EXTRACT FROM PLANT STEEPED IN ALLULOSE AND PREPARATION METHOD THEREFOR

Abstract

The present application relates to a plant-soaked solution including a saccharide containing allulose and a method of preparing the same.

Claims

1. A plant-soaked solution comprising a saccharide containing allulose.

2. The soaked solution according to claim 1, wherein the saccharide containing allulose is included at 33 to 67 parts by weight with respect to 100 parts by weight of the soaked solution.

3. The soaked solution according to claim 1, allulose is contained at 1 to 100 parts by weight with respect to 100 parts by weight of the saccharide containing allulose based on dry content.

4. The soaked solution according to claim 1, wherein the saccharide containing allulose does not comprise sucrose.

5. The soaked solution according to claim 1, wherein the plant is fruit.

6. The soaked solution according to claim 5, wherein the fruit is Prunus mume or lemon.

7. The soaked solution according to claim 6, wherein the Prunus mume-soaked solution further comprises polyphenol.

8. The soaked solution according to claim 6, wherein the Prunus mume-soaked solution is a health-functional food for antioxidation.

9. A method for preparing a plant-soaked solution, comprising: adding a saccharide containing allulose to a plant.

10. The method according to claim 9, wherein the saccharide containing allulose is added at 50 to 200 parts by weight with respect to 100 parts by weight of the plant.

11. The method according to claim 9, wherein the saccharide containing allulose or the allulose has a crystalline form.

12. The method according to claim 9, further comprising: after the step of adding the saccharide containing alluose to the plant, further adding a new plant, which is the same as the plant, to the result of the previous step, and adding a new saccharide, which is the same as that containing allulose.

13. The method according to claim 9, wherein the method does not include adding sucrose.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG. 1 is a set of photographs of tissues of Prunus mume soaked; FIG. 1A shows the tissue of Prunus mume steeped in sucrose for 3 months, and FIG. 1B shows the tissue of Prunus mume steeped in allulose for 3 months.

[0038] FIG. 2 is a spider map of sensory evaluation for Comparative Example 3 and Experimental Example 3 of exemplary embodiments of the present application.

[0039] FIG. 3 is a graph comparing the dissolution rates of sucrose and allulose during soaking.

[0040] FIG. 4 is a set of images comparing the dissolution rates of sucrose and allulose during soaking.

MODES FOR CARRYING OUT THE INVENTION

[0041] Although the present application will be described in detail with reference to the following Examples, the following examples are provided by way of illustration, and the present application is not limited thereto.

PREPARATION EXAMPLE 1

Preparation of Prunus mume-Soaked Solutions using Allulose

[0042] Domestic Prunus mume fruit (green plum) was cleanly washed with distilled water and allowed to dry naturally for one day. Then, stems were removed, and the fruit was heated in hot water with a temperature of 100 C. for 10 minutes, and then 0.95 kg of the resulting fruit was put into a naturally-dried container (glass, capacity of 5 kg). Afterward, 0.95 kg of allulose (crystalline, purity of 99% or more, C J Cheilj edang), the same amount of the Prunus mume and the same amount of allulose were sequentially added one more time. Subsequently, the resulting product was maintained under cold and dark conditions (4 C., light-blocked condition, Korean Food Code) for 1, 2 or 3 months, and then filtered with a sieve (8 mesh). The filtrate was collected, thereby preparing Prunus mume-soaked solutions [Experimental Example 1 (maintenance for 1 month), Experimental Example 2 (maintenance for 2 months) and Experimental Example 3 (maintenance for 3 months)].

PREPARATION EXAMPLE 2

Preparation of Lemon-Soaked Solution using Allulose

[0043] Lemon was washed with baking soda, washed with distilled water to remove a pesticide residue from the surface of the lemon, and naturally dried for one day. The lemon was sliced to a thickness of 0.5 to 2 cm, and then seeds were removed. By the same method as described in Preparation Example 1, 400 g of the lemon slices were put into a container (glass, capacity: 1 kg), 400 g of allulose was added thereto, and then the same amount of lemon slices and the same amount of allulose were sequentially added one more time. Subsequently, the resulting product was maintained under cold and dark conditions (4 C., light-blocked condition, Korean Food Code) for 15 days, and then filtered with a sieve (8 mesh). The filtrate was collected, thereby preparing a lemon-soaked solution (Experimental Example 4).

PREPARATION EXAMPLE 3

Preparation of Prunus mume-Soaked Solutions and Lemon-Soaked Solution using Sucrose

[0044] Prunus mume-soaked solutions [Comparative Example 1 (maintenance for 1 month), Comparative Example 2 (maintenance for 2 months), and Comparative Example 3 (maintenance for 3 months)] and a lemon-soaked solution were prepared in the same manner as described in Preparation Examples 1 and 2 only by replacing allulose with sucrose (crystalline white sucrose, C J CheilJedang).

EXAMPLE 1

Evaluation of Prunus mume-Soaked Solutions

[0045] 1-1. Evaluation of Tissue Change

[0046] In the production of the Prunus mume-soaked solution, the moisture in the raw material of Prunus mume was drained from the inside of the tissue to outside thereof due to osmosis, thereby shrinking the tissue. Therefore, it is usually judged that the more tissue of soaked Prunus mume contracts, the further the soaking progresses. Thus, changes in Prunus mume tissues after 3 months from the start of soaking in Preparation example 1 and Preparation example 3 were visually observed.

[0047] As a result, it was confirmed that tissue of the soaked Prunus mume of Preparation Example 1 (FIG. 1B) contracted at the same level of the soaked Prunus mume of Preparation Example 3 (FIG. 1A) (FIG. 1).

[0048] 1-2. Evaluation of Physical Properties (Solid Content, pH and Color Value) of Soaked Solution

[0049] In order to verify whether the soaking was carried out in the preparation of a Prunus mume-soaked solution using allulose at the same level as in the Prunus mume-soaked solution using sucrose, physical properties (solid content, pH and color value) of Comparative Examples 1, 2 and 3 and Experimental Examples 1, 2 and 3 were measured and compared.

[0050] Specifically, the solid content (g content of solid content dissolved in 100 g of soaked solution) was measured using a refractometer (ATAGO, Automatic Digital Refractometer RX-5000), and the pH was measured using a digital pH meter (METTLER TOLEDO, SEVEN COMPACT with InLab Viscous Pro pH). 5 g of each soaked solution as a sample was put into a beaker, and then diluted using the following proportional expression of Expression 1, thereby preparing an aqueous solution diluted to 30 Brix % (hereinafter, a diluted sample). After a 1-cm cell was filled with the diluted sample, absorbance was measured at a wavelength of 420 nm using a spectrophotometer (HITACHI, Double Beam Spectrophotometer U-2900), and the color value of each sample was calculated according to the following Expression 2.

Proportional Expression: Brix % of sample x weight of sample=Brix % of diluted sample(weight of sample+weight of distilled water) [Expression 1]

Color value (IU)=AB/CD [Expression 2]

*A: Absorbance (nm) at 420 nm, B: Conversion factor 1000 to IU value, C: Length (cm) of sample cell, D: Sampling amount (g/mL)=(Brix %/100)specific gravity

[0051] Statistical analysis was performed using the SAS 9.1 program (SAS Inc., Cary, N.C., USA), and the results were analyzed using a Student's t-test. All analyses were tested for significance at p<0.05.

[0052] As a result, there were no significant changes in solid content and pH in Experimental Examples and Comparative Examples, but the color values in Experimental Examples were significantly lower than those of Comparative Examples (Table 1). Therefore, when the Prunus mume-soaked solution was prepared using allulose, the solution had the same levels of solid content and pH as that using sucrose, and had a lower color value than that using sucrose, showing that the color preference of Experimental Example 3 is better than that of Comparative Example 3.

TABLE-US-00001 TABLE 1 Solid content (Brix %) pH Color value (IU) Comparative Comparative Comparative Comparative Comparative Comparative Comparative Comparative Comparative Example 1 Example 2 Example 3 Example 1 Example 2 Example 3 Example 1 Example 2 Example 3 57.75 56.15 54.87 3.12 3.21 3.34 130 1579 2331 Experimental Experimental Experimental Experimental Experimental Experimental Experimental Experimental Experimental Example Example Example Example Example Example Example Example Example 1 2 3 1 2 3 1 2 3 53.69 53.09 53.04 3.14 3.21 3.28 74 86 163

[0053] 1-3. Confirmation of Citric Acid Content in Soaked Solution

[0054] In order to verify whether the soaking is carried out at the same level as for the Prunus mume-soaked solution using sucrose to extract useful components in the preparation of the Prunus mume-soaked solution using allulose, a content of citric acid, which is one of the major useful components of Prunus mume, in the Prunus mume-soaked solution was measured by High Performance Liquid Chromatography (HPLC).

