The effectiveness of egg white protein and β-cyclodextrin during frozen storage: Functional, rheological and structural changes in the myofibrillar proteins of Culter alburnus

Abstract

This study focused on the effects of egg white protein (EWP) and β-cyclodextrin (βCD) mixture (3:1, EWP/βCD) at 0, 2, 4 and 6% concentrations on fish (Culter alburnus) myofibrillar proteins (MP) during 60 days of frozen storage (−18 °C) by analyzing functional, rheological and structural changes in MP and MP gels. After 60 days of storage, circular dichroism (CD) and Fourier transform infrared (FTIR) spectroscopy revealed a decrease in the MP α-helix content, and EWP/βCD addition improved the MP secondary structural properties by inhibiting protein aggregation induced by exposure of hydrophobic residues. Particularly, the 6% EWP/βCD treatment significantly decreased (P < 0.05) the pores and spaces of MP gels formed during frozen storage, resulting in a denser network. Moreover, compared with the control (0%), EWP/βCD addition significantly increased (P < 0.05) the gel hardness, springiness, gumminess and cohesiveness as well as whiteness and water holding properties. Dynamic rheological analysis showed that 6% EWP/βCD also increased the MP storage modulus (G’) and loss modulus (G”). This research provides useful information for increasing the commercial life of fish products by frozen storage and contributes to the potential application of EWP/βCD as a low-sweetness cryoprotectant for Culter alburnus fish.