Environmental issues caused by plastic films promote the development of biodegradability packaging materials. Copper ion-modified nanocellulose films were prepared through a one-pot reaction and systematically investigated their structural characteristics, thermal stability, mechanical properties, antibacterial activity, and biodegradability. The results indicate that the film prepared by co-soaking CNCs and copper in NaOH solution for 12 h has favorable performance. Introduction of copper ions as crosslinkers increases tensile strength of film from 36.8 MPa to 56.4 MPa and water contact angle of film from 46 degrees to 92 degrees. Copper coordination also endows the film excellent antibacterial activity, inhibiting growth of Escherichia coli and Staphylococcus aureus. Moreover, biodegradability tests indicate that although the introduction of copper ions slightly reduce biodegradation rate of films, they could still be decomposed significantly within four weeks as burying in soil. This simple process for preparing cellulosic films with water resistance, thermal stable, antibacterial ability, and biodegradable shows potential application in flexible packaging film.

The environmental impact of food packaging, transportation and disposal are escalating, contributing significantly to global solid waste. There's an increasing focus by industry and research on seeking new sustainable solutions for waste valorization. This study investigates the isolation process of biopolymers from legumes (lentil) products and fish (gilthead seabream) waste, with the aim of producing composite films. The developed films were characterized for optical, mechanical and water barrier properties, hydrophobicity (via contact angle measurement), moisture content, water solubility, and biodegradability. Results indicated that lentil and fish protein concentrates may be effectively utilized to fabricate biodegradable packaging materials with adequate moisture barrier properties and excellent optical characteristics. The composite materials from lentil proteins and pectin had higher elongation at break compared to the respective value of the films produced using fish protein and gelatin (44.94 +/- 2.81 % and 10.52 +/- 1.21 %, respectively). Regarding the composite animal based film, the WVTR and WVP values were measured at 119.50 +/- 2.90 g x s(-1) x m(-2) and 5.04 +/- 0.06 x 10(-8) x g x m(-1) x s-(1)xPa(-1), respectively. The composite plant based materials had higher WVTR and WVP (139.17 +/- 8.01 g x s(-1) x m(-2) and 7.80 +/- 0.91 x 10(-8) x g x m(-1) x s-(1)xPa(-1), respectively). The composite film of pectin and concentrated lentil protein exhibited hydrophobic behavior (contact angle 98.63 +/- 3.78 degrees), whereas for gelatin and concentrated fish protein films, the contact angle was determined as 57.37 +/- 4.00 degrees, indicating hydrophilic behavior. All produced films biodegraded in <20 days during burial test in soil with high relative humidity (80 %). The results of the study show the utilization of food industry potential waste for producing environmentally friendly packaging materials.