A glucomannan-containing composite and a method of manufacturing thereof

Abstract

A method for manufacturing a glucomannan-containing composite product, the method comprising: producing a filler comprising a glucomannan-containing gel and a coagulating agent, mixing granules made of glucomannan-containing material and the filler together to form a composite, placing the composite on a water-permeable screen, and pressing the composite to remove at least part of the liquid and filler out of the composite, whereby a porous composite having empty space and filler around the granules has been produced Corresponding product and arrangement are also presented.

Description

[0001] A GLUCOMANNAN-CONTAINING COMPOSITE AND A METHOD OF MANUFACTURING THEREOF

[0002] FIELD OF THE INVENTION

[0003] Generally, the present invention relates to the use of glucomannans extracted from botanical feedstocks in manufacturing of foods for human and animal consumption, pharmaceuticals, and / or other industrial products. Particularly, however not exclusively, the present invention pertains to a method for manufacturing a glucomannan-containing composite from a konjac plant and / or from wood-derived feedstocks.

[0004] BACKGROUND

[0005] Sushi is a globally-renowned dish that originates from Japan. Traditionally sushi comprises at least boiled and vinegar-seasoned rice that is used to form a bed of rice, usually by hand, for which toppings may be placed upon. The rice used in sushi contains starch that acts as a binding agent when the rice grains press against each other when the rice mass is being formed. The process of forming the rice mass sticks the rice grains together, forming a composite where rice grains act as both an aggregate and filler material or binding agent. The rice mass can be used to form blocks, balls or may be spread as a sheet to be rolled. However, common to all forms of sushi is that it uses rice which contains high levels of carbohydrate and calories. High levels of carbohydrate and calories are not ideal for consumers who, for example, follow a ketogenic diet or otherwise try to limit their carbohydrate and / or calories intake. As such, consumers who monitor their carbohydrate and / or calories intake often need to leave sushi out of their diet.

[0006] In this regard, it would be desirable to update the field of technology related to production of sushi and other rice-based food products, in view of exploiting an entire range of nutritive components included in rice substituents and / or avoiding health risks potentially associated with (over)consumption of carbohydrates and calories. Hence, further advances in development of alternatives for rice-based food products suitable for a broader range of consumer groups is still highly looked for. It is further desirable that the resulted rice substitute product would be appealing to the customer in terms of aroma, taste and appearance. SUMMARY OF THE INVENTION

[0007] The objective of the embodiments of the present invention is to at least alleviate one or more of the aforementioned drawbacks evident in the prior art. One or more objectives are achieved by various embodiments of a process for manufacturing a glucomannan-containing composite, related products, arrangements and uses as defined herein. Thereby, in one aspect of the invention the manufacturing process is provided, according to what is defined in the independent claim 1.

[0008] An advantage of the present invention is that it allows for an alternative to a high-carbohydrate and high-caloric rice without losing the taste sensation and mouthfeel of rice. Additionally, the konjac composite product is suitable for consumers who limit their carbohydrate and / or calories intake.

[0009] In accordance with one aspect of the present disclosure a method for manufacturing a glucomannan-containing composite product, the method comprising: a. producing a filler comprising a glucomannan-containing gel and a coagulating agent, b. mixing granules made of glucomannan-containing material and the filler together to form a composite, c. placing the composite on a water-permeable screen, and d. pressing the composite to remove at least part of the liquid and filler out of the composite, whereby a porous composite having empty space and filler around the granules has been produced.

[0010] In embodiment, the method comprises setting the internal temperature of the composite to a temperature which activates the coagulating agent. The internal temperature of the composite can be set to the temperature of activation of the coagulating agent before the pressing step (d), during the pressing step (d), or after the pressing step (d). Thereafter, the composite can be cooled down using conventional cooling methods.

[0011] By internal temperature we refer to the temperature of the product as opposed to the ambient temperature. Accordingly, to another aspect of the present disclosure a glucomannan- containing composite product obtainable by the method according to any one of claims 1-7, the product comprising: (a) granules made of a glucomannan-containing material, and (b) a filler, wherein the product is a porous composite product having empty space and filler around the granules, wherein the composite comprises granules (a) in an amount within a range of about 60 wt-% to about 90 wt-% of the composite and filler (b) in an amount within a range of about 10 wt-% to about 40 wt-% of the composite.

