JPS637767A - Method for clarifying fruit juice - Google Patents

Abstract

PURPOSE:To clarify a fruit juice without using a large-sized membrane apparatus, by washing contaminated membrane surface by the variation of flow of fruit juice in the treatment of fruit juice with ultrafiltration membrane, thereby maintaining the average membrane permeation rate at a high level. CONSTITUTION:In the treatment of a fruit juice with an ultrafiltration membrane, the flow of supplied fruit juice is stopped for 5sec-5min at an interval of <=30min. The fouling substance deposited on the membrane surface is removed by the variation of the fruit juice flow caused by the above operation. The process is periodically repeated to keep the average membrane permeation rate at a high level. Furthermore, the stock fruit juice left in the module is discharged by blasting air into the module when the flow of supplied fruit juice is stopped.

Description

Detailed Description of the Invention (Industrial Application Field) Fruit juice is often consumed as it is for beverages, but as a component of beverages, it does not become turbid and maintains a clear state when mixed and prepared. Demand for fruit juice 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 with an enzyme such as pectinase. However, as the enzymatic reaction is carried out at a high temperature of 40 to 60 degrees Celsius over several hours, it loses its aroma and adds a certain amount of bad odor, resulting in deterioration of the quality of the fruit juice.Furthermore, the enzymes used are expensive. Therefore, it has the disadvantage that the cost of clarification increases.

As a method to overcome these drawbacks, a method is being tested in which pectin is removed separately from P at room temperature in combination with an ultra-diaphragm membrane.

(Problems to be Solved) A problem with the method of treating fruit juice with an ultrafon membrane is that the membrane permeation rate rapidly decreases over time. This requires a dog-sized membrane device to process a given amount of fruit juice in a given amount of time, and this drawback may prevent it from being a viable alternative to enzymatic methods. - The present invention devises a simple and inexpensive membrane permeation rate recovery method in the process of membrane treatment of fruit juice, and maintains a high average membrane permeation rate by periodically applying this method, which is a disadvantage of increasing the scale of membrane equipment. It is an attempt to overcome the

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 a method of removing the fouling layer by flushing at high speed, a method of scraping with a solid such as a sponge ball added to the stock solution, and a method of allowing the permeate to permeate the membrane to remove the fouling layer on the membrane surface. There are methods of separating the ring layer. However, the method of adding solids is only possible with tubular membrane modules and cannot be applied to space- and energy-efficient hollow fiber membrane modules or spiral or pleated modules. Although the method of allowing a portion of the permeated liquid to permeate through the membrane is effective, it has the disadvantage of returning the liquid that has permeated the cornea to the original solution, and the disadvantage of requiring a pump to pressurize the permeated liquid in order to permeate the membrane.

In view of this situation, the present inventors have arrived at the present invention as a result of intensive studies.

(Structure of the Invention) That is, the present invention provides the following features: (1) The flow of the supplied fruit juice is controlled for 5 seconds to 5 seconds at a cycle of 30 minutes or less.
A method for clarifying fruit juice characterized by maintaining a high average membrane permeation rate by removing fouling substances deposited on the membrane surface by changing the flow of the juice after stopping for a minute.

(2) The method for clarifying fruit juice according to item (1), in which the flow of the supplied fruit juice is stopped and, at the same time, the fruit juice stock solution remaining in the module is expelled from the air blower K.

It is.・ The present invention will be explained in detail below.

FIG. 1 is a schematic diagram showing an apparatus for carrying out the method of clarifying fruit juice of the present invention.

With this device, it is sufficient to stop the flow of the supplied fruit juice and to make it flow again by simply turning the supply pump 2 ON and OFF. Moreover, the fruit juice stock solution remaining in the module 6 can be expelled by blowing air by opening the valve 10 and blowing air. When the pump 2 is stopped by these operations, no permeated liquid comes out, but this loss is compensated for and the membrane permeation rate is sufficiently restored, so the amount of linear permeated liquid becomes considerably larger than during continuous operation. The reason for this is that when the pump stops, the pressure on the fouling material that was pressed against the membrane surface disappears, and the fouling material loosens and is removed by the turbulence when the pump starts operating again. Conceivable.

