Method for modifying functional plant fibers

Abstract

The invention relates to a method for producing a functional plant fiber with modified properties, in particular to the reactivation of an aged functional plant fiber. The invention further relates to the modified functional plant fiber obtained using said method and to the use thereof as a stabilizer, a thickener or a structuring agent in food products and in non-food products. The invention lastly relates to a food product, a food supplement, a feed product, a beverage, a cosmetic product, a pharmaceutical product or a medical product which has been produced using the modified functional plant fiber according to the invention.

Description

[0001] Process for modifying functional plant fibers

[0002] The present invention relates to a process for producing a functional plant fiber with modified properties, and in particular to the reactivation of an aged functional plant fiber. The invention further relates to the modified functional plant fiber obtained by this process and its use as a stabilizer, thickener, or structuring agent in food products and non-food products. Finally, the invention relates to a food, dietary supplement, feed product, beverage, cosmetic product, pharmaceutical product, or medical device produced using the functional plant fiber modified according to the invention.

[0003] Background of the invention

[0004] Dietary fiber is a largely indigestible food component, usually 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.

[0005] The consumption of 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 is not sufficiently swollen before ingestion, it absorbs additional water in the stomach. The resulting increase in volume leads to an increased feeling of satiety. Furthermore, fiber prolongs the time the food stays in the stomach and intestines. Water-soluble fiber such as pectin binds bile acids from cholesterol metabolism in the intestines, thus leading to a lowering of cholesterol levels.

[0006] Soluble fiber, in particular, is thought to reduce glucose absorption, slow glucose adsorption and starch processing, and control postprandial glucose levels in serum. People who consume high amounts of fiber have a reduced risk of numerous lifestyle diseases, particularly obesity, high blood pressure, coronary heart disease (CHD), stroke, diabetes, and various gastrointestinal diseases. Accordingly, the German Nutrition Society (DGE) recommends a minimum of 30 g of fiber as a guideline for daily intake.

[0007] The use of plant fibers as dietary fiber in food production is becoming increasingly important. One reason for this is the fact that plant fibers represent a mixture of insoluble fibers such as cellulose and soluble fibers such as pectin, thus ideally providing the health-promoting spectrum of effects listed above. Through the use of plant fibers, the functional properties of food products can be specifically optimized and adjusted, for example, with regard to viscosity, emulsion formation, gel formation, dimensional stability, or texture. Plant fibers can thus replace other less accepted or even harmful additives in food. As non-E-classified substances, they lead to simpler product labeling and thus increased product acceptance.

[0008] Plant fibers suitable for developing the functional properties of foods are also known as functional plant fibers. Through the targeted selection of plant-based raw materials, such as citrus or apple pomace, and the application of complex pulping processes, functional fibers with advantageous rheological properties such as increased water-binding capacity, viscosity build-up, stabilization, texturizing, and consistency improvement can be obtained.

[0009] WO 01 / 17376 discloses a process for producing apple or citrus fibers with increased water binding capacity of 15 to 17 g water / g fiber.

[0010] EP 4 051 011 A1 describes a process for producing activated pectin-containing apple fibers, which comprises acid digestion, multiple washings with an organic solvent, and final vacuum drying. The fiber has a water-binding capacity of more than 20 g / g and a viscosity of more than 100 mPa s.

[0011] EP 4 051 012 A1 describes a process for producing activated pectin-containing citrus fibers, which comprises acid digestion, multiple washings with an organic solvent, and final vacuum drying. The fiber has a water-binding capacity of more than 22 g / g and a viscosity of more than 650 mPa s.

[0012] WO2012 / 016201 A2 discloses a process for modifying the properties of a citrus fiber. This complex process involves hydrating the fiber, followed by homogenization, a washing step with an organic solvent, desolventization, and drying to obtain the modified fiber with increased viscosity. Although the prior art reports that functional plant fibers with useful properties are obtained, there is still a need to further improve the properties of functional plant fibers.

[0013] In addition to cellulose, the functional plant fibers also contain hemicellulose and pectin and, as a highly processed biomaterial, represent a fibrillar structure with a complex composition. It has been shown that these functional plant fibers age, meaning their advantageous rheological properties decrease with storage, resulting in products that can only be sold with a limited shelf life (typically two years). These aged fibers, which would still be very suitable for use in the food or non-food sector from a sensory and microbiological perspective, are no longer suitable due to their suboptimal rheological properties and must be disposed of.

[0014] There is therefore a need for new processes for the rheological modification and in particular for the rheological improvement of functional plant fibers.

[0015] The present invention is based on the object of improving the state of the art or offering an alternative to it.

[0016] Summary of the invention

[0017] 1 . According to a first aspect of the present invention, the stated object is achieved by the rheological modification of a functional plant fiber, comprising the following steps: a. Providing a functional plant fiber; b. Mixing with an aqueous liquid to form an aqueous suspension of the functional plant fiber, c. Incubating the aqueous suspension for at least 10 minutes, wherein the suspension is subjected to a heat treatment at a temperature of 30 to 85°C for a duration of at least 30 seconds; d. Obtaining an aqueous suspension of the functional plant fiber with modified rheological properties thereof.

[0018] The production process according to the invention leads to functional plant fibers with modified rheological properties.

[0019] As the inventors have discovered, the modified functional plant fibers produced using the process according to the invention exhibit significantly improved rheological properties. The fibers according to the invention are in rehydrated form and can be used directly for specific applications, while retaining the advantageous rheological properties in the respective application.

[0020] The process is easy to implement, cost-effective and scalable and can therefore be carried out not only on a large industrial scale but also on a small scale, for example by end users.

[0021] As has been shown, the process is widely applicable: It can be used for fibers of different origins (e.g. apple and citrus), fibers with different fiber properties and for both freshly produced and aged fibers.

