JPS62272957A - Clarification of fruit juice - Google Patents

Abstract

PURPOSE:To carry out clarification of fruit juice keeping the average membrane permeation rate at a high level over a long period and facilitating the cleaning of stained membrane surface, by supplying a fruit juice e.g. to a hollow fiber UF membrane module, etc., while periodically repeating the permeation of the juice, the closure of the delivery port of the permeate liquid and the release of applied pressure for a specific time. CONSTITUTION:Concentrated and reduced juice of orange, lemon, pineapple, etc., is clarified with a hollow fiber UF membrane module, etc., having high space efficiency and energy efficiency. In the above process, the average permeation rate of membrane can be maintained at a high level over a long period by periodically repeating the closure of the delivery port of the membrane permeate liquid for >=20sec and the release of applied pressure at an interval of <=30min, thereby removing the fouling of the membrane surface by the flow of supplied fruit juice and recovering the lowered permeation rate of the membrane.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention (Field of Industrial Application) Fruit juice is often consumed in its raw form as a beverage, but it can also be used as a component of a beverage in a mixed and prepared state. Demand for fruit juice that does not produce cloudiness and maintains its clear state has been increasing recently. The present invention provides a method for producing clarified fruit juice having the above characteristics from raw fruit juice. Target fruit juices include citrus fruits (Wenzhou, Heshuo, etc.), berries (strawberries, etc.), and plums (
Contains almost all fruit juices such as plums, peaches, etc.), apples, grapes, pineapple, etc.

(Prior Art) A method has been put into practical use in which suspended pulp is removed by centrifugation or ultracentrifugation, and then dissolved pectin is decomposed using an enzyme such as pectinase. but,
As the enzymatic reaction is carried out at a high temperature of 40 to 60 degrees Celsius for several hours or more, it loses its aroma and adds a characteristic odor, making it impossible to avoid deterioration of the quality of the fruit juice.Furthermore, the enzymes used are expensive, so clarification is difficult. The disadvantage is that the cost of conversion is high.

As a way to overcome these drawbacks, ultra-I membranes can be used to treat pectin at room temperature. Other methods of removal are being tested.

(Problems to be Solved) A problem with the method of treating fruit juice with an ultra-I membrane is that the membrane permeation rate rapidly decreases over time. For this reason, a large-scale membrane device is required to process a predetermined amount of fruit juice in a predetermined time, and this drawback may prevent the method from being advantageous enough to replace the enzymatic method.

The present invention has devised a simple and inexpensive membrane permeation rate recovery method in the process of membrane treatment of fruit juice, and by periodically applying this method, the average membrane permeation rate can be maintained high and the drawbacks of increasing the scale of membrane equipment can be overcome. It's something you try to overcome.

As a method to recover the decreased membrane permeation rate, surfactants, acids,
Washing conditions using alkali, oxidizing agents, enzymes, hot water, etc. are well known and are very effective if properly selected. However, this method can only be carried out after the operation has been completed and the liquid has been recovered. Membrane permeation rate recovery methods that can be carried out during operation include reversing the flow direction of the stock solution, flushing at high speed to remove the fouling layer, creating an air-liquid interface by blowing air bubbles into the stock solution, and adding gas to the stock solution. There are methods such as a method of scraping with a solid material such as a sponge ball, and a method of reversely permeating the permeated liquid to remove a fouling layer on the membrane surface.

However, the method of adding air bubbles or solids is only possible with tubular membrane modules, and cannot be applied to hollow fiber membrane modules or spiral or pleated modules, which have good space and energy efficiency. Although the method of allowing a portion of the permeate to pass back through is effective, it has the disadvantage of returning the liquid that has permeated the cornea back to the original solution, and the disadvantage that it requires a pump to pressurize the permeate for reverse permeation. The simplest method is to reverse the flow direction of the stock solution or release the applied pressure to flush the solution at high speed, but it is less effective.

