Valorisation of Protein from Underutilised Harbour Crab (Liocarcinus depurator) as an Egg Yolk Replacer in Mayonnaise-like Sauce Production

The present study aimed to valorise the harbour crab (<i>Liocarcinus depurator</i>), a common bycatch species, by evaluating its protein as an egg yolk substitute in a mayonnaise-type sauce. The harbour crab was firstly characterised for its physicochemical and elemental composition (including amino acid profile, macrominerals, trace, and heavy metals). Protein was extracted by precipitation at the isoelectric point (with or without a previous delipidation step), and the foaming and emulsifying properties of the resulting protein extracts were evaluated. The method that did not involve prior delipidation resulted in a higher protein extraction yield. Furthermore, this method resulted in a protein extract with superior emulsifying activity. This protein extract was used as an egg-yolk replacer in the preparation of a mayonnaise-type sauce. Sensory evaluation revealed that the sauce formulated with crab protein was comparable to the egg-based control in terms of overall flavour and acceptability, but only with the addition of curry to mask the seafood taste. The results of this study demonstrate that crab meat protein, when extracted without previous lipid removal and combined with curry, can be used as a viable egg yolk substitute in mayonnaise-type sauces.