How to reduce the dry consumption of cold storage food?

During the process of cooling, freezing and refrigeration, the weight of the food is reduced due to the evaporation of water in the food or the sublimation of ice crystals, which is commonly known as the "dry consumption" of the food.

The drying time of food is not only weight loss. According to relevant information, every 1kcal of heat entering the cold storage will cause the dry consumption of refrigerated products to be 0.15~0.2g. The surface of the food will appear dry, and the quality of the food will decline.

For example, when the dry consumption of fruits and vegetables reaches 5%, they will lose their fresh and plump appearance and show obvious withering phenomenon.

Eggs in cold storage can cause air cells to increase due to evaporation of water.

During storage, the surface of frozen fish will be dry due to sublimation of ice crystals, and under the action of oxygen in the air, the fat will be oxidized and rancid, and the surface will turn yellow and brown, which will not only deteriorate in appearance, but also decrease in taste, flavor and nutritional value.

Therefore, it is of great economic significance to reduce the dry consumption of food in cold storage.

How to reduce the dry consumption of cold storage food?

Usually reducing dry consumption starts from two aspects:

First, it is necessary to improve the design, that is, reduce the refrigeration temperature, shorten the cooling or freezing time of commodities, reasonably increase the area of ​​the evaporative exhaust pipe, improve the form of cooling equipment, reasonably arrange the position of the evaporative exhaust pipe, improve the efficiency of the thermal insulation layer, reduce The temperature difference between the evaporation temperature and the storage temperature, etc.;

Second, start with operation management to reduce dry food consumption and maintain a reasonable warehouse temperature and humidity.

The experience of reducing the dry consumption of commodities that the refrigeration workers have carefully summarized over the years mainly includes the following points:

1) Reasonable operation to shorten the cold working time. In order to reduce the dry consumption of commodities in the process of cooling and freezing, it is first necessary to maximize the effect of refrigeration equipment and shorten the cold processing time as much as possible. The cooling room or freezing room must be cooled to the lowest designed temperature before purchasing, that is, the cooling room should be cooled before purchasing, and the fan should be turned on after the product is finished. When the product reaches the required low temperature, the fan will be stopped and the warehouse will be transferred. When using the cooling room and freezing time, if the quantity of goods purchased is small, the cooling room should be minimized, and the cold room should be avoided to process a small amount of goods. Otherwise, cold working and fan working time should be shortened accordingly. Larger or fatter meat, etc., should be hung closer to the exhaust pipe or where the wind speed is high to improve the efficiency of cold processing.

2) Keep the cold room as far as possible to the minimum temperature specified in the design. The temperature and humidity in the warehouse should be kept uniform, and there should be no large fluctuations. Food storage should be done at one time as much as possible.

3) The responsible personnel should strengthen the maintenance and management of the thermal insulation layer and moisture-proof layer. Regular inspection of loose materials is necessary to organize replacement if problems are found.

4) Reduce external heat into the warehouse. There should not be a large number of workers in the warehouse to select goods. Turn off the lights and close the cold storage door in time.

5) It is required to stack frozen goods in the refrigerated room as much as possible. The same owner should try to stack the same variety of goods as closely as possible, and try to make the pile as large as possible, so that the warehouse is often fully loaded. When there are not many commodities, similar commodities or commodities that can be mixed can be put together. However, packaged and unpackaged goods are generally not stored in the same refrigerated room, or stacked in categories.

6) Try to avoid using a small-capacity upper layer, a refrigerated room with poor heat insulation or a large heat flow for long-term refrigeration of frozen commodities.

7) When commodities such as poultry, fish and by-products are refrigerated, the surface should be coated with ice as much as possible. If long-term refrigeration is required, water can be sprayed on the surface of the stack for curing, but water should be prevented from dripping on floors, walls and cooling equipment. After the frozen meat is palletized, it can be covered with tarpaulin or plastic sheeting. The goods in the corridor or near the refrigerated door should be covered well. Generally, it is required to spray water into a 3mm thick ice coat (the ice coat can be sprayed with water in stages). When the heat flow is large, the ice coat is easy to melt, so pay attention to always maintain a certain thickness of the ice coat.

8) For the refrigerating room with air cooler, the airflow distribution in the warehouse should be reasonable, and it should be refrigerated at a low wind speed (not exceeding 0.2-0.4m/s).

9) The food in cold storage should be packed with plastic film and carton or coated with ice as much as possible.