(Means for Solving the Problems) As a result of intensive research, the present inventors have considered a simple and effective method for restoring membrane permeation rate. That is, the permeate outlet is closed to stop membrane permeation, preferably the back pressure regulating valve is opened to flush the stock solution, and more preferably the flow direction of the stock solution is reversed. 30
This membrane permeation rate recovery method is characterized by continuing for 20 seconds or more, preferably 1 minute or more, at intervals not exceeding 1 minute.

(Effects of the Present Invention) According to the method of the present invention, the membrane surface contaminated by fruit juice treatment can be cleaned by a simple operation, and the membrane permeation rate is restored. By carrying out this process periodically, the average membrane permeation rate can be maintained high for a long period of time, thereby reducing the capital investment required to increase the scale of the membrane device in advance of anticipating fouling of the membrane surface.

(Example) The following will be explained based on examples.

Comparative example 1 Satsuma mandarin orange straight fruit juice (sugar content Brix 10.7°
) 50 / with a gap of 0.2 mm x 0.2 mn + I
After passing it through a cloth, use the device shown in Figure 1 to pump the pump at a pump discharge rate of 1 or 2 m3/h and a module outlet pressure of 1 kg7cm.
It is supplied to the hollow fiber UP membrane module under the following conditions: clarified fruit juice type, effective membrane area 0.44 m, hollow fiber inner diameter 0.8 mm
, hollow fiber effective length 270cm, membrane material polyether sarpsin inhibitor (molecular weight 280,000) rejection rate 65-85%
, ovalbumin (molecular weight 45,000) has an exclusion rate of 99% or more.

As shown in FIG. 2, the membrane permeation rate (=clarified juice production rate) decreased rapidly over time.

Therefore, an operation was performed to reverse the flow direction of the stock solution in the module every 20 minutes, but no effect was observed in preventing or reducing the decrease in permeation rate over time.

Example 1 Comparative example! Clarified fruit juice was produced using the same juice, the same module, and the same conditions. Instead of reversing the flow direction of the stock solution every 20 minutes, the permeate outlet was closed for 2 minutes every 30 minutes.

In addition, the flow direction of the stock solution during the operation of closing the permeate outlet was alternately kept as it was and reversed.

The results are shown in Figure 3. Closing the permeate outlet and flowing the stock solution has a great effect in restoring the reduced membrane permeation rate, and it is even more effective to reverse the flow direction of the stock solution at that time. The permeation rate recovery effect of this operation is shown in Table 1 as a recovery rate defined by the following equation.

Rn: Transmission rate recovery rate (%) Pn: Transmission rate immediately after operation P'n-1: tt Immediately before 〃Pn-,:
2 Immediately after the previous operation Table 1 Example 2 Satsuma mandarin orange concentrate juice (sugar content Brix 11.1°)
30! Is it rough with 7 cloths with air gap Q, 2ms+X0.2ram?
After that, a membrane permeation experiment was conducted using the apparatus of Comparative Example I under the same conditions. The permeate was also refluxed to the tank except for a small amount of sampling, so that the concentration of the stock solution was kept constant.

FIG. 4 shows the effects on the recovery effect of varying the interval and closing time of closing the permeate acid outlet and simultaneously reversing the flow direction of the stock solution. The effects of each operation are expressed in terms of permeation rate recovery rate and are shown in Table 2. When the operation was performed at 10 minute intervals, a remarkable recovery effect was observed when the operation time was 20 seconds or longer, and approximately 100% recovery was observed when the operation time was 1 minute or longer.

Also, by comparing operations (b), (d), and (f) in Table 1, the effect decreases when the interval between operations is 40 minutes or more. *It should have recovered with the previous recovery operation, but the operation time was short and it recovered. It became bigger because I was also recovering from what I couldn't do. Therefore, when calculated for the operation before the previous one, it becomes 100%.

Example 3 Lemon concentrated and reduced juice (sugar content Brix 6.0') 15/
was supplied to the hollow fiber UP membrane module for clarification using the same small flow line device used in Comparative Example I under conditions of pump discharge rate of 0.6 m''/h and module outlet pressure of 1.6 kg/cn+'. Fruit juice was produced.The module used was the same as that used in Comparative Example 1 except that the number of hollow fibers was half and the effective membrane area was 1/2.During operation, the permeate (= The process was continued for 2 hours while closing the outlet for clear fruit juice for 1 minute and reversing the flow direction of the stock solution.The permeation rate recovery rate for each operation was 57% as shown in Figure 5. 80%, 86%, 100%
.

