Steviol glycoside solution

Abstract

Steviol glycoside solutions and methods of making steviol glycoside solutions are described. The steviol glycoside solutions are clear and stable, and have long-term stability of the clear solution.

Description

Background of the Invention

[0002] This invention relates to a method for preparing a stable steviol glycoside solution, which can be used as a sweetener, flavoring agent, flavor enhancer, etc. in food, beverages and other products.

[0003] With increasing awareness that many diseases are linked to the consumption of sugary foods and beverages, there is growing interest in sugar alternatives. However, due to safety concerns, many artificial sweeteners such as cyclamate, saccharin, and artificial sweeteners are banned or restricted in some countries. Therefore, naturally derived, calorie-free sweeteners are gaining popularity. The sweet herb stevia (Steviarebaudiana) produces many diterpenoid glycosides, which possess superior sweetness and sensory properties compared to many other highly effective sweeteners.

[0004] The aforementioned glycosides share a common glycosidic aglycone, steviol, and differ in the number and type of carbohydrate residues at the C13 and C19 positions. Stevia leaves can accumulate up to 10-20% (based on dry weight) of steviol glycosides. The main glycosides found in stevia leaves are leboside A (2-10%), leboside (2-10%), and leboside C (1-2%). Other glycosides such as leboside B, D, E, and F, steviol disaccharides, and raspberry glycosides are found in lower amounts (approximately 0-0.2%).

[0005] Two major glycosides—stevioside and rebaudioside A (reb A)—have been extensively studied and characterized in terms of their suitability as commercially viable high-intensity sweeteners. Stability studies in carbonated beverages have confirmed their thermal stability and pH stability (Chang SS, Cook, JM (1983) Stability studies of stevioside and rebaudioside A in carbonated beverages. J. Agric. Food Chem. 31: 409-412).

[0006] The differences between steviol glycosides lie not only in their molecular structure but also in their taste characteristics. It is generally found that sucrose glycoside is 110-270 times sweeter than sucrose, leptoside A is 150-320 times sweeter, and leptoside C is 40-60 times sweeter. Dulcoside A is 30 times sweeter than sucrose. Leptoside A has the least astringency, the least bitterness, and the shortest lingering aftertaste, thus possessing the most favorable sensory properties among the major steviol glycosides (Tanaka O. (1987) Improvement of taste of natural sweeteners. Pure Applied Chem. 69: 675-683; Phillips KC (1989) Stevia: steps in developing a new sweetener. In: Grenby The ed. Developments in sweeteners, vol. 3. Elsevier Applied Science, London. 1-43).

[0007] Methods for extracting and purifying glycosides from stevia (Stevia rebaudiana) using water or organic solvents are described, for example, in U.S. Patent Nos. 4,361,697; 4,082,858; 4,892,938; 5,972,120; 5,962,678; 7,838,044 and 7,862,845, each of which is incorporated herein by reference in its entirety.

[0008] In addition to extracted and purified steviosides, modified steviosides are frequently used due to the enhanced functional and sensory properties achieved through modification.

[0009] Despite the benefits of using steviol glycosides and their modified forms, the solubility and stability of steviol glycosides in clear solutions remain issues for their use in consumer food and beverage products, particularly those prepared on a commercial scale. Stevia-derived components, especially those in higher purity, face solubility challenges in aqueous solutions. While crude stevia leaf extracts can be water-soluble, steviol glycosides become difficult to dissolve and maintain in solution when purified from the leaf extracts. Purified steviol glycoside extracts typically have water solubility values ​​of 0.05% to 1% (w / w) at room temperature and are difficult to maintain in clear solution form for extended periods.

[0010] Commercial food and beverage production typically requires the use of stable ingredients that can be delivered in various forms and can withstand temperature changes, forces, and chemical interactions with other ingredients.

[0011] Therefore, there is a need to provide a steviol glycoside solution that can be used in liquid form and remains stable over time and under various conditions. Invention Overview

[0013] This invention relates to overcoming the problems associated with using steviol glycosides in liquid form. The invention describes a method for preparing stable, clear liquid steviol glycoside components, which can be used as sweeteners, sweetness enhancers, flavoring agents, and / or flavor modifiers in a variety of foods and beverages.

[0014] The method of the present invention includes the following steps: providing steviol glycosides, combining them with a polyol (e.g., propylene glycol), optionally heating the mixture under stirring, and subsequently cooling the mixture to obtain a liquid steviol glycoside component. The liquid steviol glycoside component is a clear solution that is stable for extended periods under various conditions. In some embodiments, the liquid steviol glycoside component is a visually clear solution that is stable for at least 45 days.

