Thermoresponsive films are favorable for the packaging of fresh fruits and vegetable products as their gas permeabilities increase to a greater extent than commercial films when temperature abuse occurs during refrigerated storage. Thermoresponsive polyurethane (PU) films were synthesized from polyethylene glycol (PEG) with three different molecular weights (400, 1000, and 1500 g mol⁻¹), castor oil (CO) with two different proportions (30 and 50 %, CO/PEG ratio) and a constant level of 1,4-butanediol (BDO). The effects of these compositional factors on the thermal, mechanical, physical, structural, and gas barrier properties of the films were investigated. Melting temperatures (T_m) of the PU films varied from 25 to 29 °C and decreased with CO content. Glass transition temperatures (T_g) of the films were all below −32 °C and decreased by increased CO content. PU films with 1500 g mol⁻¹ PEG and 30 % CO/PEG ratio had better shape memory (R_r) and shape fixity (R_f) properties than others. O₂ permeabilities of the PU films were in the range of 1.99–7.25 barrer while their CO₂ permeabilities were between 10.3 and 18.3 barrer. The temperature sensitivity of the gas permeabilities of the PU films was higher than that of a commercial LDPE film, which makes them more appropriate for fresh produce packaging. Nevertheless, PU films were mechanically weaker and they had higher water vapor permeability compared to the LDPE film. These properties of the PU films need further improvements for potential packaging applications.

A series of drug-loaded pectin hydrogels were prepared by mixing method in two ion types, Ca⁺² or Zn⁺², for wound dressing applications and their drug release performances were investigated at pH 6.4 in four different calcium ion concentrations of external solution. Pectin hydrogels were synthesized in three different concentrations of initial pectin solution and theophylline was used as a model drug. Fourier transform infrared spectroscopy, scanning electron microscopy, and atomic force microscopy were used for hydrogel characterization. Additionally, fluid handling capacity, swelling behavior, dehydration rate, dispersion characteristic, dressing pH determination, water vapor permeability, oxygen permeability, surface contact angle, flexibility, mass per unit area, and thickness were determined for selected hydrogels. One of the most valuable contributions of our study is that the concentration of initial pectin solution and calcium ion concentration of external solution are very important parameters to obtain an effective drug release. After evaluating all data, we have shown that flexible and transparent pectin-based wound dressings can be synthesized as a controlled drug release system. Zinc-containing hydrogel was antibacterial against Staphylococcus aureus and Escherichia coli but not suitable for cell migration. On the other hand, calcium-based hydrogel was nontoxic on the fibroblast cells and it had no negative effect on cell migration.