate γ̇. According to the present method, the yield strength τ0 [Pa] is at a shear rate γ̇ ≥ 0.1 s⁻¹. -1 exceeded. Measuring device: Rheometer Physica MCR series (e.g. MCR 301, MCR 101) Measurement system: Z3 DIN or CC25 Measuring cup: CC 27 P06 (ribbed measuring cup) Number of measuring sections: 3 Measurement temperature: 20 °C Measurement parameters: Section 1 (rest phase): Section settings: - Target size: Shear stress [Pa] - Value: 0 Pa constant - Section duration: 180 s - Temperature: 20 °C Section 2 (Determination of the yield point after rotation measurement): Section settings: - Target size: Shear stress [Pa] - Profile: Ramp log. - Starting value: 0.1 Pa - Final value: 80 Pa - Section duration: 180 s - Temperature: 20 °C Evaluation:

[0091] The yield stress τ0 (unit [Pa]) is read from section 2 and is the shear stress (unit: [Pa]) at which the shear rate last exceeds Y ≤ 0.10 s -1 amounts.

[0092] The yield point measured using the rotation method is also referred to as the "yield point (rotation)".

[0093] The yield strength (rotational) was measured using a fiber suspension (simply stirring the fiber in with a spoon = corresponds to a non-activated fiber) and is also referred to as "yield strength rotation II" within the scope of the invention. The yield strength was also measured using a fiber dispersion (stirred in under the influence of high shear forces; e.g., with Ultra Turrax = corresponds to an activated fiber) and is also referred to as "yield strength rotation I" within the scope of the invention. 3. Test method for determining the yield strength (oscillation measurement) Measuring principle:

[0094] This yield point also provides information about the structural strength and is determined in the oscillation test by increasing the amplitude at a constant frequency until the sample is destroyed by the ever-increasing deflection and then begins to flow.

[0095] Below the yield point, the substance behaves like an elastic solid, meaning that the elastic components (G') are higher than the viscous components (G''), while when the yield point is exceeded, the viscous components of the sample increase and the elastic components decrease.

[0096] By definition, the yield strength is exceeded at the amplitude when there are equal numbers of viscous and elastic components G' = G'' (Cross Over), the corresponding shear stress is the measured value. Measuring device: Rheometer Physica MCR series (e.g. MCR 301, MCR 101) Measurement system: Z3 DIN or CC25 Measuring cup: CC 27 P06 (ribbed measuring cup) Measurement parameters: Section settings: - Amplitude specifications: deformation - Profile: Ramp log. - Value: 0,01 - 1000% - Frequency: 1.0 Hz - Temperature: 20 °C Evaluation:

[0097] The shear stress at the crossover is evaluated using the rheometer software Rheoplus after exceeding the linear-viscoelastic range.

[0098] The yield point measured using the oscillation method is also referred to as the "yield point crossover".

[0099] The yield strength crossover was measured using a fiber suspension (simply stirring in the fiber with a spoon = corresponds to an unactivated fiber) and is also referred to as "yield strength crossover II" within the scope of the invention. The yield strength was also measured using a fiber dispersion (stirred in under the influence of high shear forces; e.g., with Ultra Turrax = corresponds to an activated fiber) and is also referred to as "yield strength crossover I" within the scope of the invention. Measurement results and their significance:

[0100] By comparing the yield strength of the fiber suspension according to the invention, stirred with a spoon (corresponding to an unactivated fiber), with the fiber dispersion according to the invention, stirred with high shear forces, e.g., Ultra Turrax (corresponding to an activated fiber), one can make a statement about the advantage / necessity of activation. The measurement results are summarized in the following table. As expected, the yield strength increases in each case due to shear activation in the dispersion. Due to the relatively low yield strength of the fiber suspension with τ0 II = 0.8 Pa, activation of the fiber is necessary for the complete implementation of the fiber properties in order to obtain the desired creamy texture. rotation Cross Over activation fiber τ0 II [Pa] Suspension τ0 I [Pa] Dispersion τ0 II [Pa] Suspension τ0 I [Pa] Dispersion Citrus fiber according to the invention 0,8 3,0 0,6 3,4 necessary 4. Test method for determining the dynamic Weissenberg number. Measurement principle and meaning of the dynamic Weissenberg number:

[0101] The dynamic Weißenberg number W' (Windhab E, Maier T, Lebensmitteltechnik 1990, 44: 185f) is a derived quantity in which the elastic components (G') determined in the oscillation test in the linear-viscoelastic range are compared with the viscous components (G'): W'=G'(ω)G''(ω)=1tanδ

[0102] The dynamic Weißenberg number provides a quantity that correlates particularly well with the sensory perception of consistency and can be considered relatively independent of the absolute strength of the sample.

[0103] A high W' value indicates that the fibers have a predominantly elastic structure, while a low W' value suggests structures with significant viscous components. The creamy texture typical of fibers is achieved when the W' values ​​are in the range of approximately 6–8; at lower values, the sample is considered aqueous (less thickened). Materials and methods: Measuring device: Rheometer Physica MCR series, e.g. MCR 301, MCR 101 Measurement system: Z3 DIN or CC25 Measuring cup: CC 27 P06 (ribbed measuring cup) Measurement parameters: Section settings: - Amplitude specifications: deformation - Profile: Ramp log - Value: 0,01 - 1000 % - Frequency: 1.0 Hz - Temperature: 20 °C Evaluation:

[0104] The phase shift angle δ is read in the linear-viscoelastic regime. The dynamic Weißenberg number W' is then calculated using the following formula: W'=1tanδ Measurement results and their significance:

[0105] By considering the dynamic Weißenberg number W' for the fiber suspension according to the invention, stirred with a spoon (corresponding to an unactivated fiber), and for the fiber dispersion according to the invention, stirred with high shear forces, e.g., Ultra Turrax (corresponding to an activated fiber), one can make a statement about the texture and, furthermore, about the necessity of activation. The measurement results are summarized in the following table. The citrus fiber according to the invention, with W' values ​​of 7.2 in the suspension and 7.5 for the dispersion, lies within the ideal range and thus exhibits an optimal texture. In both cases, it has a creamy texture. The results for the dynamic Weißenberg number show that activation of the fiber is not absolutely necessary with regard to the desired creamy texture. fiber W' Suspension W' dispersion texture Citrus fiber according to the invention 7,2 7,5 Creamy with and without activation; viscosity / yielding point is regulated via the dosage. 5. Test method for determining strength: Procedure:

[0106] Place 150 ml of distilled water in a beaker. Then, using a spoon, stir in 6.0 g of citrus fiber until lump-free. Allow this fiber-water mixture to stand for 20 minutes to swell. Transfer the suspension to a container (90 mm diameter). The strength is then measured using the following method.

[0107] Measuring device: Texture Analyzer TA-XT 2 (Stable Micro Systems, Godalming, UK) Test method / option: Measurement of force in the direction of pressure / simple test Parameter: - Test speed: 1.0 mm / s Parameter: - Distance: 15.0 mm / s Measuring tool: P / 50

[0108] According to the present method, the strength corresponds to the force required by the measuring body to penetrate 10 mm into the suspension. This force is read from the force-time diagram. 6. Test method for determining grain size. Measurement principle:

[0109] In a sieving machine, a set of sieves with progressively larger mesh sizes (increasing from the bottom to the top) are arranged one above the other. The sample is placed on the uppermost sieve—the one with the largest mesh size. Sample particles with a diameter larger than the mesh size remain on the sieve; the finer particles fall through to the next sieve. The proportion of the sample on the different sieves is weighed and expressed as a percentage. Implementation:

[0110] The sample is weighed to two decimal places. The sieves are fitted with sieving aids and stacked on top of each other with increasing mesh size. The sample is quantitatively transferred to the uppermost sieve, the sieves are clamped in place, and the sieving process proceeds according to defined parameters. The individual sieves are weighed with the sample and sieving aid, as well as empty with the sieving aid. If only one limit value in the particle size distribution of a product is to be checked (e.g., 90% < 250 µm), then only one sieve with the corresponding mesh size is used. Measurement specifications: Sample quantity: 15 g of sieving aids: 2 per sieve tray Sieving machine: AS 200 digit, Retsch GmbH Sieve movement: three-dimensional Vibration amplitude: 1.5 mm Sieving time: 15 min

[0111] The sieve assembly consists of the following mesh sizes in µm: 1400, 1180, 1000, 710, 500, 355, 250 followed by the bottom.

[0112] The grain size is calculated using the following formula: Percentage per sieve = Weight in g on the sieve × 100 / Sample weight in g 7. Production of a 2.5 wt% fiber dispersion

[0113] Recipe: 2.50 g fiber 97.5 g demineralized water (room temperature) Spreading time: 15 seconds

[0114] The required amount of water (room temperature) is placed in a 250 ml beaker. The precisely weighed quantity of fibers is slowly sprinkled directly into the agitator (Ultra Turrax) at 8000 rpm (stage 1) while the agitator is running. The sprinkling time depends on the amount of fibers; it should be 15 seconds per 2.5 g of sample. The dispersion is then stirred for exactly 60 seconds at 8000 rpm (stage 1). If the sample is to be used to determine the viscosity, the yield strength (rotational), the yield strength (crossover), or the dynamic Weissenberg number, it is placed in a temperature-controlled water bath at 20°C.

[0115] To measure viscosity, the yield stress I (rotation), the yield stress I (crossover), or the dynamic Weissenberg number, the sample is carefully poured into the rheometer's measuring system after exactly one hour, and the respective measurement is started. If the sample settles, it is gently stirred with a spoon immediately before filling. 8. Preparation of a 2.5 wt% fiber suspension

[0116] Recipe: 2.50 g fiber 97.5 g demineralized water (room temperature)

[0117] The required amount of water (at room temperature) is placed in a 250 ml beaker. The precisely weighed amount of fibers is slowly sprinkled in with a plastic spoon while stirring continuously. The suspension is then stirred until all fibers are wetted with water. If the sample is to be used to determine the viscosity, the yield strength II (rotational), the yield strength II (crossover), or the dynamic Weissenberg number, it is placed in a temperature-controlled water bath at 20°C.

[0118] To measure viscosity, the yield stress II (rotation), the yield stress II (crossover), or the dynamic Weissenberg number, the sample is carefully poured into the rheometer's measuring system after exactly one hour, and the respective measurement is started. If the sample settles, it is gently stirred with a spoon immediately before filling. 9. Test method for determining water binding capacity. Procedure for water binding capacity of untreated samples:

[0119] Allow the sample to swell with excess water for 24 hours at room temperature. After centrifugation and subsequent decantation of the supernatant, the water-binding capacity can be determined gravimetrically in g H₂O / g sample. The pH value of the suspension should be measured and recorded. The following parameters must be adhered to: Sample weight: - Plant fiber: 1.0 g (in centrifuge tube) - Adding water: 60 ml - Centrifugation: 4000 g - Centrifugation time 10 min

[0120] Twenty minutes after centrifugation begins (or ten minutes after centrifugation ends), the supernatant is separated from the swollen sample. The sample containing the bound water is then weighed.

