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DE-102025144456-A1 - Method for producing an activated pectin-containing citrus fiber

DE102025144456A1DE 102025144456 A1DE102025144456 A1DE 102025144456A1DE-102025144456-A1

Abstract

The invention relates to a process for producing an activated and hydrolyzed citrus fiber with a high pectin content and high water-binding capacity, which requires no heating of an aqueous-alcoholic solution and in which citrus seeds are completely separated. Furthermore, the invention relates to an activated and hydrolyzed citrus fiber with a high pectin content and high water-binding capacity.

Inventors

  • Stefan Latza
  • Mike Richter

Assignees

  • DÖHLER GmbH

Dates

Publication Date
20260513
Application Date
20251030
Priority Date
20241112

Claims (12)

  1. A process for producing an activated pectin-containing citrus fiber, comprising the following steps: a) providing a pectin-containing cell wall material from an edible citrus fruit, containing an insoluble fiber component and an insoluble protopectin component; b) washing the cell wall material provided in step (a) with water at least twice, separating the washed cell wall material from the wash water after each washing; c) mixing the washed cell wall material from step (b) with an alcohol-free, aqueous solution, preferably water, to form an aqueous suspension; d) adding at least one acid to the suspension obtained in step (c) to adjust the pH of the suspension within a range of 1.5 to 3.5; e) activating the pectin-containing cell wall material contained in the pH-acidic suspension from step (d) by heating it to a temperature above 60 °C; f) Separation of citrus seeds from the suspension from step (e); g) Mixing the citrus seed-free material from step (f) with an aqueous solution of an alcohol, wherein the amount of alcohol in the resulting mixture is at least 30 wt% based on the total weight of this mixture to achieve precipitation of the dissolved pectin components together with the cell wall material, and wherein the mixing in step (g) is carried out at a temperature of no more than 40°C; h) Separation of the precipitated material from step (g) from the aqueous-alcoholic liquid; i) Optionally, washing the precipitated material from step (h) at least once with an aqueous solution of an alcohol, preferably wherein the alcohol content in the mixture resulting after the addition of the alcohol solution is at least 30 wt% based on the total weight of the mixture.
  2. Procedure according to Claim 1 , characterized in that after step (i) an additional step (j) of drying and, if necessary, a further step (k) of grinding the product from step (j) takes place.
  3. Procedure according to Claim 1 or 2 , characterized in that the pectin-containing cell wall material of an edible citrus fruit in step (a) contains or represents citrus residue and/or citrus peel.
  4. Procedure according to one of the Claims 1 until 3 , characterized in that the washing in step (b) is preferably carried out at a maximum of 30 °C, particularly preferably at room temperature.
  5. Procedure according to one of the Claims 1 until 4 , characterized in that after step (b) an additional step (b1) drying of the washed cell wall material from step (b) is carried out for storage and its subsequent further processing in step (c), wherein before step (c) an additional step (c0) rehydration of the washed, dried cell wall material is carried out.
  6. Procedure according to one of the Claims 1 until 5 , characterized in that the acid added in step (d) is an acid suitable for the production of foodstuffs, wherein the acid may preferably be selected from the group comprising inorganic acid, in particular hydrochloric acid and/or sulfuric acid, organic acid, in particular citric acid, or mixtures thereof.
  7. Procedure according to one of the Claims 1 until 6 , characterized in that the activation by heating in step (e) is preferably carried out to a temperature of at least 70 °C, particularly preferably at least 80 °C, most preferably at approximately 90 °C, wherein the heating time is between 1 and 90 minutes, preferably between 5 and 60 minutes, particularly preferably between 15 and 45 minutes.
  8. Procedure according to one of the Claims 1 until 7 , characterized in that the separation of citrus seeds in step (f) can be carried out with any device known to the skilled person and suitable for this purpose, preferably with the aid of a sieve machine, wherein the sieve hole size is selected such that the hard citrus seeds are retained and the soft, deformable and comminuteable particles of the activated cell wall material and the dissolved pectin components can pass through.
  9. Procedure according to one of the Claims 1 until 8 , characterized in that the mixing in step (g) is preferably carried out at a temperature of at most 30 °C, particularly preferably at room temperature; and that the alcohol in the aqueous solution in step (g) is preferably selected from the group comprising isopropanol, ethanol, methanol or mixtures thereof.
  10. Procedure according to one of the Claims 1 until 9 , characterized in that after step (f) an additional step (f1) is carried out to adjust the material freed from citrus seeds to a pH value of 1.0 to 2.0 by adding an acid.
  11. Procedure according to one of the Claims 1 until 10 , characterized in that the optional at least one washing of the precipitated material in step (i) for the purpose of partial neutralization is carried out with an alkaline aqueous solution of an alcohol, wherein it is preferred that the alcohol content in the mixture resulting after the addition of the alcohol solution is at least 30 wt.% based on the total weight of the mixture.
  12. Activated pectin-containing citrus fiber, produced using a process according to one of the Claims 1 until 11 , characterized in that it preferably represents an activated and hydrolyzed pectin-containing citrus fiber; and that it comprises one or more properties from the following group: - a water binding capacity of 14 g/g to 20 g/g , - a ratio of hydropectin to protopectin of 2 to 6, - a total amount of pectin component of 30 to 50 wt.%, preferably of 35 to 45 wt.% based on the dry mass of the activated pectin-containing citrus fiber.

