Characterization of Red Cabbage Extracts incorporated in Green Based Gelatin Active Films

Abstract

This study aimed to assess red cabbage extracts obtained using solvents with different pH levels and alcohol concentrations, comparing their phytochemical quantities and functional characteristics. Solvents—purified water (PW, pH 7), 70% and 99% ethanol (70%E and 99%E, pH 6.5), and acidified ethanol (AE, pH 2)—were employed for extraction. When the different pH solutions were applied to the red cabbage extracts, they altered the extract's color, ranging from pink to yellow, influenced by various anthocyanin forms responsive to pH levels. The AE-extracted red cabbage displayed the highest UV and visible light barrier and total phenolic content (TPC). Then, the AE extract was used to formulate the green-based gelatin active films, alongside the 99%E extract, which had similar alcohol content and TPC values. The films averaged 20-21 μm in thickness. Moreover, incorporating both extracts into the gelatin films increased moisture content and water solubility, though the change in water vapor permeability was not significant compared to the neat gelatin film. The gelatin film incorporating AE-extracted red cabbage (GAE) showed higher water solubility than that incorporating the 99%E extract (GE). Both green-based gelatin active films showed differences in appearance color in the third week. The GAE film exhibited greater color stability, attributed to anthocyanin's distinctive chemical structures favoring acidic environments. This gelatin film incorporating red cabbage by AE-extracted holds promise as an eco-friendly active food packaging material.