Quality and storage stability of fish tofu as affected by duck albumen hydrolysate-epigalocatechin gallate conjugate

The impacts of duck albumen hydrolysate-epigalocatechin gallate (DE)-conjugate at different levels (0.5-2.0 g/100g) on gel properties, sensory characteristics and storage stability of fish tofu during 21 days of refrigerated storage were evaluated. The incorporation of DE-conjugate increased breaking force, deformation, hardness, chewiness, cohesiveness, and springiness of fish tofu as the levels of DE-conjugate were augmented by enhancing protein cross-linking in fish tofu gel network (P < 0.05). However, fish tofu containing DE-conjugate showed lowered whiteness and L*, while Delta E*, a*, and b* values were augmented (P < 0.05). Fish tofu containing 1.5-2.0 g/100g DE-conjugate showed higher likeness scores than the control (P < 0.05). Additionally, DE-conjugate with antioxidant activity could effectively retard lipid oxidation (LO) of fish tofu during the storage ascertained by lowered increases in peroxide value (PV) and thiobarbituric acid reactive substances (TSARS). Fish tofu incorporated with 1.5-2.0 g/100g DE conjugate had lower psychrophilic bacterial count (PBC) and total viable count (TVC) throughout the storage than those containing 0.5-1.0 g/100g DE-conjugates and the control. Thus, DE-conjugate could be considered as a potential protein cross-linker, antimicrobial agent, and antioxidant to assure quality and extend shelf-life of fish emulsion gels.