Lactic Acid

Lactic acid is an important organic acid, the second organic acid after citric acid in terms of production and consumption. It is usually a colorless or slightly yellow liquid.

Lactic acid is a widely used organic acid and can be used in brewing, medicine, leather, cigarettes, chemicals, food, printing and dyeing, etc. The usage distribution of lactic acid in Japan is roughly as follows: brewing accounts for about 20%, food use accounts for about 50%, lactic acid derivatives account for about 10%, and leather and other industrial uses account for about 20%. 

1. Brewing industry The brewing industry uses about 80% lactic acid. Adding lactic acid can prevent the reproduction of miscellaneous bacteria, promote the development of yeast, prevent the turbidity of wine and enhance the flavor of wine, and can also increase the yield of wine.

2. The food industry generally uses lactic acid with a content of 50%. Mainly used in lactic acid drinks, refreshing drinks, pastries, pickles and sour agents. Lactic acid can make food slightly acidic without masking the natural flavor and aroma of fruits and steamed vegetables. Therefore, it is widely used in canned foods such as tomatoes, olives, pickled cucumbers, and pickled cabbage, and kefir drinks made with lactic acid bacteria are also very popular.

3. In the pharmaceutical industry, lactic acid can be directly formulated into medicine or used as lactate. Oral administration can be used for intestinal disinfection. It can also dissolve protein and cutin, and is particularly sensitive to the corrosive effect of diseased tissue, so it can be used to treat laryngeal tuberculosis, diphtheria, lupus and other diseases. In addition, it is also used for sterilization: containing cough agents, coating agents, bladder injection agents, and vaginal cleansing agents. The hydrophilic nature of lactic acid is combined with insoluble drugs to increase drug absorption and prevent side effects. Lactic acid is also a raw material for making erythromycin sugar coating, so it is widely used in the pharmaceutical industry.

4. In the leather industry, the lactic acid content for general leather is 40%. It does not have high requirements on the quality of lactic acid. It can be used for dark colors and smelly leather. The tanning industry mainly uses it to remove lime from tanned leather, also called deliming. The quality of leather delimed with lactic acid is better than that of other acids. For good deliming quality, high-grade leather must be treated with lactic acid.

5. In cigarette production, lactic acid can be used to remove impurities in tobacco and remove the bitter and spicy taste. Therefore, lactic acid treatment can improve the grade of low-grade tobacco.

6. Lactic acid is used as a pH control agent in celluloid coating production.

7. In the wool spinning industry, it is used for pre-chromium mordant dyeing of dyes to reduce the chromate content of wool and prevent fiber oxidation; in the post-processing of silk and rayon, it is used as a pH regulator for brightening treatment to increase yarn color.