Phase behaviour, rheology and microstructure of mixture of meat proteins and kappa and iota carrageenans

The phase behaviour of mixtures of salt soluble meat proteins, kappa (κ) and iota (ι) carrageenan in non-gelling conditions (45 °C) were determined at pH 5.6, 6.2 and 7.1. The concentration of meat proteins ranged from 0.1 to 1.0 percent and that of κ-carrageenan and ι-carrageenan from 0.02 to 0.3 percent in the mixtures. Mixtures separated under gravity to form soluble/liquid and gelled/complex phases. For meat proteins- κ-carrageenan mixtures, phase separations at all meat protein/carrageenan ratios were observed. For meat protein-ι-carrageenan mixtures, soluble complexes were formed at low meat protein to ι-carrageenan ratios and gels at higher ratios. The yield of the complex/gels increased with the increase in the concentration of the meat proteins and carrageenans and decreased with increase in the pH of the initial mix. The complex/gels formed became stronger with the increase in carrageenan in the mix and with κ-carrageenan compared to ι-carrageenan. Chemical analyses and scanning electron and phase contrast microscopy indicated that in phase separated mixtures, the bulk of the meat proteins and carrageenan were found in the gel compared to the liquid phase; and that meat protein interacted with carrageenan in the gel and formed soluble complexes with carrageenan in the liquid phase. SDS-PAGE showed that the meat proteins that interacted to form the complex/gels with carrageenan included myosin heavy chain, α-actinin, actin, myosin light chains and proteins with molecular weights around 150 and 50 kD. The outcomes of the present study could be used in the formulation of multi-component foods with a range of consistencies containing meat proteins.

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