Edible film production using Aronia melanocarpa for smart food packaging

Although smart packaging systems protect food, they also provide information about the shelf life of the content. This information is provided by the formation of severe shifts in color as a result of the reaction of the gases released by the decomposition of the food, the colorant used in smart packaging. The inks or films used in smart packaging systems may exhibit this feature. Because both ink and film materials come into direct contact with the food product in smart packaging, it is more suitable for the intended use of the packaging to be produced from edible and natural resources. In this study, we aimed to investigate the production of films and their use in active packaging systems using the natural source starch and another bio source black chokeberry (Aronia melanocarpa) fruit in order to produce smart packaging. In this study, the coloring matter was extracted from Aronia melanocarpa fruit using ethyl alcohol. The monomeric anthocyanin and total phenol contents of the extracted Aronia melanocarpa were determined by the pH differential method. Colorimetric edible films sensitive to pH changes were produced using starch biopolymer by adding different amounts of the obtained aronia extract. The chemical structures of the produced films were determined by ATR-FTIR, the color properties were determined using spectrophotometer, and the contact angles were determined using goniometer. In addition, the swelling ability was calculated based on the pH. The disk diffusion method was applied to the obtained films against gram-positive and gram-negative bacteria, and the antibacterial properties of the films were determined. The swelling ability of the films prepared with aronia and starch was approximately half as low as the blank film. The prepared films maintained their stability at all pH levels, including high acids and bases. While the edible films produced had a pink-red color at acidic pH, they turned dark blue at basic pH values. This shows that the color of the films changes depending on the nitrogen output from the spoiled meat and can be used as smart packaging. When the antibacterial properties were examined, the blank film (F0) did not have any antibacterial properties, however as the amount of aronia increased, an increase of 17-22 mm (F1 to F4) against gram-positive bacteria and 4-9.9 mm (F1 to F4), respectively, was observed against gram-negative bacteria. In addition, the fact that the films produced have inhibitory properties against gram-positive bacteria adds an extra feature to the packaging material, as it protects the food against degradation. © 2022 Walter de Gruyter GmbH, Berlin/Boston.