Designing Sustainable Packaging Materials: Citric Acid-Modified TPS/PLA Blends with Enhanced Functional and Eco-Performance

Starch extracted from the domestically cultivated Scala potato variety was explored as a renewable resource for the formulation of biodegradable thermoplastic starch (TPS)/polylactic acid (PLA) blends intended for environmentally friendly food packaging applications. The isolated starch underwent comprehensive physicochemical and structural characterization to assess its suitability for polymer processing. TPS derived from Scala starch was compounded with PLA, both with and without citric acid (CA) as a green compatibilizer to enhance phase compatibility. The resulting polymer blends were systematically analyzed using Fourier-transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) to evaluate thermal and structural properties. Mechanical performance, water vapor permeability (WVP), water absorption (WA), and biodegradability in soil over 56 days were also assessed. The incorporation of citric acid improved phase miscibility, leading to enhanced structural uniformity, thermal stability, mechanical strength, and barrier efficiency. Bio-degradation tests confirmed the environmental compatibility of the developed blends. Overall, the results demonstrate the potential of Scala-based TPS/PLA systems, particularly those modified with citric acid, as viable candidates for sustainable food packaging, while highlighting the importance of further formulation optimization to balance functional and biodegradative performance.