JPH0215189B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for producing vinegar and an apparatus therefor.

High concentrations of acetic acid and ethanol in acetic acid fermentation have various inhibitory effects on the growth of acetic acid bacteria and acid production, so especially when carrying out fed-batch culture, it is necessary to detect their concentrations in the fermentation mash and adjust the ethanol concentration. It is extremely important to control it within a certain range. In the conventional fed-batch culture method, a portion of the moromi is removed over time,
A method is used in which acetic acid and/or ethanol are analyzed, their concentrations in the moromi are measured, the necessary amount of ethanol is calculated, and ethanol is added into the moromi. However, this method requires a great deal of labor and time for the analysis of acetic acid and/or ethanol and the fed-batch operation of ethanol, resulting in delays in understanding the current state of fermentation, inability to take prompt measures according to fermentation conditions, and poor performance of fermentation. It has been declining.

The present inventors have greatly reduced the troublesomeness of measuring the amount of acetic acid produced and the amount of residual ethanol in the fermentation liquid, and are now able to monitor the progress of fermentation and perform various operations without having to collect almost any samples. After many studies in search of a method, we put the raw material for vinegar into a closed fermentation tank, inoculated it with acetic acid bacteria, and then supplied oxygen to maintain the oxygen partial pressure in the gas phase within the tank at an appropriate level. When acetic acid fermentation was carried out and the relationship between the amount of oxygen supplied and the amount of acetic acid produced was investigated, it was found that the amount of acetic acid produced was completely proportional to the amount of oxygen supplied, except in the early stages of fermentation. Using this proportional relationship, it is possible to calculate the required amount of oxygen from the amount of acetic acid produced, and conversely, the amount of acetic acid produced can be measured from the amount of oxygen supplied, so if the amount of oxygen supplied is continuously measured, the measurement result It has been found that various operating conditions can be appropriately determined using this as an index.

The present invention is based on this knowledge, and the raw material moromi is placed in a closed fermentation tank, inoculated with acetic acid bacteria, and then oxygen is supplied to carry out acetic acid fermentation without substantially evacuation. The ethanol concentration in the moromi is calculated from this measurement value.
After the concentration of ethanol in the moromi has decreased to 0.1 to 1% by volume, ethanol feeding is started, and while maintaining the ethanol concentration in the moromi below 1.5% by volume, a certain amount of ethanol is continuously fed or a certain amount of ethanol is added intermittently. When the acetic acid concentration in the moromi, calculated from the cumulative oxygen supply amount, reaches the target concentration, the ethanol feeding process is terminated, and the acetic acid fermentation is continued, and the acetic acid concentration calculated from the above measured value is reached. This vinegar brewing method is characterized in that fermentation is terminated after the residual ethanol is less than 1%.

Furthermore, the present invention connects the closed fermentation tank and the oxygen supply source through an oxygen supply pipe, and provides an on-off valve or an oxygen integrating flowmeter connected to an oxygen amount measuring device in the middle of the pipe, and furthermore, connects the fermentation tank with the fed-batch oxygen supply pipe. The liquid storage tank is communicated with a fed-batch liquid supply pipe, a fed-batch pump is provided in the middle of this pipe, and a pump controller that operates this pump is electrically connected to the oxygen amount measuring device or oxygen integrating flow meter. This is a brewing apparatus for the vinegar brewing method of the present invention, characterized in that:

The raw material mash used in the present invention may be any common mash for vinegar brewing, and generally an ethanol solution containing sake lees, sake, acetic acid, yeast extract, etc. is used.
The ethanol concentration in the raw material moromi is preferably 4 to 8% by volume. It is preferable to use ordinary seed vinegar for the acetic acid bacteria.

The oxygen concentration in the gas phase of the fermentation tank is preferably 20 to 60% in the static fermentation method, and 10 to 40% in the aerated stirring fermentation method. If the oxygen concentration is outside this range, the production of acetic acid will be slow and high-concentration vinegar cannot be obtained in a short period of time.

When carrying out the present invention, first, raw material mash is charged into a tank, and after inoculation with acetic acid bacteria, oxygen is supplied to the fermentation tank, and oxygen fermentation is allowed to proceed while maintaining the oxygen concentration almost constant. The amount is measured, and using this measured value as an index, ethanol feeding is started after the ethanol concentration in the moromi has decreased to 0.1 to 1% by volume.

