Acetic acid in vinegar

Historically, vinegar was a by-product of the winemaking industry; the name is derived from the French words vin, meaning wine and aigre meaning sour.

During the souring process, the alcohol in the wine would be converted into acetic acid by the action of Acetobacter. Acetic acid, CH3COOh, is a colorless, volatile liquid at ambient temperature. The pure compound, glacial acetic acid, owes its name to its ice-like crystalline appearance at 15.6 °C.

The acetic acid of the vinegar is the preservative agent. Vinegar is formed by acetic acid fermentation of alcoholic liquids. The acetic acid formed will preserve the liquid, provided air is excluded after vinegar fermentation is over.

Acetic acid

Vinegar is industrially produced by two methods: a slow process involving static surface acetic acid fermentation, and a fast-producing, submerged fermentation process. Generally, the static fermentation method is used in traditional vinegar production.

Bacteria normally found in the environment, the classic culture source, often fostered fermentation that yielded undesirable flavors and characteristics.

As is the case in almost all modern fermentation, vinegar fermentations today use specific bacterial cultures that have been isolated and proved to be most effective for this purpose.

Vinegars are extensively employed in preparing salad dressings and mayonnaise, sour and sweet pickles, and numerous sauces and catsups.
Acetic acid in vinegar

Acetic acid as food preservative

Acetic acid us lipid soluble and able to rapidly diffuse through the plasma membrane, a factor that has a dramatic effect on the pH of a cell.

Acetic acid is a natural metabolite in human metabolism and because it has been used in food preservation for thousands of years, it is not classified as a food preservative in EU Directive.

Structure of acetic acid

The acetic acid of the vinegar is the preservative agent. Vinegar is formed by acetic acid fermentation of alcoholic liquids. The acetic acid formed will preserve the liquid, provided air is excluded after vinegar fermentation is over.

Vinegar normally is used as a preservative in pickling relishes and other foods that have been heated.

As little as 0.1% of the undissociated acid will inhibit the growth of most food poisoning and spore-forming bacteria and 0.3% will prevent the growth of mycotoxigenic moulds.

In vinegar preserves the effect of the acetic acid is frequently enhanced by the presence of salt.

Acetic acid as food preservative