JP2010190442A - Method of quickly freezing sugar solution and quick-frozen ice - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a quick freezing method suitable for freezing preservation of preference beverages such as soft drink, and quick-frozen ice. <P>SOLUTION: After pre-cooling of a sample down to 2°C, temperature drop transition is continuously measured. Time dt until a temperature difference (dT) between the start temperature (2°C) and sample temperature reaches 90% of a temperature difference (ΔT) between the start temperature (2°C) and refrigerant temperature (dT=0.9×ΔT) is measured and is defined as temperature drop speed (dT/dt). It is revealed that at any refrigerant temperature levels, in the condition of dT/dt≥0.02 (°C/sec), variation of both concentration difference characteristics and melting start time characteristics decreases. It is revealed that in particular, this tendency is remarkable in the condition of 0.09 (°C/sec) or more. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a quick freezing method and quick freezing ice of an aqueous saccharide solution, and more particularly to a quick freezing method and quick freezing ice suitable for cryopreservation of a favorite beverage such as a soft drink.

When soft drinks and the like are frozen in a refrigerator or the like, a concentration distribution is generated in the ice generated on the outside and center of the bottle due to the freezing point depression due to the additive. Moreover, when ice melts, it first becomes a high concentration solution, and becomes a solution having a low concentration with time. For this reason, when drinking frozen beverages, there is a problem that the taste changes over time.
As a method for producing ice containing an additive uniformly, for example, a method according to Patent Document 1 has been proposed. As shown in FIG. 10, the uniform ice manufacturing apparatus 100 according to this method fills a stainless steel freezer container 101 around which a refrigerant pipe 102 is arranged with a frozen liquid 103 and floats an icemaker container 104 therein. A raw material liquid 106 prepared by adding a target additive to preheated water is placed in an ice making container 104, and the freezing liquid 103 is caused to flow by rotating the freezing container 101 by a motor 105 disposed at the bottom of the freezing container 101. . In this state, the ice making container 104 is immersed in the freezing liquid for about 4 to 5 hours to freeze the raw material liquid 106 in the container.

  For example, Patent Document 2 is known as a technique for producing ice having a uniform concentration by quick freezing. The production method of functional ice (rapid-frozen ice) by this technology is to freeze ice or a plurality of solutions separately to produce ice particles, and then freeze in a state where the ice particles are immersed in another liquid. To make ice in which individual components are independently incorporated. Specifically, as shown in FIG. 11A, in the functional ice manufacturing apparatus 200, a metal bowl 202 slightly smaller than the inner dimension of the tank is fitted in a tank 201 filled with ice liquid nitrogen. . A plurality of dropping nozzles 203 are installed on the tank 201, and the liquid (chlorine water) stored in the liquid tank 204 is dropped into the bowl 202 to produce fine chlorine water ice particles. Next, as shown in FIG. 2B, an ice tray 206 having a plurality of recesses is placed in an ice maker, and ice particles of chlorine water produced earlier are filled into the recesses to the edges. Place the lid 205 with a hole in the center of the recess, pour chlorine water that has been cooled to 0 ° C in advance, fill all the gaps with fine chlorine water, wait for it to freeze completely, To take out.

JP 2007-3116 JP 2002-277119 A

According to the method of Patent Document 1, although uniform ice can be formed, there is a problem that it takes a long time to manufacture.
On the other hand, the method of Patent Document 2 is characterized in that the solute is uniformly distributed as compared with ice obtained by slow freezing. Moreover, since it is in a supercooled state, the thawing start time is delayed, and the ice is in a long time. However, the purpose of this method is to produce ice containing a solute in a high concentration or ice that isolates and contains a plurality of components and performs a mixed reaction at the time of melting to achieve the function. Since it is complicated, it is unsuitable for simple quick freezing such as beverages. Furthermore, there is no disclosure about a specific temperature drop rate.

As a result of intensive studies, the inventors of the present application have found an optimum freezing method and confirmed it by a test to complete the present invention. The gist of the present invention is as follows.
That is, the quick freezing method for rapidly freezing the aqueous saccharide solution according to the present invention,
(1) A method of rapidly freezing an aqueous solution containing a carbohydrate component, wherein cooling control is performed so that a temperature drop rate (dT / dt) of the aqueous solution is 0.02 ° C./sec or more. .
In the present invention, “carbohydrate” is a polyhydric alcohol having an aldehyde group or a ketone group, and is a concept including monosaccharides, oligosaccharides, polysaccharides, and sugar derivatives.
As a quick freezing method according to the present invention, for example, a container filled with an aqueous solution containing a target carbohydrate component is immersed in an ultra-low temperature refrigerant (for example, LNG) tank, and the amount of refrigerant and the internal volume of the container are set so as to achieve the above-described temperature drop rate.・ Achievable by selecting material, thickness, etc.
Moreover, as an industrial and continuous manufacturing method, for example, it can be realized by spraying a cryogenic refrigerant onto a container filled with an aqueous solution flowing on a belt conveyor.

(2) More preferably, the cooling rate is 0.09 ° C./sec or more.
(3) The aqueous saccharide solution is 5 to 20%.
For taste beverages such as coffee, soft drinks, juice / fruit juice drinks, and sports drinks, the sugar concentration is generally 5-20%, which is suitable for the present invention.
In addition, the quick frozen ice according to the present invention,
(4) Quick-frozen ice produced by the quick-freezing method described in (1) to (3) above.

Although the object frozen by each of the above inventions melts in a room temperature environment, the solution concentration can always be kept uniform. For this reason, when it uses for a drink, for example, it can enjoy the taste which is almost the same as the drink before freezing.
Compared to ice produced by a conventional production method, it has a feature that the melting start time is slow, so that quality maintenance can be maintained even if there is temporary heat input during cryopreservation.
The ice produced according to the present invention is floated in a solution, and there is an effect that a flavor having a substantially constant concentration can be enjoyed while maintaining a cooling effect.

It is a figure which shows the test apparatus outline | summary of Example 1,2. It is a figure explaining the concept of a temperature fall rate. It is a figure which shows the density | concentration difference characteristic (The relationship between the temperature fall rate and the density | concentration difference of the melt | dissolution start and the melt | dissolution end) in Example 1 (8% sucrose aqueous solution). It is a figure which shows the melting start time characteristic same as the above (the relationship between the temperature fall rate and the time until it starts to melt). FIG. 4 is a diagram illustrating details of a concentration difference characteristic for each sample container type in Example 1. It is a figure which shows the detail for every sample container type of a melting start time characteristic same as the above. It is a figure which shows the density | concentration difference characteristic and melting start time characteristic in Example 2 (10% sucrose aqueous solution). It is a figure which shows the density | concentration difference characteristic and melting start time characteristic in Example 2 (15% sucrose aqueous solution). It is a figure which shows the density | concentration difference characteristic and melting start time characteristic in Example 2 (20% sucrose aqueous solution). It is a figure which shows the conventional uniform freezing apparatus 100. FIG. It is a figure which shows the conventional quick freezing apparatus 200. FIG.

  Hereinafter, embodiments of the quick freezing method according to the present invention will be described in more detail with reference to FIGS. Needless to say, the scope of the present invention is described in the claims and is not limited to the following examples.

<Relationship between temperature drop rate and freezing characteristics>
The heat transfer was changed by using various refrigerants with different temperature levels, and the temperature drop rate and the characteristics of the frozen ice produced were compared and evaluated.
(Test equipment)
FIG. 1 shows the outline of the test apparatus 1, and Table 1 shows the specifications of the sample / refrigerant type / sample container.
The sample container 3 into which the sample 4 (8% sucrose aqueous solution, 100 mL) is injected is placed in the freezing container 2. Next, the refrigerant 5 is put into the freezing container 2 and the sample container 3 is immersed in the refrigerant 5 (only in the case of liquid refrigerant). Further, the sample container 3 is accommodated in the temperature-controlled room 2 at a predetermined temperature (−10 ° C. or −35 ° C.) (however, LNG is installed outdoors in consideration of safety). The temperature drop rate of the sample 4 can be adjusted by the combination of the refrigerant type and the sample container type. A thermocouple 6 was placed in the center of the sample container 3 so that the transition of the temperature drop could be measured.

(Test method)
(A) Freezing process As shown in FIG. 2, after the sample is pre-cooled to 2 ° C., the temperature drop transition is continuously measured. The temperature difference (dT) between the starting temperature (2 ° C.) and the sample temperature reaches 90% (dT = 0.9 × ΔT) of the temperature difference (ΔT) between the starting temperature (2 ° C.) and the refrigerant temperature. Time dt was measured and set as a temperature drop rate (dT / dt).
(B) Transfer the ice obtained by the melting process (a) to a funnel, measure the amount of liquid that melts in a room temperature (22 ° C) environment and the change in concentration, and determine the difference in concentration between melting and melting We asked for time to start.

(Test results)
(A) Comparison of concentration difference characteristics depending on refrigerant temperature level FIG. 3 shows the relationship between the temperature drop rate and the concentration difference between the start of melting and the end of melting (concentration difference characteristics). FIG. 4 shows the relationship between the temperature drop rate and the time until melting starts (melting start time characteristics). 5 and 6 show details of the concentration difference characteristics and the melting start time characteristics for each sample container type.
From these results, it was found that the amount of change is small under the condition of dT / dt ≧ 0.02 (° C./sec) or higher for both refrigerant temperature levels in both the concentration difference characteristic and the melting start time characteristic. Further, it was found that the tendency is particularly remarkable under the condition of 0.09 (° C./sec) or more.

<Relationship between solute concentration and freezing characteristics>
In the above examples, the 8% sucrose aqueous solution was found to have substantially the same freezing characteristics under the condition where the temperature drop rate was a predetermined threshold value or more. Furthermore, in order to evaluate the difference in freezing characteristics when the solute concentration was changed, a similar test was performed using a sucrose aqueous solution having a concentration different from that in Example 1. Table 2 shows the samples, refrigerant types, and container types used in the test.

(Test results)
FIG. 7-9 shows (a) concentration difference characteristics and (b) melting start time characteristics for each aqueous solution concentration. It can be seen that, regardless of the sample concentration, the amount of change is small under the condition of dT / dt ≧ 0.02 (° C./sec) or more as in Example 1. Furthermore, it was found that the tendency is remarkable at 0.09 (° C./sec) or more.

  The present invention is widely applicable not only to beverages containing carbohydrates, such as coffee, soft drinks, juice / fruit juice drinks, sports drinks, but also to quick freezing of beverages containing teas and alcohol components.

DESCRIPTION OF SYMBOLS 1 ... Test apparatus 2 ... Freezing container 3 ... Sample container 4 ... Sample 5 ... Refrigerant 6 ... Thermocouple

Claims (4)

A method of rapidly freezing an aqueous solution containing a carbohydrate component,
A method for rapidly freezing an aqueous solution containing a carbohydrate component, wherein the aqueous solution is cooled so that the temperature drop rate (dT / dt) is 0.02 ° C./sec or more. The method for rapidly freezing an aqueous solution containing a carbohydrate component according to claim 1, wherein the rate of temperature decrease is 0.09 ° C / sec or more. The method for rapidly freezing an aqueous solution containing a carbohydrate component according to claim 1 or 2, wherein the concentration of the carbohydrate component in the aqueous solution is 5 to 20%. Quick-frozen ice produced by the quick-freezing method according to claim 1.

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