There are three types of sorbic acid, potassium sorbate and calcium sorbate.
Sorbic acid is insoluble in water, when using it must first be dissolved in ethanol or potassium bisulfate, it is inconvenient and irritating when used, so it is generally not commonly used; calcium sorbate fao/who stipulates that its use range is small, so it is not often used; potassium sorbate does not have their shortcomings, soluble in water, wide range of use, we can often see its figure in some drinks, preserved fruits, cans and other foods; here I focus on potassium sorbate: it is unsaturated hexacarbonate Potassium sorbate sold on the general market is white or light yellow particles, the content is 98%--102%; odorless, or slightly odorous, easy to absorb moisture, easy to oxidize and brown, stable to light and heat, relative density of 1.363, melting point decomposed at 270 °C, the ph: 7-8 of its 1% solution.
Potassium sorbate is an acidic preservative, with high antibacterial properties, inhibiting the growth and reproduction of mold; it is mainly by inhibiting the dehydrogenase system in the microbial body, so as to inhibit the growth of microorganisms and play an antiseptic effect, and inhibit bacteria, mold, yeast; its effect weakens with the increase of ph, ph reaches 3 when bacteriostatic reaches its peak, ph reaches 6 when it still has bacteriostatic ability, but the bottom concentration (mic) can not be bottomed at 0.2%, Experiments have proved that ph:3.2 is 2-4 times shorter than ph2.4 potassium sorbate solution impregnated, and the shelf life of unbilled food is 2-4 times shorter.
Sorbic acid, potassium sorbate and calcium sorbate they have the same mechanism of action, the toxicity is smaller than benzoic acid and paraben, the daily allowable amount is 25mg/kg, benzoic acid 5 times, 2.5 times the paraben is a relatively safe food preservative; it can be used in China for soy sauce, vinegar, noodle sauce, jam, pickles, cans and some wines and other foods.