In the current study, nanocomposite films were produced based on corn starch:chitosan (CS:CH) biopolymers and the films were reinforced with nettle essential oil nanoemulsions (NEONEs) and starch nanocrystals (SNCs) to improve their physicochemical and mechanical properties. CS: CH at 70:30, 50:50, and 30:70 (w/w) ratios; SNCs at 2, 4, and 6% (w/w), and NEONEs at 0.5, 1, and 1.5% (w/w) were selected as variables. Then the various physical and mechanical attributes of chitosan-starch blended film containing SNCs and NEONEs were optimized using response surface methodology. The desirability function technique for the second-order polynomial models revealed that the following results could be achieved as the optimized treatment: water solubility of 51.56%; water absorption capacity of 128.75%; surface color of L (89.60), a (0.96), and b (1.90); water vapor permeability of 0.335 g/s Pa m, oxygen permeability of 2.60 cm3 μm/m2 d kPa; thickness of 154.41 µm, elongation at break of 53.54%; and tensile strength of 0.20 MPa at CS:CH of 38:62, SNC of 6.0%, and NEONEs of 0.41%. The nanocomposite film obtained can be employed as a novel biofunctional film with boosted physical mechanical and physical characteristics for food packaging applications.
Keywords: chitosan-starch composite; nettle essential oil; optimization; starch nanocrystals.