Benzoic acid is a chemical substance commonly used as a preservative in the food industry. It is a substance that is found in nature, including prunes, cinnamons, apples, cloves and ripe olives, etc. It is available on the market in the form of white crystalline powder or flakes. It is often used in combination with sorbic acid and parabens as a preservative.
Benzoic acid is often used in the form of a salt of sodium benzoate compound because it is better soluble in water than its acid form ( it can be dissolved in 100 ml of water at 74.2 grams at 100 ºC and is more soluble in oil, alcohol, propyleneglycol, ether and chloroform.
Benzoic acid and benzoate salt are aromatic acid compounds that can be produced from the oxidation of benzaldehyde with air at room temperature to form perbenzoic and then benzaldehyde and perbenzoic are oxidized again to become benzoic acid.
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Physical and chemical properties
• Chemical name : benzoic Acid
• Synonyms name :
– benzene carboxylic acid
– benzene formic acid
– benzene methonic acid
– carboxy benzene
– diacylic acid
– oracylic acid
– phenyl carboxylic acid
– phenyl formic acid
• Molecular formula : C7H6O2
• Molecular weight : 122.12 g/mole
• Appearance : White
• Physical state : Solid
• Odor : Odorless
• Melting point : 122 °C
• Boiling point : 249 °C
• Flammability : 570 °C
• Flash point : 120 °C
• Specific gravity : 1.32 g/cm3
• Solubility : Soluble in water 0.1-1 g/100 ml at 21 °C, freely soluble in Chloroform.
• Sublimation at 100 °C and evaporation when contacted with the steam.
• CAS No. : 65-85-0
Benefits of benzoic acid and benzoate
Benzoic acid and benzoate salt are chemical substances widely used as a preservative for various food industries, such as beverages, fruit juices and fermented foods, as well as used for maintaining the quality of cosmetics and toothpastes.
Use of benzoic acid in foods
- Margarine and similar fats use a concentration of about1%.
- Pickling vegetables and spices use a concentration of about07 to 0.1% andmayadd50-100milligrams of sulfur dioxide per one kilogram of food to help maintain food colors.
- Mayonnaise,salad dressings and sauces use a concentration of about1 to 0.15%.
- Egg yolks and salted eggs use a concentration of about1-0.5%.
- Semi-cooked fish or crabs use a concentration of about02 to 0.1%.
- Fruit juices use a concentration of about1 to 0.15%.
- Non-alcoholic drinks use a concentration of about025 to 0.035%.
- Jams,jellies,can dies and desserts use a concentration of about1-0.2%.
Benzoic acid and benzoate salts are a good antimicrobial agent in acidic conditions of lower than 4.5. Therefore, foods using benzoic acid and benzoate salts to extend their shelf life should be foods that are highly acidic, such as drinks and fruit juices, jams, jellies, pickling vegetables and fruits, salad dressings, fruit salads and margarines. According to the standards in some countries, the allowable quantity of use is no more than 1000 mg/kg of food.
Acid Ionization Constant
– pH 2.0 : 98%
– pH 3.0 : 95%
– pH 4.0 : 60%
– pH 4.5 : 30%
– pH 5.0 : 10%
Effects of benzoic acid
Benzoic acid can inhibit the growth of microorganisms. Due to its infiltration into microbial cells, it can inhibit the production and function of enzymes so microorganisms cannot grow further. The effects of benzoic acid are very good for bacteria and yeasts but are less for fungi.
Benzoic acid does not accumulate in the body because the body can remove it well according to the following body’s removal process:
- Benzoic acid + coenzyme A → benzoyl coenzyme A with synthetase as a catalyst
- Benzoyl coenzyme A+ glycine → hippuric acid with acyltransferase as a catalyst
- Excretion in the urine
The remaining benzoic acid will combine with glycuronic acid to form benzoyl glycuronic acid that will then be excreted in the urine. Typically, the excretion of hippuric acid in the urine is about 1.0 to 2.5 g / day from benzoic acid intake of 0.7 to 1.7 g / day.
Benzoic acid is acidic and can vaporize when heated. Eye contact or inhalation of its vapors can cause irritation, eye soreness, and irritation of mucous membranes of respiratory tract. In addition, ingestion of benzoic acid in large quantities can cause stomachache, diarrhea, nausea and vomiting as well as cause a decreased performance of liver and kidneys decline or even disability.