Functional native potato protein, and method for producing same

Abstract

The invention relates to a method for producing potato protein and to a functional native potato protein with a molecular weight of 10 - 120 kDa (based on the SDS-PAGE primary structure), said potato protein being producible from potato fruit water which is obtained by means of a mechanical solids / liquid separation of comminuted, cleaned potato parts, comprising: a) a protein content of at least 84 wt.% (bone dry); b) a moisture content as a dry protein of maximally 10 wt.%; c) a product solubility / protein solubility in water of 75 -100%; and d) an ash content of maximally 3 wt.%. The potato protein can be produced by a) comminuting the raw plant material of the potatoes; b) mechanically separating the potato mash into a solid phase and a liquid phase (potato fruit water); c) setting the pH value to 6 - 9; d) carrying out an ultrafiltration of the liquid phase; d) carrying out a dialfiltration of the ultrafiltration retentate; e) optionally prior to or after step d), removing undesired flavoring agents using adsorption techniques; f) sterilizing the obtained protein solution; and g) optionally drying the protein solution.

Description

[0001] Native functional potato protein and process for its production

[0002] Description

[0003] The invention relates to a potato protein with a molecular weight of 10 - 120 kDa (according to SDS-PAGE primary structure), as well as a process for its production and its use in food.

[0004] 1. Technical area:

[0005] The potato fruit water produced during the crushing of cleaned potatoes, such as in potato starch production, poses a challenge for the industry, as disposal in sewage treatment plants or discharge into water bodies without further treatment is not possible. Separation of the proteins contained (approximately 2%) is essential. Precipitation often occurs by sharply increasing the temperature to > 90 °C and / or shifting the pH, followed by isolation of the coagulated proteins by mechanical separation. The resulting proteins no longer exhibit any functional properties (no functionality, no solubility, no gelling or foaming), as the tertiary structure of the proteins is irreversibly destroyed during thermal coagulation.In addition, protein fractions isolated in this way have a strong aftertaste and often contain high levels of antinutritional substances, particularly glycoalkaloids. All of this makes their use in the food industry unattractive and, due to the high glycoalkaloid content, even prohibited by law.

[0006] 2. State of the art:

[0007] The use of plant proteins in human nutrition is becoming increasingly important for various reasons. Vegetarian and vegan diets are becoming increasingly popular, and the use of animal proteins is sometimes discouraged for religious, ethical, or health reasons (e.g., allergies to milk proteins, etc.). Furthermore, animal proteins have a shorter shelf life when moist. However, plant proteins often have the disadvantage of not being complete in terms of their amino acid spectrum and therefore having a lower biological value. Potato protein has one of the best values ​​among plant proteins, boasting a high nutrient content, high digestibility, and a balanced amino acid spectrum comparable to milk and egg protein.Due to the high lysine content in potato protein, it represents a good substitute for lysine-poor proteins such as those from cereals. The textbook "Advances in Potato Chemistry and Technology", Elsevier Inc. 2016, which is currently in its second edition and will appear in its third edition in 2024, apparently due to high demand, is considered to be the generally known state of the art on potato proteins. From Chapter 4, pp. 75 - 104, Potato Proteins, "Functional food Ingredients" of this standard work, it emerges that potato protein - which here refers to the proteins found in potato tubers - consists of three main groups: patatin (MW: 40-45 kDa - as well as a dimer of approx. 88 kDa, represents approx. 40 wt.% of the soluble tuber protein), protease inhibitors (MW: 7-21 kDa, approx. 50 wt.% of the soluble tuber protein) and higher molecular weight proteins (MW > 40 kDa, approx. 10 wt.% of the soluble tuber protein).

[0008] Patatin, also known as tuberin, is a group of glycoproteins and exhibits lipid acyl hydroxygenase activity. It has an isoelectric point of approximately 4.9. It is temperature-sensitive and irreversibly loses its tertiary structure above 45°C, and the alpha-helical part of patatin denatures above 55°C (see p. 76, 2.2. "Patatin"). Precipitation in acidic conditions has a similar effect. It has a biological value similar to egg albumin or lysozyme, possesses antioxidant properties, and is better emulsifying than soy protein. Unlike most plant proteins, patatin contains a high proportion of the essential amino acid lysine and sulfur-containing amino acids. It should be noted that the different protein groups are unevenly distributed in the tuber - many valuable components occur only in the outer area under the skins (see G. Barel, I. Ginzberg, J. Exp. Bot. 2008, 59,3347-3357).In addition, many elements such as potassium, calcium, magnesium, iron, zinc, manganese, and copper cations are more concentrated in the potato skin (see p. 116, Chapter 5: “Potato Proteins, Lipids, and Minerals” by SO Kärenlampi, PJ White, from “Advances in Potato Chemistry and Technology”).

[0009] Protease inhibitors, also known as tuberinins, belong to the storage proteins. The higher molecular weight proteins in this highly diverse group include lectins, phenoloxidases, and lipoxygenases, and some possess peptidase or carboxypeptidase inhibitor properties.

[0010] It should be noted that all reported values, as well as the analytical values, are subject to fluctuation, as is inevitable with natural products. They may also contain small amounts of aggregates and compounds with higher molecular weights that are not visible in the SDS gel. The SDS gel chromatogram only shows larger amounts; small amounts do not produce bands. Furthermore, only qualitative conclusions about the sample composition can be drawn, not quantitative ones.

[0011] Low- to undenatured potato protein exhibits good functional properties such as solubility in aqueous and alcoholic solutions (globulins dissolve in alcoholic solutions), gel and foam formation, and good emulsifying properties, which, in addition to its nutritional properties, make it attractive for use in food. The functional properties are strongly influenced by the protein's production conditions (heat, pH, salts, shear forces, stress), as these can lead to denaturation and thus a loss of functionality. As explained on page 87 of "Advances in Potato Chemistry and Technology" under 2.3.3. "Foaming Properties," ultrafiltration can be used to improve the foaming properties of potato protein (v. Koenigsveld 2002). "Potato Chemistry" also explains that high mechanical stress leads to denaturation of potato protein.

[0012] In "Applied Food Protein Chemistry" (edited by Z. Ustunol, Chapter 4: "Physical, Chemical and Processing-induced Changes in Proteins", 2015, 1st Edition, Wiley Blackwell), the fundamental effects of physical and chemical influences on proteins and their functionalities are described in great detail. Z. Ustunol is a professor at the University of Michigan, meaning this information is passed on to students of food technology and is considered expert knowledge. Denaturation refers to changes in the tertiary and secondary structure of a protein that lead to the reversible or irreversible unfolding of the protein. In this process, inter- and intramolecular interactions are broken by external factors. Heat reduces the stability of non-covalent interactions and breaks bonds such as hydrogen bonds. The moisture content of the protein also influences its stability to heat.A hydrated protein is more mobile and can unfold more easily, which is why it is also less stable against heat denaturation.

[0013] Damodaran described as early as 2008 (see "Amino Acids, peptides and proteins" in Fennema's Food Chemistry, 2008, 5th Edition, CRC Books) that heat coagulation is an irreversible denaturation of most proteins. High pressures also lead to protein unfolding, as native proteins have cavities that are not present in the denatured (unfolded) state. In addition, Bianco described in 2012 (V. Bianco, S. Iskrov, G. Franzese, J. Biol. Phys. 2012, 38, 27-48) that high pressures can force water into the protein cavities, leading to swelling and denaturation. Similarly, mechanical shear forces (e.g., from centrifugation, shaking, mixing, beating, etc.) can also lead to denaturation.