[0022] The inventive manufacturing process results in modified functional plant fibers that retain all the other advantages of the fibers used (e.g., tasteless and odorless) and are therefore still advantageous for use in the food industry. The inherent flavor of the other ingredients is not masked and can therefore develop optimally.

[0023] The inventive modification of the functional plant fibers does not require any additives or additives. The fibers therefore continue to represent natural ingredients with known positive properties.

[0024] Thus, the plant fibers modified according to the invention continue to be established and accepted in the food industry, so that corresponding compositions can be used immediately and internationally without lengthy approval procedures.

[0025] The invention in detail

[0026] According to step a. of the process, a functional plant fiber is provided. In the context of the present application, a functional plant fiber is defined as a fiber that, as an isolated plant fiber, acquires positive rheological properties as a result of a multi-stage production process, which typically includes fiber pulping. According to step a. of the process, an isolated functional plant fiber is thus provided. This isolated functional plant fiber is subjected to a multi-stage production process, the end product of which is an isolated pulped plant fiber with positive rheological properties, namely the isolated functional plant fiber.Such a manufacturing process typically involves numerous coordinated process steps, such as acid digestion, separation of coarse particles, water washing with separation of the washing liquid, multiple washings with organic solvents, and, after final drying, yields an isolated functional fiber as the final product. The functional plant fiber provided in step a. is not apple or citrus pulp, which is precisely the raw material from which the isolated functional plant fiber according to the invention must first be produced using the described multi-stage manufacturing process.Through the targeted selection of plant-based raw materials, such as citrus or apple pomace, and the application of complex pulping processes, functional fibers with advantageous rheological properties such as increased water-binding capacity, viscosity build-up, stabilization, texturizing, and consistency improvement can be obtained.

[0027] According to step b of the process, the functional plant fiber is mixed with an aqueous liquid to produce an aqueous suspension of the functional plant fiber. A suspension according to the application is defined as a heterogeneous mixture of a liquid and finely distributed fiber particles.

[0028] For this purpose, either the liquid is first introduced and then the fiber is added, or vice versa: the fiber is introduced and the liquid is added. A functional plant fiber contains not only water-soluble components such as pectin, but also water-insoluble components such as cellulose or hemicellulose. Due to these water-insoluble components, the plant fiber forms a suspension, forming a heterogeneous mixture with the aqueous liquid, in which the plant fiber is present as a dispersed phase, finely divided, in the liquid as the dispersion medium.

[0029] The person skilled in the art is aware of numerous ways of preparing a suspension, typically by stirring, ultrasonication or other dispersion techniques to achieve uniform distribution in the liquid.

[0030] According to step c of the method, the aqueous fiber suspension is incubated for at least 10 minutes, wherein the suspension is subjected to a heat treatment at a temperature of 30 to 85°C for a duration of at least 30 seconds.

[0031] The incubation can take place over a period of at least 10 minutes, at least 20 minutes, at least 30 minutes, and preferably for <24 hours, more preferably for <12 hours, and in particular for <60 minutes. The heat treatment can be carried out at various phases of the incubation; for example, the fiber suspension can be subjected to heat treatment at the beginning of the incubation, during the incubation, or at the end of the incubation. The heat treatment preferably takes place at the beginning of the incubation, wherein the suspension is preferably prepared by mixing with a suitably heated liquid, and then the suspension is kept heated for a period of at least 30 seconds.

[0032] According to step d. of the process, an aqueous suspension of the functional plant fiber with modified rheological properties is obtained as a result of step c.

[0033] This fiber suspension can be used directly for the manufacture of a product, provided it is mixed and processed with the other components of the respective composition.

[0034] It can be used as a semi-finished product, i.e. it is an unfinished product that must undergo further processing steps before it becomes a final product.

[0035] In an alternative embodiment, the aqueous liquid according to step b. represents the further components of a formulation, so that the modification of the plant fiber takes place directly in the formulation and thus leads to the final product in a simple manner.

[0036] In the process according to the invention, the aqueous suspension can be subjected to a shear treatment in step b or step e. As the inventors were able to demonstrate, the combination of incubation under heat treatment and a shear treatment leads to a further modification of the functional plant fibers. For example, an increase in viscosity induced by heat incubation is further enhanced by the shear treatment.

[0037] To achieve the most effective modification possible, this shearing treatment is preferably carried out on the already heated suspension. Conveniently, the liquid heated to the target temperature can be added here, and the functional plant fiber is mixed into this liquid under shearing treatment.

[0038] The functional plant fiber provided in step a. can be a functional fruit fiber or a functional vegetable fiber. The functional fruit fiber is preferably selected from the group consisting of citrus fiber, apple fiber, pear fiber, plum fiber, damson fiber, apricot fiber, pineapple fiber, and mango fiber. The use of an apple fiber or a citrus fiber is particularly preferred.

[0039] The functional vegetable fiber is preferably selected from the group consisting of carrot fiber, tomato fiber, sugar beet fiber, pea fiber, and onion fiber. The use of carrot fiber is particularly preferred.

[0040] In a preferred embodiment, the functional plant fiber provided in step a. is a functional depectinized fruit fiber or a functional depectinized vegetable fiber which, during its production, has undergone lignin degradation to brighten the fiber.

[0041] In this case, a depectinized fruit or vegetable fiber as starting material can be subjected to lignin degradation during fiber processing, which is preferably carried out by incubating the fiber with a lignin-degrading solution, whereby the lignin degradation takes place by enzymatic or alkaline treatment and a brightened functional fruit or vegetable fiber results as the end product.

