LUO HAN GUO JUICE AND PREPARATION METHOD THEREOF

Abstract

Luo han guo juice and a preparation method thereof. The method comprises: preparing fresh luo han guo fruits, and washing and grinding the same; adding a macerating enzyme; and performing enzymolysis under an ultra-high pressure of 120-220 MPa and maintaining the pressure for 10-15 minutes.

Claims

1. A preparation method of LUO HAN GUO juice, wherein the method comprises the following steps: taking fresh LUO HAN GUO fruits, adding a macerating enzyme, and performing enzymolysis while maintaining an ultra-high pressure of 120 to 220 MPa for 10 to 15 min to obtain enzymolyzed LUO HAN GUO juice.

2. The method according to claim 1, wherein the method comprises the following steps: taking fresh LUO HAN GUO fruits, adding a macerating enzyme, and performing enzymolysis while maintaining an ultra-high pressure of 140 to 180 MPa for 12 to 14 min to obtain enzymolyzed LUO HAN GUO juice.

3. The method according to claim 1, wherein the enzymolysis is performed under an ultra-high pressure condition at a temperature of ≤30° C.

4. The method according to claim 1, wherein the usage amount of the macerating enzyme is 0.5‰ to 1‰ of the weight of fresh fruits, and the composition ratio of the macerating enzyme is as follows: pectinase 3500 to 5000μ/g, cellulase 100 to 200μ/g, amylase 2000 to 3000μ/g, protease 4000 to 8000μ/g, and xylanase 3500 to 5000μ/g.

5. The method according to claim 1, wherein the method comprises the following steps: taking the enzymolyzed LUO HAN GUO juice, and inactivating enzyme while maintaining an ultra-high pressure of ≥400 MPa for 5 to 10 min to obtain enzyme-inactivated LUO HAN GUO juice.

6. The method according to claim 5, wherein the method comprises the following steps: taking the enzyme-inactivated LUO HAN GUO juice, and processing by a filter press or a high-speed centrifuge to obtain clarified LUO HAN GUO juice.

7. The method according to claim 6, wherein when a filter press is used for processing, the LUO HAN GUO juice obtained after enzyme inactivation is passed through a filter screen of 200 to 400 mesh with an operating pressure of ≥0.2 MPa.

8. The method according to claim 6, wherein when a high-speed centrifuge is used for processing, the rotation speed is 2000 to 4000 r/min, and the centrifugation time is 5 to 10 min.

9. The method according to claim 6, wherein the method comprises the following steps: taking the clarified LUO HAN GUO juice, adding a yeast and treating for 30 to 480 min, and then separating the yeast to obtain LUO HAN GUO juice treated with yeast.

10. The method according to claim 9, wherein the usage amount of the yeast is 1.5‰ to 2.0‰ of the weight of the fresh fruits, and the yeast is dry yeast or fresh yeast.

11. The method according to claim 9, wherein the method comprises the following steps: taking the LUO HAN GUO juice treated with yeast, and treating with activated carbon to obtain LUO HAN GUO juice treated with activated carbon.

12. The method according to claim 11, wherein the activated carbon is used in an amount of 2.5‰ of the weight of the fresh fruits, provided with a particle size of 60 to 120 mesh, and loaded on a chromatography column with a diameter of ≥5 cm to allow the LUO HAN GUO juice treated with yeast to pass through the chromatography column.

13. The method according to claim 11, wherein the method comprises the following steps: allowing the LUO HAN GUO juice treated with activated carbon to pass through an ultrafiltration membrane, concentrating the filtrate portion by a nanofiltration membrane to obtain concentrated LUO HAN GUO juice, adjusting the pH of the concentrated LUO HAN GUO juice to 4.0 to 6.5 to obtain LUO HAN GUO juice with weakly acidic pH.

14. The method according to claim 13, wherein the molecular weight cut-off of the ultrafiltration membrane is 50,000 to 60,000 Daltons, the molecular weight cut-off of the nanofiltration membrane is 100 to 150 Daltons, and the Brix of the concentrated LUO HAN GUO juice is 5° to 65°.

15. The method according to claim 13, wherein the method comprises the following steps: taking the LUO HAN GUO juice with weakly acidic pH, and sterilizing under an ultra-high pressure of 500 to 550 MPa at a temperature of ≤30° C. and maintaining the pressure for 20 to 30 min to obtain sterilized LUO HAN GUO juice.

16. A LUO HAN GUO juice, wherein the LUO HAN GUO juice is prepared by the method of any one of claims 1 to 15.

Description

SPECIFIC MODES FOR CARRYING OUT THE EMBODIMENTS

[0032] The following examples are intended to illustrate the present invention, but are not intended to limit the scope of the present invention.

