Physicochemical and Antioxidant Properties of White (Fiano cv) and Red (Negroamaro cv) Grape Pomace Skin Based Films

Grape pomace, as by-product of wine making, is a source of polyphenols, fibers, fatty acids, metals, and organic acids, which could be used as raw component for the production of sustainable materials. Novel biodegradable films based on pomaces, from Negroamaro (red) and Fiano (white), Italian grape cultivars, were fabricated. Physical, chemical and antioxidant properties of material produced were characterized. In particular, migration tests of phenols from pomace films to aqueous food simulant medium were investigated. Data obtained allowed to evaluate the antioxidant activity in terms of total phenol assay and Trolox Equivalent Antioxidant Capacity assay and phenols profile. The characterization of phenolic composition confirmed the peculiarity of some compounds such as anthocyanins (191.17 +/- 10.3 mu g/g film) in red skin pomace film (NPF) and a great amount of flavanols (76.36 +/- 1.72 mu g/g film) in white skin pomace film (FPF). Antioxidant activity of polyphenols resulted in active films and was confirmed in migration test with aqueous food simulants. Physical properties of produced films were then studied in terms of morphological, thermal, mechanical and barrier properties. Finally, in the framework of sustainability and circular economy, the presented data paves the way to the design and production of active materials for packaging application starting from a widely available by-product derived from wine-making chain.