[0014] In addition to the physical means mentioned above, proteins can also be denatured chemically. One common method is adjusting the pH. The isoelectric point of a protein is the pH value at which the protein's total charge is zero. This minimizes the repulsive forces of the charges, which is why proteins can aggregate and coagulate, so that their solubility is lowest at the isoelectric point. At pH values ​​below and above this value, the protein's solubility increases again. Extreme pH conditions that lead to high positive or negative charge of the protein can also cause strong intramolecular repulsion and thus denaturation (see S. Damodaran, “Amino Acids, peptides and proteins” in Fennema's Food Chemistry, 2008, 5th Edition, CRC Books; J. Culbertson, “Proteins functional properties” in Food Chemistry: Principles and Applications, 2012, 3rd Edition, Science Technology).

[0015] Electrostatic interactions can also be exploited to precipitate proteins using organic solvents that are less polar than water. This effect can be used for protein precipitation in extractions or for purification (Z. Ustunol, 4.2.2.2 Organic-solvent-induced denaturation in "Applied Food Protein Chemistry" 2015, 1st Edition, Wiley Blackwell).

[0016] The addition of salts also strongly influences protein properties. Ustunol describes that protein solubility is increased in dilute salt solutions of low ionic strength (< 0.2 M), regardless of the type of salt. At high salt concentrations (> 1 M), however, the opposite effect occurs. The salt interacts with the water, enhancing protein-protein interactions, which leads to protein precipitation. The salt concentration at which precipitation occurs depends on the type of protein.

[0017] Osborne was able to exploit these effects as early as 1905 (see TB Osborne, GF Campbell, J. Am. Chem. Soc. 1896, 18, 575-582; TB Osborne, IF Harris, Am. J. Phys. 1905, 13, 35-44 and TB Osborne, "Die Pflanzenproteine" in Ergebnisse der Physiologie 1910, 10, 47-215) to obtain the so-called Osborne fractions from cereal protein, which could be isolated according to their different solubilities: While albumins can be extracted with water, globulins can be extracted with saline solutions. Prolamins can be extracted with ethanol (70%). The glutelins, on the other hand, remain in the residue. The name of these so-called Osborne fractions has become established throughout the field of plant proteins.

[0018] For these reasons, the starting material (with peel), the protein production process, and the conditions of further processing into the food product have a huge influence on the condition, functionality, and composition of the resulting protein. All processing steps therefore impact the properties of the final protein product. All methods involving heating, such as pasteurization, drying, sterilization, blanching, cooking, and others, result in complete or partial denaturation of the protein, which begins at temperatures as low as 40°C. Due to the attractive properties of potato protein and the increased demand for protein mentioned above, a variety of different processes for producing potato protein are now known. The first patents for potato protein production were filed as early as 1997.Several scientific publications have also been published on this topic in the form of review articles, describing the most common production methods and listing their advantages and disadvantages (see, for example, Y. Fu, W.-N. Liu, OP Soladoye, Int. J. Food Sci. Technol. 2020, 55, 2314-2322 or S. Lokra, KO Straetkvern, Food 2009, Special Issue 1, 88-95). The processes can be divided into three main methods: 1) Precipitation / coagulation - by adjusting temperature and / or pH, adding a precipitant, or complexing; 2) Membrane separation; 3) Chromatography. The starting material is predominantly potato fruit water, a by-product of the starch industry, which contains approximately 1-2% potato protein.

[0019] In industry, the proteins contained in potato juice are often isolated by coagulation, adjusting the temperature to > 60 °C and / or adjusting the pH to < 6, followed by mechanical separation of the coagulated protein. This, as stated in "Advances in Potato Chemistry and Technology," is extremely detrimental to the properties of solubility, water-binding capacity, emulsifying ability, foaming ability, and stability. The proteins obtained in this way are therefore not very suitable for use in food for human consumption because, as already explained, they have hardly any functionalities (solubility, foaming, gelling, etc.) and also have a strong off-flavor. They have a large particle size, which results in an unpleasant, sandy mouthfeel, a coarse, grainy structure of the proteins, and limits their film-forming ability.

[0020] In order to reduce the above-mentioned disadvantages of obtaining potato proteins by coagulation, further processes have been developed to improve the product quality of the coagulated potato proteins.

[0021] WO 2017 / 142406 describes an improvement in protein properties (lower hardness, smaller particles, lower density, less off-flavor) when the coagulated potato protein is washed prior to drying to a wash water conductivity of <1 mS / cm. Likewise, an improvement in the protein properties of solubility and water-binding capacity can be achieved by physically reducing the particle size of the protein, as described in WO 2016 / 133448, or by extraction steps with low-molecular-weight alcohols such as ethanol or propanol-water mixtures, as outlined in WO 2020 / 171708. In the last example, the precipitation of proteins using organic solvents described above is used. Despite the sensory improvements of the coagulated potato proteins achievable in this way and the resulting application in food, the significant loss of protein functionality caused by denaturation remains irreversible.

[0022] Therefore, the development of processes for the large-scale isolation of potato proteins that proceed without denaturation is of great interest. WO 2014 / 011042 describes the fractionation of proteins from potato fruit water into a high-molecular-weight and a low-molecular-weight fraction using a functionalized support material by adsorption and desorption steps of the individual fractions. WO 2008 / 069650 describes the isolation of proteins and the protease inhibitor from potato fruit water using expanded-bed chromatography, which separates them into two protein fractions. This allows for the extraction of pure native potato proteins with high functionality, but not a total fraction. Chromatographic processes are associated with high process costs, difficult upscaling, and high technical and energy expenditure, which is why processes without these steps are of great interest.WO 2018 / 183770 describes the isolation of a dispersible potato protein powder for use in food, feed, and beverages with a protein content of 30–91%, a content of α-glycoalkaloids < 300 ppm, an ash content of 1–20%, and a particle size of 10–100 pm. It comprises the following steps:

[0023] • Microfiltration of potato fruit water

[0024] • Ultrafiltration

[0025] • Microparticulation if necessary

[0026] • Spray drying

[0027] • Glycoalkaloid removal before or after ultrafiltration and optionally reverse osmosis

[0028] Furthermore, WO2020 / 242299A1 describes the production of a potato protein from peeled potatoes. Protein isolation may include isoelectric precipitation, coagulation, microfiltration, and ultrafiltration, as well as diafiltration against a salt solution with a conductivity of 5–20 mS / cm. This document explicitly mentions and claims the unavoidable peeling of the tubers before processing. Peeling is said to produce a cleaner protein with reduced microbial contamination and a reduced glycoalkaloid content, thus requiring fewer purification steps. Furthermore, the protein thus obtained has a different protein composition than that of peeled tubers.While the protein obtained from peeled tubers contains higher levels of tyrosine, proline, arginine, glutamine, glutamate, asparagine, and aspartate, many essential amino acids are found in the tuber's peel, which are lost during peeling. This applies primarily to threonine, leucine, isoleucine, methionine, and phenylalanine. Furthermore, as mentioned above, many minerals are concentrated in the peel.

