PH-sensitive intelligent films offer a novel strategy for real-time monitoring of food freshness via visible color changes. This study valorizes onion peel powder (OPP), a polyphenol-rich agro-industrial by-product, by incorporating it into cassava starch-based films at three concentrations (1O, 2O, 3O). Increasing OPP content led to significantly higher total phenolic and flavonoid levels, enhancing the films’ antioxidant properties (p < 0.0001). While the films exhibited selective antibacterial effects, pronounced inhibition zones were observed against Pseudomonas aeruginosa and Escherichia coli, two relevant meat spoilage and pathogenic bacteria. The films displayed clear and gradual color shifts from light to dark brown across a wide pH range (1–13), confirming their suitability as pH indicators. When applied as labels in minced beef packaging stored at 4 °C, the films successfully tracked freshness over 13 days. Film color changes were strongly correlated with microbial load and pH variations, accurately flagging spoilage onset. These findings support the potential of cassava starch/OPP films as biodegradable, cost-effective intelligent packaging tools, contributing to food safety, waste reduction, and circular bioeconomy principles. The system provides a practical, non-invasive solution for meat freshness monitoring without requiring instrumentation.

This study valorizes onion peel, an agro-industrial by-product rich in phenolic compounds and structural carbohydrates, for the development of cassava starch-based biodegradable films. The films were prepared using the solution casting method; a cassava starch matrix was mixed with a 2.5% glycerol solution and heated to 85 °C for 30 min. A separate solution of onion peel powder (OPP) in distilled water was prepared at 25 °C. The two solutions were then combined and stirred for an additional 2 min before 25 mL of the final mixture was cast to form the films. Onion peel powder (OPP) incorporation produced darker and more opaque films, suitable for packaging light-sensitive foods. Film thickness increased with OPP content (0.138–0.218 mm), while moisture content (19.2–32.6%) and solubility (24.0–25.2%) decreased. Conversely, water vapor permeability (WVP) significantly increased (1.69 × 10⁻⁹–2.77 × 10⁻⁹ g·m⁻¹·s⁻¹·Pa⁻¹; p < 0.0001), reflecting the hydrophilic nature of OPP. Thermal analysis (TGA/DSC) indicated stability up to 245 °C, supporting applications as food coatings. Morphological analysis (SEM) revealed OPP microparticles embedded in the starch matrix, with FTIR and XRD suggesting electrostatic and hydrogen–bond interactions. Mechanically, tensile strength improved (up to 2.71 MPa) while elongation decreased (14.1%), indicating stronger but less flexible films. Biodegradability assays showed slightly reduced degradation (29.0–31.8%) compared with the control (38.4%), likely due to antimicrobial phenolics inhibiting soil microbiota. Overall, OPP and cassava starch represent low-cost, abundant raw materials for the formulation of functional biopolymer films with potential in sustainable food packaging.

Synthetic plastic pollution represents a major global concern, driving the search for sustainable and biodegradable packaging alternatives. However, many biodegradable plastics suffer from inadequate mechanical performance. This study aimed to develop a biodegradable film based on cassava starch, incorporating onion peel powder (OPP), a byproduct rich in quercetin derivatives, as a reinforcing agent and plasticized with crude glycerol. A Central Composite Design (CCD), implemented using Minitab 19, was employed to investigate the effects of starch (60–80%) and OPP (0–40%) content on the mechanical properties and biodegradability of the resulting bioplastics. Three optimized formulations were identified according to specific performance criteria. The first formulation, containing 72.07% starch and 21.06% OPP, was optimized for maximum tensile strength while maintaining target values for elongation and biodegradability. The second, composed of 77.28% starch and 37.69% OPP, was optimized to enhance tensile strength and biodegradability while minimizing elongation. The third formulation, with 84.56% starch and 27.74% OPP, aimed to achieve a balanced optimization of tensile strength, elongation, and biodegradability. After a 30-day soil burial test, these formulations exhibited weight loss percentages of 31.86%, 29.12%, and 29.02%, respectively, confirming their biodegradability. This study optimized the mechanical and biodegradability properties of cassava starch-based bioplastics using statistical modeling. The optimized formulations show potential for application in sustainable food packaging.

Synthetic plastic pollution represents a major global concern, driving the search for sustainable and biode-gradable packaging alternatives. However, many biodegradable plastics suffer from inadequate mechanical performance. This study aimed to develop a biodegradable film based on cassava starch, incorporating onion peel powder (OPP), a byproduct rich in quercetin derivatives, as a reinforcing agent and plasticized with crude glycerol. A Central Composite Design (CCD), implemented using Minitab 19, was employed to investi-gate the effects of starch (60–80%) and OPP (0–40%) content on the mechanical properties and biodegradabil-ity of the resulting bioplastics. Three optimized formulations were identified according to specific performance criteria. The first formulation, containing 72.07% starch and 21.06% OPP, was optimized for maximum tensile strength while maintaining target values for elongation and biodegradability. The second, composed of 77.28% starch and 37.69% OPP, was optimized to enhance tensile strength and biodegradability while minimizing elongation. The third formulation, with 84.56% starch and 27.74% OPP, aimed to achieve a balanced optimiza-tion of tensile strength, elongation, and biodegradability. After a 30-day soil burial test, these formulations ex-hibited weight loss percentages of 31.86%, 29.12%, and 29.02%, respectively, confirming their biodegradability. The physico-chemical, mechanical, thermal, morphological, and colorimetric properties of the optimal formu-lations are currently being investigated in detail. These forthcoming results will provide valuable insights into the functional performance of cassava starch-based bioplastics for food packaging applications.