Blog

Benzoic acid, also known as benzoic acid, is an aromatic acid that has antibacterial activity when not dissociated.

Sodium benzoate is a sodium salt of benzoate, which has no odor or a slightly soothing aroma. It can be partially converted into active benzoic acid in acidic substances, and its anti-corrosion mechanism is the same as benzoic acid.

Due to its greater solubility in water and stability in air, sodium benzoate has a stronger inhibitory effect on yeast and bacteria, making it more commonly used than benzoic acid. Benzoic acid and sodium benzoate are widely used as food preservatives and are also one of the commonly used preservatives for oral liquid medicine. Studies have shown that benzoic acid and sodium benzoate are often abused by unscrupulous manufacturers in food and medicine due to their low cost. Therefore, excessive intake of benzoic acid and sodium benzoate during consumption is inevitable, which can be harmful to the human liver and even carcinogenic. At present, the main methods for detecting residual amounts of benzoic acid and sodium benzoate include spectrophotometry, high-performance liquid chromatography, ion exclusion chromatography, gas chromatography, thin-layer chromatography, non-aqueous titration, high-performance capillary electrophoresis, and gas chromatography-mass spectrometry.

1、 The anti-corrosion mechanism of benzoic acid and sodium benzoate

Benzoic acid is an acidic preservative with antibacterial activity in non dissociated acids, exhibiting the strongest activity in liquid environments at pH 2.5-4.0; But it has no bactericidal or antibacterial effects in alkaline media. Sodium benzoate can partially convert into active benzoic acid in acidic foods, and its anti-corrosion mechanism is the same as benzoic acid. Sodium benzoate has strong lipophilicity and is easily able to penetrate the cell membrane and enter the cell body, thereby interfering with cell membrane permeability; Inhibiting the absorption of amino acids by the cell membrane can acidify the intracellular reserve base and selectively inhibit the activity of intracellular respiratory enzymes, effectively preventing acetyl CoA condensation reaction and thus achieving the purpose of preservation.

2、 Safety evaluation of benzoic acid and sodium benzoate

Benzoic acid and sodium benzoate can be used as preservatives for food and medicine, effectively preventing food and medicine from spoiling and becoming acidic, and having the effect of extending the shelf life; But there are strict limit requirements for its addition amount. Over the years, numerous application and toxicity tests have been conducted in various countries, and the following conclusion has been drawn: when benzoic acid is added to the drug at a concentration of 0.06 g/kg, it has no "three carcinogenic" (carcinogenic, teratogenic, and mutagenic) effects.

The GB 2760-2011 National Food Safety Standard for the Use of Food Additives in China also specifies the amount of benzoic acid and sodium benzoate used in 21 types of food. In addition, food is not allowed to add benzoic acid and sodium benzoate as preservatives. There is also experimental data showing that benzoic acid has no accumulation or antigenic effect in the human body. That is, benzoic acid can be quickly absorbed by the human body, and most of it combines with glycine to form hippuric acid (glycine benzoyl). The remaining will combine with glucuronic acid to form 1-benzoyl glucuronic acid. About 80% of benzoic acid is excreted from the human body within 6 hours, and the remaining 20% is completely excreted from the body after about 4 hours (FAO, 1974). This detoxification effect prevents benzoic acid from accumulating in the body; But long-term consumption can also have various toxic side effects on the human body. There are reports that cats are more sensitive to benzoic acid, and exposure to or excessive consumption of benzoic acid can cause symptoms such as nervousness, excitement, loss of balance, and vision loss;