[0055] A test solution was prepared by inputting 1 g of one sample of Experimental Example 1, 2 and 3, and Comparative Example 1, 2 and 3 into a 50 mL volumetric flask, dissolving the sample in distilled water to adjust the solution to a volume of 50 mL (20 g/L), and then filtering the resulting solution through a 0.2 m filter. A standard solution was prepared by inputting 0.5 g of citric acid monohydrate (Sigma Aldrich) into a 50 mL volumetric flask, dissolving the citric acid monohydrate in distilled water to adjust the solution to a volume of 50 mL (10 g/L), diluting the solution to concentrations of about 0.3125 g/L, 0.625 g/L, 1.25 g/L, 2.5 g/L, 5 g/L and 10 g/L, and filtering the diluted solution through a 0.2 m filter.

[0056] The prepared test solution and standard solution were analyzed by HPLC (Alliance, Waters, e2695 Separation Modules, USA/Waters Column Heater Module/RI detector Water 2414/Empower Software) under the conditions listed in Table 2 below.

TABLE-US-00002 TABLE 2 Mobile phase 5 mM H.sub.2SO.sub.4 Column 300 mm 7.8 mm Amninex 87H (Bio Rad) Flow rate 0.6 mL/min Temperature 35 C. Input volume 20 L Detector Diode Array Detector (DAD)

[0057] After HPLC analysis, a calibration curve was obtained with the citric acid content (g/L) as the abscissa axis, and an area of the chromatogram as the ordinate axis, and the citric acid area of each of Experimental Examples 1, 2 and 3 and Comparative Examples 1, 2 and 3 was read, and then the citric acid content was calculated from the calibration curve using Expression 3 below.

[00001]$\begin{array}{cc}\mathrm{Citric}.Math..Math.\mathrm{acid}.Math..Math.\mathrm{content}\left(g.Math./.Math.100.Math..Math.g.Math..Math.\mathrm{of}.Math..Math.\mathrm{soaked}.Math..Math.\mathrm{solution}\right)=\frac{\begin{array}{c}\mathrm{Concentration}.Math..Math.\mathrm{of}.Math..Math.\mathrm{obtained}.Math..Math.\mathrm{from}.Math..Math.\mathrm{calibration}\\ \mathrm{curve}.Math..Math.\left(g.Math.\text{/}.Math.L\right)\mathrm{Diluted}.Math..Math.\mathrm{volume}\left(\mathrm{mL}\right)100\end{array}}{\mathrm{Sampling}.Math..Math.\mathrm{amount}.Math..Math.\left(g\right)1000}& \left[\mathrm{Expression}.Math..Math.3\right]\end{array}$

[0058] As a result, it was confirmed that there is no significant difference in citric acid content between Experimental Examples 1, 2 and 3 and Comparative Examples 1, 2 and 3 (Table 3). Therefore, it can be confirmed that, when the soaked solution was prepared using allulose, the solution with the same level of the useful component as when using sucrose was prepared.

TABLE-US-00003 TABLE 3 Citric acid content (g/100 g of soaked solution) Comparative Comparative Comparative Example 1 Example 2 Example 3 2.0 2.1 2.9 Experimental Experimental Experimental Example 1 Example 2 Example 3 1.9 2.0 2.7

[0059] 1-4. Organoleptic Evaluation

[0060] Samples of Experimental Example 3 and Comparative Example 3 were diluted in lukewarm water at a ratio of 1:3, and each diluted sample was subjected to organoleptic analysis by 10 trained panelists to evaluate four intensity attributes (flavor/color/sour taste/sweet taste) and preference attributes (flavor/color/sour taste/sweet taste/overall preference).

[0061] Glossary of Organoleptic Evaluation

[0062] 1) Flavor intensity/preference: the intensity/personal preference of a flavor of the soaked solution

[0063] 2) Color intensity/preference: the intensity/personal preference of the lightness and thickness of the color of the soaked solution

[0064] 3) Sour taste intensity/preference: the intensity/personal preference of a sour taste

[0065] 4) Sweet taste intensity/preference: the intensity/personal preference of a sweet taste from the saccharide

[0066] 5) Overall preference: overall personal preference

[0067] As a result, as shown in Example 1-2, it was confirmed that Experimental Example 3 has a significantly lower color intensity than Comparative Example 3, but has a significantly higher color preference. It is determined that this is because Experimental Example 3 is clearer and more transparent than Comparative Example 3. It was confirmed that Experimental Example 3 exhibits similar organoleptic attributes, specifically, intensity and preference attributes, to Comparative Example 3 (Table 4 and FIG. 2).

