Welcome to visit Beijing Songyuan Huaxing official website！
E-mail： sales@bjsyhx.com.cn
Product List
Breaking News
Analysis on the drying principle of freeze dryer
How to properly maintain an industrial vacuum freeze dryer?
What is the control system of industrial vacuum freeze dryer?
Analysis of periodic inspection and maintenance methods of pilot freeze dryer
Contact Us
Beijing Songyuan Huaxing
Service Line：+86-13161061291
Song Yuan：+86-13161061291
Your Location: Home >> News >> Technical support >> Such a healthy freeze-drying method is easy to learn

Such a healthy freeze-drying method is easy to learn

Release Date： 2018/8/24 17:38:28 .
Browse： 829

Such a healthy freeze-drying method is easy to learn
　　Freeze drying and lyophilization are synonymous. Freeze drying is a water removal process typically used to preserve perishable materials, to extend shelf life or make the material more convenient for transport. Freeze drying works by freezing the material, then reducing the pressure and adding heat to allow the frozen water in the material to sublimate.
　　Freeze Drying’s 3 Primary Stages
　　Freezing Phase
　　Primary Drying (Sublimation) Phase
　　Secondary Drying (Adsorption) Phase
　　Freeze drying method
　　1. Prepare the ampoule tube, use the 2% HO to set the bubble 8 10, rinse it with tap water several times, and finally wash it with sorrow water for 1~2 times. Dry. The label with the name of the trade name and the date of the aid is placed in the Anen tube. The side with the word should be placed on the wall of the tube, and the tube 1 is stuffed with cotton and sterilized at 0.1 MPa for 30 min.
　　2. Prepare skimmed milk, first boil the milk, remove the upper layer of fat, then use cotton wool to pass through the centrifuge and centrifuge for 15 minutes in a 3 000 t/min centrifuge. If not, centrifuge again until the fat is removed. So far, the milk was degreased, sterilized at 0.056 MPa for 30 min and sterilized.
　　3. Prepare the bacterial suspension, use 3~4ml of sterile skim milk in the cultured mature slanted strain, gently scrape the lawn on the inclined surface with a pipette to make a dense suspension with uniform dispersion, and control the number of cells. At 10~10/ml.
　　4. Dispense and use a sterile long dropper or capillary pipette to absorb the bottom of the ampoule tube that is sterilized by the bacteria and immersed in the tube. Do not stain the tube wall, 0.2 ml per tube.
　　5. Pre-freeze, freeze the bacterial suspension in the ampoule into ice, and sublimate the water in a frozen state, so as to prevent the bacterial suspension from boiling during vacuum drying, and bubbles will overflow. The pre-freezing temperature should be low and the speed should be fast. It can be placed in a low-temperature refrigerator (-45~-35C) or in an anhydrous ethanol dry ice bath. If the pre-freezing temperature is higher than -25C, the suspension will be suspended. Liquid ice is not solid and easily fails when vacuum dried.
　　6. Freeze and dry, cut off the cotton plug outside the ampoule tube, push the inner cotton plug to about 1cm below the tube mouth, and then connect the ampoule tube to the side tube on the branch tube with a rubber tube. The other end of the branch pipe is connected to a vacuum pump. All joints are sealed with liquid paraffin. Then put the ampoule into the saturated ice brine. When the suspension at the bottom of the bottle is completely frozen, immediately start the vacuum pump to pump air. When the appearance of the sample is basically dry, raise the branch tube and leave the ice bath at room temperature. Then the line is pumped and dried for about 1 hour.
　　7. Determine the moisture, measure the residual moisture by the weight loss method, and check the degree of drying. Generally, the residual moisture is controlled to be 3% or less, and if it is higher than 3%, vacuum drying is required.
　　Freeze-drying is very healthy. First, many hot substances do not degenerate or inactivate. When dried at low temperatures, some of the volatile components in the material lose little. Secondly, in the process of lyophilization, the growth of microorganisms and the action of enzymes cannot be carried out, so that the original traits can be maintained. Since the drying is carried out in a frozen state, the volume is almost constant, the original structure is maintained, and concentration does not occur. Since the moisture in the material exists in the form of ice crystals after pre-freezing, the inorganic salt-soluble substances originally dissolved in the water are uniformly distributed in the material. When sublimating, the dissolved substances dissolved in water are precipitated, which avoids the phenomenon that the inorganic salt carried by the internal moisture migration to the surface in the general drying method is precipitated on the surface to cause surface hardening. The dried material is porous and spongy. After adding water, it dissolves quickly and completely, and the original trait is almost immediately restored. Since drying is carried out under vacuum, there is very little oxygen, so some oxidizable substances are protected. Then drying can remove 95% to 99% of the water, so that the dried product can be preserved for a long time without deterioration.

share to:
Songyuan Freeze Dryer logo
Email：sales@bjsyhx.com.cn Facebook：SYHXfreezedryer