Method for producing a coffee substitute

Abstract

METHOD FOR PRODUCING A COFFEE SUBSTITUTE In an aspect of the invention, there is provided a method for producing a coffee substitute, the method comprising: (a). carrying out a first fermentation by fermenting a first sulphur-containing food substrate with a first microorganism to form a first fermented product; (b). carrying out a second fermentation by fermenting a second carbohydrate-containing food substrate with a second microorganism to form a second fermented product; (c). mixing the first and second fermented products to form a fermented mixture; and (d). drying the fermented mixture to obtain the coffee substitute.

Description

METHOD FOR PRODUCING A COFFEE SUBSTITUTEFIELD OF THE INVENTION

[0001] The present invention relates to a method for producing a coffee substitute that is suitable for making a coffee-like beverage.BACKGROUND OF THE INVENTION

[0002] Coffee is a beverage prepared by roasting coffee beans and enjoyed by all due to its distinctive taste and effects.

[0003] Coffee production has a significant environmental impact. Cultivating coffee beans requires large amounts of water, pesticides, and fertilisers, contributing to deforestation, soil degradation, and water pollution.

[0004] As such, there is a need to produce coffee as an alternative to traditional coffee cultivation.SUMMARY OF THE INVENTION

[0005] In an aspect of the invention, there is provided a method for producing a coffee substitute, the method comprising: (a), carrying out a first fermentation by fermenting a first sulphur-containing food substrate with a first microorganism to form a first fermented product; (b). carrying out a second fermentation by fermenting a second carbohydrate- containing food substrate with a second microorganism to form a second fermented product; (c). mixing the first and second fermented products to form a fermented mixture; and (d). drying the fermented mixture to obtain the coffee substitute.

[0006] By “coffee substitute”, it is meant to refer to any product that can be brewed or prepared to form a food or drink that has a coffee-like or coffee-type flavour or taste. In various embodiments, the coffee substitute product produced by a method of this invention may be a ground dry product that can be treated the conventional “coffee powder” that may be brewed into a coffee-like beverage. In various embodiments, the coffee substitute may be used an addictive for the preparation of any food product or beverage.

[0007] By “fermentation”, it is meant to include any process of culturing a microorganism or microorganisms in the sulphur-containing food substrate or carbohydrate-containing foodsubstrate whereby a metabolic process is initiated. The metabolic process may include catabolism or anabolism. It also includes any process where sugars in the sulphur- containing food substrate are transformed into new product(s) through chemical reactions carried out by microorganisms. In various embodiments the sulphur-containing food substrate may be fermented with the microorganism(s) in a controlled vessel wherein at least one of a temperature, a pH or a dissolved oxygen content is controlled during processing of the sulphur-containing food substrate. In such embodiments, the incubation may be carried out in a controlled vessel. A controlled vessel is any vessel capable of controlling one or more operating parameters. In various embodiments the controlled vessel may be a bioreactor, an incubator or a double-jacketed steam vessel or any other scalable industrial vessel. In various embodiments the operating parameters may be temperature, pH, dissolved oxygen, biomass and / or concentration of any compound. In various embodiments, the fermentation in the controlled vessel may be maintained in a hygienic environment and under biologically suitable conditions for the particular microorganism used for the fermentations process.

[0008] In various embodiments, there may be three or more fermentation steps resulting in the mixing of three or more fermentation products. Preferably, each fermentation step produces the precursors to coffee aroma volatiles. By “precursors”, it is meant to include any flavour compounds that may be converted into aroma volatiles via the Maillard reaction. An example might be furfural as a precursor to furfurylthiol (coffee aroma volatile). The Maillard reaction of sulfur and carbohydrate gives rise to the cyclic thiols / volatiles present in coffee products. Advantageously, the Maillard reaction that occur during the drying and / or roasting steps transform the flavour precursors that have been created or produced from the fermentation processes.

[0009] In various embodiments, the method further comprises pasteurising the first sulphur-containing food substrate and the second carbohydrate-containing food substrate prior to the fermentation steps (a) and (b).

[0010] By “pasteurising”, it is meant to include any treatment to remove, destroy, deactivate or eliminate pathogens or any microorganisms or enzymes that may affect the fermentation process of this invention. Any suitable methods such a heating or radiation may be used as appropriate.

[0011] In various embodiments, the microorganism is selected from the group consisting of Bacillus subtilis, Aspergillus oryzae and Rhizopus oligosporus.

[0012] By “food substrate”, it is meant to include any biomass on which the microorganisms may grow and able to metablise. As such, by “sulpfur-” or “carbohydrate-”containing food substrate, it is meant to include any biomass that contains sulpfur compounds or carbohydrates.