TABLE-US-00004 TABLE 4 Comparative Experimental 5-point scale Example 3 Example 3 p-value Flavor intensity 3.4 2.9 0.09 Color intensity 3.2 2.2 0.02* Sour taste intensity 3.5 3.5 0.90 Sweet taste intensity 3.4 2.9 0.14 Flavor preference 3.2 3.1 0.75 Color preference 2.5 3.9 0.00* Sour taste preference 2.9 2.9 1.00 Sweet taste preference 3.1 2.8 0.27 Overall preference 3.2 3.1 0.72 *p < 0.05

[0068] 1-5. Confirmation of Dissolution Rates of Sugar and Allulose used in Soaked Solutions

[0069] Dissolution rates were observed by measuring heights of the remaining saccharide by elapsed days after the addition of sucrose and allulose to Prunus mume in Preparation Example 1 and Preparation Example 3. Stirring was performed 20 times at intervals of 3 days immediately after the addition of each of sucrose and allulose. The resulting solutions were allowed to stand for 6 hours, and then a height of the remaining saccharide (cm) was measured using a ruler (FIGS. 3 and 4).

[0070] As a result, it was confirmed that sucrose crystals were completely dissolved on day 31 after addition, but allulose crystals were completely dissolved on day 24 after addition. It was confirmed that, when the soaked solution was prepared using allulose, compared with when using sucrose, the convenience of use is increased due to a high dissolution rate of crystals.

[0071] 1-6. Confirmation of Allulose Dissolution

[0072] In order to verify whether the calorie reduction effect and functionality of allulose were maintained in the soaked solution prepared using allulose, it was confirmed whether allulose used in the preparation of the soaked solution was decomposed or not.

[0073] Specifically, the contents of allulose and free saccharides (sucrose, glucose and fructose) in Experimental Examples 1, 2 and 3 and Comparative Examples 1, 2 and 3 were measured using HPLC. A test solution was prepared by inputting 1 g of each sample of Experimental Example 1, 2 and 3 and Comparative Example 1, 2 and 3 into a 50 mL volumetric flask, dissolving the sample in distilled water to adjust the solution to a volume of 50 mL (20g/L), and filtering the solution through a 0.2 m filter. A standard solution was prepared by inputting 1 g of a standard product of sucrose (SigmaS7903, CAS No. 57-50-1), glucose (SigmaG7528, CAS No. 50-99-7), fructose (SigmaF0127, CAS No. 57-48-7) or allulose (SigmaP8043, CAS No. 551-68-8) into a 50 mL volumetric flask, dissolving the same in distilled water, diluting the resulting solution to a concentration of, for example, about 0.625 g/L, 1.25 g/L, 2.5 g/L, 5 g/L, 10 g/L or 20 g/L, and filtering the diluted solution through a 0.2 m filter.

[0074] The prepared test solutions and standard solutions were analyzed using HPLC (Alliance, Waters, e2695 Separation Modules, USA/Waters Column Heater Module/RI detector Water 2414/Empower Software) under the conditions listed in Table 5 below.

TABLE-US-00005 TABLE 5 Mobile phase Distilled water (HPLC Grade) Column 7.8 mm 300 mm Aminex HPX87C (Bio Rad) Flow rate 0.6 mL/min Temperature 80 C. Input volume 20 L Detector refractive index detector (RID)

[0075] After HPLC analysis, a calibration curve was obtained with the contents (g/L) of allulose and free sugars (sucrose, glucose and fructose) as the abscissa axis, and the area of the chromatogram as the ordinate axis, and the allulose and free sugar areas of each of Experimental Examples 1, 2 and 3 and Comparative Examples 1, 2 and 3 were read, and the allulose and free sugar contents were calculated from the calibration curve using Expressions 4 and 5 below.

