In the process of making dried fish, the heat treatment process is mainly concentrated in the two stages of drying and heating, using heat energy to remove moisture from the fish body to achieve the effect of preservation and flavor enhancement. Specifically, the heat-using links and temperature settings of dried fish production are as follows:
- The main heat-using links in the production of dried fish
Drying stage
This is the most critical heat-using link in the production of dried fish. After cleaning and marinating, the fish body usually needs to be dried at an appropriate temperature to reduce the moisture content in the fish body, so as to achieve the purpose of long-term storage. Drying not only helps to extend the shelf life of the fish, but also improves the flavor of the dried fish.
Heat source method: Traditional heat sources include modern energy-saving equipment such as electric heating, gas or high-temperature heat pumps. In modern dried fish production, high-temperature heat pumps are widely used because of their energy-saving, environmental protection and ability to accurately control temperature and humidity.
Temperature setting: Different fish and production processes have different temperature requirements. Generally, the drying temperature is in the range of 50°C to 75°C, which is adjusted according to the fish species and the required degree of drying.
1.2 Baking stage (if applicable)
Some dried fish products (such as dried fish with special flavors or barbecue taste) will be baked for a short time. This stage is usually heated directly at high temperature, forming a relatively crispy and hard shell on the surface, while retaining a certain amount of moisture and taste inside.
Temperature setting: Generally between 80°C and 100°C, but since this step is mainly to bake the surface of the fish, the time is shorter, usually **10 to 30 minutes.
1.3 Preheating stage (for some dried fish varieties)
Some special dried fish varieties (such as fish with a shallow salting depth or requiring special drying treatment) may be preheated to further activate the enzyme activity of the fish or evaporate some water before entering the drying stage.
Temperature setting: Generally between 40°C and 50°C, the temperature is relatively low to avoid premature coagulation of protein or affect the texture of the fish meat.
- Temperature control and humidity management
In the entire dried fish production process, temperature control and humidity management are very critical links. Too high a temperature may cause the surface of the dried fish to dry and harden prematurely, affecting the discharge of internal moisture; too low a temperature may lead to insufficient drying and affect the quality.
-Humidity control: In the drying stage, in addition to temperature, humidity must be controlled to keep the air dry to promote the evaporation and removal of moisture. Excessive humidity will slow down the evaporation of moisture, causing the surface of the dried fish to soften or produce the risk of mold.
- Temperature requirements for different fish
The drying temperature and processing technology of different fish are slightly different. The following are the drying temperature recommendations for several common fish:
Herring: about 60°C to 70°C, the drying time is relatively long.
Cod: about 50°C to 60°C, lower temperatures help maintain the flavor of the fish.
-Eel: about **55°C to 65°C, relatively low temperatures are conducive to maintaining the texture of the fish.
-Sea bass**: about 65°C to 75°C, high temperatures help to quickly remove water and retain the unique taste of dried fish.
- Drying time
Drying time is closely related to temperature and humidity. Generally speaking, the drying time of dried fish is between 8 hours and 24 hours, depending on the thickness and type of the fish. Too high a temperature may shorten the drying time, but caution is needed to avoid over-drying or affecting the flavor.
Summary
The heat-using process in the production of dried fish is mainly concentrated in the drying, heating and (if applicable) baking stages. The temperature of each link needs to be finely adjusted according to the characteristics of the fish species and production requirements to ensure the quality and taste of the dried fish. In general, the drying temperature is generally set between 50°C and 75°C, while the baking stage may require a higher temperature (80°C to 100°C). Throughout the process, humidity control and temperature stability are the key to making high-quality dried fish.
