Fabrication of a versatile and efficient ultraviolet blocking biodegradable composite film consisting of Tara gum/PVA/Riceberry phenolics reinforced with biogenic riceberry phenolic-rich extract-nano‑silver.

The demand for UV-protective and biodegradable packaging materials has been increasing with greater awareness about environmental sustainability and human safety. In this work, the effect of incorporating riceberry phenolic extract (RPE) as well as combined RPE and green synthesized biogenic nano‑silver (RPE-NS, into Tara gum/PVA (TP)-based matrix was evaluated on the physical, mechanical, functional, biocompatible and biodegradable attributes of the resultant composite films. Integration of RPE (2 wt%) and RPE-NS (0.8 wt%) resulted in nanocomposite (TP/RPE-NS) film with improved physical properties relative to the plain TP and TP/RPE films. The TP/RPE-NS film displayed a compact structure and homogenous distribution of the nano‑silver. Increased molecular interactions, crystallinity and thickness was also observed for the nanocomposite film. Compared to plain TP film, TP/RPE-NS film exhibited improved water vapor barrier properties and surface hydrophobicity due to the extract and nanoparticles. The tensile strength and elongation-at-break of TP/RPE-NS were markedly higher (41.76 MPa and 37.40 %) compared to that of plain TP film (36.07 MPa and 20.80 %). Whereas TP/RPE film provided good UV protection (UPF value of 31.85) compared to the minimal protection by TP film (UPF value of 2.72), combination of RPE/RPE-NS ensured that TP/RPE-NS availed an excellent UV-barrier performance (UPF value of 61.09). Furthermore, TP/RPE-NS film exhibited significant antioxidant activity relative to TP film. Besides, all TP-based films were found to be compatible with rat erythrocytes and biodegradable. Taken together, these findings indicate that TP/RPE-NS holds good potential for the development of UV-protective and biodegradable packaging material.