ε-Polylysine Hydrochloride is a polypeptide amino acid and a metabolic product produced by Streptomyces albulus, a species of Streptomyces. It is obtained through adsorption, desorption, and purification using ion exchange resins.ε-Polylysine hydrochloride consists of a polymer of lysine molecules connected by amide bonds formed between the α-carboxyl group of one lysine molecule and the ε-amino group of another. It typically contains 25 to 35 L-lysine residues. This substance appears as a pale yellow to white powder with strong hygroscopicity and a slightly bitter taste. It is highly soluble in water, with a solubility of at least 500 g/L. More importantly, it is safe for human consumption, as it can be digested and absorbed by the body, breaking down into lysine, an essential amino acid.
ε-Polylysine Hydrochloride exhibits significant inhibitory effects on a wide range of microorganisms, including Gram-positive and Gram-negative bacteria, yeasts, and molds. Its primary antimicrobial mechanisms are as follows:
·Disruption of Cell Membrane Structure: As a polycationic antimicrobial peptide, ε-Polylysine Hydrochloride binds to the anionic surfaces of microbial cells, disrupting their membrane structures and causing leakage of intracellular contents, which leads to antimicrobial effects.
·Interference with Bacterial Respiration: ε-Polylysine Hydrochloride can penetrate bacterial cells and interfere with their respiratory processes, thereby inhibiting growth and reproduction.
·Inhibition of Enzyme and Protein Synthesis: Once inside bacterial cells, ε-Polylysine Hydrochloride can also inhibit the synthesis of enzymes and proteins, thereby disrupting the metabolic processes of the microorganisms.
Due to its broad-spectrum antimicrobial properties, the addition of ε-Polylysine Hydrochloride to food significantly impacts the microbial community structure within the product. Specifically:
·Reduction of Harmful Microorganisms: ε-Polylysine Hydrochloride effectively reduces the population of harmful microorganisms in food, such as *Escherichia coli* and *Salmonella*, thereby lowering the risk of spoilage and degradation.
·Inhibition of Pathogens: It demonstrates strong inhibitory effects on common pathogens like *Staphylococcus aureus* and *Listeria monocytogenes*, contributing to improved food safety.
·Impact on Microbial Diversity: The prolonged use of ε-Polylysine Hydrochloride as a preservative may affect the microbial diversity in food. While this helps reduce the number of harmful microorganisms, it may also impact natural fermentation processes and food flavor.
Despite its excellent performance as a food preservative, several points must be considered during its application:
1. Usage Limits: According to GB2760 regulations, the usage of ε-Polylysine Hydrochloride in food should be controlled within specified limits to ensure both safety and efficacy.
2. Combination Usage: To enhance the preservative effects in food, ε-Polylysine Hydrochloride is often used in combination with other preservatives to form a preservative system. However, attention must be paid to the synergistic effects and safety of combined products.
3. Storage Conditions: ε-Polylysine Hydrochloride should be stored in a dry, cool, and well-ventilated environment, avoiding direct sunlight and high temperatures to maintain its stability and efficacy.
The impact of ε-Polylysine Hydrochloride on microbial populations in food primarily lies in its broad-spectrum antimicrobial effects. By reducing harmful microorganisms and inhibiting pathogenic growth, it helps ensure food safety and extend shelf life. However, when applying ε-Polylysine Hydrochloride, attention must be paid to usage limits, combination strategies, and storage conditions to optimize its benefits while maintaining safety and stability.