The effects of calcium chloride on the gel properties of porcine myosin–κ-carrageenan mixtures

Calcium chloride (CaCl2) is used in low-fat meat products containing κ-carrageenan to improve their functional properties. However, the mechanism of how CaCl2 affects these meat systems has not been clearly elucidated. The aim of this study was to investigate the effects of adding CaCl2 with different concentrations (0.02 M, 0.04 M, 0.06 M, 0.08 M, 0.10 M and 0.12 M) on the gel properties of porcine myosin–κ-carrageenan mixtures. The usage of CaCl2 improved the water-holding capacity (WHC) and gel strength, but higher concentrations (0.10 M and 0.12 M) of CaCl2 led to decreased WHC. The low-field nuclear magnetic resonance results demonstrated that the addition of CaCl2 decreased the position of T22 and increased the proportion of T22, which indicated that the percentage of the water trapped within the gel matrix increased. Scanning electron microscopy was used to explain the above results. The addition of CaCl2 caused the formation of a compact gel phase. However, higher concentrations of CaCl2 induced the formation of large aggregates and cavities, which could cause the decrease in WHC. Furthermore, Raman analysis revealed that the addition of CaCl2 induced more hydrophobic residues to be exposed and an increased percentage of the β-sheet structure. However, higher concentrations of CaCl2 induced fewer hydrophobic residues to be exposed, indicating an excessive aggregation of myosin. In conclusion, a suitable concentration of CaCl2 could improve gel properties by inducing stronger hydrophobic interactions and forming more β-sheet structures, while excessive additions of CaCl2 induced extensive myosin aggregation, leading to a reduction in gel properties.