Effect of hydrogen peroxide treatment on the quality of epsilon-poly-L-lysine products

epsilon-poly-L-lysine (e-PL) is a novel biopreservative with wide antibacterial spectrum, high safety, and stable property. However, the color of epsilon-PL generating from manufacturing process lowers its appearance and limits its application. This work aimed to decolorize epsilon-PL by hydrogen peroxide. Impacts of hydrogen peroxide concentration, pH, duration time and temperature were discussed. Physicochemical property and bioactivity of epsilon-PL were explored. Results indicated that 43.2 % color saturation and 94.54 % recovery rate were reached when the concentration of hydrogen peroxide, pH, duration time and temperature were 3.0 %, 7.0, 1.5 h and 70 degrees C respectively. Furthermore, the MIC (minimal inhibitory concentration) of the hydrogen peroxide treated epsilon-PL for Bacillus subtilis, Escherichia coli, and Staphylococcus aureus were 2 mg/mL, 0.1 mg/mL, and 0.1 mg/mL respectively, which was similar with untreated epsilon-PL. At last, cytotoxicity test indicated that no cytotoxicity could be observed at concentration lower than 2 mg/mL epsilon-PL. As a result, hydrogen peroxide treatment on epsilon-PL could significantly decolorize epsilon-PL without impairing the antibacterial performance and changing the cytotoxicity. Hydrogen peroxide treatment is a promising method to improve the appearance of products, to reduce the cost of decoloration, and to enlarge the application in food and cosmetics industry.

Automated summary

This study demonstrated that decolorizing epsilon-PL with hydrogen peroxide is effective in maintaining its antibacterial activity while improving its appearance. The hydrogen peroxide treatment is a promising method to enhance product aesthetics, reduce decolorization costs, and broaden applications in the food and cosmetics industry.