The growing demand for environmentally sustainable and biodegradable materials has intensified interest in alternative solutions for thermal insulation. This study explores the development of composite materials using mango seed shell biochar (MSSB) and soy protein isolate (SPI) as a biodegradable matrix-filler system. Mango seed shells, an abundant agro-industrial waste, were subjected to pyrolysis at 500 degrees C for 2 hours to produce biochar. The resulting MSSB was incorporated into SPI with glycerol as a plasticizer to fabricate composite sheets containing 10%, 20%, and 30% biochar by weight Thermal conductivity tests showed that increasing MSSB content led to a notable reduction in thermal conductivity, with the 30% MSSB composite achieving a value of 0.035 W/mK-comparable to commercial synthetic foams such as expanded polystyrene. Mechanical analysis revealed a tradeoff between tensile and compressive properties. While tensile strength decreased from 1.8 MPa for pure SPI to 0.7 MPa at 30% MSSB, compressive strength improved with increasing biochar content, peaking at 1.5 MPa.Biodegradability was evaluated through an 8-week soil burial test, which demonstrated accelerated degradation in composites with higher MSSB content, reaching up to 55% weight loss at 30% loading. These findings highlight the potential of MSSB-SPI composites as eco-friendly insulation materials suitable for green building and packaging applications. Future work will focus on mechanical property enhancement to expand the material's structural utility.

Excessive use of nondegradable plastics has raised environmental concerns, promoting the development of high-performance and eco-friendly materials. Polysaccharides and proteins, which offer advantages such as affordability and biodegradability, have potential in packaging but are limited in barrier and mechanical properties. Herein, using 30% acetic acid as a solvent for soy protein isolate (SPI) and introducing oxidized arabinogalactan (OAG) into the system, highly transparent (90%) and ultraviolet-shielding SPI/OAG flexible films were successfully prepared via Schiff base chemical cross-linking and hydrogen bond interactions between the components. The synergistic cross-linking of SPI and OAG effectively increased mechanical strength (tensile strength of 6.93 MPa), improved oxygen and water vapor barrier properties, and reduced swelling in the SPI/OAG films. The films exhibited good antioxidant activity (81.75% for ABTS and 85.34% for DPPH), effectively retarded browning and weight loss of strawberry and apple pieces, and were biodegradable in soil. The prepared SPI/OAG films had advantages over existing SPI-based films, including a uniform structure, low oxygen permeability, and excellent sustainability. This research demonstrates that SPI/OAG cross-linked films have strong potential in biodegradable packaging and as a substitute for petroleum-based plastics.

Herein, we report for the first time the incorporation of riboflavin as a bioactive additive in soy protein isolate films, along with investigating the impact of UV light treatment, thereby creating functional packaging material. Our investigation involves a comprehensive characterization of the films, including morphological, physicochemical, and mechanical properties, as well as their effectiveness as light barriers, antimicrobial potential, and biodegradation properties. The UV treatment of riboflavin/soy protein dispersions leads to the formation of films exhibiting minor water swelling and total soluble matter compared to those untreated with UV light, suggesting the development of a cross-linked network. Moreover, increased riboflavin content enhances the cross-linked network's robustness. The mechanical properties of the films exhibit a notable improvement with UV treatment and with increasing riboflavin content until a limit value, showcasing increased tensile strength and Young's modulus. Films showed homogeneous surfaces with an absence of pores and cracks and the ability to act as a barrier for oil passage. Films were assayed as a coating material for chia oil samples exposed to highintensity UV light, showing great protection capacity. It has been demonstrated that an increase in riboflavin concentration enhances the UV light-blocking properties, making these films promising candidates for storing light-sensitive food products while preserving their nutritional quality. In addition, antibacterial action against S. aureus was determined by disk diffusion assay. Furthermore, the films exhibited relatively short disintegration times under soil burial conditions, even after chemical modification. This research contributes valuable insights to the innovative field of sustainable food packaging materials.