Sorbic acid

Sorbic Acid as a Preservative

Sorbic acid (E200) is a natural organic compound, widely used as a preservative in the food industry due to its absolute safety.

Especially interesting are its antifungal properties, which make it commonly used in food products such as cheeses (to control the growth of mold and yeasts on the crust), yogurt, lemonades, lemon juice, fruit juices, sauces, tomato sauce, ketchup, salad dressings, rye bread, alcoholic and non-alcoholic flavored drinks, gnocchi, polenta, cakes, bakery products, wine and cider. Sorbic acid, in fact, is much more effective in slightly acidic foods than in neutral ones; its antifungal power is equal to that of benzoates, and even higher at pH between 4.0 and 6.0 (the indissociated form is therefore more active than the dissociated one). This characteristic supports its antifungal properties, given that molds, unlike bacteria, develop in an acid environment and are unlikely to grow on alkaline foods. Sorbic acid, very active on molds and yeasts, shows a synergistic action with benzoic acid, more active on bacteria. To maximize its effi cacy, it is important that sorbic acid is added to hygienically unexceptionable products, to prevent the residual microorganisms metabolizing it by inactivating it.

Despite the discreet antibacterial properties of sorbic acid, especially at pH values ​​below 4.5, lactic bacteria are resistant to its action; as we have seen, therefore, this additive is used successfully in yoghurts and in all products that undergo lactic fermentation. Another important advantage of sorbic acid is the absence of significant influences on the taste of food, although in certain sweet white wines it can react to give geraniol, with a taste that is not exactly inviting. In wine, sorbic acid is used as an antifermentative in partial substitution of sulfur dioxide, which has a marked antibacterial effect, but can reveal unpleasant odors and flavors on the palate.

At room temperature, sorbic acid appears as a white solid with a soft and characteristic odor; as shown in the figure, its chemical formula is C ₆ H ₈ O ₂ .

In foods, sorbic acid is generally added as a calcium, sodium and potassium salt; we generally speak of "sorbates", respectively indicated with the letters E201 (Sodium sorbate), E202 (Potassium Sorbate) and E203 (Calcium Sorbate). Sorbic acid is only slightly soluble in water (solubility improves in hot) but completely soluble in alcohol; potassium sorbate, on the other hand, is very soluble in water, but slightly soluble in alcohol; calcium sorbate is mainly used in dairy products.

In nature, sorbic acid is found in apples, plums and rowan fruits ( Sorbus aucuparia ), from which another sorbitol, an interesting additive with a sweetening and anti-aging power, is obtained. However, sorbic acid and sorbates are industrially synthesized through various and different chemical processes; given the synthetic origin there are no restrictions on food, therefore sorbic acid and its salts can be consumed by all religious groups, vegans and vegetarians.

Side effects

In the body, sorbic acid is metabolized to carbon dioxide (CO ₂ ) and water (H ₂ O) with the same mechanism as the fatty acids normally found in food. As a rule, therefore, there are no side effects to the concentrations used; only in a small percentage of individuals the sorbic acid can trigger allergic reactions, while its contact with the skin produces a hives supported by non-immunological mechanisms, due to a non-specific mastocytic degranulation with histamine release (the same induced by the bites of nettle).

Sorbic acid against Candida

Lastly, the presence of sorbic acid and / or sorbates also in herbal products and in those intended for personal hygiene, to prolong its shelf-life, should be noted. In some forums the use of sorbic acid against candida is recommended ; in reality it is basically wrong advice, considering the slightly alkaline pH of the intestinal content, but above all the body's ability to absorb and metabolize this substance with extreme ease, preventing it from reaching the colon where its antifungal action is required; theoretically, the use of high concentration sorbic acid in capsules or controlled release tablets could instead help. Another solution could be to take sorbic acid together with fiber supplements, for example psyllium seeds; in this way the substance could be trapped inside the water and fiber gel, bypassing absorption in the small intestine; plus the soluble fiber tends to acidify the faeces, amplifying the antifungal effect of sorbic acid and / or its salts. Thus the same argument made for caprylic acid and its efficacy against candida is valid.