METHOD FOR PRODUCING PULP-CONTAINING JUICE AND PULP-CONTAINING JUICE PRODUCED THEREBY

Abstract

The present disclosure relates to a method for producing pulp-containing juice, which may produce pulp-containing juice without loss of nutrients while maintaining the flavor and color of a raw material. The method includes squeezing raw material for juice to obtain juice and sterilizing the juice by non-thermal high-pressure processing. Thus, the method may inactivate microorganisms or enzymes, maintain the quality of the juice in a fresh state, and prevent the flavor and nutrients of the raw material from being lost by high-temperature sterilization. In addition, through a quick freezing process, it is possible to prevent the layer separation phenomenon from occurring, prevent the nutrients from being destroyed by temperature changes, and maintain the uniform color of the pulp-containing juice even without using a colorant. A user can conveniently drink the pulp-containing juice produced by this method while feeling the flavor of the fruit thereof without loss of nutrients.

Claims

1. A method for producing pulp-containing juice, the method comprising: (a) squeezing raw material for juice to obtain juice; (b) filling a container with the juice and then sealing the container to produce a final product; (c) sterilizing the final product by non-thermal high-pressure processing at a pressure of 3,500 to 8,000 bar for 10 to 240 seconds to obtain a sterilized product; and (d) freezing the sterilized product at a temperature of −25 to −45° C. for 6 to 24 hours.

2. The method of claim 1, wherein the raw material in step (a) is one or more selected from the group consisting of watermelon, orange, calamansi, pineapple, guava, passion fruit, coconut, avocado, purple yam, carrot, and beet.

3. The method of claim 1, wherein step (b) comprises filtering the juice at least once through a 50 to 300-mesh filter and then filling the container with the filtered juice.

4. The method of claim 1, wherein step (c) comprises sterilizing the final product by non-thermal high-pressure processing at a pressure of 4,000 to 6,000 bar for 60 to 180 seconds.

5. The method of claim 1, wherein step (d) comprises freezing the sterilized product at a temperature of −30 to −40° C. for 10 to 18 hours.

6. Pulp-containing juice produced by the method of claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 is a process diagram showing a method for producing pulp-containing juice according to one embodiment of the present disclosure.

[0028] FIG. 2 depicts photographs showing the results of observing the layer separation phenomenon of watermelon juice, produced according to one embodiment of the present disclosure, depending on freezing conditions.

DETAILED DESCRIPTION

[0029] Hereinafter, the method for producing pulp-containing juice according to the present disclosure will be described in more detail with reference to the accompanying drawings. However, this description is provided by way of example only to facilitate the understanding of the present disclosure, and the scope of the present disclosure is not limited by this illustrative description.

Example 1. Production of Watermelon Juice

[0030] A ripe watermelon (produced in Vietnam) was washed in running water to remove foreign matter and then cut. The cut watermelon was squeezed with a hydraulic oil pressure juicer (58 to 116 psi) to obtain watermelon juice from the watermelon pulp. The watermelon juice was filtered through a 100-mesh filter, a PET bottle was filled with the filtered juice and sealed at a temperature of 10° C. or below, and a label (product information and expiration date) was attached to the bottle, thereby producing final watermelon juice. The final watermelon juice was placed in an high-pressure system and sterilized by non-thermal processing at 5,500 bar for 120 seconds. Then, the sterilized watermelon juice was transferred to a freezing warehouse and frozen at −35° C. for 12 hours. The frozen watermelon juice was packed and stored at −18° C. or below.

Test Example 1. Sensory Test

[0031] A sensory test for the watermelon juice of Example 1 and commercially available watermelon juices (Comparative Examples 1 to 3) was performed. The watermelon juice (frozen state) of Example 1 was thawed at room temperature and cold-stored, and the watermelon juices of Comparative Examples 1 to 3 were also cold-stored. [0032] Comparative Example 1: Pulmuone I'm Real Watermelon (containing 90% watermelon juice, coconut juice, and grape concentrate juice) [0033] Comparative Example 2: Tipco Watermelon watermelon juice (containing 80% watermelon juice, coconut water, purified water, and apple juice concentrate) [0034] Comparative Example 3: H2 Watermelon Juice (containing 100% watermelon)

[0035] The sensory test was performed by three panelists for color, taste and flavor based on a five-point scale as shown in Table 1 below.

TABLE-US-00001 TABLE 1 Items Scoring criteria Color 1. Good color is scored as 5. 2. Moderately good color is scored as 4 or 3 depending on the degree thereof. 3. Poor color is scored as 2. 4. Significantly poor color is scored as 1. Taste 1. Good taste is scored as 5. 2. Moderately good taste is scored as 4 or 3 depending on the degree thereof. 3. Poor taste is scored as 2. 4. Significantly poor taste, off-taste or off-flavor is scored as 1. Flavor 1. Good flavor is scored as 5. 2. Moderately good flavor is scored as 4 or 3 depending on the degree thereof. 3. Poor flavor is scored as 2. 4. Significantly poor flavor, off-taste or off-flavor is scored as 1.

[0036] The color, taste and flavor of each watermelon juice were evaluated, and the average scores thereof are shown in Table 2 below.

TABLE-US-00002 TABLE 2 Comparative Comparative Comparative Example 1 Example 1 Example 2 Example 3 Color 5 5 5 5 Taste 5 4 4 3 Flavor 5 4 3 3

[0037] As shown in Table 2 above, it was confirmed that the watermelon juice (Example 1) sterilized by non-thermal processing according to the present disclosure had an excellent taste and flavor by retaining the flavor of watermelon, compared to the watermelon juices (Comparative Examples 1 to 3) produced through thermal processing during processing of the raw materials or products.

[0038] Thereafter, the taste and flavor of each cold-stored watermelon juice were evaluated for overall changes over time six times at 2-day intervals, and the average scores thereof are shown in Table 3 below.

TABLE-US-00003 TABLE 3 Run Comparative Comparative Comparative No. Example 1 Example 1 Example 2 Example 3 1 5 5 4 4 2 5 4 4 4 3 5 4 4 3 4 5 4 3 3 5 5 4 3 3 6 5 4 3 3

[0039] As shown in Table 3 above, it was confirmed that the watermelon juice (Example 1) according to the present disclosure maintained constant color and flavor of watermelon even when it was cold-stored for two weeks after thawing, whereas the flavors of the conventional watermelon juices (Comparative Examples 1 to 3) weakened over times.

Test Example 2. Observation of Layer Separation Phenomenon Depending on Freezing Conditions

[0040] During freezing of watermelon juice, temperature- and time-dependent changes were evaluated.

[0041] The watermelon juice produced in the same manner as in Example 1 was sterilized and then frozen at each of −38° C. and −18° C. In order to observe whether the watermelon juice was separated into layers during freezing at each temperature, the images of the watermelon juice were captured after 6, 12 and 24 hours of freezing at each temperature, and the results are shown in FIG. 2.

[0042] Referring to FIG. 2, it was confirmed that, when the watermelon juice was frozen under the freezing condition (−38° C.) of the present disclosure, the watermelon juice was not separated into layers, and retained the characteristic bright red color of watermelon.

[0043] On the other hand, when the watermelon juice was frozen under the general freezing condition (−18° C.), it was confirmed that a layer separation phenomenon appeared due to floating of the pulp in the watermelon juice, and the color of the watermelon juice did not remain uniform. For this reason, in this case, a problem arose in that the commercial value of the watermelon juice was lowered.

Example 2. Production of Calamansi Juice

[0044] Ripe calamansi (produced in Vietnam) was washed in running water to remove foreign matter and then cut. The cut calamansi was squeezed to obtain calamansi juice from the pulp. The calamansi juice was filtered through a 100-mesh filter, a PET bottle was filled with the filtered juice and sealed at a temperature of 10° C. or below, and a label (product information and expiration date) was attached to the bottle, thereby producing final calamansi juice. The final calamansi juice was placed in an high-pressure system and sterilized by non-thermal processing at 5,500 bar for 120 seconds. Then, the sterilized calamansi juice was transferred to a freezing warehouse and frozen at −35° C. for 12 hours. The frozen calamansi juice was packed and stored at −18° C. or below.

Test Example 3. Physicochemical, Microbial and Sensory Tests

[0045] Physicochemical, microbial and sensory tests for the calamansi juice of Example 2 were performed. The calamansi juice (frozen state) of Example 2 was thawed at room temperature and stored at cold temperature (0 to 10° C.) or 15° C. for 9 months. During storage, pH, acidity, microbial and sensory tests for the calamansi juice were performed at 1-month intervals.

