Classification and characteristics of commonly used preservatives(1)

Briefly introduce the product performance, anticorrosive mechanism and scope of use of commonly used anticorrosive agents in China.

1、Benzoic acid and its salts

White granules or crystalline powder, odourless or with a slight benzoin smell. Its antiseptic best PH is 2.5-4.0, in the PH5.0 above the product, the sterilization effect is not very ideal. Because its safety is only 1/40 of that of potassium sorbate, its use in food has been completely banned in Japan.

There are two types of benzoic acid and sodium benzoate; benzoic acid is also known as benzoic acid, so sodium benzoate is also known as sodium benzoate. Benzoic acid is insoluble in water at room temperature, slightly volatile in air (especially hot air), hygroscopic, about 0.34g/100ml at room temperature; but soluble in hot water; also soluble in ethanol, chloroform and non-volatile oils. 

Whereas sodium benzoate is used in both; benzoic acid and sodium benzoate have similar properties and preservative properties. I briefly introduce sodium benzoate: sodium benzoate is mostly white granules, odourless or slightly with benzoin smell, slightly sweet taste, astringent; easily soluble in water (room temperature) 53.0g/100ml or so, PH in about 8; sodium benzoate is also an acidic preservative, no bactericidal and antibacterial effect in alkaline medium; its best PH for preserving is 2.5-4.0, 5% solution at PH5.0 bactericidal The effect is not very good either. 

Sodium benzoate is lipophilic, easy to penetrate the cell membrane into the cell body, interfere with the permeability of the cell membrane, inhibit the absorption of amino acids in the cell membrane; enter the cell body ionization acidification of the cell's alkali storage, and inhibit the activity of the cell's respiratory enzyme system, prevent acetyl coenzyme A condensation reaction, so as to play the purpose of food preservation.

2、Sorbic acid and its salts

White crystalline powder or yellowish crystalline powder or scaly. Potassium sorbate is an acidic preservative with high antibacterial properties and inhibits the growth and reproduction of moulds, mainly by inhibiting the dehydrogenase system in microorganisms, thus inhibiting microorganisms and playing the role of preservative. It has an inhibitory effect on bacteria, moulds and yeasts. The anti-corrosion effect is significantly higher than that of benzoic acid, which is 5-10 times higher than that of benzoate. The toxicity of the product is low, equivalent to half that of table salt. Its antiseptic effect decreases with the increase of PH, and is best when PH=3. When PH reaches 6, it still has the ability to inhibit bacteria, but the minimum concentration cannot be less than 0.2%. It is less toxic than nipagin ester.

It is mainly divided into three types of varieties: sorbic acid, potassium sorbate and calcium sorbate. Sorbic acid is insoluble in water, when using it must first dissolve in ethanol or potassium hydrogen sulfate, when using inconvenient and irritating, so generally not commonly used; calcium sorbate FAO/WHO provisions of its use range is small, so also not often used; potassium sorbate is not their shortcomings, easily soluble in water, wide range of use, often in some drinks, dried fruit, canned food and other food to see its body.

Sorbic acid, potassium sorbate and calcium sorbate have the same mechanism of action, and the daily allowance is 25mg/Kg, which is a relatively safe food preservative; it can be used in soy sauce, vinegar, pasta sauce, jam, pickles, canned food and some wines, etc.