The main production methods of L- carnitine are as follows: ① Extraction method: that is, direct extraction from meat or dairy food, which is generally used less because of its high cost; (2) enzymatic conversion: that is, racemic carnitine is produced by industrial chemical synthesis, and high-purity L-carnitine can be obtained by enzymatic treatment after treatment; ③ Biological fermentation: L-carnitine exists in many microorganisms. Microbial fermentation can be used to select excellent strains and produce L- carnitine. This method has been industrialized in Switzerland. Besides, there are many other ways. At present, only a few countries such as Switzerland, Italy and Japan can produce L-carnitine, and domestic demand mainly depends on imports, which is expensive. China Northeast Pharmaceutical Factory and other enterprises have also started production, and Jiangsu Institute of Microbiology has carried out research on enzyme preparations.

L- carnitine, as an important food nutrition fortifier, has been widely used in many aspects. It has a considerable market demand. As a food nutrition fortifier, it is mainly used in the following aspects: infant food: L-carnitine is a conditionally essential nutrient for infants. The L-carnitine synthesis ability of infants is only 65,438+05% of that of adults, and it can be maintained at a normal level only by feeding breast milk or milk powder. However, there is almost no carnitine in infant formula food based on soybean protein and weaning food based on grain, which should be strengthened. European experts believe that the dose should be 1000 kcal 1.2 mg. Premature infants and low birth weight infants should be supplemented with L-carnitine. L-carnitine plays a certain role in maintaining infant life and promoting infant development. At present, L-carnitine has been added to infant milk powder in 22 countries in the world, and breast-fed milk powder with L-carnitine has also been listed in China.

Diet food: L-carnitine can burn excess fat in the body as energy. Can lose weight, reduce the body fat content, has the function of losing weight, and is an ideal weight loss method without dieting, anorexia, fatigue and diarrhea. Weight loss and fitness food with L-carnitine as the main ingredient is very popular in Europe and America, and a small number of similar products are listed in China.

Athletes' food: L-carnitine is beneficial to improve the explosive power and endurance of sports. It has been widely used in sports health food abroad, but it is rarely used in China at present. L-carnitine, an important nutritional supplement for middle-aged and elderly people, has anti-myocardial ischemia, anti-arrhythmia and hypolipidemic effects in clinic. Foreign countries have listed it as an important substance to prevent and reduce coronary heart disease in middle-aged and elderly people, and supplementation can increase myocardial capacity. For people with diabetes and kidney disease, L-carnitine should also be supplemented to meet the deficiency in the body.