Development and Application of Modified Poly(L-Lactic Acid) Based Film for Storage of Yogurt

The quality of yogurt deteriorates during storage due to exposure to oxygen and UV light, and high-barrier packaging effectively mitigates this issue. Concurrently, there is increasing interest in replacing petroleum-based packaging with eco-friendly alternatives. In this study, poly(lactic acid-butylene itaconate) (PLBI), developed as a modified version of poly (L-lactic acid) (PLLA) to enhance toughness, was combined with poly (vinyl alcohol) grafted with acryloyl chloride (PVA-g-AC) through UV curing. The resulting PLBI/PVA-g-AC films exhibited significantly improved barrier properties. They were used to package stirred yogurt alongside polyethylene/nylon (PE/NY) films for comparison. Quality assessments, including acidity, water-holding capacity, and viable bacterial counts, demonstrated that PLBI/PVA-g-AC films provided superior preservation. Metabolomics analysis revealed increased flavor compounds, such as acids and alcohols, and decreased sugar levels in these packaged yogurt. This work expands potential applications of PLLA-based materials in food packaging and offers insights into the influence of oxygen on yogurt storage quality.