PROTEIN-POLYURONIDE CONJUGATES AND THEIR USE AS EMULSIFIERS

Description

[0001] The present invention relates to protein-polyuronide conjugates, cream-stable edible emulsions, beverage syrups, ready-to-drink beverages, the use of protein-polyuronide conjugates for producing foodstuffs and cosmetic or medicinal products, the use of protein-polyuronide conjugates as emulsifiers, and a process for producing protein-polyuronide conjugates and the protein-polyuronide conjugates produced by the process.

[0002] Many foods that have a pleasantly creamy and full mouthfeel consist partly or entirely of an emulsion or were in an emulsified state during the manufacturing process. Examples of these foods include soft drinks, milkshakes, ice cream, mayonnaise, dressings, sauces, and soups. Consumers are accustomed to finished foods always being of consistent quality. This means that the food is homogeneously mixed, the homogeneous mixture is highly stable, and different batches of the food have consistent sensory and visual properties. Separation of the mixed phases (creaming) and the associated settling of a water or oil phase can lead consumers to perceive the food as inferior.In order to ensure the required consistent quality and, above all, stability, the use of emulsifiers has become indispensable in the food industry.

[0003] In thermodynamic terms, an emulsion is an unstable system that tends to return to the lowest-energy state of a two-phase system. Physical processes that describe this disruption of the emulsion include creaming, sedimentation, Ostwald ripening, aggregation, and coalescence of oil droplets. These processes can occur superimposed over time, with creaming or sedimentation usually preceding them.

[0004] The emulsion is considered to have sufficient physical stability if no demixing of the dispersed system is observed within the required shelf life of the food. If the system lacks sufficient physical stability, creaming and oil ring formation will be observed at the bottle neck if the oil density is lower than that of the aqueous phase. If the oil density is higher, sedimentation will be observed at the bottom of the bottle if the physical stability is insufficient.

[0005] In the food industry, emulsifiers such as lecithins (E 322), propylene glycol alginate (E 405), and mono- and diglycerides of fatty acids (E 471) are used as emulsifiers. Emulsifiers in food are increasingly being criticized by consumers and consumer advocates, and consumers are demanding that food be produced without emulsifiers or other additives, if possible, or that natural substances be used as emulsifiers wherever possible. For example, emulsifiers can sometimes be replaced with other ingredients, such as mustard, honey, or egg yolk. These ingredients naturally contain a certain amount of emulsifiers (such as lecithin in egg yolk or mustard), so the addition of further emulsifiers can be avoided. However, these ingredients usually have a strong flavor of their own, which is not desirable in all foods.In addition, the proportion of emulsifiers is relatively low, so that sufficiently stable emulsions cannot always be obtained.

[0006] Proteins also possess surfactant properties and, due to their amphiphilic nature and film-forming properties, can be used as efficient emulsifiers in food emulsions. However, protein-stabilized emulsions have been shown to exhibit low stability at high or low pH values, high ionic strength, and elevated temperatures. At pH values ​​close to the isoelectric point of the protein, at which the protein molecules no longer carry a net charge, the protein molecules aggregate and precipitate, thus losing their stabilizing effect. High temperatures lead to protein denaturation and thus also to a loss of the stabilizing effect.

[0007] The use of proteins as emulsifiers is therefore only possible within narrow pH and / or temperature limits, which restrict the possible processing and application of the food.

[0008] In the context of the present invention, reference is made to EP 1 338 210 A1, WO 2008 / 119482 A1, WO 2006 / 132529 A1, JP H01 233300 A and FR 2 817 870 A1 as prior art.

[0009] The object of the present invention was to provide an emulsifier which has increased stability against external influences, such as pH and / or temperature, and preferably has sufficient taste neutrality.

[0010] This object was achieved by a protein-polyuronide conjugate, wherein at least one polyuronide is bound to a protein by means of a covalent bond and the protein is of plant origin, characterized in that the protein is a potato protein or a rapeseed protein.

[0011] Surprisingly, it has been shown that the pH and / or temperature ranges in which the protein-polyuronide conjugate is stable are significantly wider than those of proteins of the same origin that have not formed a polyuronide conjugate. Emulsions produced using the protein-polyuronide conjugate according to the invention as an emulsifier also exhibit greater stability against external influences, so that the emulsions remain stable over a wider pH and / or temperature range.

[0012] A protein of plant origin (here according to the invention a potato protein or a rapeseed protein) is understood in the context of the present invention to mean a protein, i.e. a biological macromolecule which is constructed from amino acids by peptide bonds, whereby the protein is obtained from plants or parts of plants (e.g. seeds or tubers). In assessing whether a protein is of plant origin, only the origin of the protein and the primary structure of the proteins are taken into account, i.e. the sequence of amino acids in the protein, whereby fragments of proteins are also understood to be proteins provided their mass is greater than 5 kDa. Fragments of proteins can arise, for example, during protein isolation if proteins are partially hydrolyzed despite careful treatment and shortened proteins (hydrolysis from the ends) or protein pieces (hydrolysis within the amino acid chain) are formed.However, it is preferred according to the invention if the protein of plant origin is present in its natural form.

[0013] In the context of the present invention, a polyuronide is understood to mean a polysaccharide which contains one or more uronic acids, which may also be present as esters, as monomeric building blocks.

[0014] Our own studies suggest that the formation of protein-polyuronide conjugates involves a reaction between one or more lysine units of the protein and the individual saccharide units of the polyuronide. It is assumed that the primary amino groups of the lysine react with the free hydroxy groups of the saccharide units of the polyuronide in a Maillard reaction. However, other linking reactions between protein and polyuronide are also conceivable. According to the invention, however, a protein-polyuronide conjugate is preferred, in which the covalent bond is formed between a lysine unit of the protein and a saccharide unit of the polyuronide. It is particularly preferred if the covalent bond was formed by means of a Maillard reaction.

[0015] Coupling the protein with the polyuronide(s) using the Maillard reaction is particularly preferred, as it eliminates the need for additional reagents during the preparation of the protein-polyuronide conjugates. Thus, a protein-polyuronide conjugate can be obtained that does not contain any unwanted reagents or require complex purification.

[0016] A protein-polyuronide conjugate according to the invention is preferred in which the polyuronide comprises uronic acid units and the carboxylic acid groups of the uronic acid units are partially or completely esterified.

