Evaluation of Five Chitosan Production Routes with Astaxanthin Recovery from Shrimp Exoskeletons

Abstract

Shrimp waste can be potentially used as source of high value products, from biopolymers to bioactive compounds. In this work, was defined a methodology for chitosan production via of depigmentation, demineralization, deproteinization and deacetylation of chitin. Five chitosan production processes were performed from the chitin present in shrimp exoskeletons using chemical agents such as hydrochloric acid (HCl) and sodium hydroxide (NaOH). Concentrations used were 1.5 M for acid, 1.0 M and 50 % w/v for base, 85 % for ethanol and 10 % v/v for acetone, and chitosan samples obtained were compared with commercial chitosan. Results shows that percentages of deacetylation obtained varied between (80 and 81.8 %) near the degree of deacetylation of the commercial chitosan (82.1 %). The extraction process with prior depigmentation using ethanol before demineralization registered the highest value of deacetylation, and the lowest value obtained was from the product obtained via ethanol followed by a second depigmentation with acetone after deproteinization of chitin. The characteristic bands of chitosan and similarity in each sample were confirmed by FTIR are NH bonds (between 3,350 – 3,500 cm-1), NH bonds of the secondary amide (between 1,420 – 1,590 cm-1), the tertiary amide band (between 1,360 – 1,380 cm-1) and C = O bonds of the primary amide (between 1,618 – 1,630 cm-1).