[0042] In a particularly preferred embodiment, the functional plant fiber provided in step a. is a bleached functional plant fiber produced by a process comprising the following steps:

[0043] (a) providing a depectinized raw material containing cell wall material of a plant;

[0044] (b) optionally washing the depectinized raw material provided in step (a) with an aqueous solution;

[0045] (c) optionally separating the washed material from step (b) from the aqueous solution;

[0046] (d) degrading lignin by incubating an aqueous suspension of the depectinized raw material from step (a), the washed material from step (b) or the material separated from the aqueous solution from step (c) with a lignin-degrading incubation solution, wherein the lignin-degrading incubation solution is preferably an alkaline incubation solution and / or an enzymatic incubation solution;

[0047] (e) separating the incubated material from step (d) from the lignin-degrading incubation solution; (f) washing the material separated in step (e) with an aqueous solution;

[0048] (g) separating the washed material from step (f) from the aqueous solution;

[0049] (h) washing the separated material from step (g) at least twice with an organic solvent and subsequently separating the washed material from the organic solvent in each case;

[0050] (i) optional additional removal of the organic solvent by contacting the washed material from step (h) with steam;

[0051] (j) drying the material from step (h) or (i) comprising drying at normal pressure or vacuum drying to obtain the brightened functional plant fiber.

[0052] The manufacturing process described above results in brightened functional plant fibers with a large internal surface area, which also increases the water binding capacity and is accompanied by good viscosity formation.

[0053] The bleached functional plant fiber and a process for its production are disclosed in the application DE 10 2024 103 960.4.

[0054] In one embodiment of the invention, the functional plant fiber provided in step a. is an aged fiber with a storage period from production of at least 6 months, preferably of at least 12 months, particularly preferably of at least 18 months, and in particular of at least 24 months. The storage period here can be, for example, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, or more months.

[0055] The fiber is preferably stored under storage conditions typical for industrial production, i.e., in hermetically sealed containers at a temperature of 5 to 40°C. The relative humidity is between 40 and 90%, preferably between 50 and 90%, and particularly preferably between 50 and 60%.

[0056] Advantageously, the functional plant fiber provided in step a. has a viscosity of 10 to 2000 mPas, preferably of 100 to 1500 mPas, particularly preferably of 150 to 1400 mPas, and especially preferably of 200 to 1300 mPas, wherein the functional plant fiber is prepared in water as a 2.5 wt.% dispersion and the viscosity is measured at a shear rate of 50 s-1 at 20°C. The viscosity can be, for example, 150, 200, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 1050, 1100, 1150, 1200, 1250, 1300, 1350, 1400, or 1450 mPas. A functional plant fiber with these viscosity values ​​can be considered an activated fiber compared to the starting material and accordingly exhibits a storage-related reduction in activity, which can be modified and, in particular, reactivated according to the process of the invention.

[0057] In one embodiment, the aqueous liquid used to prepare the fiber suspension can be selected from the group consisting of fruit juice, sauce, fruit puree, shakes, emulsions, dressings, spreads, dips, creams, sorbets, and beverages. Thus, the modified functional fruit fiber can be incorporated directly into an intermediate or final product.

[0058] In an alternative embodiment, the aqueous liquid can be selected from the group consisting of low-salt water, distilled water, double-distilled water, tri-distilled water, deionized water, drinking water, industrial water, low-salt water, ultrapure water, and ultrapure water. The aqueous liquid is preferably drinking water.

[0059] The process thus produces an aqueous suspension of the modified plant fiber, which can be used as a recipe component in the respective applications.

[0060] The aqueous suspension prepared in step b. of the process may contain the functional plant fiber in a concentration of 0.5 to 5 wt.%, preferably 1.0 to 4 wt.%, particularly preferably 1.5 to 3 wt.%, especially preferably 2.25 to 2.75 wt.% and especially 2.5 wt.%. The fiber concentration in the suspension can be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1,0, 1,1, 1,2, 1,3, 1,4, 1,5, 1,6, 1,7, 1,8, 1,9, 2,0, 2,3, 2,4, 2,5, 2,6, 2,7, 2,8, 2,9, 3,0, 3,1, 3,2, 3,3, 3,4, 3,5, 3,6, 3,7, 3,8, 3,9, or 4.0 wt.%.

[0061] The weight concentration refers to the fiber minus the water content and corresponds to the dry mass.

[0062] The aqueous suspension prepared in step b. of the process can have a pH of 3.5 to 5, preferably 3.75 to 4.75, and particularly preferably 4.0 to 4.5. The pH can be, for example, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, or 5.0.

[0063] According to an advantageous embodiment, the heat treatment during incubation according to step c of the method is carried out for a duration of 30 seconds to 15 minutes, preferably from 60 seconds to 10 minutes, and particularly preferably from 90 seconds to 5 minutes. The duration of the heat treatment can be, for example, 30, 45, 60, 75, 90, 120, 150, 180, 240, or 300 seconds, or 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 minutes.

[0064] The heat treatment, according to the previously taught duration, can be carried out at various stages of the incubation. Thus, the fiber suspension can be subjected to heat treatment at the beginning of the incubation, during the incubation, or at the end of the incubation. Preferably, the heat treatment is carried out at the beginning of the incubation, whereby the suspension is preferably prepared by mixing it with a suitably heated liquid, and then the suspension is kept heated for a period of at least 30 seconds.

[0065] According to an advantageous embodiment, during the heat treatment, the aqueous suspension is initially brought to the heated temperature and then cooled to room temperature after mixing with the functional plant fiber, wherein the cooling rate is preferably 0.1 to 5°C per minute, particularly preferably 0.2 to 2.5°C per minute and especially preferably 0.5 to 1.5°C per minute.

