Views: 304 Author: Site Editor Publish Time: 2020-06-24 Origin: Site
There are many technical methods for food drying. Most of them rely on natural ventilation and sunlight to achieve the purpose of drying, but they are constrained by natural conditions and hygiene of food is difficult to guarantee. The use of mechanical ventilation and heating can improve the production conditions. However, during the processing of animal-based foods, it is easy to result in the oil oxidation and so on, which will hugely affect the quality of food. Vacuum freeze-drying is mostly used in the processing of plant-based foods.
The temperature-adjusting dehumidifier is used in a special method that simulates the natural environment in winter such as low temperature and low humidity, wind to reach the goal of rapid dehydration and drying.
In order to shorten the production cycle and achieve the aim of uninterrupted production throughout the year, it is necessary to create a production condition with low temperature, low humidity and wind in high speed, which artificially simulates the natural environment outdoors in winter.
The temperature, humidity, wind speed, and pressure required for air-drying of food are related to the type of food, packaging, and production cycle and so on. Generally speaking, food in low content of water and other conditions can appropriately reduce the requirements in temperature and humidity, but it must be tested and sufficient data should be obtained before the design indicator can be confirmed.
In order to form the special environment for food drying, units of industrial dehumidifiers should be used, and exhaust and supply system of air should be configured as well. According to the range of temperature and humidity range for food drying, and the special requirements of hygiene, the equipment should be selected according to the functions of freezing, dehumidification, heating and temperature regulation. It can be automatically operated and it should consider the ratio of air and volume in different seasons to increase the rate of water removal and to reduce energy consumption.
As for the principle of dehumidifier, the food hanging in the drying room emits moisture into the surrounding air. Then, the humid air is sucked into the dehumidifier. In the dehumidifier, the air first encounters the coil in low temperature to cool down and condenses into drops of water, and then the drops will be heated up to reduce the relative humidity. After that, the dehumidifier will send it to the air-drying room by winds of constant speed. In this way, the moisture in the food is continuously discharged by the dehumidifier. After several hours, the food will be dried.
According to the climate characteristics of different seasons, the dehumidifier can adjust the the operation of the equipment to reduce the energy consumption.
All in all, the technology of thermostatic dehumidification of food is a new technology which comprehensively uses science in food processing, freezing, air conditioning and other fields. It draws on the experience of traditional food processing. Finally, with suitable machinery, it can artificially simulate the natural environment for air-drying. This technology has been tested and popularized in many food enterprises, and it has become increasingly mature after continuous practice.