Freezing-induced myofibrillar protein denaturation: Contributions of freeze-concentration and role of cellobiose

Herein, we investigated the potential relationship between freeze-concentration and myofibrillar protein (MFP) denaturation during freezing, and explored the inhibitory effect of cellobiose (CB) on the freeze-concentration. To observe the freeze-concentration of solutes in 2 L solutions, homogeneous sections of three frozen solutions (NaCl, NaCl + MFP and NaCl + MFP + CB) were performed sequentially and the solute concentrations of 45 representative samples for each frozen solution were analyzed. The results indicated that all solutes during freezing were concentrated toward the center and bottom of the solution. Nevertheless, the addition of cellobiose resulted in a more uniform solute distribution, which could be attributed to the lower specific heat of solution induced by cellobiose, accelerating the freezing rate. Additionally, the formation of protein aggregation caused by freeze-concentration was effectively inhibited by the addition of cellobiose. The cellobiose may be a beneficial additive to improve the quality of frozen aquatic products. • Freeze-concentration formation upon freezing of protein solution was studied. • Myofibrillar protein or cellobiose reduced the specific heat of NaCl solution. • The solutes concentrated in the center and bottom of the solution after freezing. • Cellobiose narrowed the degree of heterogeneity in frozen protein system. • Cellobiose inhibited protein aggregation formation caused by freeze-concentration.