[0029] The fact that the extraction of potato proteins from potato fruit water is basically possible by ultrafiltration and diafiltration is already known to the expert from the above-mentioned textbook “Advances in Potato Chemistry and Technology” (see also e.g. WO 97 / 42834; HJ Zwingenberg, AJN Kemperman, ME Boerrigter, M. Lotz, JF

[0030] Dijksterhuis, PE Poulsen, G.-H. Koops, Desalination 2002, 144, 331-334; BJ Oosten, The Strength 1976, 4, 135-137; G. Eriksson, B. Sivik, Potato Res. 1976, 19, 279-287; I

[0031] Wojnowska, S. Poznanski, W. Bednarski, J. Food. Be. 1981, 47, 167-172).

[0032] The principle of removing flavor and harmful substances from protein-containing food products using adsorption techniques is also fundamentally known. WO 2008 / 069651 describes the adsorption of glycoalkaloids on activated carbon itself or on activated carbon coated with a gel-like agent. DE 29 47207 A1 from 1979 already describes the removal of undesirable flavors from a potato albumin fraction of potato fruit water using activated carbon treatment.

[0033] Potato patatin, a major component of potato protein, can cleave fatty acids from triglycerides. The selectivity of this reaction depends heavily on the chain length and structure of the fatty acids, as is evident, for example, from P. Pinsirodom, KL Parkin, J. Am. Oil Chem. Soc. 1999, 76, 1119-1125 and C. Anderson, P. Pinsirodom, KL Parkin, J. Food. Biochem. 2002, 26, 63-74. The fundamental interaction of lipases with triglycerides and the dependence of their selectivity on the chain length of the fatty acids is a principle that has long been known (see textbooks such as "Advances in Potato Chemistry and Technology," p. 78, 2nd paragraph), as is also evident from EP 232933A1 or Römpp, keyword "Lipases," 11th edition.

[0034] To avoid the formation of off-flavor notes due to this lipase activity and the associated cleavage of fatty acids, patatin is only used in the literature with longer-chain fats (e.g., US 2017 / 0196243), which it cannot cleave. However, the cleavage of triglycerides can also be used to deliberately create a flavor note by specifically using fats with shorter chain lengths, as shown in US 2009 / 053191 and by Spelbrink et al. (REJ Spelbrink, H. Lensing, MR Egmond, MLF Giuseppin, Appl. Biochem. Biotechnol. 2015, 176, 231-243). Preferred oils in which patatin does not break down triglycerides and therefore does not cause any changes in taste are listed in the publication: “Fatty Acids Composition of Vegetable Oils and Its Contribution to Dietary Energy Intake and Dependance of Cardiovascular Mortality on Dietary Intake of Fatty Acids” (J. Orsavova, et al., Int. J. Mol. Sci.2015, 16, 12871-12890), which is incorporated by reference. The fact that patatin exhibits this lipase activity was first described in 1971 by Galliard (T. Galliard, Biochem. J. 1971, 121, 379-390). Also the 2008 Wikipedia article on patatin.

[0035] (https: / / en.wi kipedia.org / w / index.php?title=Patatin&oldid=193784497) already describes the enzyme activity of patatin as a lipase with the ability to cleave fatty acids and refers to the review article "Tuber Storage Proteins" published in 2003 by PR Shewry (PR Shewry, Ann. Bot. 2003, 91, 755-769), which provides a comprehensive overview of the lipase activity, properties, and behavior of patatin. Therefore, when using total potato protein fractions in foods, special consideration must be given to lipase activity. Care must be taken when working with fats. As mentioned above, some fats are more suitable if the formation of off-notes by free fatty acids is undesirable. Inactivation of the enzyme activity, e.g., by heating to the denaturation temperature of the heat-sensitive lipase, can also be helpful.

[0036] The known processes for producing a highly functional potato protein could therefore be improved in various respects.

[0037] The object of the invention is to obtain a native, functional potato protein of natural structure from potato fruit water in a simple manner on an industrial scale.

[0038] This object is achieved by a method according to claim 1 and a potato protein according to claim 8. Advantageous further developments or embodiments emerge from the dependent claims. According to the invention, this is obtainable with high yield by the method using the key technologies of membrane filtration and adsorbent treatment. By processing unpeeled potatoes, a more complete amino acid spectrum is obtained in the product, a complex process step (peeling) is avoided, and less waste is generated.

[0039] A typical potato protein according to the invention with a molecular weight of 10 - 120 kDa (according to SDS-Page primary structure) is available by:

[0040] Present chopped, cleaned potatoes, if necessary with oxidation protection;

[0041] Mechanical separation of the solids from the crushed potatoes to produce potato juice and solids;

[0042] Adjusting the pH of the potato fruit water to a pH value between 6 and 9; separating insoluble components and suspended solids by centrifugal separation;

[0043] Ultrafiltration of pH-adjusted potato fruit water;

[0044] Diafiltration of the ultrafiltration retentate to reduce the electrical conductivity of the retentate solution by 50-90%, preferably 65-90%, particularly preferably 75-85%, while obtaining the potato protein solution; optionally, drying the potato protein solution and optionally sterilizing it.

[0045] The liquid potato protein ultrafiltration retentate can be converted into dried potato protein by gentle drying. Suitable methods include spray drying, lyophilization, vacuum drying, and similar processes. It can also be added to other substances in liquid form.

[0046] The highly functional potato protein product, thus economically obtained on an industrial scale, is of high quality and exhibits advantageous functional properties for food applications (e.g., gelling, emulsion formation, and foam formation). It can also be used as an adhesive for specialty applications – for pharmaceutical carrier materials, e.g., cellulose and its derivatives. Furthermore, unlike other plant proteins, the potato protein according to the invention offers the ability to gel hot with high viscosity. The water-binding capacity of the gel results in a better mouthfeel and a softer texture.

[0047] The taste of the protein was also greatly improved by this treatment.

[0048] In one embodiment, the invention relates to a dried native, functional potato protein with a molecular weight of 10 - 120 kDa (according to SDS-PAGE primary structure), producible from potato fruit water obtained by the mechanical solid / liquid separation of crushed, cleaned potato parts, characterized by: a) protein content of at least 84 wt.% atro b) moisture content of max. 10 wt.% c) foam volume 1400 - 2000 mL d) foam stability of at least 90% e) product solubility / protein solubility in tap water of 75 - 100% f) maximum gel strength of at least 1000 gg) ash content of max. 3 wt.% In one embodiment, the protein according to the invention has a molecular weight of 10 - 120 kDa (according to SDS-PAGE primary structure).It has three main fractions: the first main fraction has a molecular weight of 10 to 20 kDa, the second main fraction has a molecular weight between 25 and 40 kDa, and the third main fraction has a molecular weight of approximately 66 kDa according to SDS-PAGE primary structure. According to HPLC chromatography, at least 70% of the proteins have a molecular weight of 3–182 kDa. The different molecular size ranges detected are due to the different analytical methods. While SDS-PAGE determines the mass of the protein in its primary structure, HPLC chromatography determines the volume of the proteins in their quaternary structure.

[0049] In one embodiment of the invention, the protein according to the invention is obtainable by: a) introducing comminuted, cleaned potato parts; b) mechanically separating the solids from the comminuted potatoes to produce potato fruit water and solids; c) adjusting the pH of the potato fruit water to a pH between 6 and 9; d) separating insoluble components and suspended matter by centrifugal separation; e) ultrafiltration of the pH-adjusted potato fruit water; f) diafiltration of the ultrafiltration retentate to reduce the electrical conductivity of the retentate solution by 50-90%, preferably 65-90%, particularly preferably 75-85%.