[00002]$\begin{array}{cc}\mathrm{Allulose}.Math..Math.\mathrm{content}\left(g.Math./.Math.100.Math..Math.g.Math..Math.\mathrm{of}.Math..Math.\mathrm{soaked}.Math..Math.\mathrm{solution}\right)=\frac{\begin{array}{c}\mathrm{Concentration}.Math..Math.\mathrm{of}.Math..Math.\mathrm{obtained}.Math..Math.\mathrm{from}.Math..Math.\mathrm{calibration}\\ \mathrm{curve}.Math..Math.\left(g.Math.\text{/}.Math.L\right)\mathrm{Diluted}.Math..Math.\mathrm{volume}\left(\mathrm{mL}\right)100\end{array}}{\mathrm{Sampling}.Math..Math.\mathrm{amount}.Math..Math.\left(g\right)1000}& \left[\mathrm{Expression}.Math..Math.4\right]\\ \mathrm{Free}.Math..Math.\mathrm{sugar}.Math..Math.\mathrm{content}\left(g.Math./.Math.100.Math..Math.g.Math..Math.\mathrm{of}.Math..Math.\mathrm{soaked}.Math..Math.\mathrm{solution}\right)=\frac{\begin{array}{c}\mathrm{Concentration}.Math..Math.\mathrm{of}.Math..Math.\mathrm{obtained}.Math..Math.\mathrm{from}.Math..Math.\mathrm{calibration}\\ \mathrm{curve}.Math..Math.\left(g.Math.\text{/}.Math.L\right)\mathrm{Diluted}.Math..Math.\mathrm{volume}\left(\mathrm{mL}\right)100\end{array}}{\mathrm{Sampling}.Math..Math.\mathrm{amount}.Math..Math.\left(g\right)1000}& \left[\mathrm{Expression}.Math..Math.5\right]\end{array}$

[0076] As a result, in Comparative Example 3, it was confirmed that only 16.1 g of sucrose remains, and about 56% of the added sucrose is decomposed into glucose and fructose, whereas in Experimental Example 3, allulose remains as is without decomposition (Table 6). Therefore, in the soaked solution prepared using sucrose, calories are generated due to sucrose, glucose and fructose included therein, and a rapid increase in blood glucose may occur when ingested, but in the soaked solution using allulose, allulose is not decomposed, suggesting that a calorie reduction effect is exhibited, compared with the conventional soaked solution.

TABLE-US-00006 TABLE 6 Sucrose content Glucose content Fructose content Allulose content Com- Com- Com- Com- Com- Com- Com- Com- Com- Com- Com- Com- parative parative parative parative parative parative parative parative parative parative parative parative Example 1 Example 2 Example 3 Example 1 Example 2 Example 3 Example 1 Example 2 Example 3 Example 1 Example 2 Example 3 42.5 23.7 16.1 8.9 11.8 14.8 4.2 4.7 5.5 Exper- Exper- Exper- Exper- Exper- Exper- Exper- Exper- Exper- Exper- Exper- Exper- imental imental imental imental imental imental imental imental imental imental imental imental Example 1 Example 2 Example 3 Example 1 Example 2 Example 3 Example 1 Example 2 Example 3 Example 1 Example 2 Example 3 53.7 53.6 53.6 (Unit: g/100 g of soaked solution)

[0077] 1-7. Confirmation of Total Polyphenol Content in Soaked Solution

[0078] To verify the functionality of the Prunus mume-soaked solution, a polyphenol content in the soaked solution was measured using a microplate reader (Powerwave XS, BioTek, USA).

[0079] A 2% sodium carbonate reagent was prepared by inputting 2 g of sodium carbonate (Sigma223484, CAS No. 497-19-8) into a 100 mL volumetric flask, and adding distilled water to adjust the solution to a volume of 100 mL. A 50% Folin-Ciocalteu's phenol reagent was prepared by mixing the Folin-Ciocalteu's phenol reagent (SigmaF9252-1L) and distilled water at 1:1, and then covered with an aluminum foil to prevent light transmission.

[0080] To prepare a test solution, the soaked solution of Experimental Example 3 or Comparative Example 3 was diluted with distilled water at 1:1, 0.1 mL of the diluted solution was mixed with 0.1 mL of the 50% Folin-Ciocalteu's phenol reagent and 2 mL of the 2% sodium carbonate, the mixture was maintained in a dark room for 30 minutes, and absorbance was measured at 750 nm.

[0081] A standard solution was prepared by inputting 0.4 g of gallic acid (SigmaG7384, CAS No. 149-91-7) into a 100 mL volumetric flask, adding distilled water to adjust the solution to a volume of 100 mL, and diluting the resulting solution to a concentration of 31.25 ppm, 62.5 ppm, 125 ppm, 250 ppm or 500 ppm. After mixing the reagents as in the method used for the standard solution, the test solution was maintained in a dark place for 30 minutes, and absorbance at 750 nm was measured.