[0066] According to an advantageous embodiment, the aqueous suspension in step b. or step c. can be subjected to a shearing treatment, wherein this shearing treatment can be carried out for a duration of 15 seconds to 15 minutes, preferably from 30 seconds to 10 minutes, particularly preferably from 60 seconds to 5 minutes, and in particular from 90 seconds to 3 minutes. The duration of the shearing treatment can be, for example, 30, 45, 60, 75, 90, 120, 150, 180, 240, or 300 seconds, or 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 minutes.

[0067] The shear treatment according to the previously taught shear duration is preferably carried out on the heated suspension.

[0068] The shear treatment can be carried out, for example, by using a rotor-stator homogenizer, such as an Ultra Turrax, a pressure homogenizer, a high-pressure homogenizer or an ultrasonic homogenizer.

[0069] In a particular embodiment, the shearing treatment is designed such that it does not lead to fiber disruption and / or significant comminution of the fiber particles. According to this particular embodiment, the shearing treatment according to the invention is not pressure homogenization or high-pressure homogenization.

[0070] In a preferred embodiment, the rheological properties of the functional plant fiber are improved by the process. Thus, the viscosity of the rheologically modified plant fiber can be increased by at least 5%, preferably by at least 25%, particularly preferably by at least 50%, and especially by at least 100%.

[0071] In a second aspect, the invention provides a modified functional plant fiber obtained by the production process according to the invention.

[0072] In a third aspect, the invention relates to the use of the modified functional plant fiber according to the invention as a stabilizer, thickener 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.

[0073] In a fourth aspect, the invention relates to a food product, a food supplement, a feed product, a beverage, a cosmetic product, a pharmaceutical product or a medical device produced using the brightened functional plant fiber according to the invention.

[0074] Definitions

[0075] A plant fiber according to the application is a component consisting primarily of fibers, isolated from a non-woody plant cell wall and consisting primarily of cellulose. The term "fiber" is somewhat misnomer because the plant fibers do not appear macroscopically as fibers, but rather as a powdered product. Other components of plant fibers include hemicellulose and pectin.

[0076] According to the invention, an apple is defined as the fruit of the cultivated apple (Malus domestica).

[0077] A pectin according to the application is defined as a plant polysaccharide which, as a polyuronide, consists essentially of α-1,4-glycosidically linked D-galacturonic acid units. 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.

[0078] Unless expressly stated otherwise, numerical values ​​expressed without decimal places refer to the full value, while those expressed with one decimal place refer to the full value. For example, 99% represents 99.0%. The mention of a document in this document does not constitute an admission that said document or its contents are within the common knowledge of the person skilled in the art.

[0079] Any feature of the invention which is intended to be present in a particular range or in a particular amount may be combined in a corresponding embodiment with the other features of that embodiment, wherein the other features may be present in the ranges or amounts disclosed herein for said other features.

[0080] All ranges and amounts for a feature of an embodiment can be combined with all ranges and amounts of the other features in that embodiment. For example, ranges or values ​​stated as preferred, more preferred, or most preferred for one feature or component of the invention can be combined with any range or amount stated for any other feature or component of the embodiment, regardless of whether the range or amount stated for the other element is stated as preferred, more preferred, or most preferred, etc., or is disclosed without such a statement or indication.

[0081] It should also be expressly pointed out that, in the context of this patent application, indefinite articles and numerical expressions such as “one”, “two”, etc. are generally to be understood as “at least” expressions, 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.

[0082] The term "comprise," as used herein, is synonymous with "containing" and does not exclude additional, unlisted elements or process steps. According to the present invention, the term "comprise" also encompasses the term "consist essentially of" or "consist of," meaning that "comprise" may be replaced by the other terms in alternative embodiments, where "consist of" excludes any element or step not expressly mentioned, and "consist essentially of" permits the inclusion of additional, unmentioned elements or steps that do not substantially affect the essential or fundamental characteristics of the composition or process in question. Where a numerical range is specified herein, this range is continuous and includes both the minimum and maximum values ​​of the range, as well as any value between these minimum and maximum values.When a range refers to whole numbers, every whole number between the minimum and maximum values ​​of such a range is included. If multiple ranges are specified to describe a feature or characteristic, these ranges may be combined. This means that, unless expressly stated otherwise, all ranges disclosed herein are to be understood as including all subranges contained therein. For example, a specified range of "1 to 10" is to be understood as including all subranges between the minimum value of 1 and the maximum value of 10, including the values ​​1 and 10. Example subranges of the range 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, and 5.5 to 10. The disclosed upper and lower limits for quantity, range, and ratio may be combined independently of one another.

[0083] Further advantages, special features and expedient developments of the invention emerge from the subclaims and the following representation of preferred embodiments with reference to the figures.

[0084] The embodiments shown here are merely examples of the present invention and should therefore not be considered limiting. Alternative embodiments contemplated by those skilled in the art are equally encompassed within the scope of the present invention.

[0085] Figures

[0086] Fig. 1 shows schematically the process according to the invention for modifying a functional plant fiber.

[0087] Fig. 2 shows the change in viscosity when the method according to the invention was applied to an aged fiber at heat treatment of 20°C, 40°C, 60°C and 80°C and incubation times of one hour or 24 hours.

[0088] Fig. 3 shows different experiments A to F together with a reference experiment for the activation of an apple fiber in a gravy and determination of the viscosity achieved.

[0089] Fig. 4A shows the viscosity of 11 different and commercially available functional plant fibers after incubation at 80°C (= modification according to the invention) or 20°C (= control) on fresh fibers ("Od") or after thermal stress at 60°C for 5 days ("5d"). Fig. 4B shows the relative increase in viscosity in % for the absolute values ​​determined according to Fig. 4A, both for the fresh fibers ("Od") and after thermal stress at 60°C for 5 days ("5d").

