Calcium-induced-gel properties for ι-carrageenan in the presence of different charged amino acids

iota-Carrageenan (IC) is a water-soluble polysaccharide containing high sulfate groups, whose gel properties are influenced by charged materials. The rheological and thermal properties, water mobility, morphology, and structure of the binary blends of calcium-iota-carrageenan (CCa) with different charged amino acids including arginine (Arg, positive), glutamine (Gln, neutrality), and glutamic acid (Glu, negative) were evaluated. Different charged amino acids affected the gel properties of CCa with different mechanisms. There were the highest elastic (G') and viscous (G '') moduli of CCa gels at 0.5 mg/mL Arg and 1 mg/mL Gln, while both G' and G '' were decreased by adding Glu. The water mobility of CCa gel was weakened by Arg and Glu, while no significant influence was observed for Gln. The thermal properties of CCa were improved by amino acids. Gln fills the gaps in the network structure through hydrogen bond and weak electrostatic interaction to stabilize the gel structure, while Arg and Glu affect the formation of gel through hydrogen bonds and strong electrostatic interaction. The information obtained from this research will provide insights into the further application of carrageenan and amino acid combinations in the food, biomedical, and cosmetic fields.

Automated summary

Different charged amino acids, such as arginine and glutamic acid, have varying effects on the gel properties of calcium-iota-carrageenan, with arginine and glutamic acid weakening the water mobility of the gel, while glutamine has no significant influence. Additionally, glutamine stabilizes the gel structure through hydrogen bonding and weak electrostatic interaction, while arginine and glutamic acid affect gel formation through hydrogen bonding and strong electrostatic interaction.