The ethanol concentration in the moromi means the amount of ethanol remaining relative to the volume of the moromi. The amount of remaining ethanol is determined as the difference between the amount of ethanol in the raw material moromi and the amount of consumed ethanol calculated from the integrated supply amount of oxygen. The amount of ethanol consumed is proportional to the amount of oxygen supplied, except in the early stages of fermentation, and the amount of ethanol corresponding to 1 amount of oxygen supplied is usually 2.4 to 2.7 ml, but since the proportionality constant varies depending on the fermentation conditions, a preliminary test was conducted. It is preferable that the

Next, ethanol feeding is carried out while maintaining the ethanol concentration in the moromi at 1.5% by volume or less.

As for the feeding method of ethanol, it is preferable to continuously feed the amount of ethanol corresponding to the amount of oxygen supplied, but it is also possible to feed the ethanol intermittently in fixed amounts. When feeding intermittently, it is preferable to determine the feeding amount so that the ethanol concentration in the moromi increases by about 0.2 to 0.5% by volume by one feeding of ethanol. Next, the oxygen supply is continued, and when the oxygen corresponding to the amount of fed-batch ethanol is supplied, the ethanol feeding is repeated. The amount of acetic acid produced is calculated from the measured value of the integrated supply amount of oxygen, and when the amount of acetic acid produced reaches a predetermined value, the feeding of ethanol is terminated.

Furthermore, in both the batch culture method and the fed-batch culture method, the amount of acetic acid produced can be calculated from the amount of oxygen supplied during fermentation, so the timing of completion of fermentation can be easily determined.

Hereinafter, the present invention will be explained with reference to the drawings.

Figure 1 shows an example of an apparatus used in the static fermentation method, with a closed fermentation tank 1 and an oxygen supply source 2.
It communicates with an oxygen supply pipe 4 having an on-off valve 3a, and the amount of oxygen gas passing through the on-off valve 3a is measured by an oxygen amount meter 3b. The fed-batch liquid is sent from the fed-batch liquid storage tank 5 to the fermentation tank 1 via the fed-batch liquid supply pipe 7 by the fed-batch pump 6, and starting and stopping of the fed-batch pump 6 is controlled by a pump controller 8.

The fermentation tank 1 contains a raw material mash 10 and a gas phase part 1.
1. Then, two points in the gas phase are connected to a pipe 1 which passes through a temperature control device 12 and a gas circulation device 13.
4 and by circulating the gas in the gas phase section 11, the temperature inside the fermentation tank 1 can be adjusted.

When the oxygen concentration in the gas phase portion 11 falls below a predetermined value, the opening/closing valve 3a is opened by the oxygen partial pressure control device 16 connected to the oxygen concentration sensing element 15. Open/close valve 3a
A solenoid valve is preferable, and a certain amount of oxygen is supplied by opening and closing once. By recording the number of openings and closings on the measuring device 3b, the relative amount and absolute amount of oxygen supplied can be known. An oxygen integrating flow meter can also be used instead of a measuring device using an on-off valve.

A pressure regulating valve 17 is provided in the fermentation tank 1, and the gas phase section 1
It is preferable to keep the pressure at 1 constant.

However, since oxygen gas is used in the present invention,
Almost all of it is utilized and consumed for acetic acid fermentation, and no gas other than oxygen, such as nitrogen gas, remains in the gas phase section 11. Therefore, oxygen fermentation can be performed substantially without exhausting the tank to the outside. Because of this, there is almost no need to operate the pressure regulating valve during brewing.

In addition, the temperature measuring body 19 is controlled by a temperature control device (not shown).
It is preferable to connect to the temperature control device 12 via a.

Figure 2 shows one of the devices used in the aerated stirring fermentation method.
This is an example, and a heat exchange device 2 is installed inside the fermentation tank 1.
1. A rotary blade 22 driven by a stirring device 23 and a ventilation pipe 24 are provided, and the gas sent from the gas circulation device 13 through the pipe 14 is injected into the raw mash 10 from the pipe 24 together with oxygen supplied from the oxygen supply pipe 4. entered.

According to the method of the present invention, since a closed system is used, there is almost no loss of ethanol and acetic acid, and since the amount of acetic acid produced during fermentation and the ethanol content can be calculated from the amount of acetic acid supplied, sampling of moromi and measurement of oxygen and ethanol are possible. You can completely omit complicated operations such as Further, the feeding start time, feeding amount, feeding end time, and fermentation end time of ethanol can be easily determined. Furthermore, since the ethanol concentration of the moromi during the fermentation period can be controlled within a certain range, the acetic acid bacteria can actively continue the acetic acid fermentation, making it possible to brew vinegar in a short period of time.

