Prospects of using melanin as an antimicrobial agent in food packaging

Melanin, known for its high physiological activity and functional properties, has attracted research interest as a potential antimicrobial agent in food systems and consumer packaging. This study investigated the antimicrobial activity of melanin derived from buckwheat hulls against the bacterial microbiota present in industrially produced cheeses. The research objects were purified melanin obtained from buckwheat hulls and the following microbial strains: Penicillium roqueforti, Bacillus subtilis, Bacillus pumilus, and Lactobacillus plantarum. The disc-diffusion method and the cultivation of test strains in the presence of melanin were employed. Statistical analysis was carried out using Statistica 10 software. The study confirmed the antimicrobial activity of melanin against Gram-positive bacteria Bacillus subtilis B-12587 and Penicillium roqueforti F-1311. At the highest tested concentration, the zone of lysis for Bacillus subtilis B-12587 was 26.4±0.2 mm, which was 1.28 times larger than that of Penicillium roqueforti F-1311 cells, 1.43 times larger than that of Bacillus pumilus B-7308 cells, and 1.58 times larger than that of Lactobacillus plantarum B-3242 cells. A strong correlation (r = 0.97) was identified between melanin concentration in the medium and the growth inhibition of Bacillus subtilis B-12587. These findings highlight the potential of plant-derived melanins as antimicrobial agents in food-grade films intended for primary packaging.