[0082] After the measurement of absorbance, a calibration curve was obtained with the absorbance of the standard solution as the abscissa axis, and the concentration of the standard solution as the ordinate axis, and a total polyphenol content of each of Experimental Example 3 and Comparative Example 3 was calculated using Expression 6 below.

Total polyphenol content (mg/mL)=(ABC)/D [Expression 6]

[0083] *A: Total volume of test solution (mL), B: Dilution factor, C: Total polyphenol concentration in test solution (mg/mL), D: Sampling volume (mL)

[0084] As a result, it was confirmed that, in Experimental Example 3, the total polyphenol content is significantly higher than that in Comparative Example 3 (Table 7). Therefore, it was confirmed that when the Prunus mume-soaked solution is prepared using allulose, the solution with a higher total polyphenol content than when using sucrose can be prepared.

TABLE-US-00007 TABLE 7 Comparative Experimental Classification Example 3 Example 3 p-value Total polyphenol 7.8 14.3 0.00* (mg/mL) *p < 0.05

[0085] 1-8. Confirmation of Antioxidant Efficacy of Soaked Solution

[0086] To verify the antioxidant efficacy of the Prunus mume-soaked solution prepared using allulose, the scavenging activity of a free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) was measured using a microplate reader (Powerwave XS, BioTek, USA).

[0087] A 100 M DPPH reagent was prepared by precisely measuring 3.9432 mg of a DPPH reagent and adjusting the reagent to a volume of 100 mL with ethanol (99.5%, Daejung Chemicals and Metals, CAS No. 64-17-5).

[0088] 1 mL of the 100 M DPPH reagent was added to each of 0.2 mL of Experimental Example 3 and 0.2 mL of Comparative Example 3, and the solution was maintained in a dark place for 15 minutes, and then absorbance was measured at 517 nm. The antioxidant efficiency of Experimental Example 3 and Comparative Example 3 was calculated using Expression 7 below.

[00003]$\begin{array}{cc}\mathrm{DPPH}\left(\%\right)=1-\left(\frac{\mathrm{Absorbance}.Math..Math.\mathrm{of}.Math..Math.\mathrm{sample}}{\mathrm{Absorbance}.Math..Math.\mathrm{of}.Math..Math.\mathrm{control}}\right)100& \left[\mathrm{Expression}.Math..Math.7\right]\end{array}$

[0089] As a result, it was confirmed that the DPPH value of Experimental Example 3 is significantly higher than that of Comparative Example 3 (Table 8). Therefore, it can be seen that when the Prunus mume-soaked solution was prepared using allulose, the solution had very high antioxidant efficiency.

TABLE-US-00008 TABLE 8 Comparative Experimental Classification Example 3 Example 3 p-value DPPH (%) 20.5 85.0 0.00* *p < 0.05

EXAMPLE 2

Evaluation of Lemon-Soaked Solution

[0090] 2-1. Evaluation of Physical Properties of Soaked Solution (Solid Content, pH and Color Value)

[0091] In order to verify whether the soaking was carried out in the preparation of a lemon-soaked solution using allulose at the same level as in a lemon-soaked solution using sucrose, physical properties (solid content, pH and color value) of the soaked-solutions of Comparative Example 4 and Experimental Example 4 were measured and compared. Methods of measuring a solid content, pH and a color value are the same as described in Example 1-2.

[0092] As a result, the solid content was 50 Brix % or more, which is the same as that of the conventional soaked solution, and there was no significant difference in pH from the lemon-soaked solution prepared using sucrose. The color value was significantly lower than that of the conventional soaked solution, showing that color preference was excellent (Table 9). Therefore, when the lemon-soaked solution was prepared using allulose, it was confirmed that the solution had almost the same levels of physical properties as the lemon-soaked solution prepared using sucrose.

TABLE-US-00009 TABLE 9 Solid Color content value Classification (Brix %) pH (IU) Comparative Example 4 59.51 3.38 2231 Experimental Example 4 55.64 3.36 1842

[0093] 2-2. Confirmation of Allulose Decomposition

[0094] In order to verify whether the low calories and functionality of allulose were maintained in the lemon-soaked solution using allulose, it was confirmed whether allulose used in the preparation of the lemon-soaked solution was decomposed or not.

