β-Chitin and chitosan from squid gladius: Biological activities of chitosan and its application as clarifying agent for apple juice

Chitin is the second most abundant polysaccharide in biomass after cellulose and the term chitosan usually refers to a family of polymers obtained after chitin deacetylation. The aim of this work was the preparation and the characterization of chitin and chitosan from the gladius (pen) of the European squid (Loligo vulgaris). A high level of deproteinization (more than 80%) was recorded using Alcalas (R) with an enzyme/protein ratio of 10 U/mg. The demineralization of the gladius was completely achieved within 8 h at room temperature in HCl. C-13 NMR, FTIR, and XRD diffractograms of prepared chitin and chitosan were taken and then degree of deacetylation of chitosan was calculated using C-13 CP/MAS-NMR Spectroscopic. Further, in vitro antioxidant capacity of chitosan was evaluated on 1,1-dipheny1-2-picrylhydrazyl method (IC50 = 3.2 mg mL(-1)) and the beta-carotene bleaching assay (IC50 = 3.3 mg mL(-1)). Antimicrobial activity was also investigated and assays indicated that prepared chitosan exhibited marked inhibitory activity against all microbial strains tested. Additionally, chitosan was tested such as clarifying agent for apple juice and showed powerful clarification capability, without affecting nutritional value. Furthermore, the results suggested that prepared chitosan could be used as alternative additive in pharmaceutical preparations and food industry. (C) 2017 Elsevier B.V. All rights reserved.