PICKLED OR PICKLED - FOOD PRESERVATION

In fermented vinegar

The fermented pickle is a food (vegetable) subjected to microbial proliferation; the biological starter is made up of microorganisms naturally present on the vegetable and the preservative agent is made up of lactic acid; the most common fermented pickles are sauerkraut and gherkins. .
The production technique is more or less the same for both pickled vegetables, and also the microbial cultures involved are almost overlapping; both sauerkraut and fermented gherkins exploit the action of some lactic bacteria such as L. mesenteroides, E. faecalis, P. cerevisiae, L. brevis And L. plantarum; among all, i head lice And L. plantarum are the most important ones, while L. brevis (especially for gherkins) represents a potentially harmful species.
The fermented pickled vinegar requires (after washing, husking and cutting) the addition of table salt (NaCl), useful for selecting the suitable microbial colony for the process (since in this way only the bacteria necessary for the process will be activated. release of lactic acid). NB: should the bacterial selection fail, softening, rot, swelling, discolouration, viscosity, etc. may occur.

In vinegar with the addition of vinegar

That in vinegar is another "natural" preservation technique of foods (especially vegetables, mushrooms and fish) previously washed, peeled, pre-cooked and immersed in a boiling ACID liquid, with a food pH of about 4.6; it is a predominantly "chemical" conservative method, more artificial than the previous one and obtained by adding food vinegar (for example, wine vinegar contains about 6% acetic acid - CH3COOH). The choice of a pH of 4,6 represents the right compromise between the palatability of the pickle (which has a characteristic acidulous flavor and aroma) and its hygienic safety, since:
the bacteria they develop mainly at a pH of 6.5-7.5, the molds at about 6, and i yeasts in a pH range oscillating between 3 and 4 (thus resulting potentially active in the NON-sterilized pickle). microbial (including yeasts!) to prevent "almost" totally the development in the preserved food.
Although acetic acid has antibiotic properties, for the more perishable preparations it is advisable to fortify the antiseptic / bactericidal effect with the addition of table salt (sodium chloride - NaCl) and spices; these ingredients represent additional useful natural preservation factors. to the prolongation of the life of the food (Obstacle theory - see NOTES). On the other hand, the concentration of acetic acid in the pickle can vary according to the type of food preserved; for example, on the label of a commercial pickle you can distinguish 3 different words1:

Flavored with vinegar: if the acidity of the preserving liquid of the pickled vinegar is less than 1.2%

With vinegar or with vinegar: if the acidity of the preserving liquid is higher than 1.2%

In vinegar: if the acidity of the preserving liquid is higher than 2.2%.

Nutritional aspects

From a nutritional point of view, pickled foods prepared by adding vinegar do not differ much from those cooked and ready to eat. The only useful consideration concerns: the possible loss of vitamins resulting from the pH variation, the possible loss of salt due to dilution in the preserving liquid and the possible increase, NOT desirable, of the sodium in the diet if table salt is added.
Regarding fermented pickled foods, they enjoy an increase in choline and cobalamin (vitamin B12) due to microbial action, while there is a parallel decrease in vitamin C (ascorbic acid) in the food. Also in this case, by addition to the preparation, the sodium intake increases in an undesirable manner.
NB. Some believe that the pH of the pickled can somehow affect the integrity of the gastric mucosa; in fact, the stomach's acid barrier is prepared to withstand acid concentrations ranging from a pH of 1 to 3, so a value of 4.6 should not affect it in any way.

NOTE: Obstacle theory: the theory of obstacles is a principle of food conservation for which, in order to obtain greater conservation safety, action is taken on several levels with respect to a single variable (reduction of the "food water + salting + pickling + essential oils" spices, etc.). In this way the risks of applying a single treatment are reduced and the quality (healthiness) of the food is improved.

Bibliography:

Food microbiology - James M. Jay, Martin J. Loessner, David A. Golden - Springer - pages 191-192

Food and health. Nutrition food course - S. Rodato, I. Gola - Clitt - page 275; 292.