[0050] In one embodiment of the invention, the dried protein according to the invention is obtainable by adjusting the pH after the mechanical solid / liquid separation to a pH of 6 - 9, preferably 6.5 - 8.2, particularly preferably 6.9 - 7.5.

[0051] In one embodiment of the invention, the dried protein according to the invention is obtained by drying by at least one of the process steps of spray drying, lyophilization, vacuum drying, freeze drying.

[0052] In one embodiment of the invention, the protein according to the invention is obtainable in that the ultrafiltration membrane is a plastic or ceramic membrane with a cut-off of 3 - 150 kDa, preferably 5 - 120 kDa, particularly preferably 10 - 100 kDa.

[0053] In one embodiment of the invention, the protein according to the invention is characterized in that the ultrafiltration retentate is treated with adsorbents selected from activated carbon, bentonites, polymeric adsorbents, or derivatives of the adsorbents. Typical polymeric adsorbents are polystyrene / divinylbenzene resins, phenol-formaldehyde resins, derivatives of the adsorbents, and combinations thereof that decolorize and remove off-flavors. In a preferred embodiment, the polymeric adsorbent used is a polystyrene / divinylbenzene resin. The resins Amberlite XAD 761, Amberlite FPX 68, Diaion HP 20, Sepabeads SP 70, Purosorb PAD 550 polymeric adsorbent, activated carbon, cellulose-based adsorbents, gelatin, cellulose-based adsorbents, tannins, are also preferred for the reduction of off-flavors - polystyrene / divinylbenzene resins, polyphenol-formaldehyde resins and combinations thereof can also be used.

[0054] In one embodiment of the invention, a protein according to the invention can be produced by gently sterilizing the ultrafiltration retentate, for example by pasteurization with microwaves or HTST pasteurization (High Temperature Short Time), PEF sterilization (Pulsed Electric Fields), HPP pasteurization (High Pressure Pasteurization).

[0055] In one embodiment of the invention, the protein according to the invention is obtainable by:

[0056] Presentation of crushed, cleaned potato parts in the form of potato mash, mechanical separation of the potato mash into solid and liquid phases (potato fruit water);

[0057] Adjust the pH to 6 - 9, preferably 6.5 - 8.2, particularly preferably 6.9 - 7.5.

[0058] Ultrafiltration of the liquid phase with membranes with a cut-off of 3 - 150 kDa, preferably 5 - 120 kDa, particularly preferably 10 - 100 kDa;

[0059] Diafiltration of the ultrafiltration retentate to a reduction in conductivity of 50 - 90%, preferably 65 - 90% and particularly preferably 75 - 85%.

[0060] Removal of anti-nutritional substances using adsorption techniques; if necessary, disinfection and drying of the protein solution.

[0061] In one embodiment of the invention, the protein according to the invention is a component of a food or food additive, a dietary food or food additive for human or animal consumption.

[0062] In one embodiment of the invention, the protein according to the invention is a component of foodstuffs or food additives, of dietary foods or food additives for human or animal consumption, both as a solution and as a solid.

[0063] In one embodiment of the invention, the protein according to the invention is a component of an adhesive. In one embodiment of the invention, the protein according to the invention is a component of a mixture with other plant proteins, preferably legume proteins, such as pea protein, bean protein, broad bean protein, lentil protein, soy protein, lupin protein, or mung bean protein, or mixtures thereof.

[0064] 3. Production of native functional potato protein:

[0065] The potato juice from washed, peeled potatoes is obtained after solid / liquid separation of chopped, cleaned potato parts, for example as a side stream from potato starch production. The first step is to clean the raw potato of sand, stones, and plant residues and then chop it, e.g., using a grater, usually with the addition of a reducing or antioxidant agent such as sodium hydrogen sulfite, or in a protective gas atmosphere. Prior peeling of the potato is undesirable for carrying out the process according to the invention, which makes it an advantageous further development in contrast to prior art processes, which explicitly describe peeling of the potatoes. By omitting peeling, the economics of the process is improved, and a nutritionally more favorable amino acid spectrum is obtained, as already explained above.With conventional peeling, a peeling loss of 10% by weight can be assumed, which, based on an initial quantity of 1,000 tons of potatoes, results in a loss of 100 tons of raw material. In addition, there are energy and electricity savings, as well as material costs that would arise from changing blades or replacing the roller peelers with mechanical peeling. With steam peeling, energy costs must also be considered, as well as the costs of electricity, water, and heating. Furthermore, during steam peeling, the potato is exposed to elevated temperatures, which can lead to protein denaturation and, due to the gelatinization of the starch, make protein isolation difficult or even impossible.

[0066] Centrifugation separates the starch into a solid phase consisting of starch and fibers, and potato fruit water as a liquid phase containing water-soluble components such as proteins, sugars, amino acids, organic acids and salts, etc. These steps are common in this or a similar way for the extraction of starch from potatoes (see, for example: J. BeMiller, R. Whistler, Starch: Chemistry and Technology, 3rd edition, Academic Press, pp. 522-555).

[0067] For a possible production process for native functional potato protein from potato fruit water, the pH is first adjusted to 6-9, preferably 6.5-8.2, particularly preferably 6.9-7.5, using a food-safe aqueous solution, such as sodium hydroxide, potassium hydroxide, or calcium hydroxide. Insoluble components and suspended solids are then separated by centrifugal separation. Through these initial process steps, the potato fruit water loses its turbidity and becomes a clear protein solution. Ultrafiltration of the separated, clear protein solution achieves a concentration of the proteins in the liquid ultrafiltration retentate, the protein solution. In one embodiment, the concentration factor is approximately 10, although higher or lower protein concentrations are also possible, depending on conditions such as energy costs.

[0068] Ceramic and plastic membranes are preferred. For example, a plastic membrane with a cutoff of 3–150 kDa, preferably 5–120 kDa, and particularly preferably 10–100 kDa is suitable. Membrane filtration is carried out at low pressures of 1–3 bar. Excessive pressure is avoided, as this mechanical stress negatively affects the functionalities of the proteins.

[0069] Before or after ultrafiltration, undesirable flavors and anti-nutritional substances, including glycoalkaloids, can be removed from the protein solution using adsorption techniques. Activated carbon or bentonite adsorption techniques have proven particularly suitable, but other adsorbents as mentioned above can also be used.

[0070] The ultrafiltration retentate is diafiltered until the electrical conductivity is reduced by 50-90%, preferably 65-90%, particularly preferably 75-85%. Diafiltration can be carried out with fully deionized water, distilled water, process water, or tap or service water. The water used can have a conductivity of 5 pS / cm-5000 pS / cm, preferably 10-50 pS / cm or even 5-50 pS / cm.

[0071] The resulting protein solution can optionally be subsequently sterilized using gentle processes. Suitable methods include microwave pasteurization, HTST (high-temperature short-time) pasteurization, PEF (pulsed electric field) sterilization, or HPP (high-pressure pasteurization). Finally, the protein solution can be dried using spray drying or other gentle drying methods, such as lyophilization or vacuum drying. Further use of the protein solution is also conceivable.

