The growing need to reduce food loss and environmental pollution has intensified research into sustainable packaging solutions, particularly in regions like the Mediterranean, which produce large quantities of perishable food. Biobased and compostable polymers offer a promising alternative to conventional fossil-derived plastics, supporting carbon neutrality and circular economy principles. However, their barrier properties often fall short of those required for effective food preservation. This study investigates the potential of poly(lactic acid) (PLA) and poly(butylene succinate-co-adipate) (PBSA) blends to enhance the performance of compostable films for packaging perishable liquid and semi-liquid foods. This study considers that a PLA/PBSA 60/40 blend was developed and evaluated for its mechanical and barrier properties, demonstrating improved flexibility, impact resistance, home-compostability and industrial recyclability. Then, by using a mini-extruder, various PLA/PBSA formulations, including nanostructured fillers like clay and talc, were produced and tested for their melt fluidity. Then the materials were used to prepare films that were tested for their ability to retain liquid whey over time. Infrared spectroscopy and analysis of morphology by Scanning Electron Microscopy were employed to assess surface and bulk characteristics of films. Results indicated that blend composition significantly influenced barrier performance, with certain formulations showing enhanced resistance to mass loss. This research highlights the critical role of material composition in designing effective compostable packaging systems for perishable food products. These findings have implications in preservation of perishable foods that may include Mediterranean fruits such as strawberries, dates, and tangerines. In fact, the development of such biobased films could contribute to reduce food waste and extending shelf life, aligning with environmental sustainability goals.