Gelation Properties of κ-carrageenan Influenced by Resistant Dextrin

With the addition of different amounts of resistant dextrin, the freeze-thaw stability, thermal stability, compressive modulus and microstructure of κ-carrageenan gel were evaluated. The results suggested that the syneresis of κ-carrageenan gel was reduced when in presence of resistant dextrin, and had a positive correlation with the resistant dextrin concentration. According to the thermal stability analysis, the κ-carrageenan gel has the maximum thermal stability and activation energy when the concentration of resistant dextrin was 4% (257.86 ℃, 106.20 kJ/mol, respectively). In addition, the compressive modulus of κ-carrageenan gel reached the maximum value (43.83 kPa) when the concentration of resistant dextrin was 4%. Fourier transforms infrared spectroscopy results indicated that the more hydrogen-bonding was formed in the gel system when resistant dextrin existed. Scanning electron microscopy images revealed that the cellular structure of the κ-carrageenan gel became more compact and smooth with the addition of dextrin. However, excessive dextrin (5%) molecular would destroy the gel network. In general, the gel properties of κ-carrageenan were improved by adding resistant dextrin into the gel system, and the optimum concentration of resistant dextrin was 4%.