Experimental example Using the aeration stirring fermentation apparatus shown in Figure 2, 3 sake and denatured ethanol (80%) were placed in fermentation tank 1.
400ml, a small amount of yeast extract, 60ml of special grade acetic acid and 6.5ml of water
After preparing the raw material moromi consisting of and adjusting the temperature of the moromi to 30℃, the partial pressure of oxygen in the circulating aeration gas was reduced to 20%.
(V/V), the rotational speed of the stirring blade was set to 800 rpm, the circulation rate was set to 5/min, and the amount of oxygen supplied by opening and closing the solenoid valve once was set to approximately 100 ml. 800ml of seed vinegar in moromi
was inoculated and fermented with aeration at a liquid temperature of 30±1°C.
Oxygen consumed during fermentation is quantitatively replenished via a solenoid valve, reducing the partial pressure of oxygen in the gas phase of the fermentation tank to 20%.
The number of openings and closings of the solenoid valve was recorded on a measuring device (counter).

During this fermentation, the number of openings and closings of the solenoid valve and the amount of acetic acid produced were checked every two hours with a measuring device. As a result, it was found that the amount of acetic acid produced was completely proportional to the amount of oxygen supplied, except in the early stages of fermentation, and a linear graph was obtained.

By acetic acid fermentation, 1 ml of ethanol is converted to about 1 g of acetic acid. This relationship is extremely important, and by displaying the amount of acetic acid in the moromi in grams and the amount of ethanol in milliliters, it is very easy to understand the relationship between the concentrations of the two. The amount of acetic acid produced and the amount of ethanol consumed in the moromi can be calculated from the amount of oxygen supplied at each point during fermentation, and the amount of ethanol and oxygen can be easily determined from the amount of acetic acid.

Example 1 Vinegar was brewed using the static fermentation apparatus shown in FIG.

A cylindrical container with a capacity of 2 is used as the fermentation tank 1, a portable oxygen analyzer is used as the oxygen concentration detection element 15, a dialapak indicating controller manufactured by Yamatake Honeywell is used as the oxygen partial pressure control device 16, and a small air pump and an on-off valve are used as the gas circulation device 13. A solenoid valve 3a, a digital counter as the measuring device 3b, a device consisting of a digital counter with a preset regulator, a timer, and an auxiliary circuit connecting these as the pump controller 8, and a peristaltic pump as the fed-batch pump 6 were used, respectively.

In fermentation tank 1, normal raw material moromi (acetic acid 2W/V%,
Add ethanol (4V/V%) 1 and lower the temperature of the moromi.
After adjusting the temperature to 30±1℃, add 100ml of seed vinegar (acetic acid 9W/V).
%), the partial pressure of oxygen in the gas phase in the fermentation tank was set to 20% (V/V), and the air flow rate of the gas circulation device was set to 0.1.
Fermentation was carried out by setting the amount of oxygen supplied by opening and closing the solenoid valve once per minute to about ml. During that time, the amount of oxygen gas consumed during fermentation is replenished via the solenoid valve 3a, and the partial pressure of oxygen in the gas phase of the fermentation tank is reduced to 20%.
The number of openings and closings of the solenoid valve was measured using a digital counter 3b.

As a result of preliminary tests, 40g of acetic acid from 40ml of ethanol
It was found that the amount of oxygen supply necessary to produce 1,950 times was expressed in terms of the number of openings and closings of the solenoid valve. Using this result, we performed the following operations.

After the start of fermentation, oxygen was supplied to keep the oxygen partial pressure in the fermentation tank almost constant. The number of openings and closings of the solenoid valve was measured with counter 3b, and when the number of openings and closings reached 1877 (ethanol 0.14V/V%, acetic acid 6.1W/V
%), 5 ml of 50V/V% ethanol was added (ethanol 0.4V/V%). After that, the solenoid valve is 122
Every time you open and close (consuming 2.5ml of ethanol)
Adjustment was made so that 5 ml of 50V/V% ethanol was added. After supplying 80ml of the fed-batch liquid in this way, if we continue the fermentation by supplying only additional oxygen, the acetic acid 9.3W/
Vinegar containing V% and ethanol 0.1V/V% approx.
1150ml was obtained.

[Calculation example for Example 1] (A) Ethanol concentration when the number of openings and closings of the solenoid valve reaches 1877 times Amount of ethanol at the start of fermentation - Amount of ethanol consumed / Raw moromi + Seed vinegar x 100 = 40 - 40 x ( 1877/1950)/1000+100×
100 = 0.14% (B) Concentration of acetic acid when the number of openings and closings of the solenoid valve reaches 1877 times Amount of acetic acid in raw mash: 20g Amount of acetic acid in seed vinegar: 9g Amount of acetic acid produced: 38.5g Therefore, 20 + 9 + 38.5 /1000 + 100 x 100 = 6.1% (C) Ethanol concentration in the moromi after the first ethanol feeding 1.5 (5 x 50%) / 1100 + 5 x 100 ≒ 0.4% Example 2 Vinegar production using the aeration stirring fermentation device shown in Figure 2 was brewed.