[0072] The potato protein according to the invention, with a molecular weight of 10 to 120 kDa (according to SDS-PAGE primary structure), is characterized by its good emulsifying and foaming properties. Furthermore, it swells when heated, enabling better processing and easier protein enrichment. Its low viscosity in the cold state also leads to good processability, whereas many other commercially available proteins already have a significantly higher viscosity. The superior gel formation properties when heated are similar to animal proteins and make the potato protein according to the invention highly attractive for use in meat substitutes, among other applications.

[0073] The invention is explained below using exemplary embodiments and the drawing figures, to which it is by no means limited. In them:

[0074] Fig. 1 : Process scheme of Production Example 1.

[0075] Fig. 2: HPLC chromatogram of the potato protein according to the invention and a protein standard.

[0076] Fig. 3: HPLC chromatogram of the potato protein according to the invention and Solanic 300®.

[0077] Fig. 4: HPLC chromatogram of the potato protein according to the invention and Solanic 200®.

[0078] Fig. 5: SDS-Page gel of the potato protein according to the invention (lane 1 = marker; 2 and 3: batches of the potato protein according to the invention)

[0079] Fig. 6: DSC diagrams for thermally treated and thermally untreated potato proteins.

[0080] Fig. 7: Viscosity measurement according to Anton Paar of the potato protein according to the invention in comparison with a sample treated with calcium chloride.

[0081] Fig. 8: Gel strength measurements of the potato protein according to the invention in comparison with a sample treated with calcium chloride.

[0082] Fig. 9: Process diagram according to claim 1.

[0083] Examples of manufacturing processes

[0084] Example 1 - Production of highly water-soluble, functional potato protein:

[0085] To produce a highly water-soluble potato protein, potatoes were cleaned and finely ground. The suspension was subjected to gravity separation (centrifugation), and the supernatant, as protein-rich amniotic fluid, was used for protein extraction. The protein-containing, cloudy solution was adjusted to a pH of 7.0 to 8.0 using aqueous sodium hydroxide solution and centrifuged again, removing fine suspended particles from the solution. The purified, clear, protein-containing solution was ultrafiltered using a 100 kDa polyvinylidene fluoride membrane at a transmembrane pressure of 2.0 bar and a differential pressure of 1.0 bar. The protein of the invention remained in the ultrafiltration retentate, while salts, sugars, and amino acids remained in the ultrafiltration permeate. The ultrafiltration retentate was then diafiltered with demineralized water until the electrical conductivity was reduced by 81%.Subsequently, anti-nutritional components were removed and decolorized using activated carbon adsorption. The potato protein according to the invention obtained after spray drying had:

[0086] The process steps of Example 1 are illustrated in Fig. 1. Example 1 represents an embodiment of the invention, but is by no means limited to it.

[0087] Example 2 - Preparation of a functional potato protein solution:

[0088] To produce one embodiment of highly water-soluble potato protein, potatoes were cleaned and finely ground. The suspension was subjected to gravity separation (centrifugation), and the supernatant, as protein-rich amniotic fluid, was used for protein extraction. The protein-containing, cloudy solution was adjusted to a pH of 7.0 to 8.0 using aqueous sodium hydroxide solution and centrifuged again, removing fine suspended particles from the solution. The purified, protein-containing, clear solution was ultrafiltered using a 100 kDa polyvinylidene fluoride membrane at a transmembrane pressure of 2.0 bar and a differential pressure of 1.0 bar. The protein of the invention remained in the ultrafiltration retentate, while salts, sugars, and amino acids remained in the ultrafiltration permeate. The ultrafiltration retentate was then diafiltered with demineralized water until the electrical conductivity was reduced by 81%.Subsequently, anti-nutritional components were removed and decolorized using activated carbon adsorption. The resulting potato protein solution showed: The process steps of Example 2 are illustrated in Fig. 9. Example 2 represents an embodiment of the invention, but is by no means limited to it.

[0089] Further application examples are given below, which show possible uses of the water-soluble protein according to the invention - further applications will be obvious to the person skilled in the art.

[0090] Example 3: HPLC

[0091] The potato protein according to the invention as prepared in Example 1 was analyzed using an HPLC from Knauer. The column used was an HPLC Xbridge BEH SEC 200A, 3.5 from Waters, eluted with an aqueous solution of 0.02 M Na2HPO4 / NaH2PO4 at pH 7. The following standards were used from Sigma-Aldrich: 670 kDa - thyroglobulin and 150 kDa - gamma globulin.

[0092] 44.3 kDa - Ovalbumin

[0093] 13.74 kDa - Ribonuclease A

[0094] UV absorption at 214 nm was used for detection. The measured HPLC chromatogram is shown in Figure 2, where time in minutes is plotted against absorbance in absorbance units. Figure 2 shows the protein standard (broken lines) with relatively sharp peaks at 10.84 min for thyroglobulin; 14.12 min for gamma globulin; and 14.12 min for glucocorticoids.

[0095] 15.74 min for ovalbumin and 18.93 min for ribonuclease. The chromatogram of the protein of the invention (solid line) was overlaid with that of the standards. Various protein fractions are clearly visible, with two main components appearing at retention times of approximately 10 and 15 minutes, as well as a mixture of various proteins in the range of 17-20 minutes.

[0096] When evaluating HPLC chromatograms, it is assumed that the volume corresponds to the peak area of ​​the signals. An analysis of the volume distribution showed that the relative peak ratios of both the protein standard and the potato protein according to the invention did not change, even at different detector wavelengths. Therefore, a semi-quantitative statement about the quantity distribution is possible, and a conclusion about their molecular weights can be drawn from the volume distribution. The volume of the proteins in the potato protein according to the invention can therefore be semi-quantitatively assigned to the molecular weights: Molar weights and retention times of the potato protein according to the invention:

[0097]

[0098] The first characteristic signal, with a retention time of 8.9 to 11.7 min, can be assigned to a molecular weight of 697 kDa at its maximum at 10.7 min. The main fraction (30% of the total fraction, retention time: 13.41–16.32 min) can be assigned to molecular weights of 43.5 kDa to 182.0 kDa. In addition, the potato protein according to the invention consists of a mixture of smaller proteins (retention time: 16.3–30.0 min). Within this low-molecular-weight range, proteins with molecular weights of 5.2 to 13 kDa make up the largest proportion.

[0099] Figure 3 shows an HPLC chromatogram of the potato protein according to the invention (solid line) and the commercially available potato protein Solanic 300® from AVEBE (broken line), with time in minutes plotted against absorbance in absorbance units. Comparing the two chromatograms, it is clearly evident that Solanic 300® represents a single fraction (99%, retention time: 15.5–27.4 min) within a specific molecular weight range.

[0100] Figure 4 shows an HPLC chromatogram of the potato protein according to the invention (solid line) and the commercially available product Solanic 200® from AVEBE (broken line), with time in minutes plotted against absorbance in absorbance units. While the protease inhibitor fraction (PI fraction) is absent in Solanic 200®, it is still present in the potato protein according to the invention, which represents a total water-soluble fraction of the potato protein.