Example 1

[0033] (1) 200 kg of LUO HAN GUO fresh fruits were taken, washed and crushed, 0.1 kg of a macerating enzyme was added, and enzymolysis was performed under an ultra-high pressure of 220 MPa by maintaining the pressure for 10 min to obtain LUO HAN GUO juice (a); (2) the LUO HAN GUO juice (a) was taken, and enzyme inactivation was performed under an ultra-high pressure of 400 MPa by maintaining the pressure for 5 min to obtain LUO HAN GUO juice (b);

[0034] (3) the LUO HAN GUO juice (b) was treated with a filter press, and the LUO HAN GUO juice (b) was passed through a filter screen of 200 mesh with an operating pressure of 0.2 MPa to obtain LUO HAN GUO juice (c);

[0035] (4) the LUO HAN GUO juice (c) was taken, 0.3 kg of dry yeast was added for treatment for 30 min, and then the yeast was separated to obtain LUO HAN GUO juice (d);

[0036] (5) the LUO HAN GUO juice (d) was treated with activated carbon, wherein the usage amount of the activated carbon was 0.5 kg, the particle size of the activated carbon was 60 mesh, the activated carbon was loaded on a chromatography column with a diameter of 5 cm, and the LUO HAN GUO juice (d) was passed through the chromatography column to obtain LUO HAN GUO juice (e);

[0037] (6) the LUO HAN GUO juice (e) was passed through an ultrafiltration membrane with a molecular weight cut-off of 50,000 Daltons, and the filtrate portion was then concentrated to 5 Brix by a nanofiltration membrane with a molecular weight cut-off of 100 Daltons to obtain LUO HAN GUO juice (f);

[0038] (7) citric acid was added to adjust the pH of LUO HAN GUO juice (f) to 4.0 to obtain LUO HAN GUO juice (g); and

[0039] (8) the LUO HAN GUO juice (g) was taken, and sterilization was performed under an ultra-high pressure of 500 MPa by maintaining the pressure for 30 min to obtain LUO HAN GUO juice (h).

[0040] The above steps were all performed in an environment at a temperature of 15° C.

Example 2

[0041] (1) 200 kg of LUO HAN GUO fresh fruits were taken, washed and crushed, 0.2 kg of a macerating enzyme was added, and enzymolysis was performed under an ultra-high pressure of 200 MPa by maintaining the pressure for 11 min to obtain LUO HAN GUO juice (a);

[0042] (2) the LUO HAN GUO juice (a) was taken, and enzyme inactivation was performed under an ultra-high pressure of 400 MPa by maintaining the pressure for 6 min to obtain LUO HAN GUO juice (b);

[0043] (3) the LUO HAN GUO juice (b) was treated with a filter press, and the LUO HAN GUO juice (b) was passed through a filter screen of 300 mesh with an operating pressure of 0.6 MPa to obtain LUO HAN GUO juice (c);

[0044] (4) the LUO HAN GUO juice (c) was taken, 0.3 kg of a fresh yeast was added for treatment for 120 min, and then the yeast was separated to obtain LUO HAN GUO juice (d);

[0045] (5) the LUO HAN GUO juice (d) was treated with activated carbon, wherein the usage amount of the activated carbon was 0.5 kg, the particle size of the activated carbon was 90 mesh, the activated carbon was loaded on a chromatography column with a diameter of 6 cm, and the LUO HAN GUO juice (d) was passed through the chromatography column to obtain LUO HAN GUO juice (e);

[0046] (6) the LUO HAN GUO juice (e) was passed through an ultrafiltration membrane with a molecular weight cut-off of 50,000 Daltons, and the filtrate portion was then concentrated to 20 Brix by a nanofiltration membrane with a molecular weight cut-off of 150 Daltons to obtain LUO HAN GUO juice (f);

[0047] (7) citric acid was added to adjust the pH of LUO HAN GUO juice (f) to 4.5 to obtain LUO HAN GUO juice (g); and

[0048] (8) the LUO HAN GUO juice (g) was taken, and sterilization was performed under an ultra-high pressure of 500 MPa by maintaining the pressure for 30 min to obtain LUO HAN GUO juice (h).

[0049] The above steps were all performed in an environment at a temperature of 20° C.

