Method for producing beverage ingredients

Abstract

The present invention provides a method for processing a beverage source extract, comprising: a. filtering a beverage source extract to obtain a beverage source extract retentate and a beverage source extract permeate; b. increasing the pH of the beverage source extract retentate to provide a treated beverage source extract retentate; and c. combining the treated beverage source extract retentate with the beverage source extract permeate to produce a recombined beverage source extract.

Description

[Technical Field]

[0001] The present invention relates to a method for processing a beverage ingredient extract and the beverage ingredient extract obtained by the method. The present invention further relates to a beverage ingredient extract. [Background technology]

[0002] Instant coffee powder is a soluble coffee powder that has been particularly appreciated by consumers for its convenience, as it allows for the easy and quick preparation of a coffee beverage. Nevertheless, instant coffee is perceived by consumers as having less aroma compared to freshly brewed coffee preparations, which are perceived as being richer in aroma, smoother (less watery), and of higher quality.

[0003] There is a consistently growing demand for instant coffee powders with premium feel and higher in-cup quality, such as having aroma content comparable to roasted and freshly ground brewed preparations.

[0004] The poor quality of conventional instant coffee powders as perceived by consumers is primarily due to the standard processes used to produce such soluble coffee powders, which typically involve multiple steps, each of which can result in a partial loss of volatile organic compounds (VOCs), i.e., aroma compounds, that are characteristic of any coffee preparation.

[0005] The conventional manufacturing process for instant coffee powder is complex and includes several steps, as described above. The first step generally involves the production of an aqueous coffee extract from roasted and ground coffee powder, which is extracted with water at high temperatures (e.g., 100-220°C). The resulting freshly brewed extract is then subjected to an aroma recovery process, where it is stripped to preserve and later reverse-add aroma compounds responsible for the freshly brewed aroma, enriching the final product with freshly brewed aroma notes. The stripped extract is then concentrated to produce liquid coffee, where the aroma compounds are reverse-added, and finally subjected to a drying process (freeze-drying and / or spray-drying) to produce instant coffee powder. High temperatures are typically used to increase the extraction yield of the process, because the extract obtained at high temperatures exhibits a high concentration of molecules with high molecular weight (HMW) compounds, particularly melanoidins, which directly translates to a better in-cup mouthfeel of the resulting instant coffee powder when dissolved in water.

[0006] Recent studies have demonstrated that these high molecular weight (HMW) compounds, particularly melanoidins, are also involved in the binding activity of volatile organic compounds (VOCs), i.e., aroma compounds, in roast and ground coffee extracts. Indeed, it has been demonstrated that certain aroma compounds (e.g., aldehydes, hydroxyphenols, thiols, and pyrazines) that play an important role in the aroma perception of any coffee beverage are bound by high molecular weight (HMW) compounds present in the coffee extract, such as melanoidins, resulting in a less aromatic and / or flatter coffee extract, and consequently in a less aromatic liquid coffee concentrate and / or instant coffee powder.

[0007] Therefore, finding the right balance between, on the one hand, reducing the binding activity of aroma compounds by high molecular weight (HMW) compounds and, on the other hand, obtaining a high yield of coffee extract that provides a good in-cup mouthfeel and aroma is very important for producing liquid coffee concentrates and / or instant coffee powders with high in-cup quality.

[0008] There are currently few effective solutions to prevent the aroma-HMW compound combination effect other than limiting or reducing the amount of dry matter extracted, i.e., the yield of the extraction process, which results in a less cost-effective manufacturing process as well as poor in-cup quality of the liquid coffee concentrate and / or instant coffee powder, with the resulting beverage being perceived as watery. Summary of the Invention [Problem to be solved by the invention]

[0009] Other conventional methods utilize aroma recovery processes to address the problem of instant coffee powders having low aroma and therefore being perceived as low quality, by stripping the aroma from the freshly brewed coffee extract before concentration and back-adding the aroma before the drying process (spray drying or freeze drying). However, the aroma recovery process is a complex and expensive step in the manufacturing process, requires specialized knowledge and is power / energy intensive.

[0010] It would therefore be advantageous to provide a method for inhibiting the agonist effects of HMW compounds while retaining key aroma compounds in the final coffee product.

[0011] It would also be advantageous to provide a method to ensure that fewer aroma compounds are bound by HMW compounds, particularly melanoidins, and to reduce the binding activity between these two species.

[0012] It would be further advantageous to provide a method for improving the quality of instant coffee powder that reduces manufacturing complexity and cost by reducing or eliminating the aroma recovery step.

[0013] It would therefore be advantageous to provide a method that can be applied to any conventional extraction method for the production of aqueous coffee extract, ie, for example, one-stage and / or two-stage processes.

[0014] It would be further advantageous to provide a liquid coffee concentrate and / or instant coffee powder that has an in-cup mouthfeel comparable to that of a freshly brewed coffee preparation, and also has the aroma complexity and content indicative of a freshly brewed beverage.

[0015] It would also be advantageous to provide a method for at least partially releasing bound aroma compounds from HMW compounds to improve the in-cup performance of coffee products (instant coffee powder and / or coffee concentrate) for preparing coffee beverages.

[0016] It is therefore an object of embodiments of the present invention to satisfy a strongly felt need for an optimized method for the production of high quality instant coffee powder and / or coffee concentrate and / or to overcome or mitigate at least one problem of the prior art, whether disclosed herein or not. [Means for solving the problem]

[0017] According to a first aspect of the present invention, there is provided a method of processing a beverage ingredient extract, the method comprising: a) filtering the beverage ingredient extract to obtain a beverage ingredient extract retentate and a beverage ingredient extract permeate; b) increasing the pH of the beverage ingredient extract retentate to provide a treated beverage ingredient extract retentate; and c) combining the treated beverage ingredient extract retentate with the beverage ingredient extract permeate to produce a recombined beverage ingredient extract.

[0018] The beverage raw material extract is preferably a coffee extract.

[0019] Without being bound by any theory, it is believed that increasing the pH of the beverage extract retentate (particularly the coffee extract retentate) creates conditions in which phenolic compounds, such as hydroxycinnamic acids ("HCAs"), including caffeic acid, ferulic acid, and p-coumaric acid, are released from the retentate's high molecular weight compounds (HMWs), such as melanoidins and arabinoxylans. The reduction in HCAs in the retentate reduces subsequent binding of aroma molecules to HCA compounds, and thus, when the retentate and permeate are combined, more aroma is available in the combined extract, creating a product with a more desirable coffee aroma. In other words, acidic hydrolysis leads to the cleavage of aromatic (e.g., HCA) compounds, and as a result, acidic hydrolysis is believed to lead to a reduction in π-π interactions. Fewer binding partners on melanoidins in the form of HCAs results in fewer non-covalent interactions with odorants such as FFTs or pyrazines.

[0020] In a further embodiment, the method may further comprise the step of filtering the treated beverage raw extract retentate after step b) to further purify it.

[0021] In another embodiment, the method may include removing aroma volatile compounds from the beverage raw material extract prior to step a) and back-adding the aroma volatile compounds after step c), wherein removing the aroma volatile compounds may include stripping and / or steam distillation.

[0022] In some embodiments, step a) may be carried out at a temperature in the range of 15 to 70° C., which may be at a pressure in the range of 1 to 3 bar.

[0023] Step a) may be carried out by means of at least one filtering element.

[0024] The at least one filtration element may comprise at least one membrane and may comprise at least one size exclusion cutoff of at least 5 kDa or preferably at least 10 kDa.

[0025] The filtration element may comprise a membrane and / or a series of membranes. In a preferred embodiment, the membrane may comprise a size exclusion membrane.

