Influence of the process parameters on β-chitin and α-chitin extraction: probing about the grinding and particles size

Chitin occurs in biomass as two main polymorphs, named as β- and α-chitin, which differ on their arrangements on the solid state. The control of chitin physical-chemistry properties by adjustments in their extraction process is an important key to improve its applications and derivatization reactions. Thus, the influences of the extraction parameters process on the β and α-chitin characteristics were studied. Squid pens (Loligo sp.) and shrimp shells (Macrobrachium r.), were used as raw material for β-chitin and α-chitin extraction, respectively. The obtained chitin, regardless polymorphs, was subjected to grinding in a knives mill, sieved and classified in different fractions according to the particles size. The fractions were characterized according to the degree of N-acetylation (DA), viscosimetric molecular weight (Mv), crystallinity, morphology and thermal stability. According to the scanning electron microscopy β-chitin particles present a fiber-like characteristic while α-chitin exhibit a flake-like shape. The procedure of grinding affected the DA and Mv of α-chitin (63%更多