Description

The invention relates to a method for producing an activated, pectin-containing citrus fiber and an activated, pectin-containing citrus fiber itself. Citrus fibers represent a declaration-friendly alternative to food additives, as they can improve the textural properties of foods as non-E-number classified food ingredients. They allow for the targeted adjustment and optimization of properties such as water retention, viscosity, gel formation, and shape stability in various food products. The production of citrus fibers is advantageously carried out from the processing residues obtained during the juicing of citrus fruits. These press residues, often referred to as citrus pomace or citrus peels, typically consist of the albedo and flavedo (the outer and inner layers of the peel), citrus seeds, and pressed pulp containing segment membranes and citrus vesicles. All citrus fruits known to those skilled in the art can be used. The fibers are located in the cell walls of citrus peels and pressed pulp and can be classified into a soluble and an insoluble fraction. The soluble fraction consists mainly of hydropectin, a form of pectin that is weakly bound to the cell wall or is freely soluble. In contrast, protopectin is the insoluble form of pectin, which is tightly bound to the cell wall. Hydropectin can easily be converted into an aqueous solution by, for example, placing a dried citrus fiber in 80 °C hot water and allowing it to soak for 10 minutes. Extracting protopectin from the cell wall structure requires highly acidic pH conditions (typically pH 1.5–3.5) and a longer cooking time, approximately 15 to 60 minutes at 90 °C. The fraction that is insoluble in water and acids under the above-mentioned conditions consists predominantly of tissue-crosslinked cellulose and hemicelluloses. Commercially available citrus fibers differ, among other things, in their pectin content. Citrus fibers with a low pectin content of less than 10 percent by weight (based on dry matter) are typically obtained from the processing residues of industrial pectin production. Citrus fibers with a native pectin content of 20 to 45 percent by weight (based on dry mass) can be classified according to whether the original ratio of hydropectin to protopectin is largely unchanged or whether the proportion of protopectin has been reduced in favor of an increased hydropectin content by the manufacturing process. A process for converting protopectin into hydropectin is referred to as "activation" in this invention disclosure. This process increases the proportion of hydropectin, as this represents the functionally active pectin component in food technology applications and enables increased viscosity and improved gel formation. This differs from the functionalization of insoluble, cellulosic cell wall components, which can be achieved, for example, by the mechanical energy input of strong shear forces and is referred to in this invention disclosure as "disruption." Disrupted cell wall components exhibit, for example, increased water-binding capacity and a smoother/softer mouthfeel in the food product. Due to their improved multifunctional properties, citrus fibers, which have a high pectin content and are both "activated" with regard to the pectin content and "opened up" with regard to the insoluble cell wall components, are of great interest in food technology. Regarding the production of an activated and also decongested citrus fiber with a high pectin content, there is a need for simplified processes compared to the state of the art. In EP 3 380 529 B1 is a process for producing an activated, pectin-containing biomass composition that includes an insoluble fiber component and a soluble pectin component This process involves the activation of a pectin-containing biomass material, which comprises both the insoluble fiber component and a soluble pectin component. This activation is achieved by treating the pectin-containing starting biomass material with an activating solution. This solution is created by adding acid to an aqueous-alcoholic mixture. The pH of the mixture is adjusted to approximately 0.5 to 2.5, and the mixture is heated to a temperature above 40 °C. A characteristic of the in EP 3 380 529 B1 A key feature of the described process is that the alcohol content in the mixture during the process is at least 40% by weight of the total mixture. Another characteristic of the process is that essentially none of the soluble pectin components are extracted from the pectin-containing starting biomass material. The process step involving the use of mechanical energy is carried out by employing at least one technology from the group consisting of pumps, plate refiners, disc refiners, extruders, rotary lobe pumps, and centrifugal pumps. One of the properties of the according to EP 3 380 529 B1 The activated, pectin-containing biomass composition obtained has a soluble pectin component content of approximately 20 to 45 percent by weight (based o