[0015] The liquid steviol glycoside component comprises steviol glycosides found in the stevia plant. The steviol glycosides are selected from the group consisting of stevia glycosides, any leucoside, such as leucoside A, leucoside B, leucoside C, leucoside D, leucoside E, leucoside F, leucoside I, leucoside M, leucoside N, leucoside O, dulcitin A, steviol disaccharides, raspberry glycosides, and steviol glycosides found in the stevia plant, and mixtures thereof. In one embodiment, the steviol glycoside is a highly purified steviol glycoside, for example, having a purity greater than 90%, 95%, 97%, or 99%. Non-limiting examples of highly purified steviol glycosides include highly purified leucoside A and highly purified leucoside D. Methods for purifying steviol glycosides are described in U.S. Patent Nos. 7,862,845, 8,293,302 and 8,377,927, each of which is incorporated herein by reference in its entirety.

[0016] In other embodiments, steviol glycosides may be used in the form of a stevia extract comprising a mixture of steviol glycosides. The extract may be obtained by any step of an aqueous extraction method, such as that described in U.S. Patent No. 7,838,044. The extract may contain near-original proportions of steviol glycosides found in the plant, or may undergo intermediate extraction and / or purification steps to provide the desired concentrations and proportions of steviol glycosides. In some embodiments, certain steviol glycosides, such as rebaudioside A, rebaudioside B, rebaudioside D, etc., are present in the stevia extract at desired concentrations.

[0017] The liquid steviol glycoside component may additionally or optionally contain modified steviol glycosides, such as glycosylated steviol glycosides. Glycosylated steviol glycosides have one or more glucose units linked to the C-13 and / or C-19 positions of the steviol glycoside structure. In some embodiments, 1-2 glucose units are added. In other embodiments, 3-9 or 10-20 glucose units, or combinations thereof, are added to the steviol glycoside. Methods for glycosylated steviol glycosides are described in U.S. Patent Nos. 8,257,948, 8,318,232, 8,318,459, 8,323,716, 8,501,261, 8,669,077, 8,735,101, 8,911,971, 8,993,269, and 9,055,761, each of which is incorporated herein by reference in its entirety. It has been found that glycosylated steviol glycosides affect the sweetness and / or flavor characteristics of the added product.

[0018] In one embodiment, steviol glycosides first undergo a gradient heating process to improve their solubility. The solubility of steviol glycosides can also be improved by using a gradient cooling method following the gradient heating method. Examples of such gradient heating and gradient cooling methods are described in U.S. Patent No. 8,993,028 and U.S. Patent Application Publication No. 20,130,330,463, each of which is incorporated herein by reference in its entirety.

[0019] The obtained liquid steviol glycosides can be used as sweeteners, sweetness enhancers, flavor enhancers and flavor modifiers in various foods and beverages, including soft drinks, liquid beverage enhancers, non-carbonated beverages, ice cream, biscuits, bread, juices, milk or dairy products, baked goods and confectionery products.

[0020] It should be understood that both the foregoing general description and the following detailed description are exemplary and explanatory, and are intended to provide further explanation of the claimed invention. Invention Details

[0022] The advantages of the present invention will become more apparent from the detailed description given below. However, it should be understood that although preferred embodiments of the invention are indicated, the detailed description and specific examples are given by way of example only, as various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art from this detailed description.

[0023] The solubility and stability of clear solutions of steviol glycosides affect their use in systems, with solubility, stability, or both being important factors. Typical steviol glycosides have water solubility levels ranging from less than 0.01% to approximately 2% at room temperature. Even when steviol glycosides have suitable solubility, the stability of the resulting solutions is typically short-lived, usually ranging from minutes to hours, making such solutions difficult to use in commercial production processes.

[0024] As used herein, the term "solubility" should be defined as the ability of steviol glycosides to form a visually clear solution. The expression "steviated solution stability" should be defined as the duration for which a steviol glycoside solution remains clear. "Clear" as used herein should be defined as visually clear, without visible precipitation or turbidity. The expression "steviol glycoside" should include any steviol glycoside, combinations of steviol glycosides, and modified forms of steviol glycosides.

[0025] Stevioside components can be used in high-purity forms or as blends, offering functional and sensory advantages. Depending on the desired results, blends can include two or more steviol glycosides or modified steviol glycosides in various proportions. In some blends, one steviol glycoside may form the majority of the blend, or steviol glycosides may be present in approximately equal amounts within the blend. Other forms of steviol glycoside components include extracts, which may be minimally processed to remove most plant impurities, or moderately or heavily processed to increase the concentration of the desired steviol glycosides in the extract.

