Tuna
Tuna is a pelagic and predatory fish that colonizes most of the planet's seas / oceans. To tell the truth, "tuna" is a generic term, which derives from the Italianization of the noun Thunnus, genus of fish to which many fish species belong. To define these fish biologically correctly it is therefore necessary to specify the relative scientific classification.
ATTENTION ! Often, the term "small tuna" or "tonnetto" is used to refer to species belonging to different genera, such as "alletterato", better defined as Euthynnus alletteratus ; the commercial value of these fish is almost exponentially lower than that of bluefin tuna.
Canned tuna
Canned tuna is a product derived from the operations of cutting, cooking, dripping, canning and sterilization, of the muscle of fish and its fragments. The various types of products thus obtained differ in two large branches: tuna in oil and tuna in brine (in fact called brine); in both cases, these are products defined as semi-preserved. What distinguishes the two foods is, of course, the governing liquid; however, as regards the QUALITATIVE aspects of the meat, the evaluation criteria are exactly the same.
In most cases, quality brands require the use of large cans (tin or glass). This is due to the fact that a small container does not lend itself to housing a real block of muscle, but rather the crumbs that remain from canning in the most capacious containers. In practice, if you open a small box and find a "ground" of cooked tuna in it, it is a poor quality food.
Even the food label betrays low-value canned tuna. Although the cooking of the muscle takes place in salt water and requires the addition of other ingredients (aromas), if the word "monosodium glutamate E621" appears in the appropriate box, it is better to put the box away and prefer one without. This fish, in fact, already has a taste of its own that (if indeed it is tuna) certainly does not require the addition of flavor enhancers.
Also on the label, the wording that disambiguates the products obtained from frozen fish compared to the fresh one should appear. To be honest, it is always better to have a good frozen frozen product on board than a fresh "not very fresh"; on the other hand, being able to choose between the two systems (assuming that they are impeccable) the cool always takes precedence, as it allows to preserve (in addition to the aroma) also a greater compactness of the muscle and a rosy color (instead of brown) .
From the economic point of view, then, canned tuna often misleads. What costs less is not always the most convenient and several times, making the difference between the gross weight and the net (drained), one realizes that the portion of liquid in government is so high as to make the less expensive one more inconvenient.
While the tuna in brine or in brine, as far as the governing liquid is concerned, is more or less uniform among the various companies, the oil in oil is diversified even substantially. Assuming the "correctness" of the producing companies, the tuna in "extra virgin olive oil" is always qualitatively superior to that in "pomace oil" or in seed oil (of whatever kind it is).
Homemade tuna in oil
Tuna in oil
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Continuing to talk about canned tuna in oil, it is impossible not to mention the very high risk of food fraud! Since many producers, even of incontrovertible poor quality, claim to use "extra virgin olive oil", it is logical to ask what convenience there can be in using a preservative that costs more than the preserved food; actually, none! This is why, in the routine checks of the competent bodies, various cases of food sophistication-counterfeiting have been revealed; to be precise, there was the presence of DIFFERENT oils (seeds, hazelnuts, etc.), perhaps enriched with chlorophyll to gain a bright green color.
Of common interest, between natural canned tuna and oil tuna, is the type of raw material used. The law requires the use of animals belonging to the Thunnus genus, it does not require defining the Species, but only requires to use one; in practice, inside the same package, the meat deriving from several Species is not allowed. Once again the bad guys did not wait, but fortunately the unspeakable scandals revealed in the past years have given way to less serious scams. For example, a recent survey conducted on 165 cans from 12 European and non-European countries (including Italy), revealed that one pack in three does NOT contain what it should, or contains more cuttings than tuna species (source: www .greenpeace.it / tonnointrappola / news-novembre.html).
Regardless, it is the concentration of contaminants detectable both in natural tuna and in tuna in oil. The most famous pollutant is certainly mercury, which is very abundant in large fish due to environmental pollution; this excess should limit its consumption to "one-off", above all considering that in tin tuna can also remain traces of lead released by the packaging. Not to mention, then, the excess of histamine (a molecule derived from the carboxylation of the amino acid histidine) which, in the human body, plays the role of neurotransmitter and chemical mediator of inflammation. Often present in foods due to microbial proliferation and intrinsic enzymatic degradation (an indication of poor preservation), excess histamine can be responsible for allergic-like reactions known as "sgombroid syndrome"; not long ago, a whole lot of one of the most renowned brands of canned tuna was withdrawn from the market because it was considered unsuitable for human consumption due to histamine excess.