[0121] The water binding capacity (WBV) in g H2O / g sample can now be calculated using the following formula: WBV(g H2O / g​ sample)=sample with bound water(g)−1.0g1.0g 10. Test method for determining viscosity Measuring device: Physica MCR series (e.g. MCR 301, MCR 101) Measurement system: Z3 DIN or CC25 (Note: The Z3 DIN and CC25 measuring systems are identical measuring systems) Number of sections: 4

[0122] Measurement parameters: Section 1: Section settings: - Target size: Shear rate [s -1 ] - Profile: constant - Value: 0 s -1 - Section duration: 60 s - Temperature: 20 °C Section 2: Section settings: - Target size: Shear rate [s -1 ] - Profile: Ramp left - Value: 0,1 - 100 s -1 - Section duration: 120 s - Temperature: 20 °C Section 3: Section settings: - Target size: Shear rate [s -1 ] - Profile: constant - Value: 100 s -1 - Section duration: 10s - Temperature: 20 °C Section 4: Section settings: - Target size: Shear rate [s -1 ] - Profile: Ramp left - Value: 100-0,1 s -1 - Section duration: 120 s - Temperature: 20 °C Evaluation:

[0123] The viscosity (unit [mPas]) is read as follows: Section 4 at = 50 s -1 11. Test method for determining the degree of esterification

[0124] This method corresponds to the method published by JECFA (Joint FAO / WHO Expert Committee on Food Additives). Unlike the JECFA method, the deashed pectin is not dissolved at low temperatures but heated. Isopropanol is used instead of ethanol. 12. Test method for determining dietary fiber content

[0125] This method is essentially identical in content to the method published by the AOAC (Official Method 991.43: Total, Soluble and Insoluble Dietary Fiber in Foods; Enzymatic-Gravimetric Method, MES-TRIS Buffer, First Action 1991, Final Action 1994). The only difference is that isopropyl alcohol was used instead of ethanol. 13. Test method for determining moisture Principle:

[0126] The moisture content of the sample is defined as the mass loss after drying, determined under defined conditions. The moisture content of the sample is determined by infrared drying using the Sartorius MA-45 moisture analyzer (Sartorius, Göttingen, Germany). Implementation:

[0127] Approximately 2.5 g of the fiber sample is weighed onto the Sartorius moisture analyzer. The instrument settings can be found in the corresponding manufacturer's instructions. The samples should be at approximately room temperature for analysis. The moisture content is automatically displayed by the instrument as a percentage [% M]. The dry matter content is automatically displayed by the instrument as a percentage [% S]. 14. Test method for determining color and brightness. Principle:

[0128] Color and brightness measurements are performed using the Minolta Chromameter CR 300 or CR 400. The spectral properties of a sample are determined using standard color values. The color of a sample is described by its hue, brightness, and saturation. These three basic properties allow color to be represented three-dimensionally.

[0129] The hues lie on the outer surface of the color body, brightness varies along the vertical axis, and saturation runs horizontally. When using the L*a*b* measurement system (pronounced L-star, α-star, b-star), L* represents brightness, while a* and b* indicate both hue and saturation. a* and b* denote the positions on two color axes, with a* corresponding to the red-green axis and b* to the blue-yellow axis. For color measurement displays, the device converts the standard color values ​​into L*a*b* coordinates. Performing the measurement:

[0130] The sample is sprinkled onto a white sheet of paper and leveled with a glass stopper. For measurement, the measuring head of the chromameter is placed directly on the sample and the trigger is activated. Three measurements are taken of each sample, and the mean is calculated. The L*, a*, and b* values ​​are displayed by the instrument with two decimal places. 15. Test method for determining water-soluble pectin in fiber-containing samples. Measurement principle:

[0131] An aqueous extraction process transfers the pectin contained in fiber-containing samples into the liquid phase. The addition of alcohol precipitates the pectin from the extract as an alcohol-insoluble substance (AlS). Extraction:

[0132] 10.0 g of the sample to be analyzed are weighed into a glass dish. 390 g of boiling distilled water are placed in a beaker, and the previously weighed sample is stirred in using Ultra-Turrax for 1 minute at the highest speed.