[0017] Typically, all or a majority of the repeating units in a polyuronide contain carboxylic acid groups. These carboxylic acid groups ensure that polyuronides have an acidic character and the ability to absorb water and / or form gels. However, in an emulsion, it is undesirable for gels to form or for large amounts of water to be absorbed or bound. Our own studies have shown that the ability of the protein-polyuronide conjugate to form emulsions can be improved if the polyuronide of the protein-polyuronide conjugate is partially or fully esterified. The esterification of the polyuronide can take place before or after the formation of the protein-polyuronide conjugate, but is preferred if it is carried out before the formation of the protein-polyuronide conjugate.

[0018] In one embodiment of the present invention, it is preferred if the polyuronide has a degree of esterification of greater than or equal to 50%, preferably a degree of esterification in the range from 60 to 85%, particularly preferably a degree of esterification in the range from 65 to 70%.

[0019] Protein-polyuronide conjugates with a degree of esterification greater than or equal to 50% have a low acidic character and are very suitable for the production of emulsions with small oil particle size.

[0020] In an alternative embodiment of the present invention, it is preferred if the polyuronide has a degree of esterification of greater than or equal to 5% and less than or equal to 50%, preferably a degree of esterification of greater than or equal to 25% and less than or equal to 48%, particularly preferably a degree of esterification of greater than or equal to 30% and less than or equal to 44%.

[0021] Protein-polyuronide conjugates with a degree of esterification in the range of 5% to less than 50% are characterized by a high stability of the emulsion produced using the protein-polyuronide conjugate.

[0022] Our own investigations have surprisingly shown that protein-polyuronide conjugates whose uronic acid units have a degree of esterification in the ranges defined above form particularly stable emulsions with small oil droplet sizes.

[0023] If the carboxylic acid groups of the uronic acid units are partially or completely esterified, it is preferred according to the invention if it is a methyl or ethyl ester, preferably a methyl ester.

[0024] According to the invention, it is preferred if the polyuronide of the protein-polyuronide conjugate is alginic acid, agaropectin, or a pectin. A protein-polyuronide conjugate is preferred according to the invention in which the polyuronide is a pectin.

[0025] Our own series of tests have shown that the use of pectin leads to particularly advantageous protein-polyuronide conjugates, which are characterized by particularly good stability at low or high pH values ​​and high temperatures. Furthermore, emulsions produced using a protein-pectin conjugate have been shown to exhibit particularly high stability.

[0026] According to the invention, it is particularly preferred if the pectin is of plant origin, preferably from fruits such as apples, quinces, citrus fruits, apricots or cherries, or beets such as sugar beets, carrots or parsnips.

[0027] Our own studies have shown that particularly stable protein-polyuronide conjugates are obtained when using potato or rapeseed proteins. Both potato and rapeseed proteins are characterized by a high lysine content and are particularly advantageous for the formation of protein-polyuronide conjugates.

[0028] According to the invention, a protein-polyuronide conjugate is preferred, wherein the protein has a lysine content of more than 2 wt.%, preferably more than 4 wt.%, particularly preferably more than 5 wt.%, based on the total amount of all amino acids of the protein-polyuronide conjugate.

[0029] For example, proteins can be obtained from potatoes with a lysine content of 6.3 to 7.9%, preferably 6.8 to 7.4%, or from rapeseed with a lysine content of 5.0 to 7.0%, preferably 5.5 to 6.5%. Our own studies have shown that particularly advantageous protein-polyuronide conjugates can be obtained using such proteins. If the lysine content is too low, the number of polyuronides bound to the protein may be too small, so that the produced protein-polyuronide conjugates exhibit improved stability (compared to pure protein), but the stability is still not sufficiently high.However, if the number of polyuronides bound to the protein is sufficient to achieve high stability, the number of remaining free amino groups of the lysine in the protein-polyuronide conjugate may be too small, so that the stability of produced emulsions is improved but not sufficiently high.

[0030] Our own studies have shown that protein-polyuronide conjugates exhibit particularly good emulsion properties when a sufficient number of polyuronides are bound to the protein and a sufficient number of free lysine amino groups are retained. It is assumed that a balance between the hydrophobic and hydrophilic components of the protein-polyuronide conjugate plays an important role. While the hydrophobic proteins adhere to the oil droplets, the attached polysaccharide chains extend into the aqueous phase and bind water molecules around the oil droplets, resulting in a network structure. The covalently bonded polyuronides thus form a thick, sterically stabilizing adsorption layer, which improves emulsion stability against aging, pH and temperature changes, as well as resistance to flocculation. The number of free primary amino groups therefore influences emulsion stability.

[0031] According to the invention, a protein-polyuronide conjugate is preferred, wherein the content of primary amino groups in a 0.1 wt. % aqueous solution, based on the protein content in the protein-polyuronide conjugate in the total amount of the aqueous solution, is less than or equal to 20 mg N / L, preferably less than or equal to 15 mg N / L, more preferably less than or equal to 10 mg N / L, more preferably less than or equal to 8 mg N / L.

[0032] According to the invention, a protein-polyuronide conjugate is preferred, wherein the content of primary amino groups in a 0.1 wt. % aqueous solution, based on the protein content in the protein-polyuronide conjugate in the total amount of the aqueous solution, is greater than or equal to 0.25 mg N / L, preferably greater than or equal to 0.5 mg N / L, more preferably greater than or equal to 1.0 mg N / L, more preferably greater than or equal to 1.5 mg N / L.

[0033] According to the invention, a protein-polyuronide conjugate is preferred, wherein the content of primary amino groups in a 0.1 wt. % aqueous solution, based on the protein content in the protein-polyuronide conjugate in the total amount of the aqueous solution, is in the range from 0.25 mg N / L to 20 mg N / L, preferably in the range from 0.5 mg N / L to 15 mg N / L, more preferably in the range from 1.0 mg N / L to 10 mg N / L, more preferably in the range from 1.5 mg N / L to 8 mg N / L.

[0034] To prepare a 0.1 wt.% aqueous solution, based on the protein content of the protein-polyuronide conjugate in the total amount of the aqueous solution, weigh in enough protein-polyuronide conjugate so that the protein content amounts to 0.1 wt.% of the aqueous solution. If the protein content in the protein-polyuronide conjugate is unknown, it is first determined. This can be done using Kjeldah nitrogen determination.

