Development of PLA-PBSA based biodegradable active film and its application to salmon slices

Due to negative impacts of non-biodegradable plastic films to the environment, biodegradable packaging materials have become a research hotspot. Novel biodegradable active films based on polylactic acid (PLA) blended with poly (butylene succinate adipate) (PBSA), carvacrol, and thymol were developed. Mechanical properties of films including tensile strength (TS), elongation at break (EAB), optical properties including transmittance (T) and haze (H), barrier properties including water vapor permeability (WVP), oxygen transmission rate (OTR), and releasing rates of active compound from films and antioxidant efficiency of films were investigated to evaluate the films. A shelf life test of salmon slices packed with PLA-PBSA bags (with and without active compound) were carried out. The results showed that PLA-PBSA based films had better mechanical properties than those of similar biodegradable films such as PLA-PHB, and even better than EVOH in terms of two major mechanical properties, TS and EAB. As to active properties, the results also showed a high release of active compound and high antioxidant efficiency of PLA-PBSA films with either carvacrol or thymol. The shelf life test of salmon slices showed the antibacterial and antioxidant properties of the PLA–PBSA films were enhanced when the active compound were released into salmon slices at equilibrium. As a result, spoilage and deterioration of the salmon slices were reduced, which extended the shelf life of salmon slices by 3–4 days during cold storage. Thus, the biodegradable PLA–PBSA films with active compound could prolong shelf life of fisheries products in particular, and food in general.