Abstract: Glycosylated squid (Symplectoteuthis oualaniensis) myofibrillar protein with dextran and acid- and alkaliextracted squid proteins were applied to prepare biodegradable films. The effect of adding different concentrations of tannic acid (TA) on the physical properties of these films was evaluated. The results showed that glycosylated protein had the lowest free amino group content. TA incorporation significantly reduced the free amino group and --SH content of protein solutions (P < 0.05). Film formed by glycosylated protein had the lowest moisture content, higher water solubility and better mechanical properties. The film exhibited a yellower color and rougher surface due to TA cross-linking under alkaline pH condition. In addition, TA led to higher film tensile strength but lower elongation at break. Among the samples, glycosylated protein-based film with 1% TA had both higher tensile strength and higher elongation at break, which were 1.26 MPa and 118%, respectively. Meanwhile it also had lower water vapor permeability. This study has important implication for exploring squid protein as packaging films to extend the shelf-life of foods.

Key words: squid myofibrillar protein, extraction methods, glycosylation, tannic acid, film performance