[0035] The content of primary amino groups is determined by a Primary Amino Nitrogen Kit The amino nitrogen groups of the free amino acids in the sample react with added N-acetyl-L-cysteine ​​(NAC) and o-phthalaldehyde (OPA) to form an isoindole derivative. The number of these derivatives formed is stoichometrically identical to the number of free primary amino groups. The derivatives can be measured photometrically via absorption at 340 nm. The method is specific for amino acids containing primary amino groups.

[0036] A protein-polyuronide conjugate according to the invention is preferred in which no primary amino group is present in 80 to 99% of the lysine units of the protein, preferably in 85 to 97%, particularly preferably in 90 to 95% of the lysine units of the protein.

[0037] A protein-polyuronide conjugate according to the invention is preferred, wherein 80 to 99% of the lysine units of the protein are covalently bound to a polyuronide, preferably 85 to 97%, particularly preferably 90 to 95% of the lysine units of the protein.

[0038] Our own investigations have shown that protein-polyuronide conjugates in which all or too many of the free amino groups have reacted or are bound to a polyuronide have good stability against pH and temperature changes, but do not produce emulsions as stable as those from protein-polyuronide conjugates that still have remaining primary amino groups.

[0039] Particularly preferred according to the invention is a protein-polyuronide conjugate in which at least one pectin is bound to a potato protein by means of a covalent bond, the carboxylic acid groups of the pectin being partially or fully esterified, and the pectin is preferably a methyl or ethyl ester. It is particularly preferred if the protein has been bonded to the pectin(s) by means of a Maillard reaction.

[0040] Within the scope of the present invention, several of the above-mentioned preferred embodiments of the protein-polyuronide conjugate according to the invention are preferably implemented simultaneously; particularly preferred are the combinations of such embodiments and the corresponding features resulting from the appended claims.

[0041] A further aspect of the present invention relates to a cream-stable edible emulsion comprising water, oil and a protein-polyuronide conjugate according to the invention.

[0042] Emulsions according to the invention are characterized by high stability against pH and temperature changes and high storage stability.

[0043] The emulsion is an oil-in-water emulsion and preferably has a density in the dispersed phase of 0.915 to 1 g / ml, more preferably between 0.93 and 0.98 g / ml. The density of the dispersed phase is adjusted by appropriate selection of the components of the oil phase.

[0044] A cream-stable edible emulsion is preferred according to the invention, wherein the oil is dispersed in the water phase with a D4.3 value of the oil particle diameter of at most 20 µm, preferably of at most 15 µm, particularly preferably of at most 10 µm, most preferably of at most 5 µm.

[0045] In a particularly preferred cream-stable edible emulsion, the oil particles have a D4.3 value of at most 2 µm, particularly preferably at most 1 µm. These cream-stable edible emulsions with very small oil particles are particularly suitable and preferred for beverages or for spray drying.

[0046] The D4.3 value is the statistical, volume-related mean diameter of the oil droplets, determined by laser beam diffraction, with a triplicate determination. This value can be used to determine the stability, i.e., flocculation and coalescence, of the emulsions.

[0047] Droplet size has a decisive influence on the stability of an emulsion. According to Stoke's law, the creaming rate can be reduced by small oil droplets in an emulsion. The formation of small oil droplets depends on the mechanical input during emulsion preparation, but also on the ability of an existing emulsifier to quickly adsorb onto the interface of these newly formed oil droplets and stabilize them. The lower the D4.3 value, the greater the stability of the emulsion.

[0048] Particularly preferred according to the invention is a cream-stable edible emulsion consisting of or comprising: Water: 80 - 96.9 wt.%, preferably 80 - 90 wt.%, Öl: 3 - 10 wt%, preferably 3 - 9 wt%, Protein-polyuronide conjugate: 0.1 - 10 wt.%, preferably 1 - 10 wt.%, each based on the entire emulsion.

[0049] In this case, a starch is in particular a starch derivative as described in EP 0 839 001. In preferred embodiments of the invention, starch comprises, consists essentially of, or consists of starch sodium octenylsuccinate (E 1450). Furthermore, a terpene oil is preferably used as the oil. A terpene oil is understood to be a terpene-containing liquid that is not water-soluble according to the understanding of a food practitioner. Preference is given to emulsions according to the invention whose terpene oil comprises citrus terpenes and / or aromatic oils. Preferred terpene oils within the scope of the present invention comprise or consist of orange, lemon and / or grapefruit oil or fractions obtainable therefrom, preferably limonene (in particular d-limonene) and / or orange oil terpenes.

[0050] Oils of vegetable or animal origin such as triglycerides can also be used according to the invention, preferably tasteless triglycerides with the same or different C 6 to C 12 fatty acid residues (MCT, medium-chain triglyceride).

[0051] The emulsion according to the invention preferably has a specific turbidity of at least 500 NTU (nephelometric turbidity units). The specific turbidity is measured according to the specifications of DIN ISO EN 27027 using 90° IR scattered light, for example, a Hach 2100N IS laboratory turbidity meter with an 860 nm (infrared) LED.

[0052] An emulsion according to the invention contains one or more food acids. Preferred food acids are citric acid, tartaric acid, lactic acid, phosphoric acid, and malic acid. The pH of the emulsions according to the invention is preferably 3-4, more preferably 3.3-3.5.

[0053] A further aspect of the present invention relates to a process for producing an emulsion according to the invention, comprising combining the emulsion components and homogenizing the emulsion components.

[0054] A further aspect of the present invention relates to a beverage syrup comprising an emulsion according to the invention and water.

[0055] In beverage syrups according to the invention, the density difference between the aqueous and oil phases is relatively large; due to the high sugar content, the density difference between the disperse phase and the aqueous phase is usually 0.12 to 0.32 kg / l, preferably 0.14 to 0.32 g / ml, which places special demands on the emulsions according to the invention so that the beverage syrups according to the invention remain cream-stable over a long period of time.

[0056] The beverage syrup according to the invention preferably has a specific turbidity of more than 500 NTU (Nephelometric Turbidity Units). The specific turbidity is preferably 500-1200 NTU, particularly preferably 600-1000 NTU.

[0057] The beverage syrup according to the invention optionally additionally contains one or more of the following conventional additives, such as fruit components, inorganic acids approved for use in the food sector, antioxidants, sweeteners, flavorings, colorings, thickeners, so-called "functional" ingredients and preservatives.

