Processing Methods and Techniques for Dry-Salted Icefish (Large Icefish)

The processing technique for dry-salted crystal icefish is simple and convenient for storage, and because this processing method preserves the inherent flavor of icefish, it is more welcomed by consumers than salt-dried products.

1. Processing workflow

Raw materials → cleaning → alum water soaking → secondary drying → stacking and cooling → packaging → storage

2. Key operational points

(1) Raw material handling: First remove mixed fish, shrimp and other impurities, pour the icefish into a wooden barrel pre-filled with half a barrel of clean water, add a few drops of edible oil, stir by hand for 2 min-3 min to remove foam and mucus.

In rainy weather, fresh icefish must be soaked and washed in alum water of different concentrations after being taken out of the water to prevent spoilage, and this can also speed up drying. However, treatment with alum water can affect quality and reduce the product yield. Therefore, the following three points must be mastered when soaking and washing with alum water:

① When the weather is good, sunlight is strong, and evaporation is fast, use little or no alum. The standard for the alum water is that it can wash off the mucus of the icefish, and the tail of the fish must not turn white from the alum. The ratio of alum to water is 1:60. The alum water can be used three times. The first soaking and washing time must not exceed 1 min, the second time can be extended to 2 min, and the third time can be extended to 5 min. After washing, dry in the sun.

② When the weather is cloudy, water evaporates slowly, so more alum can be used. The standard for the alum water is that it can turn the fish tail white from the alum, but it must not turn the fish body white from the alum. The ratio of alum to water is 4:60. The alum water can also be used three times, and the length of time is mainly determined by just enough for the fish tail to turn white from the alum.

③ In rainy weather, the air is humid and the fish is prone to mold and spoilage. The ratio of alum to water is 12:60. Soak the icefish in the alum water until the whole body turns white, then after the weather clears, rinse with clean water and dry in the sun. This is generally used when it rains continuously for one to two days during the thunderstorm season.

(2) First drying: On the boat, spread the treated raw materials on a fish-drying net rack and press gently and evenly, then dry in the sunlight. When drying the fish, spread them thin and evenly to shorten the sun-drying time and speed up drying. After drying, collect them into the cabin for temporary storage.

(3) Second drying: After 3-5 days, dry again in the sun on a cement yard. The thickness of the spread depends on the degree of the first drying. If the first drying reached 70-80 percent, spread to a thickness of 6 cm-10 cm; if it reached more than 90 percent, spread to a thickness of 10 cm-15 cm. After drying for 1 h, turn them over. After that, in order to make the finished product dry evenly, turn them once every 10 min-15 min, and once every 5 min under strong sunlight, until they are completely dry.

(4) Standards for dry-sunning: To judge whether they are sun-dried, in addition to there being no wet feeling when grasped by hand, take one icefish, place it flat on the separated middle finger and index finger, and press the middle section of the fish body with the thumb. If it has become brittle and can be broken, or has white marks of breakage, it is completely dry. Special attention should be paid during sun-drying: it must not be overdried, otherwise it is likely to break apart after packing.

(5) Packaging: Fully dried icefish are moved into the warehouse and stacked on wooden boards. After one day and night, once the heat has dissipated and they are completely cooled, package them. If packaged while still hot, they are likely to be crushed or to heat up and deteriorate. They can be packed in gunny sacks, 50 kg or 100 kg per sack. When packaging, press them tightly; otherwise, not only will the volume be large and handling difficult, but the large gaps in between will also easily absorb moisture and cause deterioration. They can also be sealed and packaged in plastic bags of different specifications. The finished product can be stored for more than half a year, and under refrigeration conditions, it can be stored for one year.