[0090] Fig. 4C shows the viscosity of 7 different and commercially available functional plant fibers after incubation at 80°C (= modification according to the invention) or 20°C (= control) on fresh fibers (“Od”) or after thermal stress at 50°C for 5 days (“5d, 50°C”), or after thermal stress at 35°C for 5 days (“5d, 35°C”).

[0091] Fig. 5A shows the graphical representation of the viscosity of the 6 high-viscosity fibers from the table in Fig. 4A along with percentages for the respective increase.

[0092] Fig. 5B shows the graphical representation of the viscosity of the 5 low-viscosity fibers from the table in Fig. 4A along with percentages for the respective increase.

[0093] Fig. 6 shows the graphical representation of the increase in viscosity achieved by the inventive process based on the values ​​from the table in Fig. 4A for the fresh fibers (“Od”) and the aged fibers (“5d”).

[0094] Fig. 7 shows the graphical representation of the viscosity of apple fiber AQ Plus in comparison to the alkaline-bleached apple fiber AQ Plus after incubation at 80°C (= modification according to the invention) or 20°C (= control) on fresh fibers (“Od”) or after thermal stress at 50°C for 5 days (“5d, 50°C”), or after thermal stress at 35°C for 5 days (“5d, 35°C”).

[0095] Fig. 8A shows the viscosity of three different AQ-Plus fibers after incubation at 80°C (= modification according to the invention) or 20°C (= control) using demineralized water, apple juice or tomato juice as suspension liquid.

[0096] Fig. 8B shows the graphical representation of the viscosity based on the values ​​from the table in Fig. 8A for the three fibers using water and tomato juice as aqueous liquid after incubation at 80°C (= modification according to the invention) or 20°C (= control).

[0097] Examples of implementation

[0098] 1. Description of the manufacturing process using a flow diagram Figure 1 shows a schematic flow diagram of a process according to the invention for producing a plant fiber with modified rheological properties. Starting from an isolated, dried, functional plant fiber, this is mixed with an aqueous liquid to form an aqueous fiber suspension. The fiber suspension can optionally be subjected to a shearing treatment, in which case the corresponding shearing tool can preferably be used directly to mix the fiber into the aqueous liquid. The aqueous fiber suspension is incubated for a defined time under heat treatment, wherein the aqueous liquid preferably has the selected target temperature (e.g., 80°C) during mixing with the fiber and cools down to room temperature or 20°C after mixing over the incubation period.As a result of the incubation, the modified functional plant fiber is obtained in suspension.

[0099] 2. Fiber activation depending on temperature and incubation time

[0100] Question:

[0101] For your 2.5 wt.% fiber suspension in water, the influence of shear treatment and incubation at different temperatures will be investigated.

[0102] Material:

[0103] • Functional apple fiber AQ AFB 200 (Herbstreith&Fox, Neuenbürg, Germany)

[0104] • 97.5 g demineralized water (temp.: = 20, 40, 60 or 80°C)

[0105] • Ultra-Turrax T25 digital with dispersing tool S 25 N - 18 G (IKA-Werke GmbH & CO. KG, Staufen, Germany)

[0106] Methods:

[0107] For the functional apple fiber, the viscosity was determined in the fresh state and after thermal stress (stored above 50°C for at least 5 days) for a 2.5 wt% suspension according to the test method in point 7.

[0108] The appropriate amount of water is placed in a 250 ml beaker at the appropriate temperature of 20°C, 40°C, 60°C, or 80°C. The precisely weighed amount of fiber is slowly sprinkled directly into the stirrer while the stirrer (Ultra Turrax) is running at 8000 rpm (speed 1). The sprinkling time depends on the amount of fiber; it should last 30 seconds per 2.5 g of sample. The suspension is then stirred for exactly 60 seconds at 8000 rpm (speed 1). The samples are placed in a temperature-controlled water bath at 20°C and incubated for 1 hour or 24 hours. The viscosity is then determined according to the test method in point 7.

[0109] Result:

[0110] During storage, the viscosity of the functional fiber decreases from 470 mPa.s to approximately 210 mPa.s. As the temperature increases, the fiber undergoes increasing rheological reactivation, reaching a viscosity of 385 mPa.s. Extending the incubation time from one hour to 24 hours leads to a further increase in viscosity, reaching a value of 440 mPa.s at 80°C.

[0111] 3. Activation of an apple fiber in gravy

[0112] Question:

[0113] For a functional apple fiber AQ AFB 200 (from Herbstreith&Fox, Neuenbürg, Germany), activation is to take place directly in a gravy. A fresh apple fiber with a viscosity of 472 mPa.s and a thermally stressed fiber with a viscosity of 196 mPa.s were used at a concentration of 1.5 wt% in each of the tests A to F. They were subjected to various shear forces and heat treatments to determine the viscosity of the gravy according to the test method in section 7.

[0114] Material:

[0115] • Functional apple fiber AQ AFB 200 (Herbstreith&Fox, Neuenbürg, Germany) o Fresh: Viscosity = 472 mPa.s Stressed: = 196 mPa.s (stored for several hours above 50°C)

[0116] • Thermomix (Vorwerk, SE & Co. KG, Wuppertal, Germany, “left stirring” represents simple mixing without shearing, while the Thermomix carries out a shearing treatment on level 10).

[0117] Methods:

[0118] A gravy was made using fresh or stressed apple fiber according to the following recipe:

[0119] The different process control in experiments A to F is shown in the table in Fig. 3.

[0120] Result:

[0121] The results of the viscosity measurements for the reference and tests A to F are shown in the table in Fig. 3. Despite the different initial viscosities of the fibers, similar results were achieved in the application tests. A continuous heating step to 85°C and an activation step through shearing are crucial for the development of viscosity.

[0122] By producing a pre-dispersion of the fiber in water and a shearing step in the final production of the application, the viscosity can be increased even beyond the initial viscosity of the fresh fiber.

