Vacuum IQF Freezing gf-machine technology is a drying method in which the material is pre-frozen to below the eutectic point temperature and the moisture in the material is removed by the sublimation process under a certain vacuum condition. The refrigeration, heating and vacuum are the three major methods. Operating system composition. Since the food processed by the vacuum freeze-drying technology maintains the low temperature state, avoids the influence of high temperature on the food, can maintain the nutrition, color, shape and flavor of the raw materials to the utmost, and the product has low water content and good rehydration, and is consistently considered It is the best dry method for producing high quality food. In recent years, food freeze-drying technology has been widely used in food, medicine, health care products and other industries. Many high-value foods such as sea cucumber, ginseng, leeches and scallops have been explored using vacuum freeze-drying technology, which has effectively improved The quality and added value of food.
However, when using vacuum IQF Freezing technology for food processing, GUANFENG believes that it is necessary to pay attention to several key issues, otherwise it will not only directly affect the quality of processed products, but also lead to energy waste. Based on the research hotspots and research progress of vacuum freeze-drying technology at home and abroad, I would like to summarizethe vacuum IQF Freezing technology to improve the drying rate, energy saving and emission reduction process requirements, and apply vacuum freeze drying technology for food for reference.
1, eutectic point and inclusive point
The eutectic point and the eutectic point are important physical parameters to be considered in lyophilization, which directly affect the quality of the freeze-dried product. Therefore, before carrying out the food vacuum freeze-drying process, it is necessary to first understand the eutectic point and the inclusive point of the food in order to be targeted. Formulate reasonable process parameters for freezing food materials, improve product quality, shorten freeze-drying time, and reduce energy consumption.
2, collapse (disintegration) temperature
The collapse temperature of food is also called disintegration temperature. It refers to the temperature at the IQF Freezing and sublimation stage. As the temperature rises, the product loses its rigidity and begins to become sticky. The temperature is similar to the collapse, melting or foaming phenomenon of landslide. Collapse in the process will seriously affect the quality of the product. Therefore, it is necessary to prevent the occurrence of collapse during the IQF Freezing of the food material. The collapse is mainly related to the product process and the nature of the material itself. Different freeze-drying parameters have an impact on the occurrence of collapse.
For example, Zuo Jianguo and others used freeze-drying microscopy to study the effects of cooling rate, sublimation pressure and solution mass fraction on the collapse temperature of the dry layer during the freeze-drying process. The results show that for 10% For the sucrose/water binary solution, the cooling rate has no obvious effect on the collapse temperature; while for the 10% t-butanol/10% sucrose/water ternary solution, the collapse temperature decreases significantly with the increase of the cooling rate; the pressure versus the collapse temperature The effect is not significant; the solution mass fraction is different, and the collapse temperature slightly changes.
However, the optimization process can reduce the occurrence of collapse. Dong Huilong explored the factors affecting the collapse of papaya freeze-dried chips. The results show that the blanching pretreatment and hardening pretreatment can slow down the collapse of freeze-dried products, and the freezing rate has no effect on product quality. Large, but insufficient freezing time will cause the freeze-dried product to collapse.
The collapse temperature is also affected by the physical properties of the food material itself. Some food disintegration temperatures are higher than the eutectic point temperature. When the IQF Freezing operation is performed, the product temperature is controlled to be lower than the eutectic point temperature; some foods have a disintegration temperature lower than that. The eutectic point temperature should be closely monitored for the disintegration temperature during the IQF Freezing operation. At present, the measurement of collapse temperature is difficult and needs to be measured by means of a freeze-drying microscope. In recent years, many studies have used IQF Freezing protectants to avoid product collapse, in order to achieve energy saving and protection of product morphology. Hamoudi optimized the formulation of the freeze-dried protectant of Geotrichum candidum, and Zeng Xiaoqun optimized the Lactobacillus casei. The best formula for dry protectants.
GUANFENG provide complete freezing solutions for all kinds of products.Every GuanFeng IQF Freezing machine is tested at our facility in China before delivery. If you interested in GuanFeng Machine, please check below link: https://www.gf-machine.com/solution/frozen-solution/ for more information.