[0013] As such, food substrate containing sulphur includes any bio-organic compounds, such as proteins (in the form of incorporated amino acids, e.g., cysteine and methionine), thioethers, thiols or mercaptans, sulfonium ions, sulfoxides and sulfones, dimethylsulfoniopropionate, dimethyl sulfoxide, sulfolane, and glutathione may be used.

[0014] The term “sulphur-containing food substrate" also includes any food substrate biomass that contains volatiles sulphur compounds (VSCs). VSCs are generally present in food substrates in trace amounts; these compounds have a strong odor and contribute to both pleasant and unpleasant flavors in foods. Amino acids containing S are methionine, cysteine, cystine, homocysteine, homocysteine and taurine. The term may also include cooked food that contain sulphur compounds, especially heterocyclic compounds such as thiazoles, thiophenes and thiazolines. Other cooked foods such as bread, potato products, nuts, popcorn, cheese and coffee also contain many sulphur compounds. Aliphatic thiols have been found in fruits, vegetables and dairy products. It has been reported that more than half of the volatile compounds in garlic, onions, leeks and chives contain sulphur. As such, examples of such food substrate for use in this invention may include any fruit or vegetable, pastry, meat and seafood, dairy products and wine.

[0015] By “carbohydrate-containing food substrate”, it is meant to include any biomass that contains a carbohydrate, i.e. that biomolecule consisting of carbon, hydrogen and oxygen atoms, usually with a hydrogen-oxygen atom ratio of 2:1. Such examples include sugards, starches and fiber. Advantageously, the fermentation of bread and spent grain produces sugars which can undergo the Maillard reaction to produce coffee aroma volatiles. The use of sesame in the fermentation step produces key aroma volatiles in coffee (e g. furfurylthiol).

[0016] In various embodiments, the sulphur-containing food substrate is soy pulp and the carbohydrate-containing food substrate is selected from the group consisting of spent grain, bread, sesame husk, pineapple pulp and sugarcane molasses.

[0017] By “soy pulp” (or okara), it is meant to include any pulp consisting of insoluble parts of the soybean that remain after pureed soybeans are filtered in the production of soy milk and tofu.

[0018] By “spent grain”, it is meant to include any residue of mashing in beer and whisky production, where sugars are extracted from malted barley. In the context of this invention, we have used barley interchangeably with spent grain.

[0019] By “sesame husk”, it is meant to include any residue of sesame oil production, after the sesame seeds are pressed to extract oils.

[0020] By “pineapple pulp”, it is meant to include any fibrous residue of the pineapple fruit after processing or juicing.

[0021] By “sugarcane molasses”, it is meant to include any residue of cane sugar production.

[0022] In various embodiments, the first microorganism is Bacillus subtilis, and the second microorganism is Aspergillus oryzae and the second carbohydrate-containing food substrate is a mixture comprising bread and spent grain.

[0023] In various embodiments, the first fermentation is carried out at a temperature of 40°C for 18 hours, and the second fermentation is carried out at a temperature of 60°C for 6 hours.

[0024] In various embodiments, the soy pulp is inoculated with 2 wt% of Bacillus subtilis.

[0025] In various embodiments, the second carbohydrate-containing food substrate is inoculated with 2 wt% of Aspergillus oryzae.

[0026] By “wt%” or “w / w”, is is meant to mean weight concentration expressed in % w / w. A suitable concentration of the inoculum may be used.

[0027] In various embodiments, the second carbohydrate-containing food substrate is a mixture comprising equal parts of bread and spent grain.

[0028] In various embodiments, the amount of soy pulp fermented may be 50 to 70 wt%, and 15 to 25 wt% each for bread and spent grain (which may include barley).

[0029] In various embodiments, the amounts of soy pulp, bread and spent grain fermented are 50 wt%, 25 wt% and 25 wt% respectively.

[0030] In various embodiments, the fermentation of bread and spent grain may be carried out together at the same time. Alternatively, the fermentation may be carried out separately which products formed separately are then mixed to form the combined second fermented product, which in turn is mixed with the first fermented product.

[0031] In various embodiments, pasteurising the sulphur-containing food substrate and carbohydrate-containing food substrate is carried out at a temperature of 120°C for 40 minutes.

[0032] In various embodiments, drying the fermented mixture in step (d) forms a cake, and the drying is carried out at a temperature between 100°C to 180°C for 3 hours, or the drying is carried out until the water content in the cake is less than 4 wt%.

[0033] By “mixing”, it is meant to include any mechanical action of stirring to combine the contents of both first and second fermented products to form a uniform mixture.

[0034] In various embodiments, the method further comprises extruding the cake to form pellets.

