Quality Enhancement of Refrigerated Hake Muscle by Active Packaging with a Protein Concentrate from Spirulina platensis

This study focused on the development of novel active packaging methods based on natural compounds. Its main objective was the quality enhancement of refrigerated packaged fish. For it, the effect of the inclusion of a protein concentrate (PC) extracted from microalga Spirulina platensis into a crosslinked gelatine-based biofilm was investigated during the preservation of hake (Merluccius merluccius) muscle. Thus, microbiological and chemical analyses related to quality loss were monitored throughout a 7-day storage at 4 °C. Statistically significant (p < 0.05) lower counts (log CFU g−1 muscle) were obtained for aerobe mesophiles, psychrotrophs, proteolytics, lipolytics, and Enterobacteriaceae in refrigerated fish muscle as a result of the microalga PC presence in the packaging medium when compared with fish corresponding to the control batch. With respect to the lipid fraction, an inhibitory effect on lipid hydrolysis development (free fatty acids formation) (p < 0.05) was concluded and, furthermore, a higher (p < 0.05) polyunsaturated fatty acid retention (polyene index value) was achieved in the PC-treated fish at the end of the storage time. Fish quality enhancement derived from the use of the spirulina PC in the packaging medium was concluded, this result being linked to the presence of preservative water-soluble molecules in the PC extract. Further research related to the optimisation of processing conditions ought to be addressed.