How to choose defoaming agent for fermentation?

1.Insoluble or difficult to dissolve in the foaming solution

To burst the foam, thedefoaming agent should be concentrated and concentrated on the bubble film. In the case of foam breakers, it should be concentrated and concentrated in an instant, and in the case of foam suppressors, it should always be maintained in this state. Therefore, the defoaming agent is in a supersaturated state in the foaming liquid. Only insoluble or poorly soluble defoaming agents can easily reach the supersaturated state. Only when it is insoluble or difficult to dissolve can it easily gather at the air-liquid interface, be easily concentrated on the bubble membrane, and can it function at a lower concentration. For defoaming agents used in water systems, the molecules of the active ingredients must be strongly hydrophobic and weakly hydrophilic. The HLB value must be in the range of 1.53 to achieve the best effect.

2. The surface tension is lower than that of the foaming liquid

Only defoaming agent intermolecular action The force is small and the surface tension is lower than that of the foaming liquid, so the defoaming agent particles can immerse and expand on the bubble film. It is worth noting that the surface tension of the foaming liquid is not the surface tension of the solution, but the surface tension of the foaming solution.

3. has a certain degree of affinity with foaming liquid

Because the defoaming process is actually a combination of the foam collapse speed and the foam generation speed competition, so the defoaming agent must be able to disperse quickly in the foaming liquid so that it can quickly play a role in a wider range of the foaming liquid. To make the defoaming agent diffuse quickly, the active ingredient of the defoaming agent must have a certain degree of affinity with the foaming liquid. If the active ingredient of the defoaming agent is too close to the foaming liquid, it will dissolve; if it is too sparse, it will be difficult to disperse. Only when the distance is appropriate can the effect be good.

4. Does not chemically react with foaming liquid

The defoaming agent reacts with the foaming liquid. On the one handDefoaming agentswill lose their effect. On the other hand, they may produce harmful substances and affect the growth of microorganisms.

5. Low volatility and long action time