Preparation and physico-chemical characterization of chitin and chitosan from the pens of the squid species, Loligo lessoniana and Loligo formosana

β-chitin and its chitosan from the pens of Loligo lessoniana and Loligo formosana has been isolated, prepared, and physico-chemically characterized to demonstrate a potential chitin source. Without deminerization due to negligible ash content, only deproteinization was used in the chitin isolation with an yield of 35–38%, without significant difference either between the two species or the collection seasons. Reducing step not only saves production cost but also obviates acid pollutant. Mild alkaline deacetylation with various time periods was employed in the chitosan preparation. Optical rotation and thermal transition of chitin from both species suggested the weak intermolecular forces compared with shrimp chitin. The results of nitrogen contents indicate the effectiveness of the deproteinization method used. The samples were categorized as a Class III: moderate hygroscopicity. Traces of elements presented in pens markedly decreases but are incapable to be got rid of within the step of chitin–chitosan preparation. In addition, a small amount of cadmium, as the contamination, was detected in the samples from L. formosana.