[0058] Fruit ingredients here primarily include fruit flavors, fruit juices, fruit purees, and fruit juice concentrates. Suitable fruit juices and fruit juice concentrates include those based on citrus fruits, such as orange, lemon, grapefruit, and mandarin orange, and other fruits, such as apple, pear, grape, apricot, and pineapple. Furthermore, fruit juices and fruit juice concentrates from soft fruits, such as blackberry, gooseberry, currant, blueberry, strawberry, and raspberry, can be used. Furthermore, fruit juices and fruit juice concentrates from exotic fruits, such as guava, papaya, passion fruit, mango, and banana, can be used.

[0059] According to the invention, the beverage syrups can contain up to 80% by weight of the specified fruit components. Fruit juice concentrates with a Brix concentration of 50°–72° are preferred. Fruit juice concentrates with a Brix concentration of approximately 65° are regularly used. Orange, lemon, apple, pear, and grape fruit juice concentrates are preferred.

[0060] The beverage syrup may also contain sweeteners. Typically, sugar, sweeteners, sugar substitutes, and sweetener compounds, as well as mixtures thereof, are used.

[0061] Suitable sugars include sucrose, fructose, and glucose, as well as mixtures thereof. Such mixtures are commercially available, for example, as invert sugar syrup or high fructose corn syrup with a dry matter content of typically 65-72 °Brix.

[0062] Suitable sweeteners include acesulfame K, aspartame, cyclamate (and its sodium and calcium salts), neohesperidin dihydrochalcone, sucralose, and saccharin (and its sodium, potassium, and calcium salts). Plant-based sweeteners such as glycyrrhicin and thaumatin may also be used. Acesulfame K, aspartame, cyclamate, sodium cyclamate, saccharin, sodium saccharin, and sucralose are particularly preferred.

[0063] Suitable sugar substitutes include sugar alcohols such as isomatitol (E 953), lactitol (E 966), maltitol, mannitol (E 421), sorbitol (E 420), xylitol (E 967), and mixtures thereof. Mixtures of synthetic sweeteners and dearomatized or non-deodorized concentrated fruit preparations can also be used as sweeteners.

[0064] The sweeteners are added to the beverage syrup according to the invention in an amount such that the resulting sweetening power corresponds to an addition of up to 250 g / l of sucrose. 180 to 220 g / l of sucrose is preferred.

[0065] The beverage syrup according to the invention also contains one or more edible acids, preferably citric acid, tartaric acid, lactic acid, phosphoric acid, and malic acid. Beverage syrups according to the invention preferably have a pH of less than 3, particularly preferably a pH of 2 to 3.

[0066] Furthermore, the beverage syrup according to the invention can contain hydrocolloids as thickeners. Suitable thickeners are carboxymethylcellulose, xanthan gum, locust bean gum, gellan gum, guar gum, carrageenan, (free) alginic acid, (free) alginates, (free) pectin, and mixtures thereof. If thickeners are used, the content of said thickeners in the beverage syrup is between 0.0025 and 1 wt.%. Emulsions and beverage syrups without added thickeners, i.e. (essentially) free of hydrocolloids, are preferred within the scope of the present invention, although a non-thickening amount of pectin may in individual cases be present in traces in the beverage syrups according to the invention, provided they contain a fruit juice concentrate.

[0067] The beverage syrup according to the invention may further contain so-called "functional" ingredients, such as vitamins (A, B, C, D, E, K), minerals, herbal extracts, fiber, prebiotic ingredients, amino acids, taurine and / or caffeine.

[0068] It can be colored with food colorings and / or coloring foods. According to the invention, the beverage syrup may contain preservatives approved for use in the food industry. Suitable preservatives include sorbic acid, benzoic acid, and their alkali salts.

[0069] The preservative is typically used in a concentration of 0.04 to 0.3% by weight in the beverage syrup.

[0070] The beverage syrup according to the invention can contain suitable natural and synthetic antioxidants. Suitable natural antioxidants include, for example, tocopherols, L-ascorbic acid, its fatty acid esters, such as L-ascorbyl palmitate, gallic acid esters, and flavonoids. Suitable synthetic antioxidants include, for example, tert-butylhydroxyanisole and tert-butylhydroquinone.

[0071] Emulsions according to the invention with the above-mentioned particle distribution can be prepared by any known, suitable method, such as high-pressure homogenization, microfluidization or emulsification via membranes.

[0072] If a high-pressure homogenizer is used, a two-stage homogenizer is preferred, in which a defined pressure level can be set at the outlet of the homogenization valve. The main pressure used, i.e., the pressure at the inlet to the homogenization valve, is between 100 and 500 bar, preferably between 160 and 300 bar, when producing the emulsion claimed here. The pressure level at the outlet is set to 1 / 3 to 1 / 15 of the main pressure, preferably 1 / 5 to 1 / 10.

[0073] The emulsions according to the invention are preferably homogenized in 2 to 6, preferably 3 to 4, passes. The temperature during homogenization is below 90°C, preferably below 40°C.

[0074] To produce the beverage syrups according to the invention, conventional technologies for producing the finished beverage can be used. The methods used to produce beverage syrups are described, for example, in the Handbook: Refreshing Drinks by Südzucker AG, Mannheim / Ochsenfurt (1998).

[0075] Typically, a base material is used in the production of juice-based beverage syrups, which in this case may also contain the claimed emulsion. It usually contains all the essential ingredients for the beverage syrup except water and, if applicable, sugar and / or sweeteners.

[0076] If the beverage syrup contains no juice components or additives such as extracts or minerals, the final manufacturer can also use the claimed emulsion, which, depending on its composition, provides the desired turbidity, color, and flavor of the beverage syrup. Of course, producing the entire beverage syrup is also conceivable.

[0077] The viscosity of the beverage syrups according to the invention is preferably, depending on the composition and °Brix, in the range of 0.004 - 3 Pas, preferably 0.005 - 2 Pas, and can optionally be adjusted by known thickeners as described above.

[0078] The measuring system is a cone-and-plate system with a diameter of 50 mm and a cone angle of 2°. The shear stress is 1 s -1< . The temperature is 25 °C. The viscosity can be determined using, for example, the Anton Paar Physica UDS 200 rheometer.

[0079] The beverage syrup according to the invention is stable against creaming for at least 6 months. "Stable against creaming" means that a ring with a maximum thickness of 0.5 mm forms in the bottle neck. Storage takes place at a constant temperature of 20 + / - 1.5°C.

[0080] According to the invention, a beverage syrup is further provided, comprising: - of the emulsion according to the invention: 0.5-3% by weight, - of water: 35-70% by weight, - of sugar(s): 25-60% by weight, - of edible acid(s): 0.5-4% by weight, - of preservative(s): 0.04-0.3% by weight, Each is based on the total weight of the beverage syrup. The weight proportions of water, sugar(s), edible acid(s), and preservative(s) are understood to be in addition to the components of the emulsion according to the invention. The beverage syrup according to the invention is surprisingly very stable when creaming and has a high specific turbidity. Sugar refers to the sum of the mono- and disaccharides of the beverage syrup, thus excluding modified starch.

[0081] A preferred beverage syrup according to the invention comprises, consists essentially of or consists of: component Range wt% Preferred wt.% Emulsion according to the invention 0,5 - 3 0,5 - 3 Water 35 - 70 45 - 68 Sugar (sum of all sugars, especially sucrose, glucose and fructose) 25 - 60 30 - 52 Sweeteners (preferably acesulfame, saccharin, cyclamate, aspartame, sucralose) optional, preferably 0.05 - 1.5 0.15 - 1.0, especially for syrups with < 35 °Brix Edible acid(s) (preferably citric acid) 0,5 - 4 1 - 3 Water-soluble vitamins (preferably B, C) optional 0,01 - 0,3 Preservatives (preferably Na or K sorbate, Na benzoate) 0,04 - 0,3 0,06 - 0,12

[0082] Another aspect of the present invention relates to a ready-to-drink beverage comprising a protein-polyuronide conjugate according to the invention and an edible diluent.

[0083] Another aspect of the present invention relates to a ready-to-drink beverage comprising a beverage syrup according to the invention and an edible diluent.

[0084] A further aspect of the present invention relates to a use of the protein-polyuronide conjugate according to the invention for the production of food or cosmetic products or medical products.

[0085] Our own investigations have shown that protein-polyuronide conjugates according to the invention are suitable not only for the production of food, but also for the production of cosmetic or medical products.

[0086] A further aspect of the present invention relates to a use of the protein-polyuronide conjugate according to the invention as an emulsifier.

[0087] According to the invention, the use in beverage emulsions or spray-drying emulsions is preferred.

[0088] A further aspect of the present invention relates to a process for producing a protein-polyuronide conjugate, preferably a protein-polyuronide conjugate according to the invention, comprising the following steps: Producing or providing a protein of plant origin (as described herein as being according to the invention) Producing or providing a polyuronide Mixing the produced or provided protein and the produced or provided polyuronide so that a mixture results Allowing the produced mixture to react so that a protein-polyuronide conjugate results.

[0089] Surprisingly, it has been shown that the protein-polyuronide conjugates produced by the process according to the invention are stable over wide pH and / or temperature ranges. The advantages stated for protein-polyuronide conjugates according to the invention apply analogously to the protein-polyuronide conjugates produced by a process according to the invention.

[0090] A process according to the invention is preferred wherein the protein and / or the polyuronide is / are prepared or provided as an aqueous solution.

[0091] A process according to the invention is preferred wherein the mixing of the produced or provided protein and the produced or provided polyuronide takes place in an aqueous medium.

[0092] A process according to the invention is preferred wherein, after mixing the produced or provided protein and the produced or provided polyuronide, the produced mixture is subjected to a drying step, and the water content is preferably less than or equal to 15 wt. %, preferably less than or equal to 10 wt. %, particularly preferably less than or equal to 7 wt. %, based on the total weight of the freeze-dried mixture. According to the invention, it is particularly preferred if the drying step is a freeze-drying, spray-drying, roller-belt-drying, or vacuum-belt-drying step.

[0093] According to the invention, it is particularly preferred if the water content is preferably greater than or equal to 1% by weight, preferably greater than or equal to 3% by weight, particularly preferably greater than or equal to 5% by weight, based on the total weight of the freeze-dried mixture.

[0094] According to the invention, it is particularly preferred if the water content is preferably greater than or equal to 1 wt.% and less than or equal to 15 wt.%, preferably greater than or equal to 3 wt.% and less than or equal to 10 wt.%, particularly preferably greater than or equal to 5 wt.% and less than or equal to 7 wt.%, based on the total weight of the freeze-dried mixture.

[0095] A process according to the invention is preferred, wherein the weight ratio between protein and polyuronide is in the range between 10:1 to 1:10, preferably in the range between 5:1 and 1:5, particularly preferably in the range between 2:1 and 1:2.

[0096] A process according to the invention is preferred, wherein the pH of the mixture is in the range between 4 and 8, preferably in the range of 5 to 7.

[0097] A process according to the invention is preferred, wherein the reaction of the mixture takes place at a temperature in the range from 40 to 90 °C, preferably at a temperature in the range from 60 to 80 °C, particularly preferably at a temperature in the range from 65 to 75 °C.

[0098] A process according to the invention is preferred, wherein the reaction of the mixture takes place at a relative air humidity in the range of 50 to 90%, preferably at a relative air humidity of 55 to 85%, particularly preferably at a relative air humidity in the range of 65 to 80%.

[0099] A process according to the invention is preferred, wherein the protein content in the mixture is 0.05 to 5 wt.%, preferably 0.1 to 2 wt.%, particularly preferably 0.2 to 0.7 wt.%.

[0100] A process according to the invention is preferred, wherein the content of polyuronide in the mixture is 0.2 to 5 wt.%, preferably 0.3 to 2 wt.%, particularly preferably 0.4 to 1 wt.%.

[0101] Within the scope of the present invention, several of the embodiments of the method according to the invention described above as preferred are preferably implemented simultaneously; particularly preferred are the combinations of such embodiments and the corresponding features resulting from the appended claims.

[0102] A further aspect of the present invention relates to a protein-polyuronide conjugate produced by a method according to the invention.

[0103] Within the scope of the present invention, several of the aspects identified above as preferred are preferably implemented simultaneously; particularly preferred are the combinations of such aspects and the corresponding features resulting from the appended claims.