[0026] In some embodiments, the size exclusion membrane can comprise a size exclusion cutoff of about 50 kDa, 40 kDa, 30 kDa, 20 kDa, 10 kDa, or 5 kDa.

[0027] In some embodiments, the filtration element may comprise a plurality of filtration elements. In further embodiments, the plurality of filtration means may comprise a plurality of membranes. The plurality of membranes may comprise a plurality of size exclusion membranes that may comprise different pore size distributions, i.e., different cutoff combinations. The cutoff combinations may include any combination of pore size distributions of about 50 kDa, 40 kDa, 30 kDa, 20 kDa, 10 kDa, and / or 5 kDa. In a preferred embodiment, at least one size exclusion membrane comprises a pore size distribution (or cutoff) of about 50 kDa.

[0028] In some embodiments, performing step b) can include treating the raw extract retentate with a pH-raising means, which can impart a pH value to the extract in the range of 7 to 14, preferably 7 to 13, and more preferably 7 to 11. In some embodiments, the pH is raised to 7 to 11 or 7 to 10. In particularly preferred embodiments, the pH is raised to 7 to 9. While higher pH values ​​release more HCA molecules and potentially prevent more aroma from binding to the retentate, pH values ​​higher than about 11 may be less desirable from a cost and handling perspective. A pH of 11 or less is preferred for superior results with potentially less cost and handling, although a pH of 11 to 13 can be used in some embodiments. The pH-raising means can be in the form of an aqueous alkaline solution, which can include, for example, aqueous NaOH, and / or resin and / or absorbent treatments, and / or combinations thereof.

[0029] Step b) may comprise treating the raw extract retentate with a pH-raising means for a time period ranging from 10 to 180 minutes, preferably from 30 to 100 minutes, more preferably from 30 to 90 minutes, and most preferably from 30 to 60 minutes, and may also comprise stirring the raw extract retentate while treating it with the pH-raising means, and preferably also increasing the temperature (of the raw extract retentate) (while treating with the pH-raising means) to a value ranging from 30 to 120° C., preferably from 60 to 90° C. In a particularly preferred embodiment, the temperature is about 60° C. and the time period is about 60 minutes.

[0030] In a further embodiment, the method may further comprise filtering the beverage raw material extract permeate at least once after step a) to produce a further extract retentate, and combining the beverage raw material extract retentate with one or more further extract retentates before performing step b).

[0031] In some embodiments, each repeated filtration of the beverage source extract permeate may involve using a filtration element with a reduced pore size compared to any previous filtration step.

[0032] In a further embodiment, the method may further include filtering the produced recombined raw material extract at least once to provide a secondary beverage raw material permeate and a secondary beverage raw material retentate, and treating the secondary beverage raw material retentate with a pH-raising means.

[0033] In some embodiments, the beverage ingredient extract may include a primary extract from a primary extraction process of roast and ground coffee powder, and / or a secondary extract extracted from spent grounds obtained from the primary extraction process in a secondary extraction process, and / or a tertiary extract from an extract of spent ground coffee powder obtained from the secondary extraction process, and / or combinations thereof. The beverage ingredient extract may include a soluble solids concentration of 2% to 15% by weight. In some embodiments, the beverage ingredient extract may include a soluble solids concentration of 15% to 80% by weight.

[0034] In some embodiments, the method may further comprise drying the recombined raw material extract to produce a soluble beverage ingredient powder, which may comprise spray drying and / or freeze drying the recombined raw material extract.

[0035] In some embodiments, the beverage ingredient extract may include an extract obtained from a beverage ingredient selected from the group of coffee, cocoa, chicory, tea, and beer.

[0036] In some embodiments, the recombined beverage ingredient extract may be converted into a soluble beverage ingredient powder.

[0037] According to a second aspect of the present invention, there is provided a beverage ingredient extract obtained or obtainable by the method of the first aspect of the present invention.

[0038] In some embodiments, the beverage ingredient extract may contain soluble solids at a concentration of about 2% to 15% by weight (a so-called "diluted" extract).

[0039] In some embodiments, the beverage ingredient extract may contain soluble solids at a concentration of about 15% to 80% by weight (a so-called "concentrated" extract).

[0040] The beverage ingredient extract of the second aspect of the present invention may comprise a beverage ingredient selected from the group of coffee, cocoa, chicory, tea, and beer.

[0041] According to a third aspect of the present invention there is provided a coffee extract obtained or obtainable by the method of the first aspect of the present invention.

[0042] According to a fourth aspect of the present invention, there is provided a use of a beverage raw material extract comprising high molecular weight compounds for reducing aroma binding to the extract, wherein the high molecular weight compounds having a molecular weight above one or more of the group comprising 5 kDa, 10 kDa, 20 kDa, 30 kDa and 50 kDa are treated in a pH increasing step.

[0043] Preferably, the beverage raw material extract is as described and defined above, more preferably a coffee extract. Preferably, at least the high molecular weight compounds above 50 kDa have been treated with a pH increasing step. [Brief explanation of the drawings]

[0044] In order that the invention may be more clearly understood, embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, in which: [Figure 1] 1 shows a schematic flow diagram of a first embodiment of a method according to a first aspect of the present invention; [Figure 2] 2 shows a schematic flow diagram of a second embodiment of the method according to the first aspect of the present invention; [Figure 3a] 3 shows a schematic flow diagram of a third embodiment of the method according to the first aspect of the present invention; [Figure 3b] 4 shows a schematic flow diagram of a fourth embodiment of the method according to the first aspect of the present invention; [Figure 4a] 1 shows a schematic flow diagram of a fifth embodiment of the method according to the first aspect of the present invention; [Figure 4b] 1 shows a schematic flow diagram of a sixth embodiment of the method according to the first aspect of the present invention; [Figure 4c] 10 shows a schematic diagram of a flow diagram of a seventh embodiment of the method according to the first aspect of the present invention; [Figure 5] 1 shows a schematic flow diagram of an eighth embodiment of the method according to the first aspect of the present invention. [Figure 6] 1H-NMR spectra of a coffee beverage obtained from a commercial coffee concentrate and a reference sample from the reference HMW binding effect study, both spiked with 2,3-diethyl-5-methylpyrazine. [Figure 7a] 1 shows the H-NMR spectra of a coffee beverage obtained from a commercial coffee concentrate to which 2,3-diethyl-5-methylpyrazine was added before and after a pH increase treatment according to a reference HMW binding effectiveness study. [Figure 7b] 1 shows the H-NMR spectra of a coffee beverage obtained from a commercial coffee concentrate to which 2,3-diethyl-5-methylpyrazine was added before and after a pH increase treatment according to a reference HMW binding effectiveness study. DETAILED DESCRIPTION OF THE INVENTION

[0045] Referring to the drawings, like numbers refer to like elements.

[0046] definition A "beverage base extract" is a solution containing soluble beverage base compounds extracted from beverage raw materials. Beverage base extracts are typically obtained by contacting beverage base powders or granules with water, typically hot water or steam. Depending on the temperature and pressure used for extraction, the yield of soluble beverage base compounds obtained from the beverage base powder varies. High temperatures can hydrolyze complex carbohydrates in the beverage base into soluble components, resulting in a high yield. While high yields are clearly desirable for commercial production, they also result in the production of high concentrations of high molecular weight (HMW) compounds. The beverage base may include a material selected from the group consisting of roast and ground coffee, cocoa powder, chicory, tea, and / or beer.

[0047] By "high molecular weight compounds" (HMW) is meant compounds present in a beverage ingredient extract that have a molecular weight of at least about 5 kDa, e.g., greater than 10 kDa, greater than 20 kDa, greater than 30 kDa, preferably greater than 40 kDa, and even more preferably greater than 50 kDa.

[0048] By "low molecular weight compounds" (LMW) is meant compounds present in a beverage raw material extract that have a molecular weight that is less than about 5 kDa, preferably less than 4 kDa, and more preferably less than 1 kDa.

[0049] "Liquid ingredient concentrate" means a concentrated solution containing soluble ingredient solids suitable for dilution to obtain a desired beverage. "Liquid coffee concentrate" means a concentrated solution containing soluble coffee solids suitable for dilution to obtain a desired coffee beverage. Liquid coffee concentrates are often sold as so-called bag-in-box products for dilution in vending machines or dried to produce instant coffee powder to obtain a coffee beverage. Liquid coffee concentrates can be obtained by conventional concentration processes (e.g., evaporation, filtration, distillation, freeze-concentration applied to aqueous coffee extracts) and can contain 6 to 80% by weight of coffee solids, preferably 10 to 65% by weight, and more preferably 15 to 50% by weight of coffee solids.

[0050] Example 1 FIG. 1 shows a flow diagram of a first embodiment of the method of the first aspect of the invention.

[0051] The aqueous coffee extract (1) is filtered to obtain a coffee extract permeate (2) and a coffee extract retentate (3). The coffee extract permeate (2) is retained for further use, while the coffee extract retentate (3) is sent to treatment in the form of an alkaline solution by a pH-raising means to produce a treated coffee extract (4). The treated coffee extract (4) is then recombined with the coffee extract permeate (2) to produce a recombined roast and ground coffee extract (5). The aqueous coffee extract (1) is obtained by conventional methods, for example, by contacting instant roast and ground coffee powder with hot water at a temperature ranging from 100°C to 220°C (or alternatively, by cold extraction at below 100°C, preferably below 80°C). Extraction is carried out in a conventional extraction vessel (not shown), such as a packed column containing the roast and ground coffee powder. Extraction can be carried out batchwise or continuously, and multiple columns can be used to increase the extraction yield. Hot water is passed through the roasted and ground coffee powder into the column(s) from the top, or alternatively from the bottom. The extraction time varies based on the number of columns used, the grind size of the roasted and ground coffee powder, and the desired extraction yield. The content of HMW compounds in the aqueous coffee extract (1) ranges from 10 to 30%, particularly from 10 to 25%.

[0052] The aqueous coffee extract (1) is delivered to the filtration means through a conventional piping system (not shown). In some embodiments, the filtration means is in the form of any conventional method for filtering a liquid, producing a retentate fraction (i.e., the fraction retained by the filtration means) and a permeate fraction of the liquid (i.e., the fraction of the liquid that passes through the filtration means). The filtration method is based on size exclusion, where the physical structure of the filtration means allows the selective passage of molecules with dimensions smaller than the critical size of the pores of the filtration means, while cutting off molecules with dimensions larger than these pores. The filtration means may include, for example, a membrane, although any other conventional method that allows for the separation of liquid fractions based on molecular size is contemplated herein, such as sequential ultrafiltration, nanofiltration, osmosis, pervaporation, diafiltration, centrifugation, dialysis, chromatography, and resin technology. In a preferred embodiment of the present invention, the filtration means is a membrane filtration system using a membrane with a molecular weight cutoff of approximately 50 kDa. Under these conditions, compounds with a molecular weight greater than 50 kDa are retained by the membrane (forming the so-called retentate), while compounds with lower molecular weights are able to pass through the membrane itself (producing the so-called permeate). The filtration process is carried out at temperatures of 15 to 70°C and pressures of 1 to 3 bar for 1 to 8 hours. The filtration process yields a coffee extract permeate (2) and a coffee extract retentate (3). The concentration of HMW compounds in the coffee extract retentate (3) is higher than that in the aqueous coffee extract (1). In particular, the concentration of HMW compounds in the coffee extract retentate (3) is more than twice as high as that in the aqueous coffee extract (1), and can be up to 10 times higher.

[0053] In some embodiments, the membrane cutoff is less than 50 kDa, for example, 30 kDa, 20 kDa, 10 kDa, or 5 kDa.

[0054] While the coffee extract permeate (2) in FIG. 1 is stored under low-temperature conditions to reduce the presence of oxygen to prevent the coffee extract permeate from stale, the coffee extract retentate (3) is subjected to a pH-increasing treatment with an alkaline solution to reduce the affinity of the primary coffee extract retentate (3) for HMW compounds, which are involved in the binding activity of aroma compounds, present in any coffee extract, particularly the coffee extract permeate (2) of the present invention. The pH-increasing treatment is carried out by adding a sodium hydroxide (NaOH) solution to the primary coffee extract retentate (3) in a conventional vessel. The resulting mixture is stirred at a temperature of 30-100°C for 30-180 minutes (preferably at 60-90°C for 30-60 minutes). The pH of the sodium hydroxide (NaOH) solution ranges from 7-14, preferably 8-11. The concentration of the solution is in the range of 0.5-5 mol / L (5M). Alternative alkaline solutions, such as NaHCO3, H2CO3, or KOH, can be used. The treated coffee retentate (4) obtained from this alkaline treatment exhibits a reduced binding activity for aroma compounds, i.e., volatile organic compounds (VOCs). Without being bound by theory, the explanation for this reduced binding activity of HMW compounds after alkaline treatment can be found in the fact that the alkaline environment, high temperature, and long treatment time facilitate the decomposition of bonds present on the long-chain conformation of the HMW compounds (particularly the ester bonds of phenolic groups that are involved in the binding effect to aroma compounds). By reducing the phenolic groups on the long-chain conformation of the HMW compounds through alkaline treatment, the binding activity for aroma compounds in the treated coffee extract (4) is reduced.

[0055] Further alternative pH-raising treatments can be used. For example, the pH-raising treatment can be carried out using an ion exchange resin and / or an absorbent. The absorbent can be carbon-based, polyacrylate-based, or polystyrene-based. Examples of commercially available absorbents include Purorite® MN200, Purorite® MN202, and Lewatic® AF5. Examples of ion exchange resins include strong-base anion exchange resins or weak-base anion exchange resins. Preferably, the ion exchange resin is a weak-base anion exchange resin. The resin can be based on polyacrylate or polystyrene, preferably polyacrylate. The functional group can be selected from the group consisting of amine functional groups, such as primary, tertiary, and quaternary amine groups, and polyamine groups, preferably tertiary amine groups. The pH value of the extract after the pH-raising treatment ranges from 7 to 14, preferably from 8 to 11.

[0056] After treatment with an alkaline solution to increase the pH, the treated coffee extract (4) in Figure 1 shows a reduction in the content of the phenolic groups in the long chain configuration of HMW compounds, ranging from 10 to 50%.

[0057] The pH of the treated coffee extract (4) after the pH increase treatment ranges from 4.9 to 5.8 after quenching after hydrolysis.

[0058] The treated coffee retentate (4) of Figure 1 is then sent through a conventional pipe system and recombined with the coffee extract permeate (2) to result in a recombined roast and ground coffee extract (5) having a lower content of the phenolic fraction than the original aqueous coffee extract (1) and reduced binding activity for aromatic compounds compared to the aqueous coffee extract (1) itself.

[0059] The roast and ground coffee extract (5) is now ready for use in a conventional manufacturing process, for example, for the production of ready-to-drink products, or alternatively, is sent to a conventional manufacturing process for the production of liquid coffee concentrate and / or instant coffee powder (not shown). These processes include concentrating the roast and ground coffee extract (5) to a coffee solids content of 6 to 80% by weight, preferably 10 to 65% by weight, and more preferably 15 to 50% by weight. The concentration step is carried out by standard, commercially available methods, such as evaporation, freeze concentration, and centrifugation. The liquid coffee concentrate is then sent to a packaging process, where it is packaged in a bag-in-box and ready for sale, for example, for use in vending machines.

[0060] Alternatively, the liquid coffee concentrate may be subjected to a further process of drying, whereby the liquid coffee concentrate is converted into instant coffee powder by conventional spray drying or freeze drying processes.

[0061] Example 2 Referring now to FIG. 2, there is shown a flow diagram of a second embodiment of the method of the first aspect of the present invention.

[0062] Briefly, an aqueous coffee extract (21) is filtered to obtain a coffee extract permeate (22) and a primary coffee extract retentate (23). The coffee extract permeate (22) is stored for later use, while the primary coffee extract retentate (23) is sent to an alkaline solution to increase the pH to produce a treated coffee extract (24). The treated coffee extract (24) is sent to a further filtration process to produce a secondary coffee extract retentate (27) and a waste permeate (26). The secondary coffee extract retentate (27) is then recombined with the coffee extract permeate (22) to produce a recombined roast and ground coffee extract (25).

[0063] The detailed process of Example 2 is as follows:

[0064] An aqueous coffee extract (21) provided by the conventional extraction method described in Example 1 is filtered to produce a coffee extract permeate (22) and a primary coffee extract retentate (23), which are stored for further use. The filtration means is of the type described in Example 1, for example, involving a conventional membrane filtration system including a membrane filtration with a cutoff of approximately 50 kDa. The filtration process is carried out at a temperature of 15 to 70°C and a pressure of 1 to 3 bar for a period of 1 to 8 hours. Alternative filtration methods to those described in Example 1 can be used. The concentration of HMW compounds in the primary coffee extract retentate (23) is higher than the concentration of HMW compounds in the aqueous coffee extract (21); in particular, the concentration of HMW compounds in the primary coffee extract retentate (23) is more than twice (and can be up to 10 times) the content of HMW compounds in the aqueous coffee extract (21).

[0065] In some embodiments, the membrane cutoff is less than 50 kDa, for example, about 30 kDa, 20 kDa, 10 kDa, or 5 kDa.

[0066] The primary coffee extract retentate (23) is sent for treatment with an alkaline agent to increase the pH, reducing the agonist effect of the phenolic groups of high molecular weight (HMW) compounds responsible for the binding activity of aroma compounds in the coffee extract. As described in Example 1, the alkaline treatment i. adding a solution of sodium hydroxide (NaOH) to the primary coffee extract retentate (23); ii. Stirring at a temperature of 30 to 100°C for 30 to 180 minutes.

[0067] The pH of the sodium hydroxide solution (NaOH) is in the range of 7 to 14, preferably 8 to 11 (concentration of 0.5 to 5 mol / L).

[0068] Alternative alkaline agents, as well as alternative resin and / or absorbent treatments as described in Example 1, may also be used.

[0069] The pH of the resulting treated coffee extract (24) after the pH increase treatment ranges from 4.9 to 5.8 after post-hydrolysis quenching.

[0070] Treated coffee extracts (24) show reduced binding activity for aroma compounds.

[0071] The treated coffee extract (24) is then sent through a conventional piping system to a further filtration process to produce a secondary coffee extract retentate (27) which is separated from a waste permeate (26), which consists primarily of the fraction of the coffee extract having compounds with a molecular weight below 5 kDa (low molecular weight, LMW, range of compounds).

[0072] If the treated coffee extract (24) of Figure 2 is sent to a further filtration process, the filtration means can be a conventional membrane with a 1 kDa cut-off, although any alternative filtration method is suitable.

[0073] The resulting secondary coffee extract retentate (27) is then recombined with the coffee extract permeate (22) to produce a recombined roast and ground coffee extract (25) having a lower phenolic fraction content than the aqueous coffee extract (21) and therefore reduced binding activity for aromatic compounds compared to the aqueous coffee extract (21). In some embodiments, the treated coffee extract (24) is sent directly for addition of the coffee extract permeate (22) without passing through a filtration step, and the waste permeate (26) is separated to produce the recombined roast and ground coffee extract (25).

[0074] The recombined roast and ground coffee extract (25) is then subjected to conventional manufacturing processes for the production of ready-to-drink, liquid coffee concentrate, and / or instant coffee powder.

[0075] The concentration process for producing the liquid coffee concentrate and / or instant coffee powder is carried out as described for Example 1. The liquid coffee concentrate is then sent to a packaging process, for example packaged in a bag-in-box package, or sent to a drying process (spray drying or freeze drying) for the production of instant coffee powder.

[0076] Example 3a: FIG. 3a shows a schematic flow diagram of a third embodiment of the method according to the first aspect of the invention.

[0077] A two-stage extraction process is applied to roast and ground coffee powder (300). A first extraction is carried out to produce a primary aqueous coffee extract (30) and so-called "spent grounds." The spent grounds are then subjected to a second extraction to produce a secondary aqueous coffee extract (31). The secondary aqueous coffee extract (31) is then filtered to obtain a coffee extract retentate (33) and a coffee extract permeate (32), which is processed according to the first aspect of the invention, as described in Example 1, to produce a treated roast and ground coffee extract (35), which is then recombined with the primary aqueous coffee extract (30) to finally obtain a recombined roast and ground coffee extract (39).

[0078] In some embodiments, the two-stage extraction process comprises an extraction process for producing an aqueous coffee extract in which extraction is carried out in two stages at different temperatures. In the first stage, extraction is carried out at a lower temperature. Roasted and ground coffee powder (300) is extracted with water at a temperature ranging from 20°C to 140°C. In the second stage, the roasted and ground coffee powder (300) remaining after the first stage (also referred to as "spent grounds") is re-extracted with water at a higher temperature ranging from 170°C to 220°C. The extract obtained from the first stage is also referred to as the primary aqueous coffee extract (30), and the extract from the second stage at the higher temperature is also referred to as the secondary aqueous coffee extract (31). The secondary aqueous coffee extract (31) can be characterized based on the chemical components present in the extract. For example, the secondary aqueous coffee extract (31) can be considered to have a concentration of high molecular weight (HMW) compounds in the range of 10-40%. Similarly, the primary aqueous coffee extract (30) is characterized by a high molecular weight (HMW) compound content of approximately 5-20%. The two-stage extraction process can increase extraction yields compared to traditional one-stage extraction processes due to the higher content of HMW compounds.

[0079] The final recombined roasted and ground coffee extract (39) shows a reduced binding activity of HMW compounds towards aroma compounds and a higher content of free aroma compounds.

[0080] The final recombined roast and ground coffee extract (39) is then sent to conventional manufacturing processes for the production of ready-to-drink, liquid coffee concentrate, and / or instant coffee powder.

[0081] The concentration and packaging process is carried out as described for Example 1.

[0082] Example 3b: Figure 3b shows a schematic flow diagram of a fourth embodiment of the method according to the first aspect of the invention.

