Preparation and characterization of highly flexible chitosan films for use as food packaging.

摘要

Highly flexible chitosan films were prepared by film casting of chitosan solutions using lactic acid solutions and acetic acid solution. Influence of chitosan mol. wt. (100 and 740 kDa), lactic acid concn. (1.0, 1.5 and 2.0% w/v) and lactic acid configurations (L- and DL-forms) on film characteristics were investigated. FTIR spectra of the films showed that there were intermolecular bonds between chitosan film matrices and lactic acids. Tensile strengths at break of the films decreased and percentage elongations increased when lactic acid was used instead of acetic acid for dissolving chitosan. Flexibility of the chitosan films increased with content of either L- or DL-lactic acids. L-lactic acid showed higher plasticization effects than DL-lactic acid. Film transparency did not change, whereas wetability of the chitosan films increased as lactic acid content increased.