[0012] In accordance with a further aspect of the present invention an arrangement for manufacturing a glucomannan-containing composite product, the arrangement comprising:

[0013] - a water-permeable screen,

[0014] - a three-dimensional mold arranged on the water-permeable screen,

[0015] - a piston arranged to move inside the three-dimensional mold,

[0016] - wherein the three-dimensional mold is arranged to receive a glucomannan-containing composite, and the piston is arranged to press against the glucomannan-containing composite inside the three-dimensional mold and against the water-permeable screen so that at least excess fluid is removed through the water- permeable screen and the glucomannan-containing composite is formed into a glucomannan-containing composite product.

[0017] Different embodiments of the present disclosure are disclosed in the dependent claims.

[0018] As briefly reviewed hereinbefore, the utility of the different aspects of the present invention arises from a plurality of issues depending on each particular embodiment.

[0019] The expression “a number of’ may herein refer to any positive integer starting from one (1). The expression “a plurality of’ may refer to any positive integer starting from two (2), respectively.

[0020] The term “exemplary” refers herein to an example or example-like feature, not the sole or only preferable option. Different embodiments of the present invention are also disclosed in the attached dependent claims.

[0021] BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Some exemplary embodiments of the present invention are reviewed more closely with reference to the attached drawings, wherein

[0023] Fig. 1 depicts a flow chart of the method for manufacturing a konjac composite product in accordance with an embodiment of the present disclosure,

[0024] Fig. 2 depicts a general illustration of the product in accordance with an embodiment of the present disclosure,

[0025] Fig. 3 illustrates the arrangement in accordance with an embodiment of the present disclosure,

[0026] Fig. 4 is a conceptual illustration of an aspect of the method in accordance with an embodiment of the present disclosure,

[0027] Fig. 5 is a conceptual illustration of an aspect of the method in accordance with an embodiment of the present disclosure, and

[0028] Figs. 6a-6e provide alternative conceptual illustration of aspects of the arrangement and method in accordance with an embodiment of the present disclosure.

[0029] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] Fig. 1 illustrates a flowchart for a method for manufacturing a glucomannan-containing composite product, hereafter, a composite product (100), as a low-carbohydrate, low-calories substitute for rice and / or other foodstuffs.

[0031] The composite product comprises granules made of glucomannan- containing material (referred to as “granules” or “granulate”) and a filler, the filler comprising a glucomannan-containing gel and a coagulating agent (coagulant) (102). The glucomannan-containing material that form the granulate can in turn be solid or semisolid material. The filler accounts for generation of a gel-like or dense structure, upon solidification of the composite product. The term “gel” refers hereby to a colloidal system in which the dispersed phase is a liquid, and the dispersion medium is a solid. In particular, the glucomannan-containing gel is formed with a three-dimensional network of polymers (herein, glucomannans) cross-linked by physical interactions (e.g. hydrogen bonding or van der Waals forces) and / or chemical interactions (e.g. covalent bonding) and having water molecules bound in their structure.

[0032] According to the present disclosure, glucomannans include, but are not limited to galactoglucomannans extracted from wood-derived feedstocks, such as Norwegian spruce (Picea abies), and / or glucomannans derived from a konjac plant (Amorphophallus konjac; Amorphophallus spp.), such as for example Amorphophallus muelleri, and / or other Amorphophallus species.

[0033] Hence, in embodiments, the glucomannan-containing granulate material and / or glucomannan-containing gel is / are obtainable from the konjac plant (Amorphophallus konjac) and / or from wood-derived feedstocks, such as Norwegian spruce (Picea abiesy Overall, any one the glucomannan- containing granulate material and the glucomannan-containing gel, or both can comprise- or consist of material derived from the konjac plant (Amorphophallus konjac) and / or wood-based feedstocks.

[0034] The konjac referred to in the present disclosure is a common name of Amorphophallus konjac, a root vegetable species native to parts of Asia. The corm of konjac is edible and is usually processed into a flour or gel which is then applied to a variety of dishes. Konjac is low in carbohydrates and calories which is why it may be used as an alternative to food items rich in carbohydrates and calories.

