What it is and what it is for
Smoking is a method used since ancient times to prolong food storage. In addition to this technological effect, thanks to the selection of various and specific types of wood, smoking provides an important contribution to color, flavor and "characteristic aroma of some food products.
How to do it
The traditional technique exploits the substances present in the smoke, released by the slow and incomplete combustion, therefore without flame, of various types of non-resinous wood. These substances penetrate into the surface layers of the food, altering its organoleptic characteristics and prolonging its shelf-life; for this purpose, hardwood chips are generally used - such as oak, chestnut, walnut, poplar, acacia, birch, beech, etc. - while aromatic plants such as thyme, bay leaf, marjoram and rosemary have the purpose of improving the organoleptic characteristics of the smoked food. By law, impregnated, colored, glued, painted or similarly treated woods and vegetables may not be used during the entire process. The use of moldy and damp woods is also not recommended.
Among the countless components of smoke, also variable according to the wood used, we remember formaldehyde, phenolic compounds and aliphatic acids (from formic to caproic), which exert a "preservative action, further enhanced by the dehydration and heating of the" food. . Furthermore, smoking is often preceded by other conservation techniques, such as drying, bagging or salting, which inactivates some microorganisms, increases dehydration, gives the product greater flavor and favors the penetration of smoke.
Today, however, the smoking of foods has practically lost this preservative value and is mostly used as a flavoring technique (since it is not able to ensure the microbiological stability of the product).
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Smoked Salmon - All the Tricks for Home Smoking
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Risks to health
Among the various substances present in the smoke, of course, there are also harmful ones, such as the aromatic polycyclics (oncogenic substances), including benzo (a) pyrene and benzo (a) anthracene.Through particular production techniques (woods used, physical filters, distillation, temperature and humidity, etc.) we try to limit as much as possible the quantity of these compounds, among other things strictly regulated by the legislator.
Depending on the temperature of the smoke used, the products can be smoked hot (50-85 ° C for 2-4 hours), parfait (25-40 ° C several hours) or cold (20-25 ° C for a few days) ). As the temperature drops, the humidity of the environment must be reduced, while the exposure times must increase (cold smoke is used, for example, for salmon and other raw foods). it takes place in special rooms, in which the smoke produced in distinct chambers (smokehouses or ovens for incomplete combustion) is conveyed, previously purified by filters of different diameters which have the purpose of retaining the largest corpuscular parts (soot).
An alternative technique uses the so-called liquid smoke, obtained by condensation and purification of the smoke derived from the combustion of wood. Distillation allows to decrease the content of potentially toxic substances, such as polycyclic aromatic hydrocarbons, see benzopyrene, which are carcinogenic.
The purified mixture is then applied to the product by spraying, showering, dipping or by injection into the mixture. In any case, the liquid smoking technique has very little preservative effect and this characteristic is obtained through the use of specific additives (such as nitrites, nitrates , ascorbic acid and ascorbates) or other preservation techniques.
Once again, therefore, we have proof that artisanal products are not always to be preferred over industrial ones, since a home-smoked food is much more at risk of severe contamination by polycyclic aromatic hydrocarbons than another subjected to industrial smoking processes. .
In the Diet
In a "balanced diet, smoked foods should have a marginal, not to say occasional role, and preferably be consumed in combination with vegetables, preferably raw. Both for the smoking technique and above all for the common joint use of nitrites, consumption Excessive smoked food is in fact considered one of the risk factors for stomach cancer, together with alcoholism, smoking, Helicobacter pylori infection and the inevitable genetic and family predisposition.
