Comparison of different combined processes of preservation on the nutritional and sensory changes of “ready to eat” mackerel fillets

The effects of three technological treatments of preservation, such as the thermal processes of conventional and microwave blanching (CB and MWB) and the nonthermal process of high pressure (HP), on the quality of "ready to eat" mackerel fillets (previously marinated and vacuum packaged) were investigsated. The protein and ash mass fractions after MWB were significantly (p < 0.05) higher than after the other treatments. Nevertheless, the samples treated by MWB showed the highest difference in lipid mass fraction (12.87% less than raw fillets) when compared to that obtained by CB (10.41%) and HP (11.18%). However, MWB had no significant (p > 0.05) effect on n - 3 fatty acid profile, nor did HP treatment. Considering the overall nutritional quality indices, as well as the chemometric assessment of the fatty acid content, microwave and hyperbaric treatments, combined with marinating, were able to preserve more monounsaturated fatty acids and polyunsaturated fatty acids in the mackerel fillets, reducing the atherogenic and thrombogenic indexes. Practical applications The combined effects of marinating, vacuum packaging, and nonconventional preservation treatments such as microwave or high-pressure processing could usefully be applied in fish processing to obtain the enhancement of some species considered economically poor, but with a high nutritional value such as oily fish. This work highlights significant results for both the food industry and consumers because it evaluates and compares the effects of conventional and nonconventional technologies on the proximate composition and fatty acid content of "ready to eat" mackerel fillets, analyzing the potential nutritional advantages resulting from their application. Considering the overall nutritional quality indices, MWB and HP treatments could represent a valid alternative to conventional heating in order to preserve and obtain healthy fish products, even if the high-pressure process should be thoroughly investigated due to the drawbacks related to fillet structure