[0083] A two-stage extraction process is applied to roast and ground coffee powder (3000). A first extraction is performed to produce a primary aqueous coffee extract (301) and so-called "spent grounds." The spent grounds are then subjected to a second extraction to produce a secondary aqueous coffee extract (310). The primary aqueous coffee extract (301) and the secondary aqueous coffee extract (310) are then filtered to obtain a primary coffee extract permeate (320), a secondary coffee extract permeate (321), a primary coffee extract retentate (330), and a secondary coffee extract retentate (331). The remaining extracted roast and ground coffee powder from the second extraction stage (so-called "waste grounds") is discharged or sent for further industrial use. The coffee extract retentates (330, 331) are processed according to the first aspect of the present invention, as described in Example 1, to produce primary and secondary treated coffee extracts (340 and 341, respectively), which are then recombined to obtain a recombined treated coffee extract (350). The recombined treated coffee extract (350) is finally added to the primary coffee extract permeate (320) and the secondary coffee extract permeate (321) to obtain a recombined roast and ground coffee extract (390).

[0084] In some embodiments, the two-stage extraction process comprises an extraction process for producing an aqueous coffee extract, as described in Example 3a, in which the extraction is carried out in two stages at different temperatures, the extract obtained from the first stage being referred to as the primary aqueous coffee extract (301) and the extract from the second stage, at a higher temperature, being referred to as the secondary aqueous coffee extract (310).

[0085] The filtration means is of the type described in Example 1, for example involving a conventional membrane filtration system comprising a membrane filtration with a cut-off of about 50 kDa.

[0086] In some embodiments, the membrane cutoff is less than 50 kDa, for example, about 30 kDa, 20 kDa, 10 kDa, or 5 kDa.

[0087] In the embodiment shown in Figure 3b, the filtration means applied to the primary aqueous coffee extract (301) comprises a membrane filtration cutoff of approximately 50 kDa, while no filtration is performed on the secondary aqueous coffee extract (310) before sending it to the pH-elevation treatment. Thus, the pH-elevation treatment is applied to the entire secondary aqueous coffee extract (310) without prior separation of high molecular weight (HMW) compounds into a secondary coffee extract retentate (not shown).

[0088] After reducing the agonistic effect of the phenolic groups of high molecular weight (HMW) compounds (responsible for the binding activity of aroma compounds in coffee extracts) by treatment with an alkaline agent to increase the pH, the resulting recombined roast and ground coffee extract (390) exhibits reduced binding activity of HMW compounds for aroma compounds, resulting in a higher content of free aroma compounds.

[0089] The recombined roast and ground coffee extract (390) is then sent to a conventional manufacturing process for the production of ready-to-drink, liquid coffee concentrate, and / or instant coffee powder.

[0090] The concentration and packaging process is carried out as described for Example 1.

[0091] Example 4a: FIG. 4a shows a schematic flow diagram of a fifth embodiment of the method according to the first aspect of the invention.

[0092] A two-stage extraction process is applied to roast and ground coffee powder (400) in the same manner as described above for Example 3a to produce a primary aqueous coffee extract (40), which is stored for later use, and a secondary aqueous coffee extract (41). The secondary aqueous coffee extract (41) is treated according to the first aspect of the present invention, as described in Example 2. The secondary aqueous coffee extract (41) is filtered to obtain a coffee extract permeate (42) and a coffee extract retentate (43). The coffee extract permeate (42) is stored for later use, and the coffee extract retentate (43) is sent to treatment with an alkaline solution to produce a treated coffee extract (44). The treated coffee extract (44) is sent to a further filtration process to produce a secondary coffee extract retentate (47) and a waste permeate (46). The secondary coffee extract retentate (47) is then recombined with the coffee extract permeate (42) to obtain a recombined roast and ground coffee extract (45), which is added to the primary aqueous coffee extract (40) to obtain a final recombined roast and ground coffee extract (49).

[0093] The secondary aqueous coffee extract (41) is produced by a conventional two-stage extraction process. First, roasted and ground coffee powder (400) is extracted with hot water at a first temperature ranging from 20°C to 140°C to produce a primary aqueous coffee extract (40). The remaining roasted and ground coffee powder (spent grounds) is then extracted again at a higher temperature ranging from 170°C to 220°C to produce a secondary aqueous coffee extract (41). The extraction is carried out in a conventional extraction means (not shown), such as a packed column containing roasted and ground coffee powder. The extraction can be carried out in batches or continuously, and multiple columns can be used to increase the extraction yield. Hot water is passed through the roasted and ground coffee powder from the top or, alternatively, from the bottom of the column(s). The extraction time varies based on the number of columns used, the grind size of the roasted and ground coffee powder, and the desired extraction yield. The content of HMW compounds in the secondary aqueous coffee extract (41) ranges from 10 to 40%.

[0094] The secondary aqueous coffee extract (41) is then filtered to produce a coffee extract permeate (42) and a coffee extract retentate (43), which are stored for further use. The filtration means is of the type described for Example 1, e.g., involving a conventional membrane filtration system including a membrane filtration material with a cutoff of approximately 50 kDa. The filtration process is carried out at a temperature of 20-70°C and a pressure of 1-3 bar for 1-8 hours. As described in Example 1, alternative filtration methods are available. The concentration of HMW compounds in the coffee extract retentate (43) is higher than the content of HMW compounds in the secondary aqueous coffee extract (41); in particular, the content of HMW compounds in the coffee extract retentate (43) is more than twice the concentration of HMW compounds in the secondary aqueous coffee extract (41). In some embodiments, the membrane cutoff is less than about 50 kDa, e.g., 30 kDa, 20 kDa, 10 kDa, or 5 kDa.

[0095] The coffee extract retentate (43) is sent for treatment with an alkaline agent to reduce the concentration and agonist effect of the long-chain conformational phenolic groups of the high molecular weight (HMW) compounds responsible for the binding activity of the aroma compounds in the coffee extract. As explained in Example 1, the alkaline treatment i. adding a solution of sodium hydroxide (NaOH) to the coffee extract retentate (43); ii. Stirring at a temperature of 30 to 100°C for 30 to 180 minutes.

[0096] The pH of the sodium hydroxide solution (NaOH) ranges from 7 to 14, preferably 8 to 11 (concentration of 0.5 to 5 mol / L). Alternative alkaline agents, such as NaHCO3, H2CO3 or KOH, as well as alternative resin and / or absorbent treatments, as described in Example 1, may also be used.

[0097] The resulting treated coffee extract (44) exhibits a pH in the range of 4.9 to 5.8 after quenching and a reduced binding activity towards aroma compounds.

[0098] The treated coffee extract (44) is then sent through a conventional piping system to a further filtration process to produce a secondary extract retentate (47) and separate it from a waste permeate (46) containing a fraction of the coffee extract having compounds with a molecular weight below about 5 kDa (low molecular weight, LMW, range of compounds).

[0099] The filtration means of the further filtration step in Figure 4a is a conventional membrane with a cut-off of 1 kDa.

[0100] The resulting secondary coffee extract retentate (47) is then recombined with the coffee extract permeate (42) to result in a recombined roast and ground coffee extract (45) having a lower phenolic content than the secondary aqueous coffee extract (41) and therefore reduced binding activity for aromatic compounds compared to the secondary aqueous coffee extract (41).

[0101] The recombined roast and ground coffee extract (45) is then added to the primary aqueous coffee extract (40) to provide a final recombined roast and ground coffee extract (49), which is then sent to a conventional manufacturing process for the production of ready-to-drink, liquid coffee concentrate, and / or instant coffee powder.

[0102] The concentration and packaging steps are carried out using standard, commercially available methods, as described in Example 1.

[0103] Example 4b Figure 4b shows a schematic diagram of a flow diagram of a sixth embodiment of the method according to the first aspect of the invention.

[0104] A three-stage extraction process is applied to roast and ground coffee powder (401).

