Synergistic effects of mixed salt on the gelation of κ-carrageenan

• Published in: Carbohydrate polymers Vol. 112; pp. 10 - 15
• Main Authors: Nguyen, Bach T., Nicolai, Taco, Benyahia, Lazhar, Chassenieux, Christophe
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 04.11.2014; Elsevier
• Subjects: Applied sciences; Biological and medical sciences; Calcium - chemistry; Calcium Chloride - chemistry; Carrageenan; Carrageenan - chemistry; Exact sciences and technology; Gel; Gels - chemistry; General and cellular metabolism. Vitamins; Medical sciences; Natural polymers; Osmolar Concentration; Pharmacology. Drug treatments; Physicochemistry of polymers; Polysaccharide; Potassium - chemistry; Potassium Chloride - chemistry; Rheology; Sodium - chemistry; Sodium Chloride - chemistry; Starch and polysaccharides; Turbidity; Carrageenan; Rheology; Polysaccharide; Turbidity; Gel; Viscoelasticity; Potassium ion; Gelation; Experimental study; Property processing relationship; Synergism; Polyelectrolyte; Calcium ion; Ionic strength; Sodium ion; Oside polymer; Kinetics; Hydrogel; Aqueous solution
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2014.05.048

•In pure CaCl2, κ-carrageenan gels are less stiff at higher CaCl2 concentration.•In the presence of KCl, κ-car gels are stiffer at higher CaCl2 concentration.•Addition of CaCl2 accelerates K+-induced gelation of κ-car.•Heterogeneous gels in pure CaCl2 become more homogeneous by addition of KCl.•The effect of Ca2+ on K+-induced gels is much stronger than Na+. The effect of the addition of calcium or sodium ions on the potassium induced gelation of κ-carrageenan (κ-car) is investigated using oscillatory shear rheology and turbidimetry. Both the gelation kinetics and the steady state shear moduli are investigated. Gelation in mixed salt solutions is compared with that in pure potassium and calcium solutions. It is shown that the elastic shear modulus increases with increasing pure KCl concentration, but decreases with increasing pure CaCl2 concentration. In mixed salts, gelation of κ-car is induced by potassium and addition of CaCl2 leads to an increase of the elastic modulus with increasing CaCl2 concentration. κ-Car gelled at low mixed salt concentrations for which it remained liquid in pure salt. At equivalent ionic strengths, the effect of adding NaCl on potassium induced gelation is much weaker. In pure KCl solutions, κ-car gels are transparent, but in pure CaCl2 they become increasingly turbid with increasing CaCl2 concentration. The turbidity of gels formed in mixed salts is intermediate.