[0035] Konjac-derived glucomannans, also referred to as konjac glucomannans (KGM) are water-soluble polysaccharides separated from konjac tubers. KGM is a biocompatible and biodegradable dietary fiber, which also has a good gelation performance.

[0036] Wood hemicelluloses obtained from side streams of forest industries represent another abundant and renewable source of polysaccharides. Galactoglucomannans (GGM) are water-soluble polysaccharides that account for about 25-30 % of dry wood mass in softwoods, such as spruce and pine. Typically, GGM are recovered from wood chips by conventional extraction methods, such as for example pressurized hot water extraction (PHWE), followed with concentration of extracts by (membrane) filtration methods, for example, and drying thus concentrated extracts by spraydrying or other suitable methods.

[0037] In embodiments, the filler is provided as the glucomannan-containing granules formed into paste. At this stage the granules and the filler form a composite which can also be referred to as raw composite (104). Additionally, the filler may comprise dry ingredients, for example salt and sugar and / or other sweeteners, and acidic liquid such as vinegar. The filler acts as an adhesive, helping to bind the granule mass together. The filler substance is angular in the sense that the glucomannan-containing gel in the filler has been cut into angular pieces using a blender or any other tool which has a cutting edge creating angular surfaces when cutting. In addition to cutting, the glucomannan-containing gel may be beat, extruded, squeezed, whisked, or torn apart in any other method that splits the gel and creates angular pieces. The angular structure of the glucomannan- containing gel in the filler helps the filler surround the granules rather than the filler particles sliding in relation to each other and off from the composite.

[0038] The composite is placed on a water-permeable screen (106). The water- permeable screen may comprise or be configured as for example a (static) tray, conveyor belt or the like. A three-dimensional mold is arranged on the water-permeable screen. Alternatively, the water-permeable screen may be a part, such as the bottom or side, of the three-dimensional mold. In configurations, the composite is thus placed into the three-dimensional mold arranged on the water-permeable screen. In different configurations, the raw composite can be heated and / or cooled to coagulate the composite. In preferred embodiment, the coagulating agent is agar. Other coagulating agents include, but are not limited to egg white, gelatine, and the like. When the composite is under the activation temperature of coagulating agent, the composite should be heated to or above the activation temperature of the coagulating agent. In some instances, the composite may be above the activation temperature of the coagulating agent, in which event the composite should be cooled down to have the coagulating agent coagulate. The internal temperature of the composite should be equal to or above the activation temperature of the coagulating agent (108). In an embodiment where the coagulating agent is agar, the activation temperature should be at least 85 Celsius degrees. After heating the composite sufficiently, the composite needs to be cooled down to at least 20 Celsius degrees. In some instances, the composite should be cooled down to about 25-45 Celsius degrees. In an exemplary embodiment, the composite needs to be cooled down to at least 45 Celsius degrees, which is the approximate temperature range for the agar to coagulate. Depending on the coagulating agent the necessary cooling temperature may vary. In another example, where the coagulating agent is egg white, an internal temperature of at least about 65 Celsius degrees for the composite is sufficient to activate the coagulating agent in egg white. In another example where the coagulating agent is gelatine the temperature is not as crucial as the gelatine may coagulate even in colder temperatures given that the gelatine is in liquid state.

[0039] In an embodiment, the water-permeable screen is configured as a perforated tray or a perforated base. In an embodiment, the water-permeable screen may comprise for example small openings. The water-permeable screen helps circulate heat evenly, and the water-permeable screen also allows excess moisture from steaming to escape the composite rather than condensing to the lower part of the composite. The water-permeable screen also allows excess liquids such as water and the filler to exit the composite and the water-permeable screen.

[0040] In embodiment, the method comprises setting the internal temperature of the composite to a temperature which activates the coagulating agent. The internal temperature of the composite can be set to the temperature of activation of the coagulating agent before the pressing step, during the pressing step, or after the pressing step. Thereafter, the composite can be cooled down using conventional cooling methods, such as blowing cold air to the composite, placing the composite to a cold space, or letting the composite set to room temperature over time.

[0041] By internal temperature we refer to the temperature of the product as opposed to the ambient temperature.