[0104] The following examples and comparative examples will further illustrate the invention: General manufacturing method for producing a protein-polyuronide conjugate:

[0105] Protein (5% w / v) and polyuronide (3% w / v) are independently dissolved in water, and the pH is adjusted to a value between 5 and 7 (see Table 1) using dilute sodium hydroxide or dilute acetic acid. The prepared dispersions are then blended in a specified ratio and stirred for 2 hours using a dispersion stirrer to ensure good contact of the colloidally dissolved substances. The pH values ​​of the protein-polyuronide mixtures are subsequently adjusted again if a deviation from the originally set value is detected. The resulting mixture is then dried by freeze-drying. For this purpose, the mixtures are frozen in stainless steel dishes at -20 °C for 24 h before being dried under vacuum at a negative pressure of 1.03 mbar and -20 °C.The freeze-dried samples, whose dry mass was between 93% and 95%, were then placed in plastic bags and finely ground externally using a mortar and pestle. To determine the proportion of free amino groups before the onset of conjugate formation, a small amount of the sample was taken (t=0). This was followed by hydrothermal treatment in a climate chamber that allows for controlled temperature and humidity. After 24 hours, a portion of the reaction mixture was removed, and the remaining portion was subjected to further hydrothermal treatment under constant conditions for a further two days. This yielded a protein-polyuronide conjugate with a short reaction time (24 hours) and a protein-polyuronide conjugate with a long reaction time (72 hours). Examples:

[0106] Using the general preparation method for a protein-polyuronide conjugate, 40 different protein-polyuronide conjugates (one each with a short and long reaction time) were prepared. Table 1 below shows the proteins used, the polyuronide, the adjusted pH value, the proportions of protein and polyuronide, as well as the temperature and humidity during the hydrothermal treatment.

[0107] The polyuronide used was a low-methylester pectin with an esterification degree in the range of 32 to 42% (referred to as "low" in the table) or a high-methylester citrus pectin with an esterification degree in the range of 68 to 76% (referred to as "high" in the table). The polyuronides used are commercially available under the names "Pektin Classic CF 703" and "Pektin Classic CJ 206" from Herbstreith & Fox KG, Turnstraße 37, 75305 Neuenbürg, Germany.

[0108] The protein used was a potato protein isolate (referred to as "potato" in the table) available under the name Solanic 300 from AVEBE UA, Prins Hendrikplein 20, 9641 GK Veendam, the Netherlands, or a rapeseed protein isolate (referred to as "rapeseed" in the table) available under the name "Teutexx isolex" from Teutoburger Ölmühle GmbH, Gutenbergstraße 17, 49477 Ibbenbüren, Germany.

[0109] The proportion of protein or polyuronide is based on the total amount of the protein-polyuronide mixture produced. Table 1: Overview of the parameters set in the examples Example number Protein source Polyuronide pH T [°C] rH [%] Protein content [wt%] Polyuronide content [wt.%] 1 Potato high 7 65 79 50 50 2 Potato low 6 70 72 50 50 3 Potato low 7 60 79 50 50 4 rapeseed high 5 65 65 25 75 5 Potato high 7 60 79 25 75 6 rapeseed low 7 70 65 25 75 7 rapeseed low 6 70 65 50 50 8 rapeseed high 6 65 79 37,5 62,5 9 rapeseed high 7 70 72 25 75 10 Potato high 6 60 72 37,5 62,5 11 Potato low 5 70 65 25 75 12 rapeseed high 6 60 72 50 50 13 Potato high 5 70 79 50 50 14 rapeseed high 7 60 65 25 75 15 rapeseed low 5 65 79 50 50 16 rapeseed low 7 60 65 50 50 17 Potato high 6 60 65 50 50 18 rapeseed low 7 70 79 50 50 19 Potato low 7 65 72 50 50 20 Potato low 6 65 72 37,5 62,5 21 rapeseed high 5 65 72 50 50 22 Potato low 5 60 65 50 50 23 rapeseed low 5 70 72 25 75 24 Potato low 6 65 72 25 75 25 Potato high 5 65 72 25 75 26 rapeseed low 6 65 65 25 75 27 Potato low 5 65 79 37,5 62,5 28 rapeseed low 7 65 72 37,5 62,5 29 Potato high 7 70 65 50 50 30 rapeseed high 7 70 79 50 50 31 Potato high 6 70 72 25 75 32 rapeseed high 6 70 79 25 75 33 Potato high 7 70 65 25 75 34 rapeseed low 7 60 79 25 75 35 rapeseed high 5 70 65 42,5 57,5 36 Potato low 7 70 79 25 75 37 rapeseed high 5 60 79 25 75 38 Potato low 5 60 79 25 75 39 rapeseed low 5 60 72 35 65 40 Potato low 7 60 65 25 75 Determination of stability against pH and temperature changes

[0110] To determine stability against pH and temperature changes, the protein-polyuronide conjugates prepared in Example 26 and Example 40 were used.

[0111] Using the protein-polyuronide conjugates from Examples 26 and 40 (the samples with long reaction times, respectively) and pure rapeseed and potato proteins as references, emulsions containing 0.5% (w / w) protein-polyuronide conjugates and protein, respectively, were prepared. The proteins used to prepare the protein-polyuronide conjugates were used as pure rapeseed and potato proteins, respectively.

[0112] The emulsions were prepared using a high-performance disperser at 17,000 rpm, while 20% (w / w) of commercial vegetable oil triglyceride from palm fruit (ρ=0.96 kg / m 3 ) was added over one minute. The speed was then increased to 24,000 rpm and dispersed for 2 minutes.

[0113] The absorbance of this prepared emulsion was measured at a wavelength of 550 nm over a temperature range of 60 - 90°C.

[0114] Even when the denaturation temperature of rapeseed or potato protein is reached, no significant increase in absorbance (corresponding to optical density) is detectable in the emulsions according to the invention, whereas an increase in absorbance is evident in the control samples. The emulsion produced using pure potato protein is already heavily flocculated at 60 °C.

[0115] The results are in the Figures 1 and 2 shown. Figure 1 shows the influence of temperature on the absorbance of the samples from Example 26 and pure rapeseed protein, where the dots represent the protein-polyuronide conjugate with a long reaction time (72 hours) (referred to as 26_3) and the triangles represent the pure rapeseed protein. Figure 2 shows the influence of temperature on the absorbance of the samples from Example 40 and pure potato protein, respectively, where the dots represent the protein-polyuronide conjugate with a long reaction time (72 hours) (referred to as 40_3) and the triangles represent the pure rapeseed protein.

