JPH028708B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention allows for continuous fermentation cycles in which a portion of the prepared vinegar leaves the fermenter for each cycle and an equal amount of new raw mash containing up to 2 g/100 ml of acetic acid and more than 10% alcohol by volume flows in. The alcohol-containing raw mash is then simply mixed by adjusting the same initial concentration of more than 6 g/100 ml of acetic acid and less than 7% alcohol by volume at each fermentation time, while maintaining the total concentration by the inflow of fresh raw mash. This invention relates to a method for producing vinegar containing more than 12 g/100 ml of acetic acid by deep fermentation in one step. In this specification, "single process" means that the entire fermentation cycle is carried out in one fermentation tank while only the prepared vinegar is taken out, and a part is taken out in the middle of fermentation and transferred to another fermentation tank. Therefore, it means not to use multiple fermenters such as performing finishing fermentation, and the initial concentration means that after draining the prepared vinegar,
This refers to the concentration of mash in the fermenter one hour after new raw material mash has been introduced. When producing vinegar containing more than 12 g/100 ml of acetic acid, it must contain proliferative acetic acid bacteria and contain 6 to 6 ml of acetic acid.
Ferment the raw mash containing 9 g/100 ml and 4 to 7% alcohol by volume while constantly and uniformly aerating until the alcohol concentration is almost zero.
After that, a part of the contents of the fermenter is discharged as prepared vinegar, and up to 2 g/100 ml of acetic acid and about 10~10 g of alcohol are discharged.
It is known that a new raw mash containing 14% by volume is gradually and immediately introduced with intimate mixing so that the concentration of acetic acid and alcohol after the inflow of the raw mash is the same at the beginning of each fermentation time. (Austrian Patent No. 265178). This concentration indicates that the growth rate of acetic acid bacteria slows down with increasing total concentration at a relatively constant alcohol content and with increasing acetic acid content and decreasing alcohol content at a total concentration held constant. It was selected based on what was revealed through experiments. This is especially true when the acetic acid content is 7.
~8g/100ml and alcohol content 5
This is the case below ~6% by volume, and therefore the growth rate is maximum at the acetic acid and alcohol contents mentioned above. Nevertheless, the fermentation time is approximately 48 hours in this known method, during which approximately 40-50% of the contents of the fermenter are discharged as prepared vinegar each time the batch is changed. Although the described process for producing vinegar containing more than 12 g/100 ml of acetic acid has led to significant advances, it is desirable to further increase the fermentation capacity. The invention is therefore based on the problem of improving the process described at the outset in such a way that even more vinegar is produced per unit time and unit volume. This problem is solved according to the invention by setting the starting concentration for each new fermentation period to be higher than 9 g/100 ml and lower than 13 g/100 ml for acetic acid, and lower than 4% by volume and higher than 2.5% by volume for alcohol. do. This is accomplished by reducing the outflow volume of the prepared vinegar to about 30% to 20% of the fermenter contents by volume, which is impressive. This is because if the outflow capacity is reduced to less than 40% by volume, an increase in the acetic acid concentration and a decrease in the alcohol concentration will inevitably occur after the inflow of new raw material mash is terminated. This is because, based on past experience, it was not considered to be a good idea to do so. The increase in the acetic acid concentration and the decrease in the alcohol concentration are due to the fact that the acetic acid bacteria must have multiplied to the number of bacteria that existed before the outflow of the prepared vinegar at each new fermentation time; This results in a decrease in Finally, vinegar fermentation with a continuous supply of raw mash and a continuous flow of vinegar is only possible with a total concentration of less than about 10% (because the total concentration is even higher). Considering that the growth rate decreases with low alcohol content and fermentation finally stops),
A detrimental effect in reducing the outflow capacity was expected. Continuous fermentation can be thought of as a transition in fermentation time that is constantly shortened. However, the increase in productivity achieved was astonishing. This unexpected result is based on the fact that due to the reduced outflow volume, a large number of productive acetic acid bacteria remain in the fermenter, thereby regulating the reduced growth rate. Furthermore, changes in the concentration of alcohol and acetic acid impair the metabolism of acetic acid bacteria, which are very sensitive to such changes in concentration, but in the present invention, the changes in concentration are extremely small, so that the adverse effects of such changes in concentration are avoided. is small. Clearly, these relationships working together achieve conditions that make it possible to significantly increase productivity. These conditions include more than 9 g/100 ml of acetic acid and 4 g of alcohol.
At an initial concentration of less than 13% by volume, then acetic acid 13
It is most suitable when the alcohol content does not exceed g/100ml and does not fall below 2.5% by volume of alcohol. Since alcohol and acetic acid are volatile, air-saving metering is necessary to achieve good yields. Since acetic acid bacteria are sensitive to oxygen deficiency, a very uniform aeration of the substrate to be fermented is necessary to achieve good fermentation capacity and oxygen utilization. Said aeration capacity therefore limits the possible number of acetic acid bacteria, thereby limiting the maximum rate of acid increase possible which, once achieved, remains constant over the remaining fermentation time. In industrial fermenters, the maximum acid increase rate did not exceed 0.16 g/100 ml/h (Austrian Patent No. 265178)
0.17, but with better utilization of atmospheric oxygen, especially when considering precise and uniform air distribution.
It is not surprising that fermentation capacities higher than g/100ml.h are achieved. The increase in acid per hour is increased by increasing the amount of air supplied.
0.17g/100ml associated with reducing spill volume and limiting alcohol content to less than 4% by volume
It is amazing that the production of vinegar per unit time and volume increases by about 70% with more acid per hour. If at high capacities, i.e. high numbers of bacteria per unit volume, the above-mentioned oxygen content is consumed and the growth of acetic acid bacteria is hindered, then the disturbance has started and now the shortened fermentation according to the invention Time only lasts for a short time until it comes to an end;
This constitutes favorable conditions and therefore the fermentation time is approx.
It can be shortened from 48 hours to about 19 hours. Example 1 Vinegar fermentation was carried out at an aeration rate of 90 m ³ /h in a fermentation tank with a diameter of 3 m and a height of 5 m, equipped with an aeration device, a cooling device, a controlling thermometer and a mechanical defoaming device, with the following values: It was carried out in The tank capacity was 24,000:

[Table] For every 27 hours of fermentation time, 6500 g of vinegar containing 14.30 g/100 ml of acetic acid could be flowed out. This corresponds to 809/24 hours of alcohol being fermented and converted to acetic acid. Example 2 In the same fermentation tank, tank internal capacity 24000, ventilation rate 105m ³ /
The following vinegar fermentation was carried out by h:

[Table] For every 19 hours of fermentation time, 6500 g of vinegar containing 14.30 g/100 ml of acetic acid could be flowed out. This corresponds to 1149/24 hours of alcohol being fermented and converted to acetic acid. With the measures according to the invention, the disadvantageous effects of influx processes and oxygen deficiency disturbances on the metabolism of acetic acid bacteria are reduced, so that the fermenter operates at full capacity almost all the time, thereby achieving the maximum possible of productivity. Moreover, the short fermentation time provides the advantage that the increased alcohol concentration and decreased acid concentration after the inflow of fresh raw mash stimulate the growth rate of acetic acid bacteria. Example 3 In the fermenter described in Example 1, the aeration rate is 90 m ³ /h and the final fermentation efficiency is 0.16 g / h for 24000 fermenters.
Acetic acid 1g/100ml and alcohol 14.0 per 100ml/h
The same alcoholic raw mash as described in Example 1 containing % by volume was fermented in experiments (a) to (d). In this case, only the volume that was drained and replaced by fresh raw mash at the end of the cycle was changed. The results are listed in Table 1. However, b is the result according to Example 1.

[Table] Austrian Patent No. 265178 describes a single step process, but in this case, the fermenter capacity is
50% is drained at the end of each cycle. In this method, 682/24 hours of alcohol was fermented and converted to acetic acid. As is clear from Table 1, by changing the outflow volume, 809/24-hour alcohol was converted to acetic acid, that is, it was possible to increase the amount to 119%. The basic requirements are first the alcohol content at the beginning of a new cycle and then the acetic acid content at the same time. This value changes depending on the amount of outflow from the fermenter capacity. The characteristic of the present invention is that ``acetic acid has a higher than 9 g/100 ml and 13
The effect of lower than 4 g/100 ml and lower than 4% and higher than 2.5% by volume for alcohol is clear from the results in Table 1. The acidity range should be lower than that for alcohol as the total concentration may vary between 12 and 15%. Example 4 In the same fermenter as in Example 2, with a slightly higher aeration rate of 105 m ³ /h (17% higher) and a slightly higher final fermentation efficiency of 0.21%/h, 1149/24 h of alcohol was fermented into acetic acid. In other words, this shows that the invention was able to be increased to 168% of the Austrian patent. Experiments were carried out with varying outflow volumes, maintaining a slightly higher final fermentation efficiency of 0.21%/. The results are summarized in Table 2 together with the result (f) from Example 2:

[Table] The feature of the present invention is that alcohol is 4% by volume.
In experiment f adapted to a concentration of ``lower and higher than 2.5% by volume,'' a very high proportion of alcohol is fermented to acetic acid. To guarantee fermentation at a total concentration lower than 14.6%, it is necessary to widen the acidity range above 9 g/100 ml and below 13 g/100 ml.

Claims (1)

[Claims] 1. In a continuous fermentation cycle, a portion of the prepared vinegar is flowed out of the fermenter for each cycle and an equal amount of up to 2 g/100 ml of acetic acid and 10 g of alcohol is added.
A new raw material mash containing more than % by volume is introduced, and at this time, the total concentration is maintained by the inflow of the new raw material mash, and at each fermentation time 6 g/mash is added.
A method for producing vinegar containing more than 12 g/100 ml of acetic acid by deep fermentation of alcohol-containing raw mash in a single step, adjusting the same initial concentration of more than 100 ml of acetic acid and less than 7% alcohol by volume. , the initial concentration at each new fermentation time is higher than 9 g/100 ml and lower than 13 g/100 ml for acetic acid and lower than 4% by volume and higher than 2.5% by volume for alcohol, and the outflow volume of the prepared vinegar is on a fermenter by volume basis. 12g/ characterized by up to about 30-20% of the content
A method for producing vinegar containing more than 100ml of acetic acid. 2 The increase in acid per hour is at least 0.17 g/hour.
The manufacturing method according to claim 1, wherein the fermentation time is increased to 100 ml.