[0101] Compared to So / an / c® products, the potato protein according to the invention represents a water-soluble total fraction of potato protein. This makes it the only highly functional total potato protein fraction that can be produced commercially and economically. Until now, only functional individual fractions or coagulated total protein fractions, which are thus significantly limited in their functionality, have been available. Total potato protein here refers to a total fraction of water-soluble proteins. Other commercial potato proteins, such as Protafy 130® from KMC, could not be analyzed by HPLC due to their low solubility. The potato protein according to the invention was also analyzed by SDS-PAGE gel chromatography - see Fig. 5. The selectivity of the method is clearly evident, as proteins with a molecular weight > 120 kDa are not present in the product.Here, as in the HPLC chromatogram, three most intense areas are visible and can be assigned to molecular weights of 10 - 20 kDa, 25 - 40 kDa and about 66 kDa according to the SDS-PAGE.

[0102] However, both analytical methods are not comparable with regard to the molecular weights determined, as the proteins are denatured differently in the measurement methods. Nevertheless, both methods show that three protein mixtures are the main components of the potato protein according to the invention. According to SDS-PAGE, this corresponds to ranges of 10-20 kDa, 25-40 kDa, and a mixture around 66 kDa. According to HPLC chromatography, the potato protein according to the invention consists of a protein mixture of 428-1627 kDa, the main fraction of 43-182 kDa, and a mixture of smaller proteins with a major fraction of 5-13 kDa.

[0103] The discrepancy in the detected molecular sizes is due to the different analytical methods: While SDS-PAGE determines the mass of the proteins in their primary structure, HPLC chromatography determines the volume of the proteins. Here, the proteins are still in their quaternary structure. The primary structure of the protein corresponds to its elongated amino acid sequence, whereas in the quaternary structure, the protein exists in a spatial structure as a protein complex—thus, there is a difference in the existing bonding relationships. For this reason, the stated molecular sizes initially appear very different.

[0104] Example 4: Differential Scanning Calorimetry (DSC):

[0105] Denaturation of a protein means that the protein's folding state is altered to a lower-order protein structure. The unfolding of a protein is an energetic balance of various interactions between protein groups and the surrounding medium, so the matrix in which the protein is dissolved influences the amount of energy absorbed during denaturation.

[0106] These folding and unfolding reactions are associated with thermal effects that can be studied using differential scanning calorimetry (DSC) analysis. In DSC analysis, the heat capacity of a protein in aqueous solution is measured as a function of temperature, with the area under the heat capacity curve corresponding to the enthalpy of denaturation. A larger enthalpy, i.e., more heat required to destroy the ordered protein structure, indicates a higher degree of folding of the protein. The peak temperature of the heat capacity profile (TdPeak) corresponds to the transition temperature.

[0107] For the measurements, approximately 60 mg of a 50% commercially available solution of the protein to be tested in demineralized water was weighed into a 100 pL aluminum crucible. The measurement was carried out on a DSC3+ Star system from Mettler Toledo® under a nitrogen atmosphere, with a temperature range of 25 - 95 °C being investigated at a heating rate of 10 °C / min. Fig. 6 shows that the animal feed potato protein (dotted line, first curve), which is a protein coagulated by increasing the temperature and adjusting the pH, does not absorb any heat. This is due to the complete denaturation of the protein. The potato protein according to the invention (dotted line, second curve), on the other hand, shows heat absorption from a temperature of approximately 64 °C, which corresponds to the onset of denaturation (T onSet). Heat absorption ends at approximately 87 °C, resulting in a denaturation peak temperature (TdPeak) of approximately 77 °C. The commercially available potato proteins Solanic 300® (short-dashed line, third curve) and Solanic 200® (long-dashed line, fourth curve) were then examined for comparison. As described above, Solanic 300® is a mixture of various low molecular weight proteins that can be summarized as a protease inhibitor fraction (Pl fraction). Solanic 200®, on the other hand, is a refined patatin in which the protease inhibitors (Pl fraction) are almost completely absent. This is reflected in the DSC measurement.

[0108] Solanic 200® begins to absorb heat at temperatures as low as 62 °C, with heat absorption ending at 79 °C (TdPeak = 72 °C). Solanic 300®, on the other hand, similar to the potato protein of the invention, begins to absorb heat at approximately 64 °C, but ends at approximately 83 °C.

[0109] The temperature profiles generally show that all proteins are distinctly different products. Generally, larger proteins are denatured more easily, i.e., at lower temperatures, than smaller proteins, which, beyond a certain size, can no longer be denatured at all. Therefore, Solanic 300® exhibits a correspondingly longer heat absorption, as, unlike Solanic 200®, it contains the PI fraction. The significantly longer heat absorption of the potato protein according to the invention clearly shows that it has a different protein fraction, which still contains small proteins.

[0110] Example 5: Analytical characterization

[0111] Dried potato protein according to the invention, prepared according to Example 1, was investigated. Analytical methods:

[0112] Humidity determination:

[0113] • Device: Surface dryer (drying temperature 105°C level 2)

[0114] Protein content:

[0115] • Nitrogen determination according to Kjeldahl (Nx6.25), DIN EN ISO 3188

[0116] Product solubility:

[0117] • Weight: 40 g tap water + 0.5 g product

[0118] • Stirring time: 1 h

[0119] • Fill to 50 mL in the volumetric flask

[0120] • Centrifuge for 30 min. at 2770 xg

[0121] • Filter through a Whatmann filter (No. 1) (paper filter with 11 micrometer pore size)

[0122] • Weigh 20 - 25 g of filtrate into a glass bowl

[0123] • Dry for 24 hours in a drying cabinet at 100°C

[0124] _ Dry matter filtrate r%l

[0125] calculation ö : 0.5 - 0.5 g ■ Moisture [%] ■ 10000

[0126] Protein solubility:

[0127] • See product solubility

[0128] • The filtrate was subjected to a nitrogen determination according to Kjeldahl (Nx6.25), DIN EN ISO

[0129] • 3188 performed

[0130] • Sample weight: approx. 6 g filtrate

[0131] The solubilities of the dried potato protein according to the invention are strongly dependent on the salt content of the water used for the analysis.

[0132] Ash:

[0133] • Sample weight: approx. 1 g product

[0134] • Microwave oven: MAS 7000

[0135] • Ashing temperature: 550°C

[0136] • Ashing time: 60 minutes

[0137] Foam activity and stability:

[0138] • Dissolve 5 g of product in 95 g of demineralized water

[0139] • Beat for 15 minutes at speed 3 (Hobart 50-N)

[0140] • Determine foam volume = foam activity in mL

[0141] • Determination of foam volume after 60 min. standing time = foam stability in % emulsion capacity:

[0142] • Weight: 80 g demin. H2O + 10 g of product

[0143] • Pour 250 mL of sunflower oil into a dropping funnel

[0144] • Stir with Ultra Turrax at 20000 rpm, maintain temperature of 20 °C

[0145] • Sunflower oil continuously until phase inversion (until emulsion

[0146] • suddenly becomes thinner)

[0147] • Determine the volume of unused sunflower oil

[0148] • 250 mL - remaining volume = consumption (sunflower oil)

[0149] • Result: 10 g product : 80 g demin. H2O : Consumption / 10

[0150] • Viscosity measurement using Brookfield HAT, spindle 4, 20 rpm

[0151] Viscosity:

[0152] Fig. 7 shows viscosity tests of the dried potato protein according to the invention (solid line) compared to a calcium chloride-treated sample (dotted line), with time in minutes plotted against viscosity in cP. To prepare the calcium chloride-treated sample, 0.5 wt.% calcium chloride, based on the mass of the potato fruit water, was added as an aqueous solution (CaCh:water = 1:3) after mechanical separation of the solids and before adjustment of the pH and centrifugal separation. All further processing steps were then carried out as described above (see Fig. 1). The viscosity profiles were recorded as follows: A 15% solution of the product in demineralized water was prepared. In the Anton Paar Physica MCR 301 (standard insert, stirrer ST24-2D, 60 rpm), 35 mL of the solution were stirred according to the temperature profile (start: 25 °C, heating 6.5 °C / min, hold at 90 °C for 12 min, cool for 25 min at 4.3 °C / min, hold at 25 °C for 10 min). Fig. 7 clearly shows that the CaCh treatment of the protein has a significant influence on the viscosity of the protein. When the temperature of 90 °C is reached, the potato protein according to the invention has a viscosity of approximately 230 cP, which increases to approximately 335 cP at the end of the cooling period and thus forms a solid gel. By adding CaCh, the viscosity even increases to approximately 350 cP when the maximum temperature of 90 °C is reached, but the gel formed is not stable. During cooling, the gel strength decreases continuously so that at the end of the measurement it is only approximately 225 cP and thus significantly lower than that of the potato protein according to the invention.

[0153] Gel strength:

[0154] Fig. 8 shows experiments on the gelation behavior of the proteins, with time in seconds plotted against force in grams. The potato protein according to the invention (solid curve) was compared with a CaCh-treated sample of potato protein (dotted line) to illustrate the influence of the salt on the protein. To prepare the calcium chloride-treated sample, 0.5 wt.% calcium chloride, based on the mass of the potato fruit water, was again added as an aqueous solution (CaCh:water = 1:3) after mechanical separation of the solids and before adjustment of the pH and centrifugal separation. All further processing steps were then carried out as previously described (see Fig. 1).The gel strength was investigated by texture analysis with the TA XT plus Texture Analyzer using the stamp (SMS P 05) (path: 20 mm, forward, test, and return speed: 1.0 mm / sec; release force: 20 g) at room temperature.

[0155] • Preparation of 2 samples: Protein (6 g or 12 g product) and add demineralized water (34 g or 68 g), stir until the protein dissolves

[0156] • Pour 30 mL of the sample solution into an Anton Paar rheometer with a metal cylinder with a hole (H-CC27-D)

[0157] • Boiling of the sample solution: Starting temperature of 25 °C, Heating phase: Heating to 90 °C at a heating rate of 6.5 °C / min, holding time at 90 °C for 15 min, Cooling phase: Cooling to 25 °C at a cooling rate of 4.0 °C, holding time at 25 °C for 10 min

[0158] • Store boiled sample solution at room temperature for 24 hours

[0159] • Texture analysis with the TA XT plus Texture Analyzer

[0160] In this measurement method, a plunger is slowly pressed into the prepared sample solution, corresponding to the first peak. As the plunger moves into the gel, a force must be applied until the plunger has completely penetrated the gel. The negative force then corresponds to the retraction of the plunger and the elastic retraction of the gel. The process is then repeated, and the plunger penetrates the gel a second time. The maximum force is usually lower during the second step, as the gel strength is still compromised by the first step. The more similar the peaks are, the greater the elasticity of the gel.

[0161] It is clearly evident that different forces are required to penetrate the gel. While a maximum force of 1265 g is required for the first peak of the potato protein according to the invention, this force decreases by 34% to 836 g upon the second penetration of the plunger. Treatment with calcium chloride has a strong influence on the gel strength of the protein. This measurement illustrates the strong dependence of the protein on external factors, as already explained in the prior art. The treated sample exhibits a maximum force of 1815 g at the first peak, which decreases by only 24% (1468 g) at the second peak. This means that the CaCh treatment significantly increases the gel strength of the potato protein and slightly improves its elasticity. Chemical test results:

[0162] Sample No.: 209-2022-00035006

[0163] Sample name: Empro K

[0164] The above-mentioned protein analysis of a single protein batch obtained is only an example of the protein according to the invention, which is subject to fluctuations depending on the potato growth conditions and storage.

[0165] The following application examples demonstrate possible uses of the potato protein according to the invention. However, its applicability is not limited to these; further applications will be apparent to those skilled in the art.

[0166] Example 6 - Chocolate Mousse:

[0167] 1 . Addition of the potato protein according to the invention to water while stirring on a stirrer plate (3 minutes, approx. 1000 rpm) to produce a 3% solution

[0168] 2. Melt the chocolate coating in the Thermomix® by heating to 65 °C at a speed of 4-5

[0169] 3. Add the previously prepared 3% solution of the inventive potato protein to the bowl of the Hobart® and beat until stiff (level 3 for 5 minutes)

[0170] 4. Slightly cool the melted chocolate and stir into the stiff solution of the potato protein according to the invention

[0171] 5. Store mousse in the refrigerator for at least 2 hours

[0172] The mousse produced with the potato protein according to the invention exhibited a better, airier structure compared to a mousse produced with egg white. Furthermore, the mousse produced with the protein according to the invention exhibited greater storage stability, as the airy structure remained unchanged even after 4 days, whereas the mousse produced with egg white hardened. Furthermore, the mousse produced with the potato protein according to the invention had a better mouthfeel and melted on the tongue. Another major advantage proved to be that the mousse produced in this way was salmonella-free, whereas the use of fresh egg always carries the risk of salmonella poisoning. Finally, the use of the potato protein according to the invention resulted in a smoother structure with a more attractive chocolate color compared to egg white.

[0173] Example 7 - Yellow Cake:

[0174] 1. Beat the 3% solution of the potato protein according to the invention until stiff

[0175] 2. Mix sugar and butter

[0176] 3. Add flour, milk and baking powder to the butter-sugar mixture

[0177] 4. Fold in the stiffly whipped solution of the potato protein according to the invention with a spoon

[0178] 5. Pour the dough into a loaf pan

[0179] 6. Bake for 50 - 60 min at 170 °C fan oven

[0180] By using the potato protein according to the invention, a light and airy batter was achieved. This makes the potato protein according to the invention ideal as a vegan egg white substitute.

[0181] Example 8 - French Meringue

[0182] 1. Beat the solution of the potato protein according to the invention (optionally with the addition of xanthan gum) in the KitchenAid® for 5 minutes until stiff peaks form.

[0183] 2. Slowly add sugar while stirring

[0184] 3. Beat for 3 minutes

[0185] 4. Place the mixture onto a baking tray using a piping bag

[0186] 5. Dry for one hour at 100 °C circulating air. Due to its very good whipping ability, the potato protein according to the invention is very suitable as a vegan chicken egg white substitute.

[0187] Likewise, the meringue can also be made by directly using the prepared protein solution without prior drying.

[0188] Example 9 - Protein-enriched pasta

[0189] 1. Mix all dry ingredients well

[0190] 2. Add approximately 450 - 530 g of cold tap water per 1000 g of dry ingredients

[0191] 3. Mix / knead with the Haussier pasta machine PN 300 VXS for about 15 min

[0192] 4. Compress and form with a single screw extruder

[0193] 5. Drying to a moisture content < 13 wt.%

[0194] The use of the potato protein according to the invention made it possible to produce a protein-enriched and at the same time gluten-free pasta.

