Comparative Effect of Cricket Protein Powder and Soy Protein Isolate on Gel Properties of Indian Mackerel Surimi

This work comparatively investigated the effects of different levels (0, 1, 3, and 5%, w/w) of cricket protein powder (CP) and soy protein isolate (SPI) on the gel properties of mackerel surimi. Both SPI and CP enhanced the rheological properties of surimi pastes during heating, as indicated by the increase in G′ and G″ and the decrease in tan δ. With increasing SPI content, the proteolytic inhibition, gel properties, water-holding capacity, and textural profiles of surimi gel were markedly enhanced. Molecular driving-force results showed that SPI markedly promoted the hydrophobic interaction, while disulfide bonds were dominant in CP-added gel. However, the whiteness of surimi gels tended to decrease with the increased levels of both additives, in particular CP. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that SPI hindered the polymerization of myosin heavy chain while CP participated in the formation of non-disulfide covalent bonds with actin. Fourier transform infrared (FTIR) spectra indicated that CP and SPI did not influence the secondary structure of proteins in surimi. Scanning electron microscopy (SEM) demonstrated that CP or SPI induced the myofibrillar protein to form smoother and compact gel network structures. Overall acceptability of the mackerel surimi gel can be improved by the incorporation of 5% SPI while CP had a negative impact on several parameters. However, CP showed the remarkable ability to prevent the lipid oxidation of the gel after storage at 4 °C for 7 days. Overall, both SPI and CP demonstrated positive impacts on the gelling characteristics of mackerel surimi; however, SPI was more advantageous than CP in terms of the gel-strengthening effect and sensory qualities. This study offered a potential use for plant and insect proteins as functional and nutritional ingredients for the production of dark-fleshed fish surimi.