[0035] In various embodiments, the method further comprises roasting the pellets to obtain the coffee substitute.

[0036] In various embodiments, roasting the pellets is carried out at a temperature between 200°C to 240°C for 20 minutes.

[0037] In various embodiments, the fermented mixture is formed by mixing the first and second fermented products in equal portions.

[0038] In various embodiments, sulphur-containing amino acids may be added into the fermentation mixtures and fermented products.

[0039] In various embodiments, the method further comprises adding cysteine or methionine to the fermentation steps (a) and / or (b), or to the roasting step.

[0040] In various embodiments, the method further comprises grinding the roasted pellets to form a ground coffee substitute product.

[0041] In another aspect of the invention, there is provided a method for producing a beverage, the method comprising: (a), making a coffee substitute according to an aspect of this invention; and (b). brewing the coffee substitute to form the beverage.

[0042] Any of the various methods of brewing coffee known to the skilled person may be carried out, e.g. drip brewing, French press, espresso, cold brew etc., to extract flavours from the ground coffee substitute produced by a method of this invention.

[0043] In yet another aspect of the invention, there is provided a coffee substitute obtained or obtainable by a process according to an aspect of this invention.

[0044] Advantageously, the method of this invention produces a coffee substitute product having coffee’s distinct aroma profile. In particular, the coffee substitute product of this invention has coffee-specific key aroma volatiles, such as thiols. In addition, the coffee substitute product is produced by a method that generates less greenhouse gas emissions than conventional coffee growing and manufacturing methods. The method includes using fermentation process that are performed under controlled settings for consistency to produce the desired coffee aroma profiles, and the product is also naturally non-caffeinated.BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The invention will be better understood with reference to the detailed description when considered in conjunction with the non-limiting examples and the accompanying drawings, in which:

[0046] Figure 1 shows a flowchart setting out the general method of producing a coffee substitute I accordance with an aspect of the invention;

[0047] Figures 2 and 3 show charts to indicate the presence and relative proportion of volatiles of interest that were observed in Prefer (right bar for each volatile of interest I odour-active compound - beverage made using the coffee substitute in accordance with a method of this invention), and a commercially obtained coffee beverage (left bar for each volatile of interest / odour-active compound); and

[0048] Figures 4 to 9 show data comparing the amounts of volatiles of interest / odouractive compounds between fermenting raw / processed bread, soy and barley. By “processed”, it is meant to include any fermented and / or roasting process of the raw ingredient. Processing of the relevant raw ingredient may increase the concentration of the key aroma volatiles present in the raw ingredient being used as a substrate.DETAILED DESCRIPTION OF THE INVENTION

[0049] With reference to Figure 1 , the method of this invention includes the main steps of mixing two or more fermented products to form a fermented mixture, drying said mixture to obtain the coffee substitute product.

[0050] In an example, two fermented products are produced. The first fermented product is produced by fermenting a first sulphur-containing food substrate with a microorganism. The first sulphur-containing food substrate may be soy pulp and it is inoculated with 2wt% of B. subtilis var. natto, mixed with 100% v / w of water at room temperature (about 26°C). The mixture is then incubated at 40°C for 18 hours without agitation. Depending on the quality and consistency of the fermented product, stirring may be necessary to improve heat and material transfer.

[0051] The second fermented product is produced by fermenting a second carbohydrate- containing food substrate with another microorganism. Here, the second carbohydrate- containing food substrate comprises a mixture of spent grain and bread in a 1 :1 w / w ratio. This mixture is inoculated with 2 wt% of A. oryzae, mixed with 100% v / w of water at room temperature (about 26°C). The mixture is then incubated at 60°C for 6 hours, with stirring.

[0052] Prior to the fermentation process, the food substrates may be steam-pasteurised at 120 °C for 40 min.

[0053] Table 1 below shows the proportions of the first and second food substrates (weighed and measured prior to fermentation) used in this example to obtain a coffee substitute to prepare beverage Prefer. The composition of the volatile compounds present inPrefer (the coffee substitute product obtained from the claimed invention’s method) are shown in Figures 2 and 3. For each odour-active compound, the left block shows an analysis of a commercially obtained coffee bean while the right block shows an analysis of Prefer.Table 1

[0054] In another example, the second fermentation is carried out using the carbohydrate-containing food substates bread and spent grain with a second microorganism. Table 2 below shows the proportions of the first and second food substrates (weighed and measured prior to fermentation) used in this example to obtain a coffee substitute to prepare beverage Prefer. The composition of the volatile compounds present in Prefer, with reference to a commercially obtained coffee bean, are shown in Figures 2 and 3.Table 2

[0055] Figure 2 shows a comparison of the aroma volatile compounds present in Prefer (a brew produced from methods of this invention) with a Reference (a commercial coffee sample). Prefer was prepared in accordance with the method described above and composition listed in Table 1.

[0056] In both examples above, the first fermentation is carried out using B. subtilis and the second fermentation is carried out using A. oryzae.

[0057] The first and second fermentation products may be slurries which are then mixed in equal proportions (1 :1 w / w), dried into a cake at 100 °C for 3 hours, and then roasted at 200 °C for 20 min.

[0058] Sulpfur-containing amino acids (e g. cysteine or methionine) may be added to the fermentation steps and / or during the roasting step.

[0059] Figures 4 to 9 show data comparing the amounts of odour-active compounds between fermenting raw / processed bread, soy and barley. For each odour-active compound, the left block shows an analysis of a raw ingredient while the right block shows an analysis of the same ingredient but processed.

[0060] The cake that is formed from mixing the fermented products may be extruded to form pellets. Each pellet may be sized to correspond to the size of a coffee bean. The cake may be dried prior to extrusion or the pellets formed may be dried. The pellets may then be roasted and stored, or grounded and then stored. When preparing a coffee-like beverage, the grounded pellets may be brewed as one would regular coffee.

[0061] While embodiments of the invention have been particularly shown and described with reference to specific embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the invention as defined by the appended claims. The scope of the invention is thus indicated by the appended claims and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced.

Claims

CLAIMS1 . A method for producing a coffee substitute, the method comprising:(a). carrying out a first fermentation by fermenting a first sulphur-containing food substrate with a first microorganism to form a first fermented product;(b). carrying out a second fermentation by fermenting a second carbohydrate- containing food substrate with a second microorganism to form a second fermented product;(c). mixing the first and second fermented products to form a fermented mixture; and(d). drying the fermented mixture to obtain the coffee substitute.

2. The method according to claim 1 , further comprising pasteurising the first sulphur- containing food substrate and the second carbohydrate-containing food substrate prior to the fermentation steps (a) and (b).

3. The method according to claim 1 or 2, wherein the microorganism is selected from the group consisting of Bacillus subtilis, Aspergillus oryzae and Rhizopus oligosporus.

4. The method according to any one of the preceding claims, wherein the sulphur- containing food substrate is soy pulp and the carbohydrate-containing food substrate is selected from the group consisting of spent grain, bread, pineapple pulp and sugarcane molasses.

5. The method according to any one of the preceding claims, wherein the first microorganism is Bacillus subtilis, and the second microorganism is Aspergillus oryzae and the second carbohydrate-containing food substrate is a mixture comprising bread and spent grain.

6. The method according to claim 5, wherein the first fermentation is carried out at a temperature of 40°C for 18 hours, and the second fermentation is carried out at a temperature of 60°C for 6 hours.

7. The method according to any one of claims 5 or 6, wherein the soy pulp is inoculated with 2wt% of Bacillus subtilis.

8. The method according to any one of claims 5 or 6, wherein the second carbohydrate- containing food substrate is inoculated with 2wt% of Aspergillus oryzae.

9. The method according to claim 5, wherein the second carbohydrate-containing food substrate is a mixture comprising equal parts of bread and spent grain.

10. The method according to claim 9, wherein the amounts of soy pulp, bread and spent grain fermented are 50 wt%, 25 wt% and 25 wt% respectively.1 1. The method according to any one of the preceding claims, wherein pasteurising the sulphur-containing food substrate and carbohydrate-containing food substrate is carried out at a temperature of 120°C for 40 minutes.

12. The method according to any one of the preceding claims, wherein drying the fermented mixture in step (d) forms a cake, and the drying is carried out at a temperature between 100°C to 180°C for 3 hours, or the drying is carried out until the water content in the cake is less than 4 wt%.

13. The method according to claim 12, further comprising extruding the cake to form pellets.

14. The method according to claim 13, further comprising roasting the pellets to obtain the coffee substitute.

15. The method according to claim 14, wherein roasting the pellets is carried out at a temperature between 200°C to 240°C for 20 minutes.

16. The method according to any one of the preceding claims, wherein the fermented mixture is formed by mixing the first and second fermented products in equal portions.

17. The method according to any one of the preceding claims, wherein cysteine or methionine is added to the fermentation steps (a) and / or (b), or to the roasting step when dependent on claim 14.

18. The method according to claim 15, wherein the method further comprises grinding the roasted pellets to form a ground coffee substitute product.

19. A method for producing a beverage, the method comprising:(a). making a coffee substitute according to the method according to claim 17; and(b). brewing the coffee substitute to form the beverage.

20. A coffee substitute obtained or obtainable by the process according to any one of claims 1 to 18.

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