Freshly caught fish are easy to identify - you just need to know what to check.
When evaluating fish we pay attention to two aspects. Its natural qualities, smell, springiness, freshness. But also on the defects that come with freshness. Let's be like an Indian guide, reading how time and processing leaves its mark on the fish or its individual parts. It is important to realise that the freshness of fish is two important things - the taste we are after and the guarantee not to poison ourselves. The rest depends on our taste preferences, as there are species that taste better or worse. Cooking skills are also important, and even whether we like to scrape, gut or pull out the bones while eating.
But before we prepare fish, we have to buy it. In a shop it usually happens that we do not have the opportunity to take the fish in our hands to thoroughly assess its freshness. We have to do it by eye from a distance and sometimes even through a glass.
If we can see the eye, it will tell us a lot about the condition of the fish. Whether it is fresh or even defrosted. A convex, shining eye is a guarantee of freshness. A defrosted fish, although still of good quality, will not have a convex eye. A sunken, cloudy eye should be a clear warning.& nbsp;
The second thing is the skin, which should be shiny, taut and therefore not sunken. Sinking tells us that the flesh beneath it no longer has natural tension. The second sign of ungrooming is areas of dryness alternating with shiny areas. This looks like a protective pattern on military clothing. This is not a good sign. Fish usually have a natural protective mucus on their skin, and this is a good sign. Even the scales have a thin layer of it.& nbsp;
If the fish is already filleted, it is difficult to assess it visually. The eye is no longer there and the skin is usually underneath. The best signal is to lay the fish on ice or even one fillet on top of another. A fresh fish still has muscle tension, so it arranges itself in such a way that it keeps its kind of individual shape. A less fresh fish will take the shape of whatever it is lying on. It will bend. While the narrow ends of the fillets, i.e. from the tail, may be more malleable, if the main body is laying on the ice like a soft material this should be a big warning.& nbsp;
Maybe it's not the norm yet, but you can now buy a whole fish with a filleting service. Scraping, gutting and filleting. Usually the seller will then ask whether you want the head and backbone for soup. Such fillets are obviously the best.
Freezing is one of the most effective methods of food preservation, resulting in the inhibition of microbiological processes as well as enzymatic and biochemical transformations, causing a significant reduction in the quality and safety of products.& nbsp;
Industrial freezing is carried out in different types of equipment or installations in such a way that the temperature range of 0 to -5°C, in which more than 70% of the water in the product crystallises, is exceeded as quickly as possible.
Usually, fresh fish (whole, carcass or fillet) lose nutrients more quickly than frozen food, because enzymatic reactions, e.g. lipid oxidation, take place all the time. This is also influenced by the development of bacterial microflora, which takes place even in refrigerated products. It is slower, but bacteria still multiply.& nbsp;
The conclusion should be one: freezing only slightly can change the nutritional value of foods (all, not just fish).
In the shop the ice should only cover the fish. In the vast majority of cases there is too much ice, but in no case should the fish protrude beyond the ice, and clearly dried, yellowed parts are completely disqualifying.
White, pink, bright red, orange or yellow - characteristic of the species. What should draw our attention and warn us before purchase? Change of specific colour, lack of gloss, appearance of black spots.
After thawing, it should be mild, pleasant, similar to melon and seaweed, specific to the species. An acidic, slightly putrid, foreign smell (e.g. of chemical compounds) disqualifies the product.
The fish should be fibrous and the meat should be firm, without delamination, tender, juicy, springy (the deformation after pressure with the finger on the dorsal part disappears quickly). What disqualifies the product? Meat tissue greasy and dried out, loosened, muscle delamination, deformation after pressure.
Species-specific. If the fish is bitter, rancid or sour, refrain from eating).
The backbone breaks when you try to tear it off. If the backbone and bones stick slightly to the meat, the fish is not suitable for eating.
The fish has normal structure and musculature, the cut line is smooth, there are no remains of viscera. Surface drying occupies no more than 10 percent of the surface. The skin of the fish has a natural colouring and shine, iridescent. The eyes are shiny and convex.
What disqualifies the product: the presence of parasites (!), damage to the outer shell, scratches, damage to the skin and meat, discoloration, white spots and tarnishing. Deep drying - dehydration of meat tissue and skin, loss of elasticity. Concave and cloudy eyes.
* by Joanna Pleszko (Zeszyty Naukowe Akademii Morskiej w Szczecinie, 2009, 18(90) p. 123-127)