What are the types of preservatives?

Preservatives refer to natural or synthetic chemical ingredients, which are used to add food, medicine, pigments, biological samples, etc., to delay the corruption caused by microbial growth or chemical changes. The main function is to inhibit the growth and reproduction of microorganisms. In order to prolong the preservation time of food and inhibit the corruption of substances, let's take a look at the types of preservatives.

Benzoic acid and its salts

Benzoic acid and its salts are white particles or crystalline powder, odorless or slightly benzoin odor, the best antiseptic PH is 2.5-4.0, and the germicidal effect is not very ideal in the products above PH5.0. Because its safety is only equivalent to that of potassium sorbate, its application in food has been completely banned in Japan.

Sorbic acid and its salts

Sorbic acid and its salts are white crystalline powder or yellowish crystalline powder or scaly, acidic preservatives, which have high antibacterial properties and inhibit the growth and reproduction of mold, mainly by inhibiting the dehydrogenase system in microorganisms. in order to achieve the inhibition of microorganisms and play a role in anti-corrosion, bacteria, mold, yeast have inhibitory effect. The anticorrosive effect is obviously higher than that of benzoic acid and 5-10 times higher than that of benzoate. The toxicity of the product is low, equivalent to half of that of salt. The anticorrosive effect decreases with the increase of PH, and the anticorrosive effect is the best in PH=3. It still has bacteriostatic ability when the PH value reaches 6, but the minimum concentration should not be less than 0.2%. It's less toxic than Nipagin ester. It can be used in soy sauce, vinegar, noodle sauce, beverage, jam and so on in our country.

Dehydroacetic acid and sodium salts

Dehydroacetic acid and its sodium salt are white or light yellow crystalline powder, stable to light and heat, degraded into acetic acid in aqueous solution and non-toxic to human body. it is a broad-spectrum preservative and has a strong inhibitory effect on bacteria, molds and yeasts in food. it is widely used in preservative preservation of meat, fish, vegetables, fruits, beverages, pastries and so on.

Nipagin esters

Nipagin esters are p-hydroxybenzoate esters, and the products are methyl p-hydroxybenzoate, ethyl ester, propyl ester, butyl ester and so on. Among them, butyl p-hydroxybenzoate has the best antiseptic effect. Ethyl p-hydroxybenzoate and propyl p-hydroxybenzoate are mainly used in China, and butyl p-hydroxybenzoate is most commonly used in Japan. The anticorrosive mechanism of Nipagin esters is to destroy the cell membrane of microorganisms, denature the proteins in the cells, and inhibit the activity of respiratory enzymes. The antibacterial active components of Nipagin ester mainly play a role in the molecular state. Because the hydroxyl groups in the molecule have been esterified and no longer ionized, 60% of the molecules still exist when the PH value is 8, so Nipagin ester has a good effect in the range of PH4~8.

Sodium diacetate

Sodium diacetate is a kind of preservative commonly used in pickles, which is safe, non-toxic and has good antiseptic effect. the final decomposition products in the human body are water and carbon dioxide. It has obvious inhibitory effect on black root fungus, Aspergillus flavus and Listeria monocytogenes. In pickles, 0.2% sodium diacetate and 0.1% potassium sorbate are used in pickles, which has a good fresh-keeping effect.

Calcium propionate

Calcium propionate is a white crystalline particle or powder, odorless or with a slight smell of propionic acid, stable to light and heat, and soluble in water. Propionic acid is the product of oxidation of amino acids and fatty acids in the human body, so calcium propionate is a safe preservative. It has inhibitory effect on mold, little inhibition on bacteria and no effect on yeast. it is often used for fermentation of flour products and mildew prevention of cheese products.

Sodium lactate

Sodium lactate is a colorless or yellowish transparent liquid, no peculiar smell, slightly salty and bitter, mixed in water, ethanol and glycerol. The maximum use limit for a general concentration of 60%, 80%, and 60% is 30 g / kg. Sodium lactate is a new type of antiseptic and antistaling agent, which is mainly used in meat and poultry products. It has a strong inhibitory effect on meat bacteria, such as Escherichia coli, Clostridium botulinum, Listeria, etc., through the inhibition of food pathogenic bacteria, so as to enhance food safety, enhance and improve meat flavor, and prolong shelf life. It has good dispersibility in raw meat and good adsorption to water, so as to effectively prevent raw meat from dehydration, achieve fresh-keeping and moisturizing effect, and is mainly suitable for barbecue, ham, sausage, chicken, duck, poultry products and sauce stewed products, etc. the reference formula for keeping fresh in meat products is 2% of sodium lactate and 0.2% of sodium dehydroacetate.

Biological food preservative

The production of biological preservatives in China began with nisin, which has a history of ten years, and some progress has been made in the research, production and application of biological preservatives. GB2760 stipulates that nisin and natamycin can be used. Polylysine has been developed since 2006. The application for polylysine to enter GB2760 is under way and will be put on the market soon. In addition, products that claim to be biological preservatives but are actually compound preparations are sold on the market.