Effect of κ-carrageenan/milk protein interaction on rheology and microstructure in dairy emulsion systems with different milk protein types and κ-carrageenanconcentrations

摘要

We investigated the effect of κ-carrageenan (κ-CG) addition and supplementationwith Na-CN, WPI, and MPI on the rheological properties, microstructure, fat globulesize distribution, and stability of low-fat cream (LFC) emulsions containing 19% milkfat. Rheological parameter (ηa,10, K, and G′) values of LFCs increased with κ-CG addition.At 0.1% κ-CG concentration, MPI-stabilized LFC had higher G′ value (64.8 Pa)than those of WPI-stabilized LFC (51.3 Pa) and Na-CN-stabilized LFC (34.8 Pa), indicatingthe strong interaction between MPI and κ-CG. Cryo-SEM images showedthe protein layers on milk fat globule membrane in dairy emulsions and revealed thatκ-CG led to depletion-flocculation of milk fat globules and promoted clustering ofglobules. The creaming index values of LFCs with 0.10% κ-CG were lower than thoseof LFCs with 0.05% κ-CG. Thus, high κ-CG concentrations can contribute to the physicalstability in dairy emulsions stabilized by milk proteins.Practical applicationsMilk proteins are widely used as emulsifiers, and κ-carrageenan (κ-CG) is added todairy emulsion products to improve their physical properties and stability. Therefore,in this study, the effect of κ-CG addition on physical properties and stability of lowfatcreams (LFCs) supplemented with different milk protein types (Na-CN, WPI, andMPI) was investigated. The strong synergistic interaction between proteins and κ-CGwas observed in MPI-stabilized LFCs when compared to Na-CN- and WPI-stabilizedLFCs. We found that the presence of κ-CG in MPI-stabilized LFCs improved the stabilityof LFCs by inhibiting the phase separation due to the high viscosity of the continuousphase. These findings suggest that dairy cream-based food products withdesirable physical properties can be realized through κ-CG addition to LFC emulsionswith milk proteins such as ice cream mix, coffee creamer, and light cream.