[0026] In one embodiment, it has been surprisingly found that using propylene glycol or other polyols to dissolve the steviol glycoside components, particularly steviol glycoside blends, provides solubility and clear solution stability to the resulting solution. Propylene glycol is provided in an aqueous solution at a concentration in the range of about 10-50% w / w (propylene glycol to water). The steviol glycosides, whether in pure form or blends, are added to the propylene glycol, optionally first heated to a temperature of about 70°C to about 90°C, or about 75°C to about 85°C. In some embodiments, the propylene glycol is first heated to a temperature of about 80°C. While adding the steviol glycoside components to the propylene glycol or heated propylene glycol, the mixture is continuously stirred until the steviol glycosides are completely dissolved. The resulting solution is visually clear and has a clarity similar to, substantially equivalent to, or equivalent to that of pure water.

[0027] In another embodiment, it was surprisingly found that propylene glycol in a substantially anhydrous system was able to dissolve steviol glycosides, particularly steviol glycoside extracts, producing a highly concentrated solution of steviol glycosides and providing the resulting solution with excellent solubility and clear solution stability. As used herein, the expression "substantially anhydrous system" means that no quantifiable amount of water is added to the system, and any water present in the system is merely a trace amount that can be inherently included in the solution components.

[0028] If propylene glycol or other polyols are heated, the liquid steviol glycoside solution is then cooled to room temperature (approximately 20°C to 25°C) for further application. The resulting solution remains clear for an extended period, from one week to one month.

[0029] Surprisingly, this method can prepare relatively high concentrations of steviol glycoside solutions, ranging from approximately 5 wt% to 40 wt%, compared to the conventional solubility levels described above. This represents an increase in solubility of approximately 2.5 to 4000 times compared to aqueous solutions of the same steviol glycosides. In some embodiments, a 2000-fold increase in solubility compared to the water solubility of the same steviol glycosides was observed. Even at these high concentrations, the steviol glycoside solutions remain clear over time.

[0030] The following embodiments are intended to enable implementation and are illustrative, not to limit the invention, the full scope of which is defined in the appended claims.

[0031] Comparative Example 1: Desktop Stevioside Sweetener

[0032] Based on the instructions provided on the website, the solubility of commercially available desktop steviol glycoside sweeteners in water and propylene glycol was evaluated.

[0033] Mix 3g of tabletop sweetener with 9ml of propylene glycol to obtain a 30% mixture. Microwave the mixture, shake by hand, and cool, repeating this process 6 times. The mixture forms a highly viscous, coarse, opaque paste.

[0034] Comparative Example 2: Commercially available, highly purified stevia extract

[0035] Reb A 97 (available from Tereos PureCircle solution) www.stevia-tereos- purecircle.com It was mixed with propylene glycol in the same manner as in Comparative Example 1. A similar viscous, coarse, opaque paste was formed.

[0036] Example 1: Blend of Stevioside Components

[0037] Blends of three commercially available steviol glycosides were prepared as follows:

[0038] Table 1A

[0039] Steviosides Amount(%w / w) Reb A+ chamomilein ≥75 Reb C+ Hedyotis diffusa glycosides ≥8 Total steviol glycosides ≥95

[0040] A series of propylene glycol solutions were prepared and each heated to approximately 80 °C. Stevioside blends were added to the propylene glycol solutions at different concentrations under constant stirring, while simultaneously maintaining the solution temperature at approximately 80 °C. The time to form a clear steviol glycoside solution was measured. The resulting steviol glycoside solutions were allowed to cool, and each solution was then aliquoted into two samples: one stored at room temperature (approximately 20 °C), and the other refrigerated at approximately 4 °C. The stability of the clear solution of the steviol glycoside components was measured after 60 days. The results are shown in Table 1B.

[0041] Table 1B

[0042] % Stevia 5％ 10％ 20％ 25％ 30％ 40％ Blend I 10g 20g 40g 50g 60g 80g Propylene glycol 100g 100g 80g 75g 70g 60g water 90g 80g 80g 75g 70g 60g total 200g 200g 200g 200g 200g 200g 60-day room temperature stability clarify clarify clarify clarify Slightly cloudy Slightly cloudy 60-day refrigeration temperature stability clarify clarify clarify clarify Slightly cloudy Slightly cloudy

[0043] Example 2: Solubility of various stevia sweeteners in propylene glycol and water in a 50:50 ratio

[0044] A solution of 50% propylene glycol and 50% water was heated to approximately 80°C. Each stevia blend was tested at different concentrations to determine the maximum solubility of the product. Stevia glycoside blends were added to the propylene glycol solution at different concentrations under constant stirring, while maintaining the solution temperature at approximately 80°C. The time to form a clear steviol glycoside solution was measured. The resulting steviol glycoside solutions were allowed to cool, and each solution was then aliquoted into two samples: one stored at room temperature (approximately 20°C), and the other refrigerated at approximately 4°C. The stability of the clear solution of the steviol glycoside components was measured after 60 days. The blend composition is shown in Table 2A, and the solubility and clarification results are shown in Table 2B.

