Enhancement of myofibrillar protein gelation by plant proteins for improved surimi gel characteristics: Mechanisms and performance

Three commonly used plant proteins, soy isolate protein (SPI), wheat gluten (WG) and pea protein (PP), were incorporated into surimi gels, and their effects on myofibrillar protein gelation and resultant surimi gel properties have been investigated. Results reveal that addition of any of these plant proteins at 5 g/100 g surimi enhanced the surimi gelation, among which SPI addition resulted in smoother, denser and whiter surimi gels (whiteness of 61.49) with superior textural attributes (hardness of 1994 g), water-holding capacity (85.67%) and structural integrity. Such improvements are attributed to the uniform distribution of SPI solution between adjacent surimi protein molecules, not only aiding in maintaining the matrix's continuity but bridging the interaction between the proteins. SPI with a higher content of charged amino acids (47.17%) exhibits a better ability to interact with the charged N- and C- terminals of surimi proteins. This interaction promoted the complete unfolding of surimi proteins, facilitated the conversion of α-helix to β structures, exposing hydrophobic ends and sulfhydryl groups, and consequently enhanced the formation of hydrophobic interactions and disulfide bonds during gelation. This study demonstrates that plant proteins, especially SPI, are effective gel-reinforcing additives in surimi gels, offering insights for developing plant protein-rich surimi products.