[0133] The sample suspension, cooled to room temperature, is divided into four 150 ml centrifuge beakers and centrifuged for 10 min at 4000 × g. The supernatant is collected. The sediment from each beaker is resuspended with 50 g of distilled water and centrifuged again for 10 min at 4000 × g. The supernatant is collected, and the sediment is discarded.

[0134] The combined centrifugate is added to approximately 4 liters of 98% isopropanol to precipitate the alcohol-insoluble substance (AIS). After half an hour, the mixture is filtered through a filter cloth, and the AIS is manually pressed off. The remaining alcohol-insoluble substance (AlS) is then added to approximately 3 liters of 98% isopropanol in the filter cloth and loosened by hand while wearing gloves.

[0135] The pressing process is repeated, the AlS is quantitatively removed from the filter cloth, loosened and dried in a drying oven at 60 °C for 1 hour.

[0136] The pressed, dried substance is weighed to 0.1 g for the calculation of the alcohol-insoluble substance (AlS). Calculation:

[0137] The calculation of water-soluble pectin in relation to the fiber-containing sample is carried out using the following formula, whereby the water-soluble pectin is obtained as an alcohol-insoluble substance (AlS): AIS in sample in wt.% (g / 100g) = dried AIS [g] × 100 / sample weight in g

[0138] The embodiments shown here are merely examples of the present invention and should therefore not be interpreted as limiting. Alternative embodiments considered by a person skilled in the art are likewise covered by the scope of protection of the present invention. Reference symbol list 10 Citrus Pomace 20 Hydrolysis (digestion) by incubation in an acidic environment 30a 1. Solid-Liquid Separation Decanter 30b 2. Solid-Liquid Separation Separator 35 Washing mixture with wet sieving 40 Solid-Liquid Separation 50 1. Washing with alcohol 60 Solid-Liquid Separation 70 2. Washing with alcohol 80 Solid-Liquid Separation 100 Fluid bed drying 110 Citrus fiber obtained

Claims

[1] Activatable pectin-containing citrus fiber, characterized by , that the activatable pectin-containing citrus fiber has a yield stress II (cross over) in a 2.5 wt% fiber suspension in demineralized water of 0.1 - 1.0 Pa and a dynamic Weissenberg number in a 2.5 wt% fiber suspension in demineralized water of 4.5 - 8.0, wherein the activatable pectin-containing citrus fiber is obtained by a process comprising: a. Providing a raw material containing cell wall material of an edible citrus fruit; b. Digestion of the raw material by incubation of an aqueous suspension of the raw material at an acidic pH value; c. Single- or multi-stage separation of the digested material from step (b) from the aqueous liquid; d. Washing the material separated in step (c) with an aqueous solution, wherein the aqueous solution is water, deionized water or a salt solution with an ionic strength of l < 0.2 mol / l, and separation of coarse or undigested particles; e. Separation of the washed material from step (d) from the aqueous liquid; f. Washing the separated material from step (e) at least twice with an organic solvent, with subsequent separation of the washed material from the organic solvent each time; g. Drying of the material from step (f) comprising drying at normal pressure to obtain the activatable pectin-containing citrus fiber; wherein the activatable pectin-containing citrus fiber obtained has less than 10 wt.% water-soluble pectin and a yield stress l (rotation) in a 2.5 wt.% fiber dispersion in demineralized water of 1.0 to 4.0 Pa. [2] Activated pectin-containing citrus fiber according to claim 1, characterized by that the activatable pectin-containing citrus fiber exhibits one or more of the following rheological properties: • A yield stress II (rotation) in a 2.5 wt% fiber suspension in demineralized water of 0.1 - 1.0 Pa, advantageously of 0.3 - 0.9 Pa and particularly advantageously of 0.6 - 0.8 Pa; • A yield stress II (cross over) in a 2.5 wt% fiber suspension in demineralized water of 0.3 - 0.9 Pa and particularly advantageously of 0.6 - 0.8 Pa; • A yield stress l (rotation) in a 2.5 wt% fiber dispersion in demineralized water of 1.5 - 3.5 Pa and particularly advantageously of 2.0 - 3.0 Pa; • A yield stress l (crossover) in a 2.5 wt% fiber dispersion in demineralized water of 1.0 - 4.5 Pa, advantageously of 1.5 - 4.0 Pa and particularly advantageously of 2.0 - 3.5 Pa; • A dynamic Weissenberg number in a 2.5 wt.% fiber suspension in demineralized water of 5.0 - 7.5 and particularly advantageously of 7.0 - 7.5; • A dynamic Weissenberg number in a 2.5 wt.% fiber dispersion in demineralized water of 5.0 - 9.0, advantageously of 6.0 - 8.5 and particularly advantageously of 7.0 - 8.

