Effect of storage conditions on the physicochemical characteristics of edible films based on whey protein concentrate and liquid smoke

In this study, whey protein concentrate-based edible films incorporated with 10% w/w of liquid smoke were prepared by casting and stored at 8 °C and 25 °C. The effect of storage conditions on physicochemical stability of films was studied. Light transmission, transparency, color, total content of carbonyl derivatives, browning index, moisture content, solubility, thickness, mechanical properties, SEM micrographs and FTIR spectra were evaluated after 0, 7, 14, 21 and 28 days of storage. Thickness and transparency did not change after 28 days of storage at any storage condition. Tensile strength and total difference color increased when storage was performed at 25 °C. Moisture content decreased after 7 days of storage for both storage conditions, but the effect was much more significant at 25 °C. Solubility decreased after 7 days of storage at 25 °C and after 28 days of storage at 8 °C. The main changes observed at 25 °C were caused by the loss of moisture and by the progress of the Maillard reaction. In general, the physicochemical characteristics of films were better preserved at 8 °C, indicating that films can be used to package foods that are stored under refrigeration condition