ε-Polylysine-mediated enhancement of the structural stability and gelling properties of myofibrillar protein under oxidative stress

The effects of ε-polylysine (ε-PL) at different concentrations (0.005 %, 0.010 %, 0.020 %, and 0.030 %) on the structure and gelling behavior of pork myofibrillar protein (MP) under oxidative stress were explored. The incorporation of ε-PL significantly restrained oxidation-induced sulfhydryl and solubility losses (up to 9.72 % and 41.9 %, respectively) as well as protein crosslinking and aggregation. Compared with the oxidized control, ε-PL at low concentrations (0.005 % - 0.020 %) promoted further unfolding and destabilization of MP, while 0.030 % ε-PL led to refolding of MP and enhanced its thermal stability. The ε-PL-induced physicochemical changes favored the formation of a finer and more homogeneous three-dimensional network structure, therefore obviously enhancing the strength and water-holding capacity (WHC) of thermally induced oxidized MP gels, with the ε-PL at 0.020 % showed the greatest enhancement. This work revealed for the first time that ε-PL can significantly ameliorate the oxidation stability and gel-forming ability of meat proteins.