|Wood, Delilah - De|
Submitted to: Journal of Food Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/1/2010
Publication Date: 3/1/2010
Citation: Azevedo, H.M., Mattoso, L.H., Avena-Bustillos, R.J., Filho, G.C., Munford, M.L., Wood, D.F., Mchugh, T.H. 2010. Nanocellulose reinforced chitosan composite films as affected by nanofiller loading and plasticizer content. Journal of Food Science. 75(1):N1-N7. Interpretive Summary: Chitosan is a biodegradable polymer which may be used to elaborate edible films or coatings to enhance shelf life of foods. This study demonstrates how cellulose nanofibers (CNF)can improve the mechanical and water vapor barrier properties of chitosan films. A nanocomposite film with 15% CNF and plasticized with 18% glycerol was comparable to some synthetic polymers in terms of strength and stiffness, but with poorer elongation and water vapor barrier, indicating that they can be used for applications that do not require high flexibility and/or water vapor barrier. The more important advantage of such fims when compared to synthetic ploymer films in their environmentally friendly properties.
Technical Abstract: Chitosan is a biopolymer obtained by N-deacetylation of chitin, produced from shellfish waste, which may be employed to elaborate edible films or coatings to enhance shelf life of food products. This study was conducted to evaluate the effect of different concentrations of nanofiller (cellulose nanofibers, CNF) and plasticize (glycerol) on tensile properties (tensile strength-TS, elongation at break-EB, and Young's modulus-YM) water vapor permeability (WVP), and glass transition temperature(Tg) of chitosan edible films, and to establish a formulation to optimize their properties. The experiment was conducted according to a central composite design, with 2 variables: CNF (0 TO 20g/100g) concentrations in the film (on a dry basis), which was produced by the so-called casting technique. Most responses (except by EB) were favored by high CND concentrations and low glycerol contents. The optimization was based on maximizing TS, YM, and Tg, and decreasing WVP, while maintaining a minimum accceptable EB of 10%. The optimum conditions were defined as:glycerol concentration, 18g/100g; and CNF concentration, 15g/100g. AFM imaging of films suggested good dispersion of the CNF and good CNF-matric interactions, which explains the good performance of the nanocomposite films.