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.
Biodegradable PLLA-based cast films were prepared via melt blending poly(L-lactic acid) (PLLA) with poly(L-lactic acid-co-butylene itaconate) (PLBI), poly(L-lactic acid-co-glycolic acid) (PLGA), and poly(L-lactic acid-co-butylene itaconate-co-glycolic acid) (PLBIGA) copolymers to enhance mechanical, barrier, and degradation properties for dairy packaging applications. Copolymers were synthesized using a one-step melt polycondensation method, and the film properties were effectively controlled by adjusting the blending ratios. All blended films exhibited significantly improved toughness while maintaining high transparency. Specifically, PLLA/PLBIGA20 % film demonstrated a 90.1 % reduction in oxygen transmission rate (OTR) and a 54.3 % reduction in water vapor transmission rate (WVTR) compared to pure PLLA, and PLLA/PLBI20 % film reduced ultraviolet (UV) transmittance to 53 % in the 280–320 nm range. The soil degradation rates of blended films were notably higher than pure PLLA, with distinct degradation mechanisms observed for each copolymer; notably, PLLA/PLBIGA20 % film degraded simultaneously in both amorphous and crystalline regions. Blended films met food-contact safety standards and, when applied to commercial yogurt packaging, effectively preserved lactic acid bacteria viability, outperforming pure PLLA film. These findings demonstrate the strong potential of PLLA-based blended films as sustainable packaging solutions for dairy products.
危险品化学品经营许可证（带存储）