Formulation and optimization of freeze-drying curve of freeze-drying technology
Briefly: Bo Yikang has been committed to the R&D and production of small-scale, pilot-scale, production-type vacuum freeze-drying equipment. In the process of long-term customer service, it was found that the majority of freeze dryers use customers to understand the mechanism of freeze-drying, and how to explore and optimize the freeze-drying process of products should not be known. In response to the above situation, special collection and lyophilization technical data will be collected to help the users to develop and optimize the freeze-drying curve.
The freeze-drying curve is a curve indicating the temperature and pressure of the product as a function of time during lyophilization. The shape of the freeze-drying curve is related to many factors such as the performance of the product, the amount of the load, the type of the container, and the equipment conditions. Develop a freeze-drying curve to determine the following parameters:
a, pre-freezing rate
The speed of the pre-freezing rate has a direct impact on the size of the grains in the product, the viability of the live bacteria and the rate of sublimation. The slow-frozen grains are large, the appearance of the product is rough, and it is not easy to damage the living bacteria, but the sublimation rate is fast. The quick-freezing grain is small, the appearance of the product is fine, and the sublimation rate is slow.
The speed of the pre-freezing rate has a direct impact on the size of the grains in the product, the viability of the live bacteria and the rate of sublimation. The slow-frozen grains are large, the appearance of the product is rough, and it is not easy to damage the living bacteria, but the sublimation rate is fast. The quick-freezing grain is small, the appearance of the product is fine, and the sublimation rate is slow.
b, pre-freezing temperature
The temperature of the product should be 5-10 ° C below its cosolvent point.
c, pre-freezing time
The time required for pre-freezing is determined by different specific conditions. The general principle is that all parts of the product should be completely frozen. After the temperature of the product drops to the predetermined minimum temperature, it needs to be kept at this temperature for 1-2 hours before sublimation can be performed.
d, condenser cooling time and temperature
The temperature of the condenser should be determined according to the temperature at which the product is sublimated. The sublimation temperature is low, and the condenser temperature is also required to be low. The optimum rate of sublimation is about one-half of the saturated vapor pressure at the sublimation temperature of the product. Too low a pressure not only does not accelerate sublimation, but also causes poor heating performance to the product and reduces the rate of sublimation.
The temperature of the condenser should be determined according to the temperature at which the product is sublimated. The sublimation temperature is low, and the condenser temperature is also required to be low. The optimum rate of sublimation is about one-half of the saturated vapor pressure at the sublimation temperature of the product. Too low a pressure not only does not accelerate sublimation, but also causes poor heating performance to the product and reduces the rate of sublimation.
e, sublimation rate and drying time
The sublimation rate is mainly determined by the heating capacity of the shelf and the water trapping capacity of the condenser. The rate of temperature increase can be increased as long as the pressure in the oven is maintained at the highest allowable pressure. When drying once, it can be roughly 1 mm in thickness of the dried product per hour. It can be judged according to the following phenomena:
1. The interface between the dry layer and the frozen layer reaches the bottom of the bottle and disappears.
2. The temperature of the product rises to near the temperature of the heat transfer oil.
3. The pressure in the drying chamber drops to the pressure of the condenser, and the two are close to each other and the pressure remains unchanged.
4. Close the septum valve, the rate of pressure rise in the tank is close to the leak rate of the dry box.
After the above phenomenon occurs, it is extended by 0.5-1 h, and one drying is completed.
The sublimation rate is mainly determined by the heating capacity of the shelf and the water trapping capacity of the condenser. The rate of temperature increase can be increased as long as the pressure in the oven is maintained at the highest allowable pressure. When drying once, it can be roughly 1 mm in thickness of the dried product per hour. It can be judged according to the following phenomena:
1. The interface between the dry layer and the frozen layer reaches the bottom of the bottle and disappears.
2. The temperature of the product rises to near the temperature of the heat transfer oil.
3. The pressure in the drying chamber drops to the pressure of the condenser, and the two are close to each other and the pressure remains unchanged.
4. Close the septum valve, the rate of pressure rise in the tank is close to the leak rate of the dry box.
After the above phenomenon occurs, it is extended by 0.5-1 h, and one drying is completed.
In the case of secondary drying, the temperature of the product can be raised below the maximum allowable temperature, so that the bound water and the water adsorbed in the dried layer obtain sufficient energy to be resolved from the molecular adsorption. The time of secondary drying is 0.35-0.5 times of the drying time.
It is necessary to continually optimize the freeze-drying process curve: a good freeze-drying process should be personalized, with the characteristics of stable product quality, short time and low energy consumption. In the research of freeze-drying process, the chemistry and molecular viewpoints are used to observe the problem, and the mechanical, electronic, and computer methods are used to control the problem.
Oat Powder is produced by the specific enzymatic hydrolysis and spray drying technology, so it is called Hydrolyzed oat powder or Enzymolysis Oat Powder. It has a pleasant oat fragrance with creamy mouthfeel and smooth texture. It retains all the soluble nutrients of oats, such as high-quality plant protein, fat, soluble dietary fiber(3-glucan>3%). It is high-viscosity and slightly sweet, easy to digest and absorb. It is stable and good resistance to acid and heat treatment after dissolution in water.
Oat Powder,Oat Milk Powder,Hydrolyzed Oat Flour,Hydrolyzed Oat Powder,Enzymolysis Oat Powder
Xi'an Gawen Biotechnology Co., Ltd , https://www.amulyn-bio.com