[0046] The pH was measured using a pH meter, and the acidity was measured according to the acidity measurement method of the Korean Food Standards Codex. The results of the measurement are shown in Table 4 below.

TABLE-US-00004 TABLE 4 pH Acidity Storage period 0 to 10° C. 15° C. 0 to 10° C. 15° C. After 1 month 2.3 2.4 5.1 4.8 After 2 months 2.4 2.4 5.1 4.8 After 3 months 2.5 2.4 5.0 4.9 After 4 months 2.4 2.4 5.0 5.0 After 5 months 2.4 2.4 5.1 5.1 After 6 months 2.4 2.4 5.1 5.1 After 7 months 2.4 2.4 5.1 5.1 After 8 months 2.4 2.4 5.1 5.1 After 9 months 2.5 2.4 5.1 5.1

[0047] In the microbial test, the number of bacterial cells and the number of E. coli cells were counted according to the microbial test method of the Korean Food Standards Codex, and the results are shown in Table 5 below.

TABLE-US-00005 TABLE 5 Bacterial cell count E. coli cell count Storage period 0 to 10° C. 15° C. 0 to 10° C. 15° C. After 1 month 0, 0, 0, 0, 0 0, 0, 0, 0, 0 0, 0, 0, 0, 0 0, 0, 0, 0, 0 After 2 months 0, 0, 0, 0, 0 0, 0, 0, 0, 0 0, 0, 0, 0, 0 0, 0, 0, 0, 0 After 3 months 0, 0, 0, 0, 0 0, 0, 0, 0, 1 0, 0, 0, 0, 0 0, 0, 0, 0, 0 After 4 months 0, 1, 0, 0, 0 0, 0, 0, 0, 0 0, 0, 0, 0, 0 0, 0, 0, 0, 0 After 5 months 0, 0, 0, 0, 0 0, 0, 0, 0, 0 0, 0, 0, 0, 0 0, 0, 0, 0, 0 After 6 months 0, 0, 0, 0, 0 0, 0, 0, 0, 0 0, 0, 0, 0, 0 0, 0, 0, 0, 0 After 7 months 0, 0, 0, 0, 0 0, 0, 0, 0, 0 0, 0, 0, 0, 0 0, 0, 0, 0, 0 After 8 months 0, 0, 0, 0, 0 0, 0, 0, 0, 0 0, 0, 0, 0, 0 0, 0, 0, 0, 0 After 9 months 0, 0, 0, 0, 0 0, 0, 0, 0, 0 0, 0, 0, 0, 0 0, 0, 0, 0, 0

[0048] The sensory test was performed by three panelists for changes in the appearance and sediment of the calamansi juice. For the sensory test, the limit value of the product level was set to 5 based on a limit sample level of 9, and the changes were evaluated. The average scores are shown in Table 6 below.

TABLE-US-00006 TABLE 6 Appearance Sediment Storage period 0 to 10° C. 15° C. 0 to 10° C. 15° C. After 1 month 9 8 8 8 After 2 months 8 8 8 8 After 3 months 8 8 7 7 After 4 months 7 7 7 7 After 5 months 7 7 6 6 After 6 months 6 6 6 6 After 7 months 6 6 5 5 After 8 months 6 5 5 5 After 9 months 5 5 5 5

[0049] As shown in Tables 4 to 6 above, it was confirmed that the pH, acidity, appearance and sediment of the calamansi juice (Example 2) sterilized by non-thermal processing according to the present disclosure did not change even when it was stored under the severe condition (15° C.). In addition, it was confirmed that less than acceptable levels of microorganisms were detected in the calamansi juice, indicating that the quality of the calamansi juice is maintained for a long period of time.

[0050] As described above, the method for producing pulp-containing juice according to the present disclosure includes squeezing raw material for juice to obtain juice and sterilizing the juice by non-thermal high-pressure processing. Thus, the method may inactivate microorganisms or enzymes, maintain the quality of the juice in a fresh state, and prevent the flavor and nutrients of the raw material from being lost by high-temperature sterilization. In addition, through the quick freezing process, it is possible to prevent the layer separation phenomenon from occurring, prevent the nutrients from being destroyed by temperature changes, and maintain the uniform color of the pulp-containing juice even without using a colorant.

[0051] A user can conveniently drink the pulp-containing juice produced by this method while feeling the flavor of the fruit thereof without loss of nutrients.