Effect of various salts and pH condition on rheological properties of Salvia macrosiphon hydrocolloid solutions

The extraction of Salvia macrosiphon seed hydrocolloid was performed successfully and the optimum hydration time and temperature were found to be 30 min and 25 °C for 12% extraction yield. The effect of solution pH (3–9) and addition of NaCl (0.5–3%), CaCl2 (0.5–3%) and Na2HPO4 (0.2–0.6%) on rheological properties of the hydrocolloid solutions were investigated. Rheologcal data were fitted with the Power law model with regression coefficient of greater than 0.95. Strong shear thinning behavior with the n value of less than 0.53 was recorded. All variables had significant impacts on rheological parameters. The minimum and maximum consistencies were found at pH 3 and the 9, respectively. This was explained with the presence of carboxylic groups on the biopolymer backbone as indicated by FTIR. NaCl, CaCl2 and Na2HPO4 had significant effects on rheological properties. Moreover, at similar salt concentration of 0.5%, Na2HPO4 had the greatest and NaCl had the lowest effect.

► pH, NaCl, