A new two-step combined modification method for preparing amylopectin biofilms with high transparency and ideal properties as foods packaging materials

This study proposes a two-step combined modification method, involving the introduction of flexible molecular long-chains and multiple crosslinking techniques. Accordingly, amylopectin (AM) biofilms with high transparency and ideal properties were prepared as foods packaging biofilms. Meanwhile, the synergistic crosslinking mechanisms were explored to expand the universality of crosslinkers. Polyvinyl alcohol (PVA) was employed as the flexible molecular long-chain, and three dual-crosslinker systems were selected for multiple crosslink modifications. It was demonstrated that the modified AM-based biofilm achieved an impressive transparency level of 92.88 %. The mechanical properties transformed from non-film forming to a stage of good flexibility, with a tensile strength value of 11.33 MPa. AM confers high transparency to films and the introduction of PVA breaks the self-crystallization of AM. Subsequently, the biofilm network structure was further enhanced by multiple crosslinking, especially the system of Boric acid-Glyoxal (BA-GLA) dual-crosslinkers. Therefore, the developed AM-based biofilms with high transparency and ideal properties have the potential for use in food packaging.