Example 3

[0050] (1) 400 kg of LUO HAN GUO fresh fruits were taken, washed and crushed, 0.2 kg of a macerating enzyme was added, and enzymolysis was performed under an ultra-high pressure of 180 MPa by maintaining the pressure for 12 min to obtain LUO HAN GUO juice (a);

[0051] (2) the LUO HAN GUO juice (a) was taken, and enzyme inactivation was performed under an ultra-high pressure of 400 MPa by maintaining the pressure for 7 min to obtain LUO HAN GUO juice (b);

[0052] (3) the LUO HAN GUO juice (b) was treated with a filter press, and the LUO HAN GUO juice (b) was passed through a filter screen of 400 mesh with an operating pressure of 1 MPa to obtain LUO HAN GUO juice (c);

[0053] (4) the LUO HAN GUO juice (c) was taken, 0.6 kg of a dry yeast was added for treatment for 90 min, and then the yeast was separated to obtain LUO HAN GUO juice (d);

[0054] (5) the LUO HAN GUO juice (d) was treated with activated carbon, wherein the usage amount of the activated carbon was 1.0 kg, the particle size of the activated carbon was 120 mesh, the activated carbon was loaded on a chromatography column with a diameter of 7 cm, and the LUO HAN GUO juice (d) was passed through the chromatography column to obtain LUO HAN GUO juice (e);

[0055] (6) the LUO HAN GUO juice (e) was passed through an ultrafiltration membrane with a molecular weight cut-off of 60,000 Daltons, and the filtrate portion was then concentrated to 40 Brix by a nanofiltration membrane with a molecular weight cut-off of 150 Daltons to obtain LUO HAN GUO juice (f);

[0056] (7) citric acid was added to adjust the pH of LUO HAN GUO juice (f) to 6.5 to obtain LUO HAN GUO juice (g); and

[0057] (8) the LUO HAN GUO juice (g) was taken, and sterilization was performed under an ultra-high pressure of 530 MPa by maintaining the pressure for 25 min to obtain LUO HAN GUO juice (h).

[0058] The above steps were all performed in an environment at a temperature of 30° C.

Example 4

[0059] (1) 400 kg of LUO HAN GUO fresh fruits were taken, washed and crushed, 0.4 kg of a macerating enzyme was added, and enzymolysis was performed under an ultra-high pressure of 160 MPa by maintaining the pressure for 13 min to obtain LUO HAN GUO juice (a);

[0060] (2) the LUO HAN GUO juice (a) was taken, and enzyme inactivation was performed under an ultra-high pressure of 400 MPa by maintaining the pressure for 8 min to obtain LUO HAN GUO juice (b);

[0061] (3) the LUO HAN GUO juice (b) was treated by a high-speed centrifuge with a rotation speed of 2000 r/min and centrifugation time of 10 min to obtain LUO HAN GUO juice (c);

[0062] (4) the LUO HAN GUO juice (c) was taken, 0.8 kg of a fresh yeast was added for treatment for 240 min, and then the yeast was separated to obtain LUO HAN GUO juice (d); (5) the LUO HAN GUO juice (d) was treated with activated carbon, wherein the usage amount of the activated carbon was 1.0 kg, the particle size of the activated carbon was 120 mesh, the activated carbon was loaded on a chromatography column with a diameter of 8 cm, and the LUO HAN GUO juice (d) was passed through the chromatography column to obtain LUO HAN GUO juice (e);

[0063] (6) the LUO HAN GUO juice (e) was passed through an ultrafiltration membrane with a molecular weight cut-off of 60,000 Daltons, and the filtrate portion was then concentrated to 50 Brix by a nanofiltration membrane with a molecular weight cut-off of 100 Daltons to obtain LUO HAN GUO juice (f);

[0064] (7) citric acid was added to adjust the pH of LUO HAN GUO juice (f) to 5.5 to obtain LUO HAN GUO juice (g); and

[0065] (8) the LUO HAN GUO juice (g) was taken, and sterilization was performed under an ultra-high pressure of 530 MPa by maintaining the pressure for 25 min to obtain LUO HAN GUO juice (h).

[0066] The above steps were all performed in an environment at a temperature of 15° C.

Example 5

[0067] (1) 500 kg of LUO HAN GUO fresh fruits were taken, washed and crushed, 0.25 kg of a macerating enzyme was added, and enzymolysis was performed under an ultra-high pressure of 140 MPa by maintaining the pressure for 14 min to obtain LUO HAN GUO juice (a);

[0068] (2) the LUO HAN GUO juice (a) was taken, and enzyme inactivation was performed under an ultra-high pressure of 400 MPa by maintaining the pressure for 9 min to obtain LUO HAN GUO juice (b);

[0069] (3) the LUO HAN GUO juice (b) was treated by a high-speed centrifuge with a rotation speed of 3000 r/min and centrifugation time of 7 min to obtain LUO HAN GUO juice (c);

[0070] (4) the LUO HAN GUO juice (c) was taken, 1.0 kg of a dry yeast was added for treatment for 480 min, and then the yeast was separated to obtain LUO HAN GUO juice (d);