[0123] Brief heating to 85°C without shear treatment is not sufficient to significantly increase the viscosity of the gravy, which is an aqueous liquid. This is only possible in combination with shearing; shearing alone, however, is not sufficient to achieve full functionality in terms of viscosity buildup.

[0124] 4. Activation of plant fibers with thermal stress at 60°C

[0125] Question:

[0126] The objective was to compare the viscosity of various commercially available fibers in their fresh state and after thermal stress for 5 days at 60°C. These fiber samples were measured either directly at 20°C or after shearing and incubation under heat treatment (80°C) according to the test method in section 7.

[0127] Material: 2.5 g functional fibers:

[0128] • Citrus Fiber Peak (CP Kelco)

[0129] • Citrus Fiber Boost (Fa. CP Kelco)

[0130] • Citrus Fiber Citri Fl 100 M 20 (Fa. Fiberstar)

[0131] • Citrus Fiber Citri Fl 100 FG (Fa. Fiberstar)

[0132] • Apfelfaser Vitracel CF 312 F (Fa. JS Rettenmaier)

[0133] • Apfelfaser Vitracel CF 312 (Fa. JS Rettenmaier)

[0134] • Citrusfaser Finix II-800 (Fa. Peel Pioneers)

[0135] • Citrusfaser Ceamfibre 7000 (Fa. Ceamsa)

[0136] • Citrusfaser Döhler 60 mesh Pwd (Fa. Döhler)

[0137] • Citrusfaser AQ Plus (Fa. Herbstreith & Fox)

[0138] • Apfelfaser AQ Plus (Fa. Herbstreith & Fox)

[0139] • 97.5 g demineralised waste

[0140] • Ultra-Turrax T25 digital with Dispergierwerkzeug S 25 N - 18 G (Fa. IKA-Werke GmbH & CO. KG, Staufen, BRD)

[0141] Methods:

[0142] For testing, an aliquot of the powdered fibers was measured fresh and a second aliquot was subjected to thermal stress for 5 days at 60°C in a drying oven to determine the influence of the stress on the viscosity.

[0143] At time t=0, 2.5 g of fiber were stirred into 97.5 g of demineralized water at either 20°C or 80°C using shear forces. The precisely weighed 2.5 g of fiber was slowly sprinkled directly into the agitator's suction while the stirrer (Ultra Turrax) was running at 8000 rpm (speed 1). The sprinkling time depends on the amount of fiber; for the 2.5 g sample used, it lasted 30 seconds. The suspension was then stirred for exactly 60 seconds at 8000 rpm (speed 1).

[0144] The 80°C samples were placed in a water bath heated to 20°C and incubated for 60 minutes. At the end of the incubation period, the sample had cooled to 20°C, and the viscosity at 20°C for both fiber samples could be determined comparatively according to the test method in section 7. This allows the influence of the activation according to the invention to be determined for all samples (fresh and stressed fibers).

[0145] Result:

[0146] The results of the viscosity measurements are shown in Table 4A and Figures 5A and 5B. Based on their initial viscosities, the fibers could be divided into two groups: the low-viscosity fibers with a viscosity below 100 mPas (shown in Figure 5B) and the high-viscosity fibers with an initial viscosity above 200 mPas (shown in Figure 5A). The percentage increase achieved by the 80°C incubation for the initial fibers (Od) and the thermally stressed fibers (5d) is shown in Figure 6.

[0147] Thermal activation of the output fibers:

[0148] All tested starting fibers were activated by incubation at 80°C, resulting in a significant increase in viscosity for all fibers (Fig. 5A, 5B "Od values"). The increase rate ranged from 5% (Ceamsafibre 7000) to 77% (Vitacel CF 312 F).

[0149] Influence of thermal stress:

[0150] Low-viscosity fibers exhibit only a slight decrease in viscosity due to thermal stress. High-viscosity fibers are more sensitive. Here, thermal stress leads to a greater reduction in viscosity.

[0151] Thermal activation of thermally stressed fibers:

[0152] All thermally stressed fibers tested were activated by incubation at 80°C, resulting in a significant increase in viscosity for all fibers. The increase rate for the low-viscosity fibers ranged from 9% to 71%, achieving values ​​that exceed those of the low-viscosity starting fibers. The high-viscosity fibers showed an increase rate of 11% to 302%. Due to the significant decrease in viscosity caused by thermal stress, the values ​​for the reactivated fibers and the starting fibers under the present test conditions are significantly lower.

[0153] In summary, all tested fibers, whether freshly measured or after thermal stress by the method according to the invention, experienced an increase in viscosity (see Figure 4B and Figure 6). 5. Activation of plant fibers with thermal stress at 35 and 50°C

[0154] In a second experiment, various commercially available fibers were compared for viscosity in the fresh state and after thermal stress for 5 days at 35°C or 50°C. The high-viscosity fibers determined according to Example 4 were tested, along with an AQ Plus apple fiber that had been bleached during its production process by an alkaline treatment. These fiber samples were measured either directly at 20°C or after shearing and incubation under heat treatment (80°C) according to the test method in Section 7.

[0155] Material:

[0156] 2.5 g functional fibers:

[0157] • Citrus Fiber Peak (CP Kelco)

[0158] • Citrus Fiber Boost (CP Kelco)

[0159] • Apple fiber Vitracel CF 312 F (JS Rettenmaier)

[0160] • Apple fiber Vitracel CF 312 (JS Rettenmaier)

[0161] • Citrus fiber AQ Plus (Herbreith & Fox)

[0162] • Apple fiber AQ Plus (Herbreith & Fox)

[0163] • Apple fiber AQ Plus, alkaline bleached (Herbstreith & Fox)

[0164] • 97.5 g demineralized water

[0165] • Ultra-Turrax T25 digital with dispersing tool S 25 N - 18 G (IKA-Werke GmbH & CO. KG, Staufen, Germany)

[0166] Methods:

[0167] For testing, an aliquot of the powdered fibers was measured fresh and a second aliquot was subjected to thermal stress for 5 days at 35° or 50°C to determine the influence of the stress on the viscosity.

