The Effectiveness of Melanin from Squid Ink (Loligo sp.) as Antibacterial Agent Against Escherichia coli and Listeria monocytogenes

Abstract

Melanin from squid ink contain bioactive compounds that can be used as antibacterial agents. E. coli and L. monocytogenes are pathogenic bacteria that cause food damage and disease in human so a natural antibacterial compound is required to replace synthetic antibacterial agent for inhibiting the growth of pathogenic bacteria. Melanin was extracted from squid ink, then it was analyzed quantitavely and qualitatively using phytochemical, testing on antibacterial activity of melanin squid ink against E. coli and L. monocytogenes. The variables measured were yield from melanin, quantitative and qualitative phytochemical test, positive control test of Amoxicilin, negative control test by using HCl and aquabidest, and inhibitory zone melanin from squid ink extract using paper disc method with concentration of 4%; 8%; 16%; and 32% with three replications. The result showed that yield from melanin was 0.692%. Dominant substances found by quantitative phytochemical on melanin squid ink were alkaloids 2390.87±0.77ppm; flavonoids 365.11±0.84ppm; phenols 292.03±0.74ppm; and saponins 173.86±0.66ppm. Qualitative phytochemical test detected steroids and triterpenoids compounds. The inhibition zones from melanin against L. monocytogenes and E. coli were between 2.15–6.18 mm and 1.84–4.69 mm, respectively which is considered as concentration of weak to medium antibacterial activity. Best concentration of melanin from squid ink was 32% on diameter of inhibition zone.