[0071] (5) the LUO HAN GUO juice (d) was treated with activated carbon, wherein the usage amount of the activated carbon was 1.25 kg, the particle size of the activated carbon was 90 mesh, the activated carbon was loaded on a chromatography column with a diameter of 9 cm, and the LUO HAN GUO juice (d) was passed through the chromatography column to obtain LUO HAN GUO juice (e);

[0072] (6) the LUO HAN GUO juice (e) was passed through an ultrafiltration membrane with a molecular weight cut-off of 50,000 Daltons, and the filtrate portion was then concentrated to 65 Brix by a nanofiltration membrane with a molecular weight cut-off of 100 Daltons to obtain LUO HAN GUO juice (f);

[0073] (7) citric acid was added to adjust the pH of LUO HAN GUO juice (f) to 6.0 to obtain LUO HAN GUO juice (g); and

[0074] (8) the LUO HAN GUO juice (g) was taken, and sterilization was performed under an ultra-high pressure of 550 MPa by maintaining the pressure for 10 min to obtain LUO HAN GUO juice (h).

[0075] The above steps were all performed in an environment at a temperature of 25° C.

Example 6

[0076] (1) 500 kg of LUO HAN GUO fresh fruits were taken, washed and crushed, 0.5 kg of a macerating enzyme was added, and enzymolysis was performed under an ultra-high pressure of 120 MPa by maintaining the pressure for 15 min to obtain LUO HAN GUO juice (a)

[0077] (2) the LUO HAN GUO juice (a) was taken, and enzyme inactivation was performed under an ultra-high pressure of 400 MPa by maintaining the pressure for 10 min to obtain LUO HAN GUO juice (b);

[0078] (3) the LUO HAN GUO juice (b) was treated by a high-speed centrifuge with a rotation speed of 4000 r/min and centrifugation time of 5 min to obtain LUO HAN GUO juice (c);

[0079] (4) the LUO HAN GUO juice (c) was taken, 1.0 kg of a fresh yeast was added for treatment for 360 min, and then the yeast was separated to obtain LUO HAN GUO juice (d);

[0080] (5) the LUO HAN GUO juice (d) was treated with activated carbon, wherein the usage amount of the activated carbon was 1.25 kg, the particle size of the activated carbon was 60 mesh, the activated carbon was loaded on a chromatography column with a diameter of 10 cm, and the LUO HAN GUO juice (d) was passed through the chromatography column to obtain LUO HAN GUO juice (e);

[0081] (6) the LUO HAN GUO juice (e) was passed through an ultrafiltration membrane with a molecular weight cut-off of 60,000 Daltons, and the filtrate portion was then concentrated to 50 Brix by a nanofiltration membrane with a molecular weight cut-off of 150 Daltons to obtain LUO HAN GUO juice (f);

[0082] (7) citric acid was added to adjust the pH of LUO HAN GUO juice (f) to 5.0 to obtain LUO HAN GUO juice (g); and

[0083] (8) the LUO HAN GUO juice (g) was taken, and sterilization was performed under an ultra-high pressure of 550 MPa by maintaining the pressure for 10 min to obtain LUO HAN GUO juice (h).

[0084] The above steps were all performed in an environment at a temperature of 30° C.

Comparative Example 1

[0085] The present Comparative Example is used to evaluate the difference in technical effects between the technical solution of enzymolysis carried out at a temperature of 15° C. under normal pressure with sterilization by heating and the technical solution of the present invention. The specific steps were as follows:

[0086] (1) 400 kg of LUO HAN GUO fresh fruits were taken, washed and crushed, 0.2 kg of a macerating enzyme was added, and enzymolysis was performed for 12 min at a temperature of 15° C. under normal pressure to obtain LUO HAN GUO juice (a);

[0087] (2) the LUO HAN GUO juice (a) was taken, and enzyme inactivation was performed under an ultra-high pressure of 400 MPa by maintaining the pressure for 10 min to obtain LUO HAN GUO juice (b);

[0088] (3) the LUO HAN GUO juice (b) was treated by a filter press, and the LUO HAN GUO juice (b) was passed through a filter screen of 400 mesh with an operating pressure of 1 MPa to obtain LUO HAN GUO juice (c);

[0089] (4) the LUO HAN GUO juice (c) was taken, 0.6 kg of a dry yeast was added for treatment for 640 min, and then the yeast was separated to obtain LUO HAN GUO juice (d);

[0090] (5) the LUO HAN GUO juice (d) was treated with activated carbon, wherein the usage amount of the activated carbon was 1.0 kg, the particle size of the activated carbon was 120 mesh, the activated carbon was loaded on a chromatography column with a diameter of 7 cm, and the LUO HAN GUO juice (d) was passed through the chromatography column to obtain LUO HAN GUO juice (e);

[0091] (6) the LUO HAN GUO juice (e) was passed through an ultrafiltration membrane with a molecular weight cut-off of 60,000 Daltons, and the filtrate portion was then concentrated to 60 Brix by a nanofiltration membrane with a molecular weight cut-off of 150 Daltons to obtain LUO HAN GUO juice (f);

[0092] (7) citric acid was added to adjust the pH of LUO HAN GUO juice (f) to 5.0 to obtain LUO HAN GUO juice (g); and

[0093] (8) the LUO HAN GUO juice (g) was taken, and treated at a temperature of 120° C. for 10 s to obtain LUO HAN GUO juice (h).

Comparative Example 2

[0094] The present Comparative Example is used to evaluate the difference in technical effects between the technical solution of enzymolysis carried out at a temperature of 45° C. under normal pressure with sterilization by heating and the technical solution of the present invention. The specific steps were as follows:

[0095] (1) 400 kg of LUO HAN GUO fresh fruits were taken, washed and crushed, 0.2 kg of a macerating enzyme was added, and enzymolysis was performed for 12 min at a temperature of 45° C. under normal pressure to obtain LUO HAN GUO juice (a);

[0096] (2) the LUO HAN GUO juice (a) was taken, and enzyme inactivation was performed under an ultra-high pressure of 400 MPa by maintaining the pressure for 10 min to obtain LUO HAN GUO juice (b);

[0097] (3) the LUO HAN GUO juice (b) was treated by a filter press, and the LUO HAN GUO juice (b) was passed through a filter screen of 400 mesh with an operating pressure of 1 MPa to obtain LUO HAN GUO juice (c);

[0098] (4) the LUO HAN GUO juice (c) was taken, 0.6 kg of a dry yeast was added for treatment for 60 min, and then the yeast was separated to obtain LUO HAN GUO juice (d);

[0099] (5) the LUO HAN GUO juice (d) was treated with activated carbon, wherein the usage amount of the activated carbon was 1.0 kg, the particle size of the activated carbon was 120 mesh, the activated carbon was loaded on a chromatography column with a diameter of 7 cm, and the LUO HAN GUO juice (d) was passed through the chromatography column to obtain LUO HAN GUO juice (e);

[0100] (6) the LUO HAN GUO juice (e) was passed through an ultrafiltration membrane with a molecular weight cut-off of 60,000 Daltons, and the filtrate portion was then concentrated to 60 Brix by a nanofiltration membrane with a molecular weight cut-off of 150 Daltons to obtain LUO HAN GUO juice (f);

[0101] (7) citric acid was added to adjust the pH of LUO HAN GUO juice (f) to 5.0 to obtain LUO HAN GUO juice (g); and

[0102] (8) the LUO HAN GUO juice (g) was taken, and treated at a temperature of 65° C. for 30 min to obtain LUO HAN GUO juice (h).

Comparative Examples 3 to 8

[0103] Comparative Examples 3 to 8 are used to evaluate the difference in technical effects between the technical solutions of enzymolysis by maintaining other high-pressure conditions and the technical solution of the present invention. In Comparative Examples 3 to 8, enzymolysis was performed by maintaining the pressures of 40 MPa, 60 MPa, 80 MPa, 100 MPa, 240 MPa, and 260 MPa, respectively, and the other steps were the same as those of Example 3.

Comparative Example 9

[0104] Comparative Example 9 is used to evaluate the difference in technical effects between the LUO HAN GUO juice prepared in reference document 1 and the technical solution of the present invention. The specific steps were as follows:

[0105] (1) 1 ton of LUO HAN GUO fresh fruits were taken and made into fruit pulp;

[0106] (2) citric acid was added to adjust pH to 5.5, the temperature was controlled at 50° C., and 4 kg of an immobilized fruit pulp enzyme was added;

[0107] (3) after enzymolysis for 30 minutes, the juice was filtered out with a plate and frame filter, 5 g of an ultrafiltration enzyme was added to the juice, and ultrafiltration was performed 60 minutes later;

[0108] (4) 1 kg of activated carbon was added to the obtained clarified juice, and centrifugation was performed after stirring for 5 minutes to separate the activated carbon; and

[0109] (5) vacuum concentration was performed till 50 Brix, then packaging was performed after instantaneous sterilization at an ultra-high temperature to obtain LUO HAN GUO juice (h).