[0168] At time t=0, 2.5 g of fiber were stirred into 97.5 g of demineralized water at either 20°C or 80°C under shearing. The precisely weighed 2.5 g of fiber was slowly sprinkled directly into the stirred vessel while the stirrer (Ultra Turrax) was running at 8000 rpm (speed 1). The sprinkling time depends on the amount of fiber; for the 2.5 g sample used, it lasted 30 seconds. The suspension was then stirred for exactly 60 seconds at 8000 rpm (speed 1). The samples, which were heated to 80°C, were placed in a water bath maintained at 20°C and incubated for 60 minutes. At the end of the incubation period, the sample was cooled to 20°C, and the viscosity at 20°C was determined for both fiber samples according to the test method in section 7. This allows the influence of the activation according to the invention to be determined for all samples (fresh and stressed fibers).

[0169] Results:

[0170] The results of the viscosity measurements are shown in Table 4C and for comparison of the Apple AQ-Plus fibers in Figure 7.

[0171] Thermal activation of the output fibers:

[0172] Consistent with the findings from Example 4, all tested starting fibers ("Od") were activated by incubation at 80°C, as their viscosity was significantly increased for all fibers (Fig. 4c "Od values"). The increase rate ranged from 14% (Citrus AQ Plus) to 70% (Vitacel CF 312 F).

[0173] Influence of thermal stress:

[0174] Stressing at 50°C resulted in a significantly smaller decrease in viscosity compared to stressing at 60°C. The decrease in viscosity was smallest at 35°C.

[0175] Thermal activation of thermally stressed fibers:

[0176] All thermally stressed fibers tested were activated by incubation at 80°C, in that their viscosity was significantly increased for all fibers, but was still below the viscosity value of the starting fibers.

[0177] The bleached AQ-Plus fiber represents a special case, as the activation of the stressed fibers according to the invention resulted in viscosity values ​​that were higher than those of the original fibers in all cases. The relative viscosity increase compared to the original fibers was 59% (Od), 27% (35°C), or 8% (50°C).

[0178] 6. Activation of plant fibers in different liquids Question:

[0179] The objective was to investigate how the inventive fiber modification process works in other liquids. For this purpose, three different fibers were prepared in water, tomato juice, or apple juice and subjected to the inventive modification process. These fiber samples were measured either directly at 20°C or after shearing and incubation under heat treatment (80°C) according to the test method in section 7.

[0180] Material:

[0181] 2.5 g functional fibers:

[0182] • Citrus fiber AQ Plus (Herbreith & Fox)

[0183] • Apple fiber AQ Plus (Herbreith & Fox)

[0184] • Apple fiber AQ Plus, alkaline bleached (Herbstreith & Fox)

[0185] • 97.5 g liquid (demineralized water, apple juice or tomato juice)

[0186] • Ultra-Turrax T25 digital with dispersing tool S 25 N - 18 G (IKA-Werke GmbH & CO. KG, Staufen, Germany)

[0187] Methods:

[0188] For the test, 2.5 g of fiber were stirred into 97.5 g of liquid (water, apple juice, or tomato juice) at a temperature of 20°C (= reference temperature) or a temperature of 80°C (= activation according to the invention) under the influence of shear forces. The precisely weighed amount of 2.5 g of fiber was slowly sprinkled directly into the stirring fluid while the stirrer (Ultra Turrax) was running at 8000 rpm (speed 1). The sprinkling time depends on the amount of fiber; for the 2.5 g sample used, it lasted 30 seconds. The suspension was then stirred for exactly 60 seconds at 8000 rpm (speed 1). The 80°C samples were placed in a water bath heated to 20°C and incubated for 60 minutes. At the end of the incubation period, the sample had cooled to 20°C and the viscosity at 20°C could be determined for both fiber samples according to the test method in point 7.This allows the activation of the three different fibers to be determined depending on the fluid used.

[0189] Results:

[0190] The results of the viscosity measurements are shown in Figures 8A and 8B. Consistent with the findings from Example 4, all tested starting fibers were activated by the 80°C incubation in water as a liquid, significantly increasing the viscosity for all fibers (Fig. 8A, Table "Water"). In tomato juice, the activation was even more pronounced, with viscosity values ​​higher than the water values ​​achieved for all three fibers. All three tested fibers showed a significantly lower viscosity in apple juice as a liquid, although this viscosity could be increased by the 80°C incubation.

[0191] 7. Test method for determining viscosity

[0192] Measuring device: Physica MCR series (e.g. MCR 301, MCR 101)

[0193] Measuring system: Z3 DIN or CC25

[0194] (Note: The Z3 DIN and CC25 measuring systems are identical measuring systems)

[0195] Number of sections: 4

[0196] Before measurement, the sample is heated in a water bath at 20°C for at least 15 minutes.