[0116] To assess the pH stability of the samples, the pH of a portion of the prepared emulsions was adjusted to 5 or 8 using diluted acetic acid or diluted sodium hydroxide. The droplet size D4.3 [µm] was then measured at time t0 and after 7 days.

[0117] In the case of pure rapeseed protein, it was found that the produced emulsions already exhibited very high D4.3 values ​​at time t0. This is due to the poor emulsifying properties of rapeseed protein. After storage for seven days, the value deteriorates even further. Using the protein-polyuronide conjugates from Example 26 (with a long reaction time), emulsions with very small particle sizes could be produced that remained stable even after seven days in both acidic and basic pH conditions. In the basic range, a slight reduction in droplet size was even observed.

[0118] In the case of pure potato protein, it was found that the produced emulsions exhibited small D4.3 values ​​at time t0. This is due to the good emulsifying properties of the potato protein. However, after storage for seven days at a pH of 5, the value deteriorates significantly. This is due to the fact that the potato protein is not stable at an acidic pH of 5. Using the protein-polyuronide conjugates from Example 40 (with a long reaction time), emulsions with very small particle sizes could be produced that remained stable even after 7 days at both acidic and basic pH.

[0119] The results are in the Figures 3 and 4 shown. Figure 3shows the D4,3 values ​​of pure rapeseed protein (RP) and protein-polyuronide conjugates from Example 26 with long reaction time (26_3), each at t0 and after 7 days of storage, where the black bar represents the D4,3 value at t0 and the hatched bar after 7 days. Figure 4 shows the D4.3 values ​​of pure potato protein (KP) and protein-polyuronide conjugates from Example 40 with long reaction time (40_3), each at t0 and after 7 days of storage, where the black bar represents the D4.3 value at t0 and the hatched bar after 7 days. Determination of free amino groups:

[0120] The number of free amino groups in the prepared protein-polyuronide conjugates was determined using the Primary Amino Nitrogen Kit (PAN Assay Kit from Megazyme, Ireland)The amino nitrogen groups of the free amino acids in the protein-polyuronide conjugates react with the added N-acetyl-L-cysteine ​​(NAC) and o-phthaldialdehyde (OPA) to form an isoindole derivative. The number of these derivatives formed is stoichometrically identical to the number of free amino nitrogens. The derivatives can be measured photometrically via absorption at 340 nm. The method is specific for amino acids containing primary amino groups.

[0121] The determination was carried out on samples taken at the beginning of the reaction directly after freeze-drying and on the finished protein-polyuronide conjugates.

[0122] The sample to be measured is first diluted with water and mixed so that each sample solution contains 0.1% protein. This is not based on the weight of the protein-polyuronide conjugate, but on the weight of the protein content in the protein-polyuronide conjugate. One NAC tablet is then mixed with 3 ml of water and 0.05 ml of protein-polyuronide conjugate solution or water for the blank in a cuvette, and the absorbance (A1) is measured after a reaction time of 2 minutes. 0.1 ml of OPA is then added, mixed, and the absorbance (A2) is measured after a reaction time of 15 minutes. Since o-phthaldialdehyde (OPA) is very light-sensitive, the reaction must be carried out under light exclusion. The absorbance difference (A2 - A1) of the blank is subtracted from the absorbance difference of the sample. The result is ΔA PAN . The concentration for PAN can then be determined. (primary amino nitrogen) can be calculated using the following formula: c = V ⋅ MW ⋅ 1000 ε ⋅ d ⋅ v Δ A PAN where: V = final volume [ml] MW = molecular weight of nitrogen [g / mol] 1000 = conversion factor from g to mg ε = extinction coefficient of an isoindole derivative at 340 nm = 6803 [l / (mol · cm)] d = path length [cm] v = sample volume [ml] is.

[0123] The results of the tests are presented in Table 2 below. The sample number marked "Example Number"_0 corresponds to a sample taken and measured immediately after mixing the protein with the polyuronide in the respective example. The sample number marked "Example Number"_1 corresponds to a sample taken and measured after 24 hours of reaction between the protein and the conjugate in the respective example. The sample number marked "Example Number"_3 corresponds to a sample taken and measured after 72 hours of reaction between the protein and the conjugate in the respective example. Example Sample number Free amino groups [mg N / l] Example Sample number Free amino groups [mg N / l] 1 1_0 44,481 21 21_0 22,291 1_1 13,506 21_1 0,342 1_3 0,835 21_3 0,063 2 2_0 36,316 22 22_0 51,202 2_1 1,848 22_1 18,383 2_3 0,949 22_3 3,106 3 3_0 35,575 23 23_0 22,375 3_1 3,218 23_1 3,688 3_3 0,052 23_3 0,575 4 4_0 30,732 24 24_0 53,139 4_1 16,366 24_1 7,658 4_3 0,535 24_3 2,608 5 5_0 32,295 25 25_0 47,772 5_1 2,205 25_1 15,013 5_3 1,115 25_3 4,329 6 6_0 - 26 26_0 30,810 6_1 3,313 26_1 5,304 6_3 0,219 26_3 2,228 7 7_0 18,300 27 27_0 43,582 7_1 1,750 27_1 7,911 7_3 0,387 27_3 1,165 8 8_0 20,524 28 28_0 21,608 8_1 2,451 28_1 2,987 8_3 0,415 28_3 0,101 9 9_0 38,375 29 29_0 37,425 9_1 0,837 29_1 0,112 9_3 0,038 29_3 0,400 10 10_0 26,195 30 30_0 48,725 10_1 7,940 30_1 4,925 10_3 3,425 30_3 4,188 11 11_0 51,838 31 31_0 29,625 11_1 5,375 31_1 1,288 11_3 1,575 31_3 0,013 12 12_0 15,633 32 32_0 20,600 12_1 3,165 32_1 2,913 12_3 0,797 32_3 0,975 13 13_0 34,342 33 33_0 50,231 13_1 9,456 33_1 0,744 13_3 0,975 33_3 0,026 14 14_0 15,526 34_0 33,382 14_1 13,256 34 34_1 4,658 14_3 2,167 34_3 2,245 15 15_0 33,049 35_0 27,077 15_1 3,866 35 35_1 1,910 15_3 0,744 35_3 1,231 16 16_0 12,383 36_0 40,449 16_1 4,617 36 36_1 3,167 16_3 2,309 36_3 0,359 17 17_0 25,489 37_0 15,984 17_1 6,713 37 37_1 2,893 17_3 4,681 37_3 1,194 18 18_0 41,188 38_0 14,959 18_1 1,175 38 38_1 4,424 18_3 0,287 38_3 0,714 19 19_0 37,854 39_0 16,555 19_1 2,744 39 39_1 0,869 19_3 0,573 39_3 0,182 20 20_0 34,305 40_0 41,647 20_1 2,256 40 40_1 5,008 20_3 0,329 40_3 3,101 Example 41: Making a beverage emulsion:

[0124] 8.46 g of 50% citric acid, 4 g of 20% potassium sorbate solution, and conjugate are added to a vessel equipped with a stirrer, resulting in a protein-polyuronide conjugate content of 0.5% of the total. Water is added until the total amount reaches 1000 g. All of the above components are completely dissolved with a slow-speed stirrer. Then, 90 g of vegetable oil triglyceride are added with a fast-speed stirrer. The stirring time is 5 minutes. The resulting emulsion is homogenized in two passes in a high-pressure homogenizer. The pressure of the first pass is 300 / 50 bar. The pressure of the second pass is 250 / 50 bar.

[0125] The droplet size distribution of the emulsion is then measured, and the stability of the emulsion is assessed visually using a slump test. To determine comparative values, the emulsions are prepared a) without protein-polyuronide conjugate and b) with pure rapeseed protein, with the protein-polyuronide conjugate replaced by rapeseed protein.

[0126] It was shown that the beverage emulsions produced using the protein-polyuronide conjugate exhibited the best properties regarding oil droplet size and emulsion stability. The beverage emulsions produced using rapeseed protein exhibited lower stability and a smaller oil droplet size. The beverage emulsions produced without the protein-polyuronide conjugate tended to cream quickly. Example 42: Preparation of a spray emulsion:

[0127] A quantity of protein-polyuronide conjugate is added to 250 g of water such that the protein-polyuronide conjugate content represents 1% of the oily components of the formulation, i.e., the flavor. Maltodextrin is added in proportion to the quantity of protein-polyuronide conjugate, so that the dry matter (conjugate and maltodextrin) amounts to 40% of the total. All of the above components are completely dissolved with a slow-speed stirrer. Then, 50 g of lemon flavor are added with a fast-speed stirrer. The dispersion time is 4 minutes. The resulting dispersion is spray-dried at an air inlet temperature of 190 °C and an outlet temperature of 80 °C.

[0128] The droplet size distribution of the emulsion and powder is then measured, and the stability of the emulsion is assessed visually using a slump test. To determine comparative values, the emulsions are prepared a) without protein-polyuronide conjugate and b) with pure rapeseed protein, with the protein-polyuronide conjugate replaced by rapeseed protein.

[0129] It was shown that the spray emulsions produced using the protein-polyuronide conjugate exhibited the best properties regarding the droplet size distribution of the emulsion and powder, as well as the stability of the emulsion. The spray emulsions produced using rapeseed protein exhibited lower stability and a narrower droplet size distribution. The beverage emulsions produced without the protein-polyuronide conjugate tended to cream quickly.

Claims

1. Protein-polyuronide conjugate, characterized in that at least one polyuronide is bound via a covalent bond to a protein and the protein is of plant origin, further characterized in that the protein is a potato protein or a rapeseed protein.

2. Protein-polyuronide conjugate according to claim 1, characterized in that the polyuronide comprises uranic acid units and the carboxylic acid groups of the uranic acid units are partially or completely esterified.

3. Protein-polyuronide conjugate according to claim 2, characterized in that it is a methyl or ethyl ester, preferably a methyl ester.

4. Protein-polyuronide conjugate according to any of the preceding claims, characterized in that the polyuronide is a pectin.

5. Protein-polyuronide conjugate according any of the preceding claims, wherein the content of primary amino groups in a 0.1 wt.% aqueous solution, based on the protein content of the protein-polyuronide conjugate, is in the range of 0.25 mg N / L to 20 mg N / L, preferably in the range from 0.5 mg N / L to 15 mg N / L, more preferably in the range from 1.0 mg N / L to 10 mg N / L, more preferably in the range from 1.5 mg N / L to 8 mg N / L.

6. Protein-polyuronide conjugate according to claim 1, characterized in that the polyuronide comprises uric acid units and the carboxylic acid groups of the uric acid units are partially or completely esterified, wherein the polyuronide is a pectin.

7. Creaming-stable edible emulsion comprising water, oil, and a protein-polyuronide conjugate according to any of claims 1 to 6.

8. Beverage syrup comprising an emulsion according to claim 7 and water.

9. Ready-to-drink beverage comprising a beverage syrup according to claim 8 and an edible diluting agent.

10. Use of the protein-polyuronide conjugate according to any of claims 1 to 6 as an emulsifier, preferably for the production of foodstuffs or cosmetic products or medical products.

11. Process for the production of a protein-polyuronide conjugate, preferably a protein-polyuronide conjugate according to any of claims 1 to 6, comprising the following steps - producing or providing a protein of plant origin, wherein the protein is a potato protein or a rapeseed protein, - producing or providing a polyuronide - mixing the produced or provided protein and the produced or provided polyuronide so that a mixture results - allowing the produced mixture to react so that a protein-polyuronide conjugate results.

12. Method according to claim 11, wherein the protein and / or the polyuronide is or are produced or provided as an aqueous solution.

13. Method according to any of claim 11 or 12, wherein after mixing the produced or provided protein and the produced or provided polyuronide, the produced mixture is subjected to a drying step and the water content is preferably less than or equal to 15 wt.%, more preferably less than or equal to 10 wt.%, even more preferably less than or equal to 7 wt.%, based on the total weight of the freeze-dried mixture.

14. Method according to any of claims 11 to 13, wherein the weight ratio between protein and polyuronide is in the range between 10:1 and 1:10, preferably in the range between 5:1 and 1:5, even more preferably in the range between 2:1 and 1:2.