Why is heat pump drying popular in recent years?
High efficiency, energy saving and low operating costs.
The operating cost of heat pump drying is only 30% of the electric heating dryer, 40% of the fuel dryer, and 60% of the coal-fired dryer.
The drying effect is good.
The heat pump dryer adopts automatic control, which can automatically adjust the running state during drying process to the setting mode. The temperature rise is stable, the temperature is uniform, and the temperature difference fluctuates less, so as to avoid the influence of human factors on the drying quality during the operation of the fuel dryer.
What are the advantages of agricultural product heat pump drying versus traditional drying?
Under the food hygienic requirements
Uses the heat pump drying fruits and vegetables, in an airtight drying room, in a gentle way of close to the natural drying and drying process, do not contact with the outside world dust impurities, thus the secondary pollution if not form material using traditional way of natural exposure, not only affected by the weather, and the drying time is long, dip them in the dust, easy to form secondary pollution.
When the heat pump is used to dry the fruits and vegetables, the drying process is completed in a closed drying house at a mild temperature, almost a close to natural drying process, without contacting the external dust and impurities, Therefore, secondary pollution will not be formed.
A traditional natural drying means exposed to the sun, it will not only be affected by the weather, but also has a long drying time, and it is easy to get dust and form secondary pollution.
Come up to first grade quality
Compared with the traditional drying method, the heat pump drying can accurately control the temperature and humidity according to the simulated drying curve, ensuring minimal the color and shape change during the drying process, and generally no dry defects such like deformation, cracking, surface hardening and darkening of colors etc.
Taking the Wolfberry drying as an example, the heat pump drying is mild, and the temperature and the amount of the circulating air can be adjusted according to the thermal requirements, thus, the surface water evaporation rate and the internal moisture moving rate to surface is almost the same, similar to natural drying process. This ensures that the dried wolfberry is of good quality, good color and high grade. However, natural exposure to the sun, or hot air drying by burning coal, fuel oil, the temperature and humidity cannot be well controlled, it is easy to cause the appearance of dried wolfberry with reddish brown or dark red, and even partially black.
Closer to the nutritional quality of natural product
Fruits and vegetables contain rich vitamins and aromatic substances, and they are sensitive to heat. The traditional drying which high temperature is application will cause the pigments such as aromatic, chlorophyll and fruit red to be lost. The heat pump drying is close to the natural drying temperature, the surface water evaporation rate is close to the internal moisture moving rate, the more the vitamin is retained, and the higher the nutritional value is.
Rehydration is an important feature of the dehydrated vegetables quality. rehydration of dehydrated products decreased, although there are cell and capillary atrophy and deformation of the reasons, but also food water loss after salt concentration, protein partial denaturation, lose the ability to reabsorb water, will also damage the cell membrane infiltration
Rehydration performance is an important feature of the dehydrated vegetables quality. If this rate is decreased, although there are reasons of cells and capillaries atrophy and deformation, the salt is concentration after the water lost, therefore, the protein is partially denatured and the ability to absorb water is lost.
In the traditional drying process, the temperature is high and difficult to control; the starch and pectin are changed by the influence of heat, so the hydrophilicity is lowered. In the heat pump drying, to make dehydrated vegetables, regulated in a medium-low drying temperature is available, so that the physical or chemical characteristics of the vegetables are less changed, and the rehydration after drying is much better.
Only the temperature is controlled, and the same important relative humidity cannot be controlled in the traditional drying process. Excessive temperature often leads to the loss of nutrients.
Studies have found that drying ginger with a heat pump can give a better flavor than traditional drying and retain more gingerol. Some materials, such as mushrooms, herbs, fungus, etc., have low heat-resistant active ingredients and nutrients, in the high temperature traditional drying process, the nutrients are lost, reducing the value of dried products, Therefore, heat pump drying can not only ensure the color and scent of the material, but also retain most of the nutrients.
