Polylysine (ε-poly-L-lysine) is a natural food preservative produced through natural fermentation using the bacteria Streptomyces and more specifically Streptomyces albulus under aerobic conditions. Polylysine consists as a small natural homo-polymer (25-30 L-lysine residues) of the essential amino acid, L-lysine. Its application includes cakes, rice, cheese and other dairy foods and meats.

Advantages

1.   Broad antibacterial spectrum: it has obvious inhibition to gram-positive bacteria and gram-negative bacteria, yeast, mould, virus and many other micro-organisms.

2.    Good thermal stability: below high temperature (120oC for 20 min). Polylysine does not decompose, nor experience inactivation, and is suitable for cooked food.

3.    Good water-solubility: Polylysine has good water-solubility, Polylysine spreads evenly in food; colorless, odorless and natural, does not affect overall food flavor.

4.    Wide pH range: broad anti-bacterial spectrum (pH 2 to 9), to supplement the weakness with most common preservatives; poor effects in neutral and alkaline conditions.

5.    Strong blends: As a natural preservative, ε- PL can be used alone. In addition, it has a synergistic effect when blending with Potassium Sorbate, Citric acid, Malic Acid, Glycine and Nisin. After blending, its bactericidal action will be improved greatly.

6.    Safe for human consumption: after eating, Polylysine does not accumulate inside the human body. It partly breaks down into L-lysine, an essential amino acid for human health. L –lysine is non-toxic, and known as the "pharmaceutical & nutrient preservative".

 7.    Health function: Recent studies show that ε-Polylysine can inhibit the enzyme activity and the fat absorption in the small intestine ester, has curative effect against, with obesity.

Application in Food  

Currently, ε-Polylysine is widely used in food, beverage such as: cake, pastry, snack foods, butter, salad, sauce, beverage, wine, meat product, cans, etc. The dosage in different types of food can be referenced in table 1.