(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. If this is carried out periodically, the average membrane permeation rate can be maintained higher for a longer period of time, and the capital investment for increasing the scale of the membrane device in anticipation of membrane surface contamination can be reduced.

(Example) The effects of the present invention will be explained below using examples.

Comparative example 1 Satsuma mandarin straight fruit juice (sugar content Brixill@,
Pulp content 5%) 25 pieces were pumped using the device shown in Figure 1 at a pump discharge rate of 1.27 FL'/h' and a module inlet pressure of 1.
．． 6kg/crI, module outlet pressure 1.0klil/
d.

An experiment was conducted to produce clear fruit juice by supplying the fruit juice to a hollow fiber UF membrane module at a temperature of 20°C. In order to avoid fluctuations in conditions, the clarified fruit juice that had permeated was immediately returned to the undiluted fruit juice tank, and the experiment was conducted under conditions such that the concentration of the undiluted fruit juice did not fluctuate.

Poison Joule is an internal pressure type manufactured by Daicel Chemical Industry ■, effective membrane area is 0.43 m, hollow fiber inner diameter is 0.8 m, hollow fiber effective length is 270 B, number of hollow fibers is 635, membrane material is polyether sulfone, pure The water permeation rate is 94-98% for ovalbumin (molecular weight 28,000), and the rejection rate for ovalbumin (molecular weight 45.OQ)
The rejection rate of O) is 99% or more.

As shown in Figure 2, the membrane permeation rate (clarified juice production rate) decreases rapidly over time.

Example 1 An experiment was conducted to produce clarified fruit juice using the same juice, the same module, and the same conditions as in Comparative Example 1. However, the pump was stopped every 15 minutes to stop the flow of fruit juice.

Figure 3 shows the results. The time indicated by the arrow in FIG. 3 is the number of seconds the pump is stopped. From this, it can be seen that stopping for 5 seconds or more has the effect of restoring the membrane permeation rate, and stopping for 10 seconds or more has a sufficient effect.

Example 2 *An experiment was conducted to produce clarified fruit juice using the same juice, the same module, and the same conditions as in Example 1. However, every 15 minutes 30
The pump was stopped for a second to stop the flow of juice.

Example 3 Under almost the same conditions as Example 1, the pump was stopped for 10 seconds to stop the flow of fruit juice.

Example 4 An experiment was conducted to produce clarified fruit juice using the same juice, the same module, and the same conditions as in Example 1. However, the pump was stopped for 30 seconds every 15 minutes, and during this period, the undiluted fruit juice remaining in the module was expelled by blowing air.

The above results are summarized in Table 1.

Table 1 As can be seen from Table 1, in Examples 2 to 4, there was almost no decrease in the average membrane permeation rate over time, and the average membrane permeation rate was higher than that of the comparative example.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the apparatus for carrying out the present invention, FIG. 2 is a diagram showing the relationship between operating time and membrane permeation rate in Comparative Example 1, and FIG. 3 is a diagram showing the relationship between operating time and membrane permeation rate in Example 1. FIG. 1... Raw fruit juice tank, 2... Supply poise,
3... Bypass pulp, 5... Pressure gauge, 6.
...Hollow system UF membrane module, 7...Permeation reduction/increase outlet, 8...Pressure gauge, 9...Air supply pipe, 1
0...Air feeding pulp, 11...Applied pressure adjustment pulp, 12...Flow meter. Patent applicant: Daicel Chemical Industries, Ltd. Representative: Patent attorney: Takashi Koshiba Figure 1

Claims (2)

[Claims] (1) The flow of the supplied fruit juice is controlled for 5 seconds to 5 seconds within a period of 30 minutes.
A method for clarifying fruit juice characterized by maintaining a high average membrane permeation rate by removing fouling substances deposited on the membrane surface by changing the flow of the juice by stopping for a minute. (2) A method for clarifying fruit juice according to claim 1, wherein when the flow of the supplied fruit juice is stopped, the fruit juice stock solution remaining in the module is expelled by blowing air.