A Detailed Explanation of the Processing Technology of Caviar and Fish Roe
The ovaries of various spawning marine fish, shellfish and freshwater fish can be used as food, and in many parts of the world fish roe is considered a very nutritious food, with high protein content, less contaminated raw materials and good-tasting finished products. Therefore, fish roe products are very popular in markets around the world.
1. Caviar processing
The term "caviar" is often used to refer to fish roe produced in a special way. In the past, the black caviar was a delicacy in foreign royal courts; now it is a beauty and health recipe for fashion-conscious people and friends who love good food yet still worry about losing weight. Caviar contains trace elements, mineral salts, protein, amino acids and reconstituted essential fatty acids needed by the skin. It can not only effectively nourish the skin but also make the skin delicate and smooth. Therefore, given its own nutritional value, it has broad market prospects.
Caviar can be made from the roe of many kinds of fish, and a specific product generally has to be identified, which includes: the name of the fish from which the roe was obtained, and in some cases also the body of water where the fish was caught. This situation is most common especially in products of high quality and high price.
The processing technology is: raw material -> roe extraction -> ovary grading -> seed extraction -> rinsing -> sorting -> salting -> draining -> sun drying -> packaging -> finished product storage
1. Raw material requirements It is best to use fresh fish roe. Frozen fish roe can also be used, but it needs to be thawed; the process is rather cumbersome and, for the protection of the roe, there are requirements for the thawing process.
2. Roe extraction To pay attention to hygiene and minimise contamination as much as possible, fish roe must be extracted carefully. Fresh fish roe is soft and indeterminate in shape and easily broken; if it is rinsed in concentrated brine, the roe will shrink due to rapid dehydration, and the economic value of the finished product will be affected. Therefore, fresh fish roe is generally subjected to a shaping treatment.
Shaping treatment generally has two methods: in-body shaping and out-of-body shaping. In-body shaping refers to treating freshly caught fish with ice and 10-12 degrees Baume brine or 10% salt, which can both preserve freshness and shorten the shaping time, with good results. Out-of-body shaping refers to shaping the roe after it has been removed from the fish body; it is suitable for mature roe taken from fresh fish, placing it into 8 degrees Baume brine as the roe is being extracted, soaking for 4 hours, and rinsing after the shape is basically fixed.
When thawing frozen fish roe, in order to maintain the freshness of the raw material and ensure product quality, the light brine thawing method is generally used. This can shorten the production cycle.
3. Ovary grading The ovaries are graded according to type and quality. In the grading process, the state of the intact ovary (the size, shape, opacity or translucency of the eggs, the firmness of the connections, etc.) and freshness (colour, firmness, flavour, etc.) are the main factors. Better-quality ovaries are used to produce caviar, while poorer ovaries are either partly or entirely salted.
4. Seed extraction The process of separating and obtaining fish roe from the ovary is called screening. This process is usually done manually, and for certain fish species automated operation can also be carried out. Manual screening is pressing the ovary through a rotating stainless steel wire mesh or other mesh material, so that the roe passes through the mesh while the connected tissue remains on top. Automated systems use mechanical force or enzyme systems to separate the roe, and use salt to preserve the roe and obtain the ideal shape and elasticity.
5. Salting The salting process is very important and reacts quickly. The salting time may need 2-20 minutes, which mainly depends on the fish species, the size and quality of the roe, and the final salt concentration.
6. Draining After salting, it is placed on a cool mat to dry in the sun or spun dry in a centrifuge, and then held in metal, plastic or other containers.
Variations in the basic processing steps depend on the species of fish and the final processed product, such as granular caviar, flavoured caviar, smoked caviar, etc. If preservatives or other additives such as colourants are added, they should be added after draining. Packaged products also need to undergo sterilisation treatment. In order to maintain good quality, vacuum packaging must be used, and the product must be stored frozen or refrigerated.