[0195] Example 10 - Vegan Burgers: 1. Allow TVP to rehydrate for 15 minutes

[0196] 2. shred the mixture to the desired particle size

[0197] 3. Add all dry ingredients and emulsify with the oil

[0198] 4. Form burger patties

[0199] The potato protein according to the invention formed a very solid gel immediately upon heating. This process was observed even at relatively low temperatures, i.e., during frying of the patties, whereas with many other proteins this process is only observed upon cooling and even at higher temperatures. Thus, the use of the protein according to the invention resulted in a significant improvement in product binding, firmness, and a meat-like mouthfeel. The gel formation of the potato protein according to the invention is irreversible.

[0200] The protein solution produced from the potato protein according to the invention, without a drying step, can be used to create an emulsion in vegan burgers. The advantage is that the potato protein according to the invention acts as an emulsifier. The above-mentioned advantages of the dried potato protein according to the invention also apply to the protein in solution.

[0201] When using the fat / oil, the lipase activity of patatin described above must be taken into account. Vegetable fats and oils have been shown to be particularly suitable for this application.

[0202] It is also possible to blanch the formed burgers in a convection oven before preparation (50% humidity, 100 °C, 15 min), which leads to optimal texturing and development of the flavor profile.

[0203] Example 11: Textured Vegetable Protein (TVP)

[0204] 1. Mix the ingredients

[0205] 2. Extrusion of the mixture using a Theysohn laboratory extruder (TSK 30) with a dry mix to water ratio of 98.5:1.5. 3. Drying of the TVPs twice using a Pavan fluid bed dryer (Model Tabatto Da Laboratorio) at 110 °C.

[0206] The potato protein according to the invention improved the stability of the TVPs (textured vegetable proteins) after rehydration, preventing them from becoming mushy. Furthermore, the use of the potato protein according to the invention improved the texture of the TVPs, making them firmer, more fibrous, more water-rich, and thus more meat-like, which can be attributed to the excellent gelling properties of the potato protein according to the invention.

[0207] In the field of textured vegetable proteins (TVP), the potato protein solution according to the invention can be used in combination with a dry mixture of dried protein according to the invention and optionally other ingredients (e.g., flours, starches, or fibers). The advantages are similar to the use of dried protein.

[0208] Example 12: Ready-to-shake drink (RTS drink)

[0209] 1. Mix all dry ingredients together.

[0210] 2. Pour about 300 mL of water or vegan milk into a protein shaker and add 30 g of the protein mix.

[0211] 3. Mix all ingredients by shaking for about 20 seconds.

[0212] The use of the potato protein according to the invention resulted in a stable foam and a stable solution. The potato protein exhibited good solubility, resulting in a creamy mouthfeel. Although no fat, which should be avoided from a nutritional point of view, was added, the potato protein according to the invention produced a creamy mouthfeel. Although the invention has been explained in more detail using exemplary embodiments, it will be apparent to those skilled in the art that a wide variety of other embodiments are possible, the scope of protection being determined solely by the claims.

Claims

Claims:

1. Process for the production of a native, functional potato protein with a molecular weight of 10 - 120 kDa (according to SDS-Page primary structure), comprising the steps: Optionally, presentation of chopped, cleaned potato particles under oxidation protection; Mechanical separation of the solids from the crushed, cleaned potato particles to produce potato juice and solids; Adjusting the pH of the potato fruit water to a pH between 6 and 9; Separation of insoluble components and suspended solids by centrifugal separation, Ultrafiltration of pH-adjusted potato fruit water; Diafiltration of the ultrafiltration retentate to reduce the electrical conductivity of the retentate solution by 50-90%, preferably 65-90%, particularly preferably 75-85%, while obtaining the potato protein solution; optionally, drying the potato protein solution and optionally sterilizing it.

2. Process according to claim 1, characterized in that the pH adjustment after the mechanical solid / liquid separation is carried out to a pH of 6 - 9, preferably 6.5 - 8.2, particularly preferably 6.9 - 7.

5.

3. Process according to one of the preceding claims, characterized in that the drying is selected from spray drying, lyophilization, vacuum drying, freeze drying.

4. Method according to one of the preceding claims, characterized in that the ultrafiltration membrane is a plastic or ceramic membrane with a cut-off of 3 - 150 kDa, preferably 5 - 120 kDa, particularly preferably 10 - 100 kDa.

5. Process according to one of the preceding claims, characterized by treating the protein solution optionally before or after ultrafiltration with adsorbents selected from activated carbon, bentonites, polymeric adsorbents, and derivatives thereof.

6. Process according to one of the preceding claims, characterized in that the ultrafiltration retentate is gently sterilized.

7. The method according to claim 6, characterized in that the disinfection is selected from pasteurization with microwaves or HTST pasteurization (High Temperature Short Time), PEF sterilization (Pulsed Electric Fields), HPP pasteurization (High Pressure Pasteurization).

8. Process according to one of the preceding claims, characterized in that the water used for diafiltration has a conductivity of 5 pS / cm - 5000 pS / cm, preferably 10 - 50 pS / cm or even 5 - 50 pS / cm.

9. Potato protein, obtainable by: Presentation of cleaned, crushed potato parts in the form of potato mash, optionally protected against oxidation, mechanical separation of the potato mash into solid and liquid phases (potato fruit water); Adjust the pH to 6-9, preferably 6.5-8.2, particularly preferably 6.9-7.

5. Separation of insoluble components and suspended solids by centrifugal separation; Ultrafiltration of the liquid phase with membranes with a cut-off of 3 - 150 kDa, preferably 5 - 120 kDa, particularly preferably 10 - 100 kDa; Diafiltration of the ultrafiltration retentate to a reduction in conductivity of 50 - 90%, preferably 65 - 90% and particularly preferably 75 - 85%; Removal of anti-nutritional substances using adsorption techniques; if necessary, disinfection and drying of the protein solution.

10. Potato protein according to claim 9, characterized by a) protein content of at least 84% atro according to Kjeldahl, b) product solubility / protein solubility of the protein dried to 10% w / w moisture in tap water of 75 - 100% and c) ash content of max. 3% w / w 11. Potato protein according to claim 9 or 10, characterized in that after drying it has a moisture content of max. 10 wt.%.

12. Potato protein according to claim 9 to 11, characterized in that it has a molecular weight of 10 - 120 kDa (according to SDS-Page primary structure).

13. Potato protein according to any one of claims 9-12, characterized in that it has three main fractions, the first main fraction having a molecular weight of 10 to 20 kDa, the second main fraction has a molecular weight between 25 and 40 kDa and the third main fraction has a molecular weight of about 66 kDa according to SDS-Page primary structure.

14. Potato protein according to one of the preceding claims 9 - 13, characterized in that it is a component of a food or food additive, a dietary food or food additive for human or animal consumption.

15. Potato protein according to one of the preceding claims 9 - 14, characterized in that it is a component of an adhesive.

16. Potato protein according to one of claims 9 - 15, characterized in that it is a component of a mixture with other vegetable proteins, preferably legume proteins, such as pea protein, bean protein, field bean protein, lentil protein, soy protein, lupin protein, mung bean protein, or mixtures thereof.

17. Potato protein according to one of claims 9-15, characterized in that it is a component of a mixture with animal proteins.

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