[0095] Specifically, the contents of allulose and free saccharides (sucrose, glucose and fructose) in Experimental Example 4 and Comparative Example 4 were measured using HPLC, and measurement methods and HPLC analysis conditions were the same as described in Example 1-6.

[0096] As a result, it can be confirmed that, in Comparative Example 4, sucrose was decomposed into glucose and fructose, whereas allulose used in the preparation of Experimental Example 4 was not decomposed but remained as is (Table 10). Therefore, it was confirmed that allulose in the lemon-soaked solution was not decomposed like in the Prunus mume-soaked solution, and thus the calorie reduction effect and functionality of allulose can be maintained as is.

TABLE-US-00010 TABLE 10 Sucrose Glucose Fructose Allulose Classification content content content content Comparative Example 4 49.4 3.6 3.1 Experimental Example 4 56.2 (Unit: g/100 g of soaked solution)

[0097] 2-3. Confirmation of Vitamin C Content in Soaked Solution

[0098] In order to verify whether the soaking is carried out at the same level as in the lemon-soaked solution using sucrose and the useful components are extracted when allulose is used for preparation of lemon-soaked solution, the content of vitamin C, which is one of main useful components of lemon, in the lemon-soaked solution was measured by high performance liquid chromatography (HPLC).

[0099] A test solution was prepared by inputting 1 g of each sample of Experimental Example 4 and Comparative Example 4 into a 50 mL volumetric flask, dissolving the sample in distilled water to adjust the solution to a volume of 50 mL (20 g/L), and then filtering the resulting solution through a 0.2 m filter. A standard solution was prepared by inputting 0.001 g of a vitamin C standard product (L-Ascorbic acid, SigmaA5960, CAS No. 50-81-7) into a 10 mL volumetric flask, dissolving the vitamin C in distilled water to adjust the solution to a volume of 10 mL (0.1 g/L), diluting the solution to a concentration, for example, about 0.00625 g/L, 0.0125 g/L, 0.025 g/L, 0.05 g/L or 0.1 g/L, and filtering the diluted solution through a 0.2 m filter. The prepared test solutions and standard solutions were analyzed by HPLC (Alliance, Waters, e2695 Separation Modules, USA/Waters Column Heater Module/RI detector Water 2414/Empower Software) under analysis conditions listed in Table 11 below.

TABLE-US-00011 TABLE 11 Mobile phase Acetonitrile 90% + formic acid 10% Column 250 mm 4.6 mm Intersil HPLC Flow rate 0.7 mL/min Temperature 35 C. Input volume 10 L Detector diode array detector (DAD)

[0100] After HPLC analysis, a calibration curve was obtained with the citric acid content (g/L) as the abscissa axis and an area of the chromatogram as the ordinate axis, and the vitamin C areas in the test solutions of Experimental Example 4 and Comparative Example 4 were read and then the vitamin C contents were calculated from the calibration curve using Expression 8 below.

[00004]$\begin{array}{cc}\mathrm{Vitamin}.Math..Math.C.Math..Math.\mathrm{content}\left(g.Math./.Math.100.Math..Math.g.Math..Math.\mathrm{of}.Math..Math.\mathrm{soaked}.Math..Math.\mathrm{solution}\right)=\frac{\begin{array}{c}\mathrm{Concentration}.Math..Math.\mathrm{of}.Math..Math.\mathrm{obtained}.Math..Math.\mathrm{from}.Math..Math.\mathrm{calibration}\\ \mathrm{curve}.Math..Math.\left(g.Math.\text{/}.Math.L\right)\mathrm{Diluted}.Math..Math.\mathrm{volume}\left(\mathrm{mL}\right)100\end{array}}{\mathrm{Sampling}.Math..Math.\mathrm{amount}.Math..Math.\left(g\right)1000}& \left[\mathrm{Expression}.Math..Math.8\right]\end{array}$

[0101] As a result, it was confirmed that there is no significant difference in vitamin C content between Experimental Example 4 and Comparative Example 4 (Table 12). Therefore, it was confirmed that, when the lemon-soaked solution was prepared using allulose, the solution with the same level of the useful component as when using sucrose was prepared.

TABLE-US-00012 TABLE 12 Vitamin C Classification (mg/100 g of soaked solution) Comparative Example 4 30.5 Experimental Example 4 28.3