What the fermentation process needs to be aware of.

China uses fermentation technology to engage in the production of wine, sauce, vinegar and other food products has a long history, and has accumulated a wealth of fermentation experience.
fermentation technology refers to the use of microorganism fermentation, the use of some technical means to control the fermentation process, large-scale production of fermentation products, called fermentation technology. The concept of
fermentation comes from the process of brewing.
fermentation technology can not only improve the flavor, color and organization of food, but also improve the nutritional value of food. What do
need to be aware of during fermentation? The fermentation process needs to control the following factorsa, fermentation temperature control.
the temperature required for fermentation varies according to the type of microorganism, all kinds of microorganisms have their own most suitable growth temperature, different microbe growth temperature requirements are different, according to their temperature requirements, can be broadly divided into 4 categories: cold-eating bacteria adapted to the growth of 0 to 26 degrees C, temperature-obsessed bacteria adapted to 15 to 45 degrees C production, heat-obsessed bacteria adapted to 37 to 65 degrees C growth, high temperature bacteria adapted to 65 degrees C growth.
in the fermentation of mixed bacteria, can control the growth rate of different types of microorganisms by regulating the fermentation temperature, so as to achieve the ideal fermentation effect.
note that the effect of temperature on the production of bacteria and product synthesis may be different.
that is, the temperature at which bacteria are most suitable for production is not necessarily the most suitable temperature for the desired metabolites.
because microorganisms have different temperature requirements during production and fermentation.
production, in order to obtain high productivity, for the characteristics of the bacteria used, the temperature needs to be controlled at all stages of the fermentation cycle, providing that the biological activity at that stage is most suitable for the temperature.
In the pre-fermentation period, the amount of bacteria is small, take a slightly higher temperature, promote the respiration and metabolism of bacteria, so that bacteria grow rapidly;
, such as soy sauce production, yeast fermentation action to 30 degrees C as appropriate, less than 10 degrees C can only reproduce, fermentation is more difficult.
The production of yeast stoytol swells above 40 degrees C is inhibited and cannot even survive and ferment.
the use of medium-temperature or low-temperature fermentation methods, adapt to extend the fermentation cycle, can increase the aroma of soy sauce.
some bacterial products form higher than the production temperature, such as glutamate production of bacteria production temperature of 30-32 degrees C, acid production temperature of 34-37 degrees C.
in addition, temperature control also according to the training conditions to consider comprehensive consideration, flexible choice.
when the ventilation condition is poor, can appropriately reduce the temperature, reduce the respiratory rate of bacteria, can appropriately increase the concentration of dissolved oxygen;
, the choice of temperature should be based on the product used in all stages of production and culture conditions, and through repeated practice to determine the most suitable temperature.
b, acidity control.
microorganisms each have their own suitable pH range, such as yeast 3.8-6.0, bacteria 6.5-7.5, mold 4.0-5.8, line bacteria 6.5-8.0.
acid has the effect of inhibiting the growth of microorganisms, that is, acid-containing foods have a certain degree of anti-corrosion ability, for most microorganisms, when pH and lt;2, it is inhibited can not grow.
But sometimes some acid-resistant microorganisms growth and reproduction can also make pH rise, such as mold in the presence of aerobics, food surface will have mold growth, because mold acid resistance, oxygen demand, acid consumption can be consumed.
yeast, acid resistance breaks down proteins, resulting in ammonia and acid consumption.
so that food lost anti-corrosion capacity, resulting in the surface of the food fat decomposition and other degradation activities, so that food corruption deterioration. The change of acidity in the
fermentation process is the embodiment of the state of fermentation process, is the result of biological growth and metabolism, but also the basis and direction of fermentation process control, and it is very important to control the acidity of fermentation to produce qualified products.
there are four ways to control pH: (1) adjust the pH of the base material, adjust it by the base medium, add the substance that maintains pH to the base material, and (2) adjust the pH by adding supplements to the consumption of glyco-nitrogen during fermentation; 3) When there is a contradiction between the supplement and the regulation pH, the pH is adjusted by the acid-base regulator, and (4) different pH values are taken according to different fermentation stages, and the production of the bacteria is observed on a timely basis, so that the pH of the highest pH is achieved by the growth of the bacteria.
c, ventilation (oxygen supply).
microbes can be divided into aerobic microorganisms and anaerobic microorganisms.
mold is oxygen-demanding, in the absence of oxygen conditions can not grow, so the production of rotting milk, soy sauce should have sufficient oxygen to ensure that fermentation is normal.
anaerobic microorganisms, such as Botox, are specialized anaerobic bacteria, and both anaerobic microorganisms such as yeast.
acetic acid bacteria is aerobic bacteria, when brewing vinegar, first let yeast in the oxygen-deficient conditions of sugar into alcohol, and then in the ventilation conditions by acetic acid bacteria will be oxidized alcohol to produce acetic acid, but the amount of ventilation is too large, acetic acid will be further oxidized, at this time if there is mold can grow and consume acetic acid.
therefore, ventilation should be appropriate to reduce the possibility of mold growth.
supply or cut off the supply of oxygen can promote or inhibit the growth of (fermented) bacteria and guide production in the desired direction.
control of d and tonics.
In the fermentation process, according to the production and metabolism law of bacteria, the use of "discharge and tonic" way, when fermentation for a certain period of time, the production of metabolites, a small number of times or batches released a part of the fermentation liquid, while replenishing a part of the fresh nutrient solution, and repeat.
the concentration of inhibitory substrates can be controlled by batch fermentation of supplements, because the substrate is too thick, which can lead to excessive osmotic pressure, causing cells to die from dehydration.
but the feeding process should also pay attention to avoid a one-time feeding too much, so as not to cause a large number of cell growth.
adaptation to the replenishment operation can ensure the production speed and efficiency of certain bacteria, extend the production of fermentation products in the same period, is conducive to improve product production capacity, while reducing product costs, but the feeding process should pay attention not to be contaminated with bacteria.
with the continuous reform and development of fermentation industry, the degree of mechanization of fermentation technology is bound to be higher and higher, fermentation technology will develop in the direction of high-tech.
the future fermentation process, in addition to the necessary inputs and outputs, will achieve a fully closed system management, people only need to set the corresponding fermentation program through the computer, can at any time monitor and realize the automatic flow of products between the processes, so as to control the entire fermentation process.
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