Nutritional Features
Canned tuna is a food that provides a caloric intake between 100 and 190kcal, therefore variable up to a ± 90% (higher than in oil). Energy is provided above all by proteins with a high biological value even if, in the oil under oil, the lipid fraction is exponentially higher than the natural one (10.1g vs 0.3g). For both, carbohydrates and fibers are absent, while cholesterol is contained in medium quantities. The breakdown of fatty acids (not shown in the table) is naturally in favor of omega 3 polyunsaturates in the natural one, while in tuna in oil it varies according to the composition of the liquid in government.
Among the mineral salts, those most present are certainly sodium, potassium and phosphorus, but their concentration is detectable only in tuna in oil. Also iron is not negligible and it is conceivable that the iodine content is satisfactory.
Sodium, which is an undesirable element, as it is often in excess in daily diet, is not mentioned in pickled tuna. However, already used in cooking meat (due to its discreet presence even in the version in oil), in natural tuna it is quite concentrated in the liquid of government; its quantity should therefore be more or less similar to that of preserved meat (salami, sausages, etc.).
With regard to vitamins, canned tuna contains significant amounts of niacin (vit. PP) and vit. TO; unfortunately, the quantity of cobalamin (vit. B12) contained in tuna meat is inexorably degraded with the initial cooking of the meat and also after autoclaving the tins.
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| Nutritional composition for 100 grams of edible part Tuna, in oil (drained): | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Tuna Consumption
Like a pig, even tuna does not throw anything away!
There are many preparations rather far from what average consumers (those outside the maritime traditions) consider "normal"; among these, the best known is the bottarga (oviparous sacs of the female specimens), but no less delicious are: the buzzonaglia (or buzzonaccia, or the "red" scraps of the meat, especially the one that remains attached to the bone), the lattume ( or figatello, seminal sac of male specimens), tuna tripe (stomach), tuna liver, etc. Even the skeleton, the skull, the skin and the fins, are used for the production of fishmeal even if, unfortunately, the substrates for the production of this fertilizer-fertilizer do not always derive from the scraps of fish processing.
Unfortunately, analyzing the statistics concerning the consumption of tuna in Italy, one cannot help but remain quite perplexed. In the first place, well beyond the sale of fillets of tenderloin or ventresca, is tinned tuna (both in olive and natural oil). Obviously, it is no coincidence that the "Bel Paese" holds the second European place for the production of these foods; however, more than a source of pride, it is a beautiful and good mortification. It is so to the point that, among all the peoples who preserve a long fish-gastronomic tradition, this primacy is the object of continual ridicule. It must then be said that every nation has its "neo"; the Japanese, for example, who are certainly the greatest seafood experts on the square, are so greedy with tuna as to endanger the trophism of the fish population in every picking area they frequent (including the Mediterranean Sea).
Tuna: Resource and Food
From a nutritional point of view, the tuna is part of the first fundamental group of foods, as its meats provide: high biological value proteins and B vitamins (especially thiamine, riboflavin, niacin, and cobalamin). It is also part of the group of blue fishes, therefore, the triglycerides that compose it are endowed with a high percentage of essential polyunsaturated fatty acids of the omega 3 group.
Who defines tuna a lean fish DOES NOT have any familiarity with its meat! Like land animals (for example light pigs), even fish have more or less lipid-rich body parts and tissues; while, like the pig, the belly of the tuna is the fat portion of the animal, the muscles of the back are extremely thin (since they are used to propel the animal, similar to the thighs, the shoulders and the loins of the quadrupeds).
For humans, tuna is an extremely widespread fishery product, which makes it a very important source of economic support. Tuna fishing takes place in open water, ie in open water, since (as it is a pelagic) there are no sustainable or applicable forms of ichthioculture proper. On the other hand, in Italy it is common (in Sicily and Sardinia), in addition to fishing, also the practice of Tonnas; these are huge traps that capture the tuna and define their living space; within these, it then becomes quite simple to take as much as necessary.
We conclude the article by recalling that some tuna species are considered "at risk", such as red tuna and bigeye tuna; furthermore, we specify that the most widespread catch method for this fish (called FAD) is considered one of the most harmful systems known to date, as it is not selective and uselessly fatal for several other species. This should moderate its use even if, at least in Italy, ecological protection is limited to affecting mainly amateur fishing; on the contrary, professional fishing using destructive systems, particularly that carried out by overseas fishermen, paradoxically, is less limited.
From consumers, it is however possible to make an informed purchase, favoring companies that respect the environment and use ONLY tuna caught with reeds (source: //www.greenpeace.it/tonnointrappola/); the detail should be clearly visible at least on the label of tuna in oil and of the natural one.
