Chitosan composite films: Thermal, structural, mechanical and antifungal properties

Based on colony spreading, chitosan from shrimp waste in agar media inhibited the growth of Aspergillus niger by 47.26%; there were not differences (P > 0.05) with respect to commercial chitosan (Fluka, BioChemika) (56.16%). All chitosan films showed similar glass transition temperatures (P > 0.05) with respect to cellophane control; however, chemically, all chitosan films showed an increase in the T_g values that could be related with the decrease (P ≤ 0.05) in elongation percentage with respect to the control film. According to FT-IR spectroscopic analysis of chitosan films, the fungistatic activity can be related to the hydrogen bonds' formation between the amino groups of chitosan with the hydroxyl groups from polymer or sorbitol. The plasticizer addition increased (P ≤ 0.05) the elongation of chitosan films. The Young's module, E, was lower (P ≤ 0.05) for all chitosan films comparing with cellophane. When incorporated into the composite films elaborated by casting, chitosan retained its fungistatic activity. Even though the activity against fungi growth was lower (15.66% for non-plasticized silage chitosan films, pC_S), a reduction (P ≤ 0.05) in the hyphae diameter of A. niger was observed. Results suggest that it is feasible to elaborate antifungal chitosan films, with good thermal stability and acceptable mechanical properties for food packaging.