0. [3] Activated pectin-containing citrus fiber according to claim 1 or 2, characterized by that the activatable pectin-containing citrus fiber in a 4 wt% aqueous suspension has a strength of between 60 g and 240 g, preferably between 120 g and 200 g and particularly preferably between 140 g and 180 g. [4] Activated pectin-containing citrus fiber according to claims 1 to 3, characterized bythat the activatable pectin-containing citrus fiber has a viscosity of 150 to 600 mPas, preferably of 200 to 550 mPas, and particularly preferably of 250 to 500 mPas, wherein the activatable pectin-containing citrus fiber is dispersed in water as a 2.5 wt.% dispersion and the viscosity is changed with a shear rate of 50 s -1 measured at 20°C. [5] Activated pectin-containing citrus fiber according to any one of claims 1 to 4, characterized by that the activatable pectin-containing citrus fiber has a water binding capacity of more than 20 g / g, preferably more than 22 g / g, particularly preferably more than 24 g / g, and particularly preferably between 24 and 26 g / g. [6] Activated pectin-containing citrus fiber according to any one of claims 1 to 5, characterized by that the activatable pectin-containing citrus fiber has a moisture content of less than 15 wt.%, preferably less than 10 wt.% and particularly preferably less than 8 wt.%. [7] Activated pectin-containing citrus fiber according to any one of claims 1 to 6, characterized by that the activatable pectin-containing citrus fiber in 1.0 wt.% aqueous suspension has a pH value of 3.1 to 4.75 and preferably of 3.4 to 4.

2. [8] Activated pectin-containing citrus fiber according to any one of claims 1 to 7, characterized by that the activatable pectin-containing citrus fiber has a particle size in which at least 90 wt.% of the particles are smaller than 450 µm, preferably at least 90 wt.% of the particles are smaller than 350 µm and particularly preferably at least 90 wt.% of the particles are smaller than 250 µm. [9] Activated pectin-containing citrus fiber according to any one of claims 1 to 8, characterized by , that the activatable pectin-containing citrus fiber has a brightness value L* > 84, preferably L* > 86 and particularly preferably L* > 88. [10] Activated pectin-containing citrus fiber according to any one of claims 1 to 9, characterized bythat the activatable pectin-containing citrus fiber has a dietary fiber content of 80 to 95 wt.%. [11] Activated pectin-containing citrus fiber according to any one of claims 1 to 10, characterized by that the activatable pectin-containing citrus fiber has less than 8 wt.% and particularly preferably less than 6 wt.% water-soluble pectin. [12] Use of the activatable pectin-containing citrus fiber according to any one of claims 1 to 11 as a thickening agent or structuring agent in a food product, a feed product, a beverage, a food supplement, a cosmetic product, a pharmaceutical product or a medical device. [13] Mixture comprising an activatable pectin-containing citrus fiber according to any one of claims 1 to 11 and a soluble pectin, which is preferably a low esterified pectin, a high esterified pectin, a low esterified amidated pectin or a mixture thereof. [14] Use of the activatable pectin-containing citrus fiber according to any one of claims 1 to 11 in a food product, food supplement, feed product, beverage, cosmetic product, pharmaceutical product or medical device.

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