[0197] Measurement parameters:

[0198] Section 1:

[0199] Section settings: - Default size: Shear rate [s -1 ]

[0200] - Profile: constant

[0201] - Value: O s- 1

[0202] - Section duration: 60 s

[0203] - Temperature: 20 °C

[0204] Section 2:

[0205] Section settings: - Default size: Shear rate [s -1 ]

[0206] - Profile: linear ramp

[0207] - Value: 0.1 - 100 s- 1

[0208] - Section duration: 120 s

[0209] - Temperature: 20 °C

[0210] Section 3:

[0211] Section settings: - Default size: Shear rate [s -1 ]

[0212] - Profile: constant

[0213] - Value: 100 s- 1

[0214] - Section duration: 10 s

[0215] - Temperature: 20 °C

[0216] 4. Section: Section settings: - Default size: Shear rate [s -1 ]

[0217] - Profile: linear ramp

[0218] - Value: 100 - 0.1 s' 1

[0219] - Section duration: 120 s

[0220] - Temperature: 20 °C

[0221] Evaluation:

[0222] The viscosity (unit [mPas]) is read as follows: 4th section at = 50 s -1

[0223] 8. Test method for determining moisture and dry matter

[0224] Principle:

[0225] The moisture content of a sample is defined as the loss of mass after drying, determined under defined conditions. The moisture content of the sample is determined using infrared drying with the Sartorius MA-45 moisture analyzer (Sartorius, Göttingen, Germany).

[0226] Implementation:

[0227] Approximately 2.5 g of the fiber sample is weighed into the Sartorius moisture analyzer. The device settings can be found in the corresponding factory measurement instructions. The samples should be at approximately room temperature for the analysis. The moisture content is automatically displayed by the analyzer in percent [% M]. The dry matter content is automatically displayed by the analyzer in percent [% S].

Claims

Patent claims 1. A method for the rheological modification of a functional plant fiber, comprising the following steps: a. providing a functional plant fiber; b. mixing with an aqueous liquid to form an aqueous suspension of the functional plant fiber; c. incubating the aqueous suspension for at least 10 minutes, wherein the suspension is subjected to a heat treatment at a temperature of 30 to 85°C for a duration of at least 30 seconds; d. obtaining an aqueous suspension of the functional plant fiber having modified rheological properties thereof.

2. Process according to claim 1, characterized in that the aqueous suspension is subjected to a shearing treatment in step b. or step c., wherein the shearing treatment is preferably carried out on the heated suspension.

3. The method according to claim 1 or 2, characterized in that the functional plant fiber provided in step a. is a functional fruit fiber or a functional vegetable fiber, wherein the functional fruit fiber is preferably selected from the group consisting of citrus fiber, apple fiber, pear fiber, plum fiber, damson fiber, apricot fiber, pineapple fiber, and mango fiber, and the functional vegetable fiber is preferably selected from the group consisting of carrot fiber, tomato fiber, sugar beet fiber, pea fiber, and onion fiber.

4. A process according to any one of claims 1 to 3, characterized in that the functional plant fiber provided in step a. is a functional fruit fiber or a functional vegetable fiber which, during its production, has been subjected to lignin degradation for fiber brightening.

5. A method according to any one of the preceding claims, characterized in that the functional plant fiber provided in step a. is an aged fiber with a storage period from production of at least 6 months, preferably of at least 12 months, particularly preferably at least 18 months and especially at least 24 months.

6. The method according to any one of the preceding claims, characterized in that the functional plant fiber provided in step a. has a viscosity of 10 to 2000 mPas, preferably 100 to 1500 mPas, and particularly preferably 150 to 1400 mPas, wherein the functional plant fiber is prepared in water as a 2.5 wt.% dispersion and the viscosity is measured at a shear rate of 50 s -1 measured at 20°C.

7. Method according to one of the preceding claims, characterized in that the aqueous liquid is selected from the group consisting of fruit juice, sauce, fruit puree, shakes, emulsions, dressing, spread, dip, cream, sorbet, beverage.

8. The method according to any one of claims 1 to 6, characterized in that the aqueous liquid is selected from the group consisting of low-salt water, distilled water, double-distilled water, tri-distilled water, deionized water, drinking water, industrial water, low-salt water, ultrapure water or high-purity water, wherein the aqueous liquid is preferably drinking water.

9. Process according to one of the preceding claims, characterized in that the aqueous suspension contains the functional plant fiber in a concentration of 0.5 to 5 wt.%, preferably of 1.0 to 4 wt.%, particularly preferably of 1.5 to 3 wt.%, especially preferably of 2.25 to 2.75 wt.% and especially of 2.5 wt.%.

10. The process according to any one of the preceding claims, characterized in that the aqueous suspension in step b. has a pH of 3.5 to 5, preferably of 3.75 to 4.75, and particularly preferably of 4.0 to 4.

5.

11. Method according to one of the preceding claims, characterized in that the heat treatment is carried out for a duration of 30 seconds to 15 minutes, preferably from 60 seconds to 10 minutes and particularly preferably from 90 seconds to 5 minutes. TI 12. The method according to any one of the preceding claims, characterized in that during the heat treatment, the aqueous suspension is initially brought to the heated temperature and then, after mixing with the functional plant fiber, is cooled to room temperature, wherein the cooling rate is preferably from 0.1 to 5°C per minute.

13. The method according to any one of claims 2 to 12, characterized in that the shearing treatment is carried out for a duration of 15 seconds to 15 minutes, preferably from 30 seconds to 10 minutes, particularly preferably from 60 seconds to 5 minutes, and in particular from 90 seconds to 3 minutes.

14. A method according to any one of claims 2 to 13, characterized in that the shearing treatment is carried out by using a rotor-stator homogenizer or ultrasonic homogenizer.

15. Process according to one of the preceding claims, characterized in that the viscosity of the rheologically modified plant fiber is increased by at least 5%, preferably by at least 25%, particularly preferably by at least 50% and especially by at least 100%.

16. Functional plant fiber obtained by the process according to any one of claims 1 to 15.

17. Use of the functional plant fiber according to claim 16 as a stabilizer, thickener 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.

18. A food product, feed product, beverage, food supplement, cosmetic product, pharmaceutical product or medical device containing a functional plant fiber according to claim 16.

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