Comparative Example 10

[0110] Comparative Example 10 is used to evaluate the difference in technical effects between the LUO HAN GUO juice prepared in reference document 2 and the technical solution of the present invention. The specific steps were as follows:

[0111] (1) 400 kg of LUO HAN GUO fresh fruits were taken, washed with water, inactivated and crushed, 0.4 kg of pectinase was added, extraction was performed by maintaining a temperature of 37° C. for 2 h, first filtration was performed, 4000 L of deionized water was added to the filter residue, pectinase with the same weight as that of the first added pectinase was added, the same temperature was maintained for 1 h for extraction, filtration was performed again, the first and second filtrates were combined, then microfiltration was performed, and the micro-filtrate was collected and concentrated;

[0112] (2) the concentrated LUO HAN GUO juice was dissolved with 3 times amount of deionized water under stirring, introduced to SPC-1 type cation exchange resin at a flow rate of 0.3 times amount of the resin per hour, and eluted with water after sample instruction was finished, and the effluent was collected from the time when effluent with sweet taste appeared until sweetness of the effluent was very light;

[0113] (3) the effluent from step (2) was introduced to a D208 decolorizing resin at a flow rate of 0.5 times amount of resin per hour, and eluted with water after the sample introduction was finished, and the effluent was collected from the time when effluent with sweet taste appeared until sweetness of the effluent was very light;

[0114] (4) the pH of the decolorized juice was adjusted to 6.2; and

[0115] (5) under the conditions of a vacuum degree of 0.07 MPa, a temperature of 50° C. and a pressure of 0.04 MPa, the decolorized LUO HAN GUO juice was concentrated to 60 Brix to obtain LUO HAN GUO juice (h).

[0116] Physical and Chemical Indicators

[0117] 1. Comparison of Juice Yield and Juicing Time

[0118] LUO HAN GUO juice (a) was prepared according to the methods of Examples 1 to 6 and Comparative Examples 1 to 2, and the juice yield was calculated (juice yield=(mass of LUO HAN GUO juice (a)/mass of LUO HAN GUO fresh fruits)×100%). The time taken to reach a juice yield of 20% was calculated. The comparison results were shown in Table 2.

TABLE-US-00001 TABLE 2 Comparison of juice yield and juicing time Juice yield % Juicing time (min) Example 1 74.5 20 Example 2 72.8 15 Example 3 71.6 14 Example 4 73.2 18 Example 5 74.1 15 Example 6 77.9 16 Comparative 59.7 42 Example 1 Comparative 60.5 26 Example 2

[0119] It can be seen from Table 2 that, compared with Comparative Examples 1 to 2 without ultra-high pressure treatment, Examples 1 to 6 of the present invention, in which a macerating enzyme is treated under ultra-high pressure, exhibit significantly higher juice yields, and the time taken to reach the juice yield of 20% is significantly shorter than that of Comparative Examples 1 to 2. It shows that the technical solution of the present invention adopting a macerating enzyme treated under ultra-high pressure has a better enzymolytic juicing effect than that of a macerating enzyme under ordinary conditions.

[0120] 2. Comparison of Residual Enzyme Activity

[0121] The macerating enzyme was treated according to the temperature and pressure conditions in Examples 1 to 6 and Comparative Examples 1 to 8, respectively, and the enzyme activities before and after the pressure-maintaining enzymolysis were measured (parallel measurement for 5 times). The residual enzyme activity was calculated based on the enzyme activity (RA %, RA %=A.sub.t/A.sub.O×100%, A.sub.t is the enzyme activity M/ml after high pressure treatment for a time period of t (min), and A.sub.O is the enzyme activity Mimi at the pressure-maintaining time of 0 min). The comparison results were shown in Table 3.

TABLE-US-00002 TABLE 3 Comparison of residual enzyme activities Residual enzyme activity % Pectinase Cellulase Protease Amylase Xylanase Example 1 110.26 ± 0.48 125.72 ± 0.39 108.58 ± 0.16 110.52 ± 0.46 118.69 ± 0.24 Example 2 112.71 ± 0.35 128.58 ± 0.41 115.62 ± 0.38 115.87 ± 0.72 125.18 ± 0.30 Example 3 115.18 ± 0.51 131.47 ± 0.45 126.25 ± 0.25 121.95 ± 0.65 124.37 ± 0.25 Example 4 108.34 ± 0.46 126.44 ± 0.32 109.37 ± 0.29 112.44 ± 0.52 118.75 ± 0.18 Example 5 113.29 ± 0.41 129.65 ± 0.49 118.76 ± 0.42 118.92 ± 0.68 120.66 ± 0.56 Example 6 117.52 ± 0.31 132.72 ± 0.45 125.47 ± 0.41 120.35 ± 0.49 122.72 ± 0.36 Comparative 101.25 ± 0.26  99.48 ± 0.36 101.52 ± 0.35 101.28 ± 0.58  99.14 ± 0.28 Example 1 Comparative 102.68 ± 0.45 101.28 ± 0.18 102.12 ± 0.39 103.58 ± 0.64 103.28 ± 0.42 Example 2 Comparative  89.52 ± 0.54  98.42 ± 0.45  95.44 ± 0.25  75.45 ± 0.38  84.82 ± 0.53 Example 3 Comparative  76.48 ± 0.49  86.72 ± 0.58  82.36 ± 0.42  76.92 ± 0.57  88.29 ± 0.68 Example 4 Comparative  75.26 ± 0.50  85.48 ± 0.54  81.95 ± 0.52  81.36 ± 0.42  89.22 ± 0.46 Example 5 Comparative  75.33 ± 0.64  84.26 ± 0.38  80.65 ± 0.46  82.43 ± 0.51  90.43 ± 0.21 Example 6 Comparative  95.62 ± 0.45 101.35 ± 0.28  99.72 ± 0.37  96.41 ± 0.46  98.25 ± 0.56 Example 7 Comparative  92.96 ± 0.32  95.63 ± 0.62  94.75 ± 0.58  90.86 ± 0.43  96.33 ± 0.54 Example 8