The average was 74% with 75%, 80%, 63%, and 50%.

Example 4 Pineapple concentrate reduced fruit juice (sugar content Brix 11.3°
) 201 with an I cloth having a gap of 0.2 mm x 0.2 mm, and then using the apparatus used in Example 3 to produce clarified fruit juice. The operation was continued for 2 and a half hours while closing the permeate outlet for 1 minute every 15 minutes. The permeation rate recovery rate for each operation is 85%, as shown in Figure 6.
,92%+'l o s%.

93%, I 00%, 80%, 77%, 100%.

The average recovery rate was 91%.

Example 5 Cherry concentrated reduced fruit juice (sugar content Brix 6.7°) 20
/ was subjected to 1 clarification treatment under the same conditions using the apparatus of Example 3.
I went for half an hour. The membrane permeation rate recovery operation was performed alternately every 15 minutes and every 20 minutes.

As seen in Figure 7 and Table 3, the recovery rate every 15 minutes is 55%.
, 72%, 71%, and the recovery rate every 20 minutes is 54%,
Both showed similar efficacy at 77%.

Next, using the same fruit juice 20/2, clarification treatment was performed under exactly the same conditions except that the membrane permeation rate recovery operation was performed every 45 minutes. The recovery rate is 38% and 49%, as shown in Figure 8.
%, average 44%, average recovery rate every 15 minutes and every 20 minutes 6
It was 273, or 6%.

Table 3 Example 6 Summer mandarin orange straight fruit juice (sugar content Brix 10.1')
50/ using the same device as Comparative Example 1, pump discharge amount 1
, 2 m3/h, module outlet pressure 1, 6 kg
The clarification process was carried out under the conditions of 1 hour and 40 minutes after the start of operation (see (a) in Figure 9). From (E) to (E)), and from the second hour onwards, after closing the permeate outlet, open the pressure regulating valve of the module outlet piping four times (from (F) to (S) in Figure 9). went.

As shown in Table 4, the average recovery rate is 48% when the permeate outlet is simply closed, whereas the average recovery rate when the pressure is released from the supplied juice is 75%, which is no recovery effect. 5
There was an increase of 6%.

Table 4

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an apparatus for carrying out the method for clarifying fruit juice of the present invention, in which l is a stock juice tank, 2 is a supply pump, 3 is a regulating valve, 4 is a flow meter, 5 is a four-way valve, 6 is a hollow fiber UP membrane module, 7 is a regulating valve, 8 is a flow meter, 9
10 is a pressure gauge, 11 is a permeate outlet. Fig. 2 shows Comparative Example 11 Fig. 3 shows Example 11 Fig. 4 shows Example 2, Fig. 5 shows Example 3, Fig. 6 shows Example 4, Fig. 7 shows the first half of Example 5, and Fig. 8 The figure shows the latter half of Example 5, and FIG. 9 shows the experimental results of Example 6. Patent applicant Daicel Chemical Industries, Ltd. Agent Patent attorney Takashi Koshiba Figure 1 Figure 2 Operating time (h) Figure 3 Operating time (h) Operating time (h) Figure 7 Operating time (h) Figure 8 Figure driving time (h)

Claims (3)

[Claims] (1) In the method of clarifying fruit juice using the membrane method, the operation of closing the membrane permeate outlet and removing fouling on the membrane surface with the flow of the supplied fruit juice to recover the decreased membrane permeation rate is performed for 30 minutes.
A method for clarifying fruit juice, characterized in that the average membrane permeation rate is maintained at a high level by carrying out the operation at intervals of not more than 1 minute and for an operation time of 20 seconds or more, preferably 1 minute or more. (2) A method for clarifying fruit juice according to claim 1, wherein the flow of the supplied fruit juice releases the applied pressure. (3) A method for clarifying fruit juice according to claims 1 and 2, wherein the flow direction of the supplied fruit juice is reversed.