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 harmlessness. Especially interesting are its antifungal properties, which make it commonly used in food products such as cheeses (to control the growth of mold and yeast on the rind), yogurt , lemonades, lemon juice , fruit juices , sauces , tomato puree , ketchup , salad dressings , rye bread , alcoholic and non-alcoholic flavored drinks, dumplings , polenta , cakes, bakery products, wine and cider. Sorbic acid, in fact, is much more effective in slightly acidic foods than neutral ones; its antifungal power is equal to that of benzoates , and even higher at pHs between 4.0 and 6.0 (the undissociated form is therefore more active than the dissociated one ). This characteristic supports its antifungal properties, given that moulds, unlike bacteria , develop in an acidic environment and are unlikely to grow on alkaline foods . Sorbic acid, very active on molds and yeasts, therefore shows a synergistic action with benzoic acid , more active on bacteria. To maximize its effectiveness, it is important that sorbic acid is added to hygienically impeccable products, to prevent residual microorganisms from metabolizing it inactivating it.
Despite the discrete antibacterial properties of sorbic acid, especially at pH lower than 4.5 lactic acid bacteria are resistant to its action; as we have seen, therefore, this additive is successfully used in yoghurts and in all products that undergo lactic fermentation. Another important advantage of sorbic acid is the absence of significant influences on the flavor of food, although in certain sweet white wines it can react to give geraniol, which has a less than inviting taste. In wine, sorbic acid is used as an anti-fermentative in partial replacement of sulfur dioxide , which has a strong antibacterial effect, but can reveal unpleasant odors and flavors on the palate .
At room temperature, sorbic acid appears as a white solid with a faint and characteristic odor; as indicated in the figure, its chemical formula is C 6 H 8 O 2 .
In foods, sorbic acid is generally added as a salt of calcium , sodium , and potassium ; we generally speak of “sorbates”, respectively indicated by the acronyms E201 ( Sodium sorbate ), E202 ( Potassium Sorbate ) and E203 ( Calcium Sorbate ). Sorbic acid is only slightly soluble in water (solubility improves in hot water) 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 interesting additive with sweetening and anti-cavity properties is obtained, sorbitol . However, sorbic acid and sorbates are industrially synthesized through various different chemical processes; given its synthetic origin there are no food restrictions, therefore sorbic acid and its salts can be consumed by all religious groups, vegans and vegetarians .
Side effects
In the body, sorbic acid is metabolised to carbon dioxide (CO 2 ) and water (H 2 O) with the same mechanism as fatty acids normally present in foods. As a rule, therefore, there are no side effects at the concentrations used; only in a small percentage of individuals can sorbic acid trigger allergic reactions , while its contact with the skin produces urticaria sustained by non-immunological mechanisms, due to non-specific mast cell degranulation with release of histamine (the same induced by dog bites). nettle ).
Sorbic acid against Candida
Finally, it is worth mentioning the presence of sorbic acid and/or sorbates also in herbal products and in those intended for personal hygiene, with the aim of prolonging their shelf-life . In some forums the use of sorbic acid against candida is recommended ; in reality this is essentially wrong advice, considering the slightly alkaline pH of the intestinal contents , but above all the body’s ability to absorb and metabolise this substance extremely easily, preventing it from reaching the colon where its antifungal action is required; theoretically, the use of high-concentration sorbic acid in controlled-release capsules or tablets could instead help . Another solution could be to take sorbic acid together with fiber supplements , such as psyllium seeds ; in this way the substance could be trapped inside the gel of water and fibers, bypassing absorption in the small intestine ; furthermore, soluble fiber tends to acidify the stool , amplifying the antifungal effect of sorbic acid and/or its salts. In this sense therefore the same applies as for caprylic acid and its effectiveness against candida .
