Rheological behaviour of polysaccharide based mixtures

Polymer gels are cross-linked polymer networks that act as viscoelastic solids. Interactions between polymer gel cross-link density and cross-linking points affect the mechanical properties. For this reason, it is important to known about the rheological properties; to determine the gelation period and provide desired properties in the gel structure. Gels which can hold water at high level in three dimensional network structures; has many applications such as hydrogels, food, agriculture, electronics, drug release systems, coatings, cosmetics, etc.. Natural polysaccharides such as alginate and carrageenan are the most preferred hydrogels due to their high biocompatibility and easy gel forming properties. In this study; the effects of calcium-containing additives on viscoelastic behavior of alginate\κ-carrageenan mixtures have been investigated. Hydroxyapatite (HAp) and calcium carbonate (CaCO3) were used as additives. The presence of κ-carrageenan in the mixture and the additives added were found to be effective on the viscoelastic behavior of the sample. Swelling tests of hydrogel spheres prepared physically cross-linked from these mixtures were carried out. It has been found that alginate with κ-carrageenan containing 1% HA has the highest swelling percentage of HAp hydrogel spheres. In studies examining viscoelastic behavior of hydrocolloid seeds, it was observed that quince seeds showed higher elasticity than flaxseed and chia seed.