Detailed Explanation of the Processing Technology for Fresh-Brined Red Drum Fish Fillets

The scientific name of the red drum (Sciaenops ocellatus) is the spotted weakfish, belonging to the genus Sciaenops, family Sciaenidae, order Perciformes. It is a eurythermal and euryhaline fish, with a suitable temperature of 10-30°C, optimally 18-25°C. It has been reported to tolerate low temperatures of 2°C. Its salinity tolerance range is very wide, and it can grow normally in freshwater, brackish water, and seawater. It is a carnivorous fish. In natural waters, it mainly feeds on shellfish, cephalopods, small fish, etc. In artificial rearing, compound feed can be used. The red drum has few diseases and grows quickly. According to reports, individuals raised in the same year can reach 500-1000 grams, and the largest individuals can reach 3 kg. It is a very promising aquaculture species. In recent years, red drum aquaculture in our province has developed rapidly, and production has continuously increased. It is mainly supplied for export or sold fresh as live fish on the domestic market, which has not only increased the economic income of fishermen and farmers but also provided new aquatic products to the market. However, with the development of aquaculture production and the increase in output, red drum @#@136@#@ sales have slowed, and prices have fallen. Therefore, we carried out research on the processing technology for fresh-brined red drum fillets, which is introduced as follows.

I. Process Flow

Rinsing → Deheading, descaling, evisceration → Cleaning → Slicing → Deodorization with compound salt → Rinsing → Seasoning → Draining → Low-temperature drying → Trimming and weighing → Vacuum packaging → Quick freezing → Frozen storage → Finished product

II. Key Operating Points

1. Raw materials: Generally, red drum of about 1-2 kg is selected as the processing raw material.

2. Deheading, descaling, evisceration: Send the cleaned red drum to the worktable, and use specialized knives to descale and eviscerate. When descaling, apply appropriate force to avoid cutting through the fish flesh, and scrape from the tail toward the head with a specialized knife. For deheading, cut off the head along the lower part of the pectoral fin, and the cross-section should be kept flat.

3. Slicing: After the "three-removal" red drum is cleaned, send it to the slicing machine worktable or slice manually. When slicing, the knife must be sharp to avoid incomplete slices and sticking of slices. At the same time, the quality of slicing must be controlled to ensure uniform slice thickness, because uneven thickness can easily make the subsequent deodorization process difficult to control, greatly affecting product quality.

4. Deodorization with compound salt: Carry out deodorization treatment at a ratio of raw fish to compound salt solution of 1:1, with the temperature controlled below 20°C, for 30-45 minutes, adjusted specifically according to slice thickness and processing season temperature.

5. Rinsing, seasoning: Soak in tap water or rinse under running water for 30 minutes; the running water treatment time can be correspondingly shortened, with the temperature controlled below 20°C. Season at a ratio of fish fillets to seasoning solution of 1:(1-2). The seasoning mainly consists of salt, sugar, monosodium glutamate, etc., and should be fully dissolved, with the temperature controlled below 20°C. The seasoning time is 30-45 minutes, and may vary slightly according to fish size and the dietary habits of different consumer groups.

6. Low-temperature drying: To prevent fat oxidation, a low-temperature dehumidifying drying method is used. Place the fish fillets on the mesh racks of a low-temperature drying tunnel and dry them with dry air below 30°C for about 2-3 hours, until the moisture content of the fish is below 60%.

7. Trimming and weighing: Trim and tidy the dried fish fillets. The surface of the fillets should have no sharp bones or spines to prevent puncturing the packaging bags, and then weigh according to requirements.

8. Vacuum packaging: Package in appropriate specifications according to product sales conditions, generally divided into packaging grades such as 250 grams, 450 grams, etc. When sealing, wipe the sealing area clean; an unclean sealing area affects the firmness of the seal. After vacuum packaging, attention should be paid to the degree of vacuum and seal strength, and spot checks should be done well, with timely adjustments made if poor conditions are found.

9. Quick freezing, frozen storage: Use an individual quick freezing production line below -35°C for quick freezing, so that the center temperature of the fillets rapidly drops below -18°C. After boxing and packing, store frozen in a cold storage below -18°C, and keep the cold storage temperature stable.

10. Finished product: The shelf life of the product at -18°C reaches more than 6 months, and a cold chain should be used for storage, transportation, and sales. When eating, it can be steamed over water or cooked in a microwave oven. Adding an appropriate amount of yellow rice wine and fresh ginger slices before steaming gives a better taste.