The antioxidant and antibacterial activities of chitosan extract from white shrimp shell (Penaeus indicus) in the waters north of Brebes, Indonesia

Abstract

Abstract. Kusnadi, Purgiyanti, Kumoro AK, Legowo AM. 2022. The antioxidant and antibacterial activities of chitosan extract from white shrimp shell (Penaeus indicus) in the waters north of Brebes, Indonesia. Biodiversitas 23: 1267-1272. Chitosan is an oligosaccharide compound produced by deacetylation of basic chitin at high temperatures. This research aimed to extract chitosan from white shrimp (Penaeus indicus) in the waters north of Brebes, Indonesia and determine its antioxidant and antibacterial activity compared to commercial chitosan. The functional structure of chitosan was carried out through Fourier Transformation-Infrared Spectroscopy. Determination of antioxidant activity using the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging method and its antibacterial activity was tested on Staphylococcus aureus and Escherichia coli bacterial strains. The chitosan extract was also tested for its average molecular weight. The degree of deacetylation of chitosan extract was higher 78.60% than that of commercial chitosan 73.46%. The IC50 of chitosan extract and commercial chitosan on DPPH radicals was 4.25 mg/mL and 5.2 mg/mL, respectively. The chitosan extract produced largest inhibition zone found at 1000 g/mL on S. aureus (14.40 ± 0.03 mm) and E. coli (13.78 ± 0.01 mm). The result of DPPH radical scavenging activity was directly proportional to the value of the degree of deacetylation produced by the chitosan extract from white shrimp (P. indicus), the greater the degree of deacetylation, the greater the antioxidant and antibacterial activity.