Properties of chitosan films as a function of pH and solvent type

• Published in: Journal of food science Vol. 71; no. 3; pp. E119 - E124
• Main Authors: Kim, K.M, Son, J.H, Kim, S.K, Weller, C.L, Hanna, M.A
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.04.2006; Institute of Food Technologists
• Subjects: absorption; acetic acid; acetylation; Biological and medical sciences; chitosan; chitosan films; deacetylation; deacetylation degree; edible films; Food industries; food packaging; formic acid; Fundamental and applied biological sciences. Psychology; lactic acid; organic acids; permeability; propionic acid; solvents; tensile strength; total soluble matter; water; water vapor permeability; Film; Permeability; Properties; Water vapor; chitosan films; water vapor permeability; Organic acids; total soluble matter; Deacetylation; pH; deacetylation degree; Chitosan; Solvent
• ISSN: 0022-1147; 1750-3841
• DOI: 10.1111/j.1365-2621.2006.tb15624.x

Two different deacetylated chitosans were dissolved in formic, acetic, lactic, or propionic acid to prepare chitosan films. The pH values of the film-forming solutions were adjusted to 3, 4, and 5. Water vapor permeability (WVP), tensile strength (TS), elongation (E), and total soluble matter (TSM) were significantly (P < 0.05) affected by acid type, pH, and degree of deacetylation (DA). Low DA (LDA) chitosan films had lower WVP and TSM, higher TS compared with high DA (HDA) chitosan films. The E values were not affected by DA. As pH increased, WVP and TSM of chitosan films tended to increase while TS decreased significantly (P < 0.05). Chitosan films with acetic and propionic acid solvents had low WVP and TSM and high TS, while films with lactic acid solvent had high E and TSM and the lowest TS. Fourier-transform infrared showed peak shifting in the spectra with different solvents and at different pH values. Chitosan films with lactic acid solvent showed a peak shift to a lower frequency range. The NH3(+) band was absent in the pH 5.0 chitosan film spectra.