Effect of the characters of chitosans used and regeneration conditions on the yield and physicochemical characteristics of regenerated products.

Chu Hsu,Rong Chen,Szu Chen,Wei Chen,Min Tsai

doi:10.3390/ijms16048621

Abstract

The objective of this study was to explore the effect of the character of chitosans used, and the regeneration conditions employed on, the yield and physicochemical characteristics of regenerated products. Different concentrations of acetic acid were used to dissolve chitosans of 61.7% and 94.9% degree of deacetylation (DD), and weight-average molecular weight (Mw) of 176 and 97 kDa, respectively; they were then precipitated with an 8 N NaOH solution, followed by washing and neutral and freeze drying to get the regenerated products. Yields of regenerated products and their physicochemical properties, such as ash content, bulk density, Mw, polydispersity index (PDI), DD, and crystallinity were measured. A higher concentration of acetic acid used resulted in a higher yield. The purity of the regenerated product increased significantly, whereas the bulk density and crystallinity decreased significantly after regeneration. The regeneration process showed its merits of narrowing down the PDI of regenerated products. The DD and structure of chitosan was changed insignificantly after the regeneration process.

Highlights

Chitosan is a high molecular weight (Mr) polysaccharide and is composed of N-acetyl-D-glucosamine and D-glucosamine, linked by β (1→4) glucoside
This may be attributed to using a higher concentration of acetic acid (1.0 M) will dissolve more chitosan than using a lower concentration (0.1 M) [29], and the insoluble materials were filtered and discarded prior to the solution proceeding to the regeneration procedure; the yield of R-2 was higher than R-1, R-4 was higher than R-3
The reasons for using higher degree of deacetylation (DD) chitosan that ends up with a higher yield than when using lower DD chitosan might be because the insoluble materials were filtered and discarded prior to the solution that proceeded to the regeneration procedure

Summary

Introduction

Chitosan is a high molecular weight (Mr) polysaccharide and is composed of N-acetyl-D-glucosamine and D-glucosamine, linked by β (1→4) glucoside. Chitosan is considered to be both a versatile and environmentally friendly raw material, and can be applied in food processing, agriculture, biomedicine, biochemistry, cosmetics, textiles, and wastewater treatment [1,2,3,4]. This is due to their versatile forms of fibers, hydrogels, membranes, microspheres, microcapsules, nanoparticles, liquid crystalline, etc.

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Conclusion