[0122] As shown in Table 3, it can be seen that, compared with Comparative Examples 1 to 8, the residual enzyme activities of each of the macerating enzymes of Examples 1 to 6 are significantly improved. The above results show that each component of the macerating enzyme treated under the ultra-high pressure of 120 to 220 MPa for 10 to 15 min exhibits significantly improved activation degree than that treated under low-temperature normal-pressure conditions and appropriate-temperature normal-pressure conditions, respectively. In addition, no matter the pressure is lower or higher than the pressure range defined by the present invention, the activity of each component of the macerating enzyme cannot be improved, and the activation of each component of the macerating enzyme is even continuously inhibited over time.

[0123] 3. Comparison of Sterilization Effects

[0124] LUO HAN GUO juice (h) was prepared according to the methods of Examples 1 to 6 and Comparative Examples 1 to 2, and samples were taken to measure the contents of microorganisms (parallel measurement for 5 times). The comparison results were shown in Table 4.

TABLE-US-00003 TABLE 4 Comparison of sterilization effects Total number Staphylococcus of aerobic Number of Number of Salmonellae aureus bacteria ≤100 molds ≤10 yeasts ≤10 Coliforms ≤10 (cf μ/25 ml) (cf μ/25 ml) cf μ/ml cf μ/ml cf μ/ml cf μ/ml not detectable not detectable Example 1 80 5 4 <1 Fit Fit Example 2 70 6 3 <1 Fit Fit Example 3 75 5 3 <1 Fit Fit Example 4 70 4 2 <1 Fit Fit Example 5 81 5 5 <1 Fit Fit Example 6 70 7 5 <1 Fit Fit Comparative 86 6 7 <1 Fit Fit Example 1 Comparative 90 8 4 <1 Fit Fit Example 2

[0125] It can be seen from Table 4 that, compared with Comparative Examples 1 to 2, there is no significant difference in each indicator such as the total number of bacteria in Examples 1 to 6 of the present invention, indicating that the sterilization effect achieved by the low-temperature ultra-high pressure sterilization adopted is equivalent to the effect of heat sterilization and meets the food requirements.

[0126] 4. Comparison of Components

[0127] LUO HAN GUO juice (h) was prepared according to the methods of Examples 1 to 6 and Comparative Examples 1 to 2 and 9 to 10, and samples were taken to measure vitamin C, amino acid, and mogroside (parallel measurement for 5 times). The comparison results were shown in Table 5.

TABLE-US-00004 TABLE 5 Comparison of components Absorbance Vitamin Total amino (460 nm, C (mg/g) acids (mg/g) Mogroside % 0.1% w/v) Example 1 0.45 ± 0.18  2.46 ± 0.37 0.51 ± 0.11 0.025 Example 2 3.08 ± 0.55 11.23 ± 1.75 1.33 ± 0.18 0.031 Example 3 2.79 ± 0.21 15.61 ± 0.97 2.72 ± 0.23 0.107 Example 4 6.25 ± 1.25 21.25 ± 2.37 6.80 ± 0.29 0.118 Example 5 6.27 ± 1.16 20.58 ± 2.28 8.91 ± 1.76 0.129 Example 6 4.93 ± 1.37 16.33 ± 1.29 5.53 ± 0.21 0.115 Comparative 2.01 ± 0.35 12.14 ± 1.87 2.52 ± 0.10 0.135 Example 1 Comparative 4.12 ± 1.75 11.52 ± 1.92 2.47 ± 0.11 0.353 Example 2 Comparative 1.24 ± 0.24  8.21 ± 1.25 2.29 ± 0.09 0.330 Example 9 Comparative 0.76 ± 0.18  1.90 ± 0.65 2.50 ± 0.11 0.175 Example 10

