A comparative analytical study on the role of banana peel in enhancing the physical, mechanical, and functional properties of starch-based bioplastic

Abstract

As the world shifts away from petroleum plastics, starch-based bioplastics emerge as a promising green alternative, though they continue to face challenges in strength and performance. This study explores the impact of incorporating banana peel into starch-based bioplastics, aiming to enhance their physical, mechanical and functional properties by comparing formulations with three treatment types: bioplastic developed from starch (SB0) as control and starch-based bioplastic prepared with 30% (SB30) and 60% (SB60) banana peel incorporation. The results revealed significant variations among SB0, SB30 and SB60 across multiple parameters. Moisture content increased from SB0 (18.4±0.3%) to SB60 (35.37±0.35%), while total solids content decreased from 81.6±0.19% (SB0) to 70.58±0.35% (SB60). Ash content rose from 0.21±0.03% (SB0) to 3.77±0.02% (SB60) with banana peel addition. Density and Thickness values for SB0, SB30, and SB60 were 1.21±0.02 g/mL, 1.15±0.11 g/mL, and 1.1±0.03 g/mL, and 0.35±0 mm, 0.72±0.01 mm, and 0.95±0.01 mm, respectively. Tensile strength decreased from 5.04±0.08 MPa (SB0), to 2.32±0.12 MPa (SB60), while elongation rates increased from 10.24±0.12% (SB0), to 18.37±0.08% (SB60). Biodegradation rates steadily improved over time and with increased banana peel addition, reaching 43.2±0.003% for SB60 on day 20. Polyphenol content and antioxidant activity were significantly higher in SB30 and SB60 samples, with gradual reductions observed over time; SB60 exhibited the highest initial antioxidant activity (62.16±0.27), compared to 28.06±0.68 in SB30 and 0.63±0.21 in SB0. SB30 exhibited the highest water solubility (45.16±2.68%), while SB60 demonstrated the lowest (27.84±0.45%). Water vapor permeability and water vapor transmission rate were lowest in SB60 (2.33 × 10-12 ±0.19 kgm⁻¹s⁻¹Pa⁻¹ and 6.23 × 10-12 ±0.53 kgs⁻¹m⁻², respectively), indicating enhanced barrier properties. Overall, these findings suggest that the incorporation of banana peel significantly improves the performance of starch-based bioplastic films, supporting their potential application in sustainable packaging.