Jumbo squid (Dosidicus gigas) myofibrillar protein concentrate for edible packaging films and storage stability

- Isoelectric-C from acidic solubilization are more preserved than alkaline.
- The loss of secondary structure at pH10 led to a more resistant film.
- pH3 induced protein hydrolysis leading to a weaker and more plasticized film.
- After storage molecular motion caused film solubility and yellowness increase.
- Acidic-F4 suffered protein aggregation but alkaline-F4 network lost its integrity.

Properties and storage stability of two different jumbo squid myofibrillar protein-based films were investigated. Myofibrillar proteins were extracted by isoelectric precipitation after acidic and alkaline solubilization, obtaining the same extraction yield. During extraction the edible fraction, which was discarded during mantle skinning, was recovered, and the fishy flavour produced by nitrogen and other undesirable compounds was removed, although some sarcoplasmic proteins were lost simultaneously. In alkaline-Concentrate (C), myosin unfolding led to water resistant films, less water vapour permeable and more mechanically resistant than acidic-Films (F); whereas acidic-C protein hydrolysis resulted in more transparent and soluble films, with higher protein release (∼80 g/L). During 4 months of storage some structure reorganization occurred, and both films incremented their yellowish tendency, especially the acidic-F, being this attributed to a Maillard reaction with plasticizers. After storage time, water solubility increased in C-films. While acidic-F aggregation led to a protein release reduction and tensile strength improvement, alkali-F became weak and brittle, loosing transparency. C-films offered different filmogenic properties, proving to be promising biodegradable packaging materials.