[0128] It can be seen from Table 5 that, compared with Comparative Examples 1, 2, 9, and 10, the components such as vitamin C and amino acids of the LUO HAN GUO juice obtained in Examples 1 to 6 of the present invention are significantly increased. It shows that the present invention activates of the macerating enzyme by adopting ultra-high pressure treatment, thereby improving the enzymolytic effect, and significantly increasing the dissolution contents of target components such as vitamin C, amino acids and mogroside; and the present invention avoids the destruction of vitamin C and amino acids caused by heat sterilization by using low-temperature ultra-high pressure sterilization subsequently.

[0129] 5. Comparison of the Sugar Contents of the Juice

[0130] LUO HAN GUO juice (h) was prepared according to Examples 1 to 6, and Comparative Examples 9 to 10, and samples were taken to measure the sugar contents of the juice. The comparison results were shown in Table 6.

TABLE-US-00005 TABLE 6 Comparison of the sugar contents of the juice Sugar contents of the juice Sucrose g/100 g Fructose g/100 g Glucose g/100 g Example 1 1< 2< 2< Example 2 3< 4< 3< Example 3 5< 9< 7< Example 4 3< 8< 6< Example 5 1< 2< 2< Example 6 1< 3< 3< Comparative 8-15 11-13  9-12 Example 9 Comparative 9-14 12-14 10-13 Example 10

[0131] It can be seen from Table 6 that, compared with Comparative Examples 9 and 10, the LUO HAN GUO juice obtained in Examples 1 to 6 of the present invention exhibit significantly reduced contents of sucrose, fructose and glucose. It shows that the sugar contents and calories in the juice of the present invention can be reduced by treating the juice with a yeast.

[0132] 6. Comparison of the Mouthfeel of the Products

[0133] The LUO HAN GUO juices (a) to (h) obtained in Example 1 were taken, and the mouthfeel were measured, respectively.

[0134] Each subject was sequentially given the LUO HAN GUO juices (a) to (h) obtained in Example 1 as the test products to be eaten with a total amount of 10 ml, which was eaten in two or three servings within 10 minutes. After each test product was eaten, it was necessary to wait for 15 min before continue to eat the next test product. Before starting of the experiment and during the waiting period, purified water and inorganic salt biscuits were used to clean up the taste of the subjects. The mouthfeel of each test product were evaluated in terms of characteristic smell, characteristic taste, sweetness, bitterness, astringency, and characteristic aftertaste. For each indicator, 0 is the minimum perception value, and 6 is the maximum perception value; and the results were expressed in average scores.

TABLE-US-00006 TABLE 7 Comparison of the mouthfeel of the products LUO HAN GUO juices a b c d e f g h Characteristic 4.8 4.5 4.6 2.5 1.4 1.0 1.2 1.2 smell Characteristic 4.2 4.4 4.3 2.6 1.8 1.5 1.4 1.4 taste Sweetness 5.7 5.6 5.7 4.5 4.4 4.3 4.3 4.2 Bitterness 2.5 2.4 2.6 1.5 1.2 1.5 1.6 1.5 Astringency 2.4 2.2 2.2 1.4 1.2 1.1 1.0 1.0 Characteristic 4.5 4.6 4.5 3.2 2.4 1.3 1.5 1.4 aftertaste

[0135] As shown in Table 7, LUO HAN GUO juices (a) to (c) exhibit no significant difference in flavor to each other, and have obvious sweetness, but still prominent characteristic smell, characteristic taste, characteristic aftertaste, bitterness and astringency, which affect the overall mouthfeel. The LUO HAN GUO juice (d) undergoing yeast treatment provides lowered scores in each item except sweetness, that is, little effect is caused on sweetness, and obvious sweetness can still be felt. The above results show that the treatment of LUO HAN GUO juice with yeast has little effect on pleasant mouthfeel such as sweetness, but can obviously eliminate the disgusting mouthfeel such as characteristic smell, characteristic taste, characteristic aftertaste, bitterness and astringency.

CONCLUSIONS

[0136] The technical solution of the present invention is superior to the prior art such as reference document 1 and reference document 2 in terms of improving the juice yield of LUO HAN GUO, shortening the juicing time, preserving the nutritional components of LUO HAN GUO juice, and improving the overall mouthfeel of LUO HAN GUO juice.

[0137] Although the general description, specific embodiments and experiments have been used to describe the present invention in detail above, some modifications or improvements can be made on the basis of the present invention, which is obvious to a person skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection of the present invention.