A jar fermenter with a capacity of 20 was used as the fermentation tank, the rotational speed of the stirring blade was 100 rpm, the circulation rate was 2/min, the amount of oxygen supplied was approximately 50 ml by opening and closing the solenoid valve once, and the amount of oxygen was supplied by operating the fed-batch pump once. The feed solution supplied was 42 ml of 50V/V% ethanol.

Put 10 pieces of raw material moromi (acetic acid 1W/V%, ethanol 6V/V% content) into fermentation tank 1, and add 500ml of seed vinegar.
(Acetic acid 10W/V%) was inoculated, oxygen partial pressure in the gas phase was set to 25%, and fermentation was carried out by controlling the temperature of the moromi at 30±1°C. Oxygen consumed during fermentation was replenished from an oxygen tank 2 via a solenoid valve 3a, and the number of openings and closings of the solenoid valve 3a was measured with a digital counter 3b.

As a result of preliminary tests, 100 ml of ethanol to 100 ml of acetic acid
It was found that the amount of oxygen supply necessary to generate 1.5 g was 750 times when expressed as the number of openings and closings of the solenoid valve. Using this relationship, we performed the following operations.

When the number of openings and closings of the solenoid valve 3a reaches 3938 when fermentation has progressed (ethanol 0.7V/V%, acetic acid 6.4W/V
%), the fed-batch pump was set to operate.
After that, the solenoid valve was opened and closed 158 times (ethanol 21
ml consumed), supplies 42 ml of fed-batch solution,
The fed-batch liquid supply amount is approximately 1.1, and the number of openings and closings of the solenoid valve is
When the temperature reached 8050, feeding was stopped and fermentation was continued, resulting in acetic acid concentration of 11.5W/V% and ethanol concentration.
Approximately 11.1 ml of vinegar containing 0.2 V/V% was obtained.

[Calculation example for Example 2] (A) Ethanol concentration when the number of openings and closings of the solenoid valve reaches 3938 times (Amount of ethanol at the start of fermentation) - (Amount of ethanol consumed) / Raw material moromi + Seed vinegar x 100 = 600 -100 (3938/750) / 1000 + 500 x 100 = 0.7% (B) Concentration of acetic acid when the number of openings and closings of the solenoid valve reaches 3938 times Amount of acetic acid in raw moromi: 100g Amount of acetic acid in seed vinegar: 50g Acetic acid produced Amount: 525.3g Therefore, 100+50+525.3/10000+500×100=6.4% (C) Ethanol concentration in the moromi after the first ethanol feeding (600−525.3)+(42×50%)/10500+42×100=0.
9%

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view schematically showing a static fermentation apparatus as an example of carrying out the present invention, and FIG. 2 is a vertical cross-sectional view of an aerated stirring fermentation apparatus.

Claims (1)

[Claims] 1. A raw material moromi is placed in a closed fermentation tank, inoculated with acetic acid bacteria, and then oxygen is supplied to carry out acetic acid fermentation without substantially evacuation. At this time, the cumulative amount of oxygen supplied is measured. After the ethanol concentration in the moromi, which is calculated from this measured value, has decreased to 0.1 to 1% by volume, ethanol feeding is started to reduce the ethanol concentration in the moromi.
While keeping the concentration below 1.5% by volume, a certain amount of ethanol is continuously added or a certain amount of ethanol is intermittently added, and the acetic acid concentration in the moromi, which is calculated from the cumulative oxygen supply amount, is the desired concentration. When a concentration of ethanol is reached, the ethanol feeding process is terminated, and the acetic acid fermentation is continued, and the fermentation is terminated when the residual ethanol calculated from the measured value becomes less than 1%. Brewing method. 2. A closed fermentation tank and an oxygen supply source are connected through an oxygen supply pipe, and an on-off valve or an oxygen integrated flow meter is installed in the middle of this pipe to connect to an oxygen amount measuring device.
Further, the fermentation tank and the fed-batch liquid storage tank are connected through a fed-batch liquid supply pipe, and a fed-batch pump is provided in the middle of this pipe, and a pump controller that operates this pump and the oxygen amount measuring device or oxygen integrating flow meter are connected to each other. A vinegar brewing device characterized by being electrically connected to.