Polylysine is a nutritional bacteriostatic agent, safer than other chemical preservatives
Polylysine is a polypeptide of the essential amino acid, L-lysine, a popular food preservative. It is used in cosmetics and beauty products for two reasons: its ability to serve as a preservative, as well as its properties as a film former and hair conditioning agent. As a preservative, Polylysine can inhibit the growth of microorganisms, and specifically produce an antimicrobial effect against yeast, fungi, and bacteria.
The research of polylysine has been relatively mature abroad, especially in Japan, and has just started. It is a natural biological metabolite. It has good bactericidal ability and thermal stability, is a biological preservative with excellent anti-corrosion performance and great commercial potential. In Japan, polylysine has been approved as a preservative added to food, and is widely used in the preservation and preservation of instant rice, wet-cooked noodles, cooked vegetables, seafood, sauces, soy sauce, fish fillets and biscuits. At the same time, it was also found that the combination of polylysine and other natural antibacterial agents has obvious synergistic effect and can improve its antibacterial ability.
Polylysine is a light yellow powder with strong hygroscopicity and slightly bitter taste. It is a linear polymer of lysine. It is not affected by pH value, is thermally stable (120°C, 20min), and can inhibit heat-resistant bacteria, so it can be heat treated after being added. However, in the case of acidic polysaccharides, hydrochlorides, phosphates, copper ions, etc., the activity may decrease due to binding. It has a synergistic effect when combined with hydrochloric acid, citric acid, malic acid, glycine and higher fatty glycerides. Polylysine with a molecular weight between 3600-4300 has the best antibacterial activity. When the molecular weight is lower than 1300, polylysine loses its antibacterial activity. Since polylysine is a mixture, it does not have a fixed melting point and starts to soften and decompose above 250°C. Polylysine is soluble in water and slightly soluble in ethanol. Its characterization and infrared spectroscopy analysis showed that there are strong absorption peaks at 1680-1640cm-1 and 1580-1520cm-1.
Polylysine is a polypeptide with antibacterial effect. This biological preservative was first used in food preservation in the 1980s. Polylysine can be broken down into lysine in the human body, and lysine is one of the eight essential amino acids for the human body, and it is also an amino acid allowed to be fortified in foods in various countries around the world. Therefore, Polylysine is a nutritional bacteriostatic agent, safer than other chemical preservatives, and its acute oral toxicity is 5g/kg. Polylysine has a broad bacteriostatic spectrum, and it is suitable for Candida acuminata, Rhodotorula spp Bacillus, Bacillus subtilis; Arthrobacter aerogenes, Escherichia coli, etc. among Gram-negative bacteria have obvious inhibitory and killing effects. Polylysine has a significant inhibitory effect on the growth of Gram-positive Micrococcus, Lactobacillus bulgaricus, Streptococcus thermos, Gram-negative Escherichia coli, Salmonella and yeast. The compound reagent of polylysine and acetic acid is effective against subtilis. Bacillus has obvious inhibitory effect.