[0045] Table 2A

[0046] sample Stevia blend Total steviol glycosides (%) 1 Leptoside A ≥ 50% ≥95％ 2 Lebodiin A ≥ 97% ≥95％ 3 Lebodiin A ≥ 99% ≥95％ 4 Lebodiin B ≥95％ 5 Leptoside A ≥ 70% ≥95％ 6 Lebodiin D≥50% ≥95％

[0047] Table 2B

[0048] sample Comment 1 20% w / w clarification and 1 month stabilization 2 20% w / w clarifies and stabilizes in 1 week, turns into a solid in 1 month. 3 Insoluble 4 20% w / w turns solid within 30 minutes 5 20% w / w clarifies and stabilizes in 1 week, becomes a semi-solid paste in 1 month. 6 Try at 10% w / w; an insoluble paste forms.

[0049] Liquid beverage enhancers

[0050] Liquid beverage enhancers, often referred to as "drops," have become very popular for flavoring, sweetening, coloring, or enhancing beverages such as water, tea, coffee, or other aqueous drinks. These beverage enhancers are typically clear solutions and usually contain a high concentration of water-soluble sweeteners. Standard serving sizes, such as 8, 16, or 24 ounces of beverage, require a high concentration to sweeten, flavor, or otherwise enhance the beverage using only one or a few drops of enhancer.

[0051] Consumers expect these enhancers to be clear and free of visible crystals or cloudiness during their shelf life. Other enhancers, such as some coffee flavorings, do not necessarily need to be clear; they can resemble milk or cream and are ideally smooth and flowable in their consistency, free of crystals or particles.

[0052] It was unexpectedly discovered that by using a substantially anhydrous system, liquid beverage enhancers using only stevia-based ingredients as sweeteners can be prepared, and these enhancers remain clear and stable throughout their desired shelf life. In some embodiments, the stevia-based ingredients are present in an amount of 5-10% w / w, such as 8 wt% or 9 wt%. In one embodiment, the substantially anhydrous system comprises food-grade propylene glycol. Other food-grade polyols include glycerol, sorbitol, and mannitol.

[0053] Example 3: Liquid Beverage Enhancer

[0054] Prepare liquid beverage enhancers using the formulations listed in Table 3.

[0055] Table 3

[0056] Element quantity Propylene glycol 34.25ml Stevia extract 3g Maleic acid 10g Potassium sorbate 0.5g Potassium citrate 1.25g Flavorings 0.825g

[0057] The liquid beverage enhancer was prepared using the following steps. A measured volume of propylene glycol was heated and maintained at 80°C, then maleic acid was added, and the mixture was sonicated and vortexed periodically to dissolve the maleic acid in the propylene glycol. Stevia extract powder was then added and dissolved, followed by the addition of dissolved potassium sorbate. Potassium citrate was added, and the mixture was sonicated and vortexed periodically until the potassium citrate was also dissolved. The solution was then cooled to room temperature, flavoring was added, and the mixture was thoroughly mixed to form the liquid beverage enhancer.

[0058] The order of steps described above can be changed, some steps can be omitted or modified to produce liquid beverage enhancers.

[0059] It should be understood that the foregoing description and specific embodiments shown herein are merely illustrative of the best mode and principles of the invention, and modifications and additions can be made by those skilled in the art without departing from the spirit of the invention. The entire scope of the invention is defined by the appended claims.

Claims

1. A method for preparing a stable, clear liquid solution of steviol glycosides, comprising the following steps: a. Provide steviol glycosides comprising ≥75% w / w Reb A and chamomile glycosides, ≥8% w / w Reb C and chamomile glycosides, and ≥95% w / w total steviol glycosides; b. Provide a solvent system comprising propylene glycol and water, wherein the w / w ratio of propylene glycol / water is 50:50 to 100:80; c. Before mixing the steviol glycosides of (a) into the heated solvent, heat the solvent system to a temperature of 80°C to 95°C; and d. Steviol glycosides of (a) are mixed in a heated solvent of (c), wherein the mixture is constantly stirred while the temperature of the solvent is maintained at 80°C to 95°C until the steviol glycosides dissolve, thereby providing a stable, clear liquid solution of steviol glycosides having a steviol glycoside concentration of 5 wt% to 25 wt%. The stable, clear liquid steviol glycoside solution exhibits 45-60 days of clear solution stability at a steviol glycoside concentration of up to 25% w / w.

2. The method of claim 1, wherein steviol glycosides are prepared by a gradient heating and gradient cooling method.

3. The method of claim 1, wherein the w / w ratio of propylene glycol / water is 100:90, 100:80, or 50:

50.

4. The method of claim 1, wherein the steviol glycoside solution is cooled after dissolving the steviol glycoside.

5. The method of claim 4, wherein the steviol glycoside solution is cooled to about 20°C.

6. The method of claim 1, wherein the steviol glycoside solution is visually clear and free from visible turbidity or cloudiness.