Commonly Used Preservatives

1. Benzoic acid and its salts

White particles or crystalline powder, odorless or slightly benzoin smell. The best anti-corrosion PH is 2.5-4.0, and the sterilization effect is not very satisfactory in the products with PH 5.0 or higher. Because its safety is only equivalent to 1/40 of potassium sorbate, Japan has completely banned its application in food.

There are two types of benzoic acid and sodium benzoate; benzoic acid is also called benzoic acid, so sodium benzoate is also called sodium benzoate. Benzoic acid is hardly soluble 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 oil. But sodium benzoate uses sodium benzoate; the properties and antiseptic properties of benzoic acid and sodium benzoate are similar. Let me briefly introduce sodium benzoate: sodium benzoate is mostly white particles, odorless or slightly benzoin smell, slightly sweet, astringent; easily soluble in water (normal temperature) about 53.0g/100ml, pH is about 8; sodium benzoate It is also an acidic preservative, and has no bactericidal or antibacterial effect in alkaline medium; its best antiseptic pH is 2.5-4.0, and the bactericidal effect of 5% solution at pH 5.0 is not very good. Sodium benzoate is highly lipophilic and easily penetrates the cell membrane into the cell body, interferes with the permeability of the cell membrane, and inhibits the absorption of amino acids by the cell membrane; enters the cell body to ionize and acidify the alkali storage in the cell and inhibit the activity of the cell's respiratory enzyme system. Prevent the condensation reaction of acetyl-CoA, thereby achieving the purpose of food preservation.

2. Sorbic acid and its salts

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

 It is mainly divided into three types: sorbic acid, potassium sorbate and calcium sorbate. Sorbic acid is insoluble in water. It must be dissolved in ethanol or potassium hydrogen sulfate before use. It is inconvenient and irritating to use, so it is generally not commonly used; calcium sorbate FAO/WHO stipulates that its use range is small, so it is also It is not often used; potassium sorbate does not have their shortcomings. It is easily soluble in water and has a wide range of applications. It can often be seen in some beverages, preserved fruits, canned food and other foods.

Sorbic acid, potassium sorbate and calcium sorbate have the same mechanism of action. The daily allowable amount is 25mg/Kg. It is a relatively safe food preservative; it can be used for soy sauce, vinegar, noodles, jams, and pickles. Food, canned food and some alcoholic beverages.

3. 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 humans. It is a broad-spectrum preservative that has a strong inhibitory effect on bacteria, molds and yeasts in food. It is widely used in the preservation of meat, fish, vegetables, fruits, beverages, cakes, etc.

4. Paraben esters (that is, parabens)

Products include methyl, ethyl, propyl and butyl p-hydroxybenzoate. Among them, butyl p-hydroxybenzoate has the best anti-corrosion effect. my country mainly uses ethyl and propyl p-hydroxybenzoate. The antiseptic mechanism of paraben esters is to destroy the cell membrane of microorganisms, denature the protein in the cell, and inhibit the activity of the cell's respiratory enzyme system. The antibacterial active ingredients of parabens mainly act in the molecular state. Because the hydroxyl group in the molecule has been esterified and is no longer ionized, 60% of the molecules still exist when the PH value is 8. Therefore, the parabens have good effects in the range of PH4-8. Does not change with the change of PH value, stable performance and lower toxicity than benzoic acid. It is a broad-spectrum preservative. As paraben esters are difficult to dissolve in water, they are first dissolved in ethanol when used. In order to better play the role of preservative, it is best to mix two or more of these esters. Ethyl p-hydroxybenzoate is generally used in fruit drinks, and propyl p-hydroxybenzoate is generally used in fruit drinks.

5. Sodium diacetate

A preservative commonly used in pickles, it is safe, non-toxic, and has a good antiseptic effect. The final decomposition products in the human body are water and carbon dioxide. It has obvious inhibitory effect on black rhizome, Aspergillus flavus, Listeria, etc. In the pickles, 0.2% sodium diacetate and 0.1% potassium sorbate are used in the pickle products, which has a good preservation effect.

6. Calcium propionate

White crystalline particles or powder, odorless or slightly odor of propionic acid, stable to light and heat, and easily soluble in water. Propionic acid is the product of the oxidation of amino acids and fatty acids in the human body, so calcium propionate is a very safe preservative. ADI (the allowable daily intake per kilogram of the human body) is not restricted. It has an inhibitory effect on molds. Bacteria inhibition is small and has no effect on yeast. It is often used in the fermentation of pasta products and the anti-mold of cheese products.

7. Sodium lactate

The product is a colorless or slightly yellow transparent liquid, no peculiar smell, slightly salty and bitter taste, miscible in water, ethanol, and glycerin. The general concentration is 60%-80%, and the maximum use limit of 60% concentration is 30g/KG. Sodium lactate is a new type of antiseptic and fresh-keeping agent, mainly used in meat and poultry products, and has a strong inhibitory effect on meat food bacteria . Such as Escherichia coli, Clostridium botulinum, Listeria, etc. Through the inhibition of food pathogenic bacteria, thereby enhancing food safety. Enhance and improve the flavor of meat and extend shelf life. Sodium lactate has good dispersibility in raw meat, and has good adsorption to moisture, so as to effectively prevent raw meat from dehydration, and achieve freshness and moisture retention. It is mainly suitable for barbecue, ham, sausage, chicken, duck and poultry products and sauce products. The reference formula for keeping fresh in meat products: sodium lactate: 2%, sodium dehydroacetate 0.2%.

8. Biological food preservatives

The production of biological preservatives in my country started with nisin and has a history of ten years. Certain progress has been made in the research, production and application of biological preservatives. GB2760 stipulates that nisin and natamycin can be used. Since 2006, polylysine has been developed (now provided by four companies). The application for polylysine to enter GB2760 is underway. I believe it will be soon Will be put on the market. In addition, there are products that claim to be biological preservatives, but are actually compound preparations on the market.

9. Nisin

Nisin is a polypeptide compound composed of a variety of amino acids, which can be absorbed and utilized by the human body as a nutrient substance. In 1969, the United Nations Food and Agriculture Organization/World Health Organization (FAL/WHO) Food Additives Joint Expert Committee confirmed that nisin can be used as a food preservative. The document approved by the Ministry of Health of China in March 1992 stated: "It can be scientifically considered that Streptococcus lactis is safe as a food preservation agent." It can effectively inhibit the growth and reproduction of many Gram-positive bacteria that cause food spoilage, such as Clostridium botulinum, Staphylococcus aureus, Streptococcus hemolyticus, Listeria, Bacillus stearothermophilus, especially for the production The spores of Gram-positive bacteria have special effects. The antibacterial effect of nisin is by interfering with the normal function of cell v membrane, causing cell membrane permeation, nutrient loss and membrane potential drop, leading to the death of pathogenic bacteria and spoilage bacteria. It is a non-toxic natural preservative and has no adverse effects on the color, aroma, taste and taste of food. It has been widely used in dairy products, canned products, fish products and alcoholic beverages.

10. Natamycin

Natamycin (Natamycin) is a white to milky white odorless and tasteless crystalline powder prepared by controlled fermentation of Streptomyces nata. It usually exists as an enol structure. Its mechanism of action is to combine with fungal ergosterol and other sterol groups to inhibit the biosynthesis of ergosterol, thereby causing cell membrane distortion, eventually leading to leakage and cell death. Surface treatment of dough with natamycin in bakery foods can significantly extend the shelf life. Adding a certain amount of natamycin to the production of foods such as sausages, beverages and jams can prevent mildew without interfering with other nutrients.