[0042] Before the composite is cooled down and the composite has set it may further be processed to appropriate shape. The composite is pressed using a mold and a piston to remove excess filler and liquid leaving enough filler as an adhesive around the essentially solid granules (110). The composite that is pressed to form may be cold or warm. In an embodiment, the composite may be heated before pressing, and after pressing the composite may be cooled down. In another embodiment, the composite may first be pressed, then heated, and after heating cooled down. In another embodiment the composite may be heated during the pressing, after which the composite is cooled down. In some configurations the composite may be heated first and then pressed, where the composite is cooled down during pressing. In some optional configuration, the composite may only be pressed and cooled down. In an embodiment, where the coagulating agent is agar, the composite needs to be pressed before the composite cools down to approximately 45 Celsius degrees and sets the composite (112). A three- dimensional mold and a piston may be used for pressing, especially if a specific shape is desired for the composite. Due to the pressing, the form of the granules changes temporarily. The pressing pushes out excess filler and liquid from the composite. After pressing the composite, the granules return to their original form which creates empty space within the structure. As a result, an airy, porous composite structure whereby the porous composite has empty space and filler around the granules has been produced as illustrated in fig. 2.

[0043] The granules may be of multiple different sizes ranging from 2 millimeters to 10 millimeters in length and 1,5 millimeters to 4 millimeters in width. In a preferred embodiment, the granules are ellipsoid. The granules may be slippery due to the ellipsoid shape of the granules. The aforementioned value ranges are preferred ranges, the present disclosure does not limit itself to the range of values discussed.

[0044] The filler of the composite comprises the glucomannan-containing gel, coagulating agent, and dry ingredients such as salt and / or sugar and / or other sweeteners. The paste obtainable from the solid granules may be made from for example konjac products, such as konjac rice, konjac noodles or a piece of konjac, and / or from pre-processed wood-derived feedstocks (e.g. spray- dried GGM extracts). A tool such as a cutter, blender or any other tool with a sharp cutting edge may be used to cut the glucomannan-containing gel to create angular pieces thereof for the filler. The angular pieces in the filler help the filler stick together without sliding off from the composite. The composite comprises approximately 0,3- 1,3 wt-% coagulating agent, which is preferably agar. However, other coagulating agents may also be used such as egg white or gelatine. 15-25 wt-% of the filler may be of dry ingredients. The filler may also contain vinegar or other edible acidic liquid 3-6 wt-% so that a suitable pH value of 3.5-4.2 is achieved for the filler. In an embodiment, where the ready composite product comprises no carbohydrates, fats, and proteins the shelf life of the ready composite product is prolonged even up to 9 months or more with the discussed pH value. Similarly, in an embodiment, where the sugar in the filler has been replaced with an artificial and / or natural, calorie-free sweetener and the glucomannan-containing gel comprises fiber and water, together with the discussed pH value, the shelf life of the ready composite product in vacuum or protective gas may be up to 9 months or more at room temperature. 69- 82 wt-% of the filler is the glucomannan-containing material (e.g. konjac) in paste form. The composite comprises glucomannan (solid) granules in an amount of about 60 wt-% to about 90 wt-% and the glucomannan- containing filler in an amount of about 10 wt-% to about 40 wt-%. The aforementioned quantities are preferred ranges; however, the present disclosure does not limit itself to the range of values discussed.

[0045] After the filler has been mixed with the granules, the composite, which may be called the raw composite at this stage, needs to be heated and / or cooled to activate the coagulating agent and let it set within the composite. In an embodiment, the internal temperature of the composite must rise to at least 85-100 Celsius degrees in order to activate the coagulating quality of agar within the composite. The composite may be warmed up to 121 Celsius degrees or higher which is beneficial for eliminating possible harmful microbes or other harmful components, but a lower temperature is also possible as discussed. The preferred method of heating the composite to the desired temperature is by steaming using an oven where 100% steaming is attainable in addition to using heating elements of an oven. The aforementioned values and ranges are examples and the current disclosure does not necessarily limit itself to the values discussed.

[0046] In an embodiment, where the coagulating agent is agar, minimum heating time with the internal temperature of the composite being at least 85-98 Celsius degrees is less than a minute but longer heating times in temperatures over 85-98 Celsius degrees, or for example heating the composite at 100 Celsius degrees for 12 minutes, can increase the shelf life of the composite. By way of example, konjac may even withstand temperatures up to 220 Celsius degrees, whereas agar starts to thermally degrade when the heating temperature is above 250 Celsius degrees. In industrial kitchen ovens the heating time may take anywhere between 5 to 15 minutes until the desired internal temperature of the composite is reached. In another embodiment, the composite may be warmed using microwaves or other source of heat that allows uniform heating of the composite mass. Microwaves are particularly effective as a heating method for glucomannan-containing gels, since they have a high water content and microwaves excel at heating products with high water content. The aforementioned values and ranges are examples and the current disclosure does not necessarily limit itself to the values discussed.

[0047] Figs. 3-5 illustrate aspects of the arrangement 300 in accordance with an embodiment of the present disclosure. Fig. 5 illustrates the composite set in a mold prior to pressing, Fig. 4 illustrates the process of pressing the composite in the mold, Fig. 3 illustrates the composite in the mold after pressing, and Fig. 2 illustrates the ready product taken from the mold. A three-dimensional mold 302 and a piston 304 may be used for pressing the composite to a desired form. The composite is pressed to form before the coagulating agent in the filler has set the composite. The mold is placed on top of the composite. The composite may be formed to a sheet with varying thickness. In an embodiment, a three-dimensional mold with geometrical shapes may be used to form, for example, triangles or rectangular pieces. A further example of such a shape is a rectangular piece used for nigiri sushi, which can be processed to be 50-60 millimeters long, 20-25 millimeters wide and 20-30 millimeters high and preferably weights 15-25 grams. The pressing, or a press cycle, of the composite may last between 0,2-5 seconds. The press cycle helps distribute the filler within the composite evenly. Additionally, excess filler is extruded from the composite and porous structure forms. The excess filler and / or liquid, such as water, may exit through any openings in the water-permeable screen 306. The water- permeable screen may also drain the excess filler and / or liquid. The current disclosure does not limit itself to the aforementioned examples, and other shapes and dimensions are also possible. The composite is pressed using the mold and a piston. The piston is moved inside the mold to press on the composite to create a desired form with the help of the three-dimensional mold, and distribute the filler inside the composite evenly. As illustrated in fig. 4, when pressed the size of the composite temporarily decreases to approximately 5-15% of the original volume, where the original volume is the uncompressed volume, of the composite. The granules return to their original shape and uncompressed volume after the pressing is over. The composite returns back to the original three-dimensional shape and volume of the composite with some of the filler in the composite having been replaced with air after the pressing is over. Approximately 0,5-3 wt-% of excess filler is extruded from the composite after pressing. In another embodiment, due to the shape of the three-dimensional mold, some excess composite may remain in the mold after pressing. The excess filler may be recycled and used in a next batch of composite. This pressing helps create the porous or sponge-like structure where each granule in the composite has a sufficient amount of filler around the granule to bind the composite mass together. As the excess filler is extruded from the composite and the granules return to their original ellipsoid shape, porous empty space is created within the composite which forms a porous texture. The aforementioned dimensions and value ranges are exemplary embodiments for which the current disclosure is not limited to, and other such embodiments are evident to a person skilled in the art.

[0048] In an embodiment, after the composite is pressed to shape, the composite is cooled down to at least 26-45 Celsius degrees for the agar in the composite to coagulate. In another embodiment, where the coagulating agent is egg white, the composite should be pressed to shape before the egg white coagulates in the composite. In an embodiment, the adjustment of the internal temperature of the composite is performed prior to, during or after the pressing of the composite. The aforementioned embodiments are exemplary and the current disclosure does not limit itself to the embodiments and examples discussed.

[0049] Figs. 6a-6e provide an exemplary conceptual illustration of aspects of the arrangement 300 and method in accordance with an embodiment of the present disclosure. In Fig. 6a the composite is placed in the three- dimensional mold 302. In Fig. 6b the composite is pressed by the piston 304 against the water-permeable screen 306 so that the excess filler is extruded from the composite. In Fig. 6c the pressing is stopped after which the granules return to their original shape, e.g. ellipsoid shape, porous empty space is created within the composite which forms a porous texture. In Fig. 6d the three-dimensional mold is removed while the piston holds the three- dimensionally formed composite product on the water-permeable screen. In Fig. 6e the piston is removed and the three-dimensionally formed composite product 200 is left on the water-permeable screen for further processing such as heat-treatment.

[0050] In an aspect, a glucomannan-containing composite product is provided. The product is advantageously obtainable by the method according to the embodiments described hereinabove. In an embodiment, the product comprises: a coagulating agent, (b) a filler and (c) granules made of a glucomannan-containing solid material, said product being configured as a porous composite product having empty space and filler around the granules.

[0051] The composite product can be configured as any one of: sushi bites, chips, cakes, noodles, and flour, as well as any other appropriate foodstuff for human or animal consumption. In an embodiment, the composite product is a replacement for rice.

[0052] The scope of the invention is determined by the attached claims together with the equivalents thereof. The skilled persons will again appreciate the fact that the disclosed embodiments were constructed for illustrative purposes only, and the innovative fulcrum reviewed herein will cover further embodiments, embodiment combinations, variations and equivalents that better suit each particular use case of the invention.

Claims

CLAIMS1. A method (100) for manufacturing a glucomannan-containing composite product (200), the method comprising: a. producing a filler comprising a glucomannan-containing gel and a coagulating agent (102), b. mixing granules made of glucomannan-containing material and the filler together to form a composite (104), c. placing the composite on a water-permeable screen (106), and d. pressing the composite to remove at least part of the liquid and filler out of the composite, whereby a porous composite having empty space and filler around the granules has been produced (HO).

2. The method of claim 1, wherein the glucomannan-containing material and / or the glucomannan-containing gel is / are obtainable from a konjac plant and / or from wood-derived feedstocks, such as Norwegian spruce (Picea abies).

3. The method of any one of claims 1 or 2, wherein the glucomannan- containing gel is cut into angular pieces.

4. The method of any preceding claim, further comprising adjusting the internal temperature of the composite to a temperature which activates the coagulating agent (108), wherein adjustment of the internal temperature is performed prior to, during or after the step (d).

5. The method of claim 4, wherein, the internal temperature of the composite is adjusted to at least 60 Celsius degrees to activate the coagulating agent.

6. The method of any preceding claim further comprising, cooling down the composite to at least 20 Celsius degrees (112).

7. The method of any preceding claim, wherein, at step d, the composite is pressed to achieve a compression volume which is approximately5-15% of the original volume of the composite, and wherein the composite is pressed for 0,2-5 seconds per a press cycle.

8. A glucomannan-containing composite product (200) obtainable by the method according to any one of claims 1-7, the product comprising: (a) granules made of a glucomannan-containing material, and (b) a filler, wherein the product is a porous composite product having empty space and filler around the granules, wherein the composite comprises granules (a) in an amount within a range of about 60 wt-% to about 90 wt-% of the composite and filler (b) in an amount within a range of about 10 wt-% to about 40 wt-% of the composite.

9. The composite product of claim 8, wherein the filler comprises dry ingredients in an amount of 15-25 wt-%, acidic liquid in an amount of 3-6 wt-%, and glucomannan-containing gel in an amount of 69- 82 wt-%.

10. The composite product of any claim 8-9, wherein the composite comprises coagulating agent in an amount of approximately 0,3- 1,3 wt-%.

11. The composite product of any of claims 8-10, wherein the coagulating agent is agar.

12. The composite product of any of claims 8-11, wherein the filler has a pH value of 3.5-4.2.

13. The composite product of any of claims 8-12, wherein the composite is pressed to achieve a compression volume which is approximately 5-15% of the original volume of the composite, and wherein the amount of filler in the composite decreases by 0,5-3% of filler mass during the pressing of the composite.

14. The composite product of any one of claims 8-13, configured as any one of: sushi bites, chips, cakes, noodles, and flour.

15. An arrangement (300) for manufacturing a glucomannan-containing composite product (200), the arrangement comprising:- a water-permeable screen (306),- a three-dimensional mold (302), and - a piston (304) arranged to move inside the three-dimensional mold (302),- wherein the three-dimensional mold (302) is arranged on the water-permeable screen (306) and configured to receive a glucomannan-containing composite, and the piston (304) is arranged to press against the glucomannan-containing composite inside the three-dimensional mold (302) and against the water- permeable screen (306) so that at least excess fluid is removed through the water-permeable screen (306) and the glucomannan- containing composite is formed into a glucomannan-containing composite product (200).

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