[0105] Generally, a first extraction is performed to produce a primary aqueous coffee extract (440) and so-called "spent grounds" (410). An aroma recovery process (900) is applied to the primary aqueous coffee extract (440), and aromas are collected (not shown) and stored for later reintroduction. A second extraction is performed on the spent grounds (410) to produce a secondary aqueous coffee extract (441) and secondary spent grounds (480). A third extraction is performed with the secondary spent grounds (480) to produce a tertiary coffee extract (482). Both the primary aqueous coffee extract (440) and the secondary aqueous coffee extract (441) are stored for later use. The tertiary aqueous coffee extract (482) is processed according to the first aspect of the present invention, as described in Example 2. The tertiary aqueous coffee extract (482) is filtered to produce a coffee extract permeate (442) and a coffee extract retentate (443). The coffee extract permeate (442) is saved for later use, and the coffee extract retentate (443) is saved for pH-increasing treatment to produce a treated coffee extract (444). The treated coffee extract (444) is sent to a further filtration process to produce a quaternary coffee extract retentate (447) and a waste permeate (446). The refined coffee extract retentate (447) is then recombined with the coffee extract permeate (442), the primary aqueous coffee extract (440), and the secondary aqueous coffee extract (441) to produce a final recombined roast and ground coffee extract (449). The aroma collected by the aroma recovery process (900) is then reintroduced into the final recombined roast and ground coffee extract (449).

[0106] The detailed process of Example 4b is as follows:

[0107] The secondary (441) and tertiary (482) aqueous coffee extracts are produced by a conventional three-stage extraction process. First, roasted and ground coffee powder (401) is extracted with hot water at a first temperature ranging from 20°C to 140°C to produce a primary aqueous coffee extract (440). The roasted and ground coffee powder (410) remaining after extraction is then extracted again at a higher temperature of 170°C to 220°C to produce a secondary aqueous coffee extract (441), and the resulting secondary spent grounds (480) are then subjected to a third extraction at a temperature above 220°C to produce a tertiary aqueous coffee extract (482). Extraction is carried out in conventional extraction means (not shown), such as a packed column containing roasted and ground coffee powder. Extraction can be carried out in batches or continuously, and multiple columns can be used to increase extraction yield. Hot water is passed through the column(s) from the top, or alternatively from the bottom, of the column(s) through the roast and ground coffee powder (401). The extraction time varies based on the number of columns used, the grind size of the roast and ground coffee powder, and the desired extraction yield. The content of HMW compounds in the tertiary aqueous coffee extract (482) ranges from 1 to 10%.

[0108] The tertiary aqueous coffee extract (482) is then filtered to produce a coffee extract permeate (442) and a coffee extract retentate (443), which are stored for further use. The filtration means is of the type described for Example 1, e.g., involving a conventional membrane filtration system including a membrane filtration material with a cutoff of approximately 10 kDa. The filtration process is carried out at a temperature of 15-70°C and a pressure of 1-3 bar for a period of 1-8 hours. As described in Example 1, alternative filtration methods are available. The concentration of HMW compounds in the coffee extract retentate (443) is higher than the content of HMW compounds in the secondary (441) and primary aqueous coffee extract (440); in particular, the content of HMW compounds in the coffee extract retentate (443) is more than twice the concentration of HMW compounds in the secondary aqueous coffee extract (441). In other embodiments, the membrane cutoff may be less than approximately 30 kDa, 20 kDa, 10 kDa, or 5 kDa.

[0109] The coffee extract retentate (443) is sent for a pH-increasing treatment using an alkaline agent to reduce the concentration and agonist effect of the phenolic groups on the long chain conformation of the high molecular weight (HMW) compounds responsible for the binding activity of the aroma compounds in the coffee extract. As described in Example 1, the alkaline treatment i. adding a solution of sodium hydroxide (NaOH) to the coffee extract retentate (443); ii. Stirring at a temperature of 30 to 100°C for 30 to 180 minutes.

[0110] The pH of the sodium hydroxide solution (NaOH) ranges from 7 to 14, preferably 8 to 11 (concentration of 0.5 to 5 mol / L). Alternative alkaline agents, such as KOH, and alternative resin and / or absorbent treatments, as described in Example 1, may also be used.

[0111] The resulting treated coffee extract (444) exhibits reduced binding activity towards aroma compounds.

[0112] The treated coffee extract (444) is then sent through a conventional piping system to a further filtration process to produce a refined coffee extract retentate (447) and separate it from a waste permeate (446) containing a fraction of the coffee extract having compounds with a molecular weight below about 5 kDa (low molecular weight, LMW, range of compounds).

[0113] The filtration means of the further filtration step to separate the waste permeate (446) in Figure 4b is a conventional membrane with a cut-off of 1 kDa.

[0114] The resulting refined coffee extract retentate (447) is then recombined with the coffee extract permeate (442) and the first (440) and second (441) aqueous coffee extracts to yield a final recombined roast and ground coffee extract (449) having a lower phenolic content than the first (440) and second (441) aqueous coffee extracts, and therefore, reduced binding activity for aromatic compounds compared to the two aqueous coffee extracts (440, 441).

[0115] The final recombined roast and ground coffee extract (449) is then sent to conventional manufacturing processes for the production of ready-to-drink, liquid coffee concentrate, and / or instant coffee powder.

[0116] The concentration and packaging steps are carried out using standard, commercially available methods, as described in Example 1.

[0117] Example 4c Referring to FIG. 4c, there is shown a flow diagram of a seventh embodiment of the method of the first aspect of the present invention.

[0118] A three-stage extraction process is applied to roast and ground coffee powder (4010), as described in Example 4b. A primary aqueous coffee extract (4400) and so-called "spent grounds" (4100) are obtained from the first extraction stage. A second extraction is performed on the spent grounds (4100) to produce a secondary aqueous coffee extract (4410) and secondary spent grounds (4800). A third extraction is performed on the secondary spent grounds (4800) to obtain a tertiary aqueous coffee extract (4820) (which is collected, stored, and later reintroduced) and waste grounds. Both the primary coffee extract (4400) and the secondary aqueous coffee extract (4410) are subjected to a filtration process, as described in Example 3b, to obtain a primary coffee extract retentate (4430), a secondary coffee extract retentate (4431), a primary coffee extract permeate (4460), and a secondary coffee extract permeate (4461). The primary (4460) and secondary (4461) coffee extract permeates are stored for later use, while the primary coffee extract retentate (4430) and secondary coffee extract retentate (4431) are treated with a pH increasing step according to the first aspect of the present invention to obtain a primary treated coffee extract (4470) and a secondary treated coffee extract (4471). The primary (4470) and secondary (4471) treated coffee extracts are then combined to provide a recombined treated coffee extract (4435). A tertiary aqueous coffee extract (4820) is finally added to the recombined treated coffee extract (4435) along with the primary (4460) and secondary (4461) coffee extract permeates to provide a final recombined roast and ground coffee extract (4439).

[0119] Optionally, an aroma recovery step (not shown) may be performed on the primary aqueous coffee extract (4400), and the recovered aromas may be reintroduced into the final recombined roast and ground coffee extract (4439).

[0120] The secondary (4100) and tertiary aqueous coffee extracts (4820) are produced by a conventional three-stage extraction process as described in Example 4b.

[0121] The content of HMW compounds in the tertiary aqueous coffee extract (4820) ranges from 1% to 10%.

[0122] The filtration means is of the type described in Example 1, for example, involving a conventional membrane filtration system comprising a filtration medium with a cutoff of about 50 kDa. In some embodiments, the membrane cutoff is less than about 50 kDa, for example, 30 kDa, 20 kDa, or 10 kDa. In some embodiments, a series of membrane filtrations with membrane cutoffs of about 50 kDa, 30 kDa, 20 kDa, 10 kDa, and 5 kDa are applied.

[0123] In the embodiment illustrated in Figure 4c, the filtration means applied to the primary aqueous coffee extract (4400) comprises a membrane filtration cutoff of approximately 50 kDa. Instead, no filtration is applied to the secondary aqueous coffee extract (4410) before sending it to the pH-raising treatment. The pH-raising treatment is applied to the entire secondary aqueous coffee extract (4410) without prior separation of high molecular weight (HMW) compounds into a secondary coffee extract retentate (not shown).

[0124] In some embodiments (not shown), the tertiary aqueous coffee extract (4820) is subjected to processing in accordance with the present invention to obtain a tertiary coffee extract permeate and a tertiary treated coffee extract, which are then added to the final recombined roast and ground coffee extract.

[0125] The primary (4430) and secondary (4431) coffee extract retentates are sent for pH-increasing treatment using an alkaline agent as described in Example 3b to reduce the concentration and agonist effect of phenolic groups on the long-chain configuration of the high molecular weight (HMW) compounds.

[0126] The resulting primary (4470) and secondary (4471) processed coffee extracts are then recombined into a recombined processed coffee extract (4435) and added to the primary (4460) and secondary (4461) coffee extract permeate to result in a final recombined roast and ground coffee extract (4439) having a lower phenolic content and therefore reduced binding activity for aromatic compounds than the primary (4400) and secondary (4410) aqueous coffee extracts combined together.

[0127] The final recombined roast and ground coffee extract (4439) is then sent to conventional manufacturing processes for the production of ready-to-drink, liquid coffee concentrate, and / or instant coffee powder.

[0128] The concentration and packaging steps are carried out using standard, commercially available methods, as described in Example 1.

[0129] Example 5 Referring to FIG. 5, there is shown a flow diagram of an eighth embodiment of the method of the first aspect of the present invention.

[0130] The aqueous coffee extract (51) is filtered to obtain a primary coffee extract permeate (52) and a primary coffee extract retentate (53). The primary coffee extract retentate (53) is retained for further use, while the primary coffee extract permeate (52) is sent to a further filtration step to provide a secondary coffee extract (520) and a secondary coffee extract permeate (521), which are retained for further use. The secondary coffee extract permeate (521) is sent to a subsequent filtration step to provide a tertiary coffee extract retentate (522) and a tertiary coffee extract permeate (523). The primary coffee extract retentate (53) and the tertiary coffee extract retentate (522) are then separately treated with an alkaline solution to produce a primary treated coffee retentate (54) and a tertiary treated coffee retentate (540). The treated coffee retentate (54, 540) is then recombined with the tertiary coffee extract permeate (523) to produce a recombined roast and ground coffee extract (55).

[0131] The filtration series of Example 5 is carried out by using a series of membranes to isolate fractions of the original aqueous coffee extract (51) containing different molecular weight compound ranges. Each fraction is then individually processed according to the method of the present invention based on the relevance and level of affinity each fraction has for volatile organic compounds (VOCs), i.e., aroma compounds. For example, a series of cutoffs of greater than about 50 kDa (first filter medium - filtration 1), greater than about 30 kDa (second filter medium - filtration 2), and greater than about 10 kDa (third filter medium - filtration 3) are used. Membranes with lower cutoffs than the previous ones allow for the isolation of fractions of the aqueous coffee extract containing reduced molecular weight HMW compounds. Filtration of each fraction of the extract is carried out on the permeate of the previous filtration step. For example, a 30 kDa cutoff membrane is used on the permeate from a 50 kDa membrane cutoff.

[0132] The roast and ground coffee extract (55) obtained from the process of the present invention has a HMW fraction with lower aroma binding compared to the aqueous coffee extract (51), and therefore a higher content of free aroma compounds (VOCs).

[0133] The roast and ground coffee extract (55) resulting from the process of the present invention can be used as is (e.g., for the production of a ready-to-drink product) or can be sent to a conventional concentration process to obtain a liquid coffee concentrate that can be sold as is in bag-in-box packaging, or can be used in a further drying process (spray drying or freeze drying) to produce an instant coffee powder with enhanced aroma levels.

[0134] Reference HMW binding efficacy test The present invention is based on the finding that reducing the concentration of phenolic groups on the long chain configurations of such high molecular weight (HMW) compounds (e.g., melanoidins) in aqueous coffee extracts is particularly advantageous because these groups are involved in binding compounds such as HCAs, which play an important role in the aroma perception of coffee beverage preparations. This binding activity results in a beverage with a weaker aroma, which in turn leads to a poorer in-cup quality perception of the beverage by the consumer.

[0135] The binding activity of HMW compounds was performed on beverage preparations obtained from commercial coffee, as shown in Figure 6. 1 This has been proven by the inventors by H-NMR spectroscopy.

[0136] Sample 1: A beverage preparation obtained from a commercial coffee concentrate at a concentration of 54 g / L was spiked with 50 mmol / L of an aqueous solution of an aromatic compound (2,3-diethyl-5-methylpyrazine, earthy flavor).

[0137] Reference sample 1: A comparative aqueous solution (without coffee) to which 50 mmol / L of an aqueous solution of an aromatic compound (2,3-diethyl-5-methylpyrazine, earthy aroma) was added.

[0138] Sample 1 and Reference Sample 1 were analyzed by NMR spectroscopy over a 30 min incubation period to confirm the binding activity of the phenolic groups of the HMW compounds present in the coffee beverage with respect to the added aromatic compound (2,3-diethyl-5-methylpyrazine).

[0139] Compared to aqueous solution (reference sample 1), the resonance signal of HC(6) in sample 1 showed significant line broadening in addition to a decrease in intensity, indicating binding between the compounds.

[0140] NMR analysis clearly showed a decrease in free 2,3-diethyl-5-methylpyrazine upon incubation with the beverage preparation, suggesting binding of aromatic compounds by the HMW compounds.

[0141] The same experiment was carried out with further samples obtained with commercial coffee extracts, as shown in Figures 7a and 7b.

[0142] Sample 2: A beverage preparation obtained from commercial coffee, i.e., 54 g / L of extract, treated with an alkaline aqueous solution at a concentration of 2 g / L, to which a 50 mmol / L aqueous solution of an aromatic compound (2,3-diethyl-5-methylpyrazine, earthy aroma) was added, followed by a pH increase step at 60 °C for 30 min.

[0143] Reference sample 2: A beverage preparation obtained from commercial coffee, concentrated at a concentration of 54 g / L, was spiked with 50 mmol / L of an aqueous solution of an aromatic compound (2,3-diethyl-5-methylpyrazine, earthy aroma).

[0144] Sample 2 and Reference Sample 2 were analyzed by NMR spectroscopy to confirm the binding activity of the phenolic groups of the HMW compounds present in the coffee beverage with respect to the added aromatic compound (2,3-diethyl-5-methylpyrazine).

[0145] FIG. 7a, which refers to untreated reference sample 2, shows a lower concentration of HMW compounds than that of FIG. 7b, which relates to treated sample 2.

[0146] NMR analysis shows that the effect of alkaline treatment is significant, and therefore the affinity of HMW compounds (especially coffee melanonides) for aroma compounds is important. The recovery of free 2,3-diethyl-5-methylpyrazine increased from 56% before alkaline treatment to 84% after treatment.

[0147] Example 6 - Binding Effect Test of Example 4c Table 1 below shows the increase in recovery (% of free major aroma compound 2,3-diethyl-5-methylpyrazine) when different processing conditions are applied to the primary, secondary, and tertiary aqueous extracts for several final recombined roast and ground coffee extracts made according to the invention of Example 4c.

[0148] Each of the primary, secondary, and / or tertiary aqueous coffee extracts produced according to Example 4c was subjected to either a series of membrane filtrations using cutoffs of 50, 30, 10, and 5 kDa (hereinafter "total processing"), or a single membrane of 50 kDa (hereinafter "single fraction processing").

[0149] The resulting fractionation retentate of each aqueous coffee extract was subjected to a pH increasing treatment according to the present invention to a pH of 13, as described in Example 4c.

[0150] Additionally, an aqueous solution of 2,3-diethyl-5-methylpyrazine at a concentration of 5.15 mol / L was used as a reference sample. The pyrazine is also considered to be the major aroma compound responsible for the earthy notes in coffee extracts.

[0151] After treatment according to the first aspect of the invention, the primary, secondary and tertiary treated coffee extracts were supplemented with an aqueous pyrazine solution to obtain the same concentration as the reference sample (5.15 mol / L).

[0152] After 30 minutes of incubation at room temperature, 1 The concentration (%) of free pyrazine was determined by 1 H-NMR.

[0153] The percent increase in recovery was determined relative to the recovery of pyrazines in an untreated final roast and ground coffee extract (hereinafter "untreated final extract" or "untreated FE") obtained by combining the primary, secondary and tertiary aqueous coffee extracts of Example 4c without any pH-elevation treatment, which represents the conditions for maximum pyrazine binding (and therefore minimum free aroma - most detrimental to providing aroma complexity and effective in-cup performance).

[0154] Table 1 - % increase in recovery compared to untreated extract for extracts treated according to the invention in Example 4c and spiked with pyrazine at the same concentration as reference sample no. 1.

[0155] [Table 1] All recombined roast and ground coffee extracts processed according to the first aspect of the present invention showed a significant increase in the % recovery of free pyrazines compared to the untreated final extract, thereby confirming that treating the retentate from any stage of a one-stage, two-stage, or more stage extraction process ensures a reduction in aroma binding by HMW compounds. Particularly effective was treatment of HMW compounds higher than 50 kDa (i.e., using a filter material with a 50 kDa cutoff), suggesting that these HMW compounds play a disproportionate role in binding free aroma in extracts not processed according to the present invention.

[0156] Sample No. 7 was comprised of a combination of primary, secondary, and tertiary extracts, each of which was produced by filtration through a series of membrane filters using cutoffs of 50, 30, 10, and 5 kDa, and the resulting fractions were combined before subjecting the combined retentate to a pH-increasing treatment according to the present invention. Sample No. 7 showed a 21% increase in free pyrazines, providing significant in-cup performance to the resulting instant coffee.

[0157] Even when the coffee extract retentate was treated using only a single membrane cutoff of 50 kDa, this resulted in a significant reduction in the overall binding effect in the final recombined roast and ground coffee extract (samples references 4 and 8).

[0158] Example 7 - Binding Effect Test of Example 4c The process of Example 6 was repeated, except that for each aqueous coffee extract, the pH of the resulting >50 kDa fraction retentate was increased to a pH of 8, 9, 10, 11, or 12. This resulted in less pyrazine release than at pH 13. pHs 8, 9, and 10 showed less than 5% recovery compared to pH 13, pH 11 showed about 20% recovery of pyrazine compared to pH 13, and pH 12 showed about 90% recovery of pyrazine compared to pH 13. While this resulted in a retentate with more aroma bound compared to increasing the pH to 13, a process carried out at a pH of 7-12, particularly 7-10, is more manageable on an industrial scale given cost and processing considerations, and releases more aroma compounds, subsequently beneficially improving the aroma of the final coffee product, compared to not increasing the pH of the extract retentate. Therefore, depending on the end use, it is useful to carry out the method of the present invention by increasing the pH of the extract retentate to any value between pH 7 and 13.

[0159] The above embodiments have been described by way of example only, and many variations are possible without departing from the scope of the invention as defined in the appended claims.

Claims

1. 1. A method for treating a coffee extract, comprising: a) filtering the coffee extract through a size exclusion cutoff of 10 kDa to 50 kDa to obtain a coffee extract retentate and a coffee extract permeate; b) subjecting the coffee extract retentate to a pH increase treatment so that the pH is in the range of 7 to 14 to obtain a treated coffee extract retentate; c) combining the treated coffee extract retentate with the coffee extract permeate to produce a recombined coffee extract.

2. 10. The method of claim 1, further comprising the step of filtering the treated coffee extract retentate after step b) to further purify it.

3. 3. The method of claim 1 or 2, further comprising the steps of removing aroma volatile compounds from the coffee extract prior to step a) and adding or combining the aroma volatile compounds with the recombined coffee extract after step c).

4. 4. The method of claim 3, wherein removing the aroma volatile compounds comprises stripping and / or steam distillation.

5. 5. The method according to any one of claims 1 to 4, wherein step a) is carried out at a temperature in the range of from 20 to 100°C.

6. 6. The method according to any one of claims 1 to 5, wherein step a) is carried out at a pressure in the range of 1 to 3 bar.

7. The method according to any one of claims 1 to 6, wherein step a) is carried out by means of at least one filtration membrane.

8. 8. The method of claim 7, wherein the at least one filtration membrane comprises at least one size exclusion cutoff of at least 10 kDa.

9. 9. The method according to any one of claims 1 to 8, wherein carrying out step b) comprises increasing the pH of the coffee extract retentate to between 7 and 11 or between 7 and 10.

10. 10. The method according to any one of claims 1 to 9, wherein the pH increasing treatment comprises treating the coffee extract retentate with an aqueous alkaline solution, and / or a resin and / or an absorbent treatment, and / or a combination thereof.

11. 11. The method according to any one of claims 1 to 10, wherein carrying out step b) comprises treating the coffee extract retentate with a pH-raising means for a time in the range of from 10 to 180 minutes, or from 30 to 90 minutes.

12. 12. The method according to any one of claims 1 to 11, wherein carrying out step b) comprises increasing the temperature of the coffee extract retentate to between 30 and 100°C while increasing the pH.

13. 13. The method according to any one of claims 1 to 12, further comprising the step of filtering the coffee extract permeate at least once after step a) to produce a further extract retentate, and combining the coffee extract retentate with at least one further extract retentate before carrying out step b).

14. 14. The method of claim 13, wherein each repeated filtration of the coffee extract permeate comprises using a filtration element having a reduced size exclusion cutoff compared to any previous filtration element.

15. 15. The method of any one of claims 1 to 14, further comprising filtering the recombined coffee extract at least once to provide a secondary coffee permeate and a secondary coffee retentate, and increasing the pH of the secondary coffee retentate.

16. 16. The method of any one of claims 1 to 15, wherein the coffee extract comprises a primary extract from a primary extraction process of roast and ground coffee powder, and / or a secondary extract extracted from spent grounds obtained from the primary extraction process in a secondary extraction process, and / or a tertiary extract from an extract of spent ground coffee powder obtained from the secondary extraction process, and / or combinations thereof.

17. 17. The method of any one of claims 1 to 16, wherein the coffee extract comprises soluble solids at a concentration of from 2% to 15% by weight.

18. 17. The method of any one of claims 1 to 16, wherein the coffee extract comprises soluble solids at a concentration of from 15% to 80% by weight.

19. 19. The method of any one of claims 1 to 18, further comprising drying the recombined coffee extract to produce a soluble coffee powder.

20. 20. The method of any one of claims 1 to 19, wherein the recombined coffee extract is a soluble coffee powder.

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