Insights on physicochemical aspects of chitosan dispersion in aqueous solutions of acetic, glycolic, propionic or lactic acid.
Chitosan is a polysaccharide well-known for its applicability as a biocompatible, biodegradable, and non-toxic material to produce drugs excipients and food coatings. Acidic media are required to disperse chitosan, and aqueous solutions of acetic acid have been typically used for this purpose. However, this acid has several sensory drawbacks. In this study, chitosan was dispersed [0.1 g·(100 mL)-1] in aqueous media containing acetic (AA), glycolic (GA), propionic (PA), or lactic (LA) acid, at 10, 20, 30, 40, or 50 mmol·L-1. The increase of acid concentration reduced pH and viscosity of the dispersions, and |ζ potential| of dispersed particles. Conversely, it increased electrical conductivity and density of the dispersions, and hydrodynamic diameter of dispersed particles. At a given concentration, these effects were slightly more pronounced for dispersions formed with GA or LA, compared to AA or PA. FT-IR data suggested more intense attractive interactions of chitosan chains with glycolate and lactate anions, than with acetate and propionate. Chitosan chains interacted more strongly with hydroxylated acids counter-anions than with their non-hydroxylated counterparts, leading to slight quantitative changes of physicochemical properties of these systems. Then, in physicochemical terms, GA, LA or PA are suitable to replace AA when preparing aqueous chitosan dispersions for technological applications.
['Soares|Lucas de Souza|LS|', 'Perim|Rayza Badiani|RB|', 'de Alvarenga|Elson Santiago|ES|', 'Guimarães|Luciano de Moura|LM|', 'Teixeira|Alvaro Vianna Novaes de Carvalho|AVNC|', 'Coimbra|Jane Sélia Dos Reis|JSDR|', 'de Oliveira|Eduardo Basílio|EB|']
D019342:Acetic Acid D000107:Acetylation D055598:Chemical Phenomena D048271:Chitosan D004553:Electric Conductivity D006016:Glycolates D006863:Hydrogen-Ion Concentration D019344:Lactic Acid D008970:Molecular Weight D012212:Rheology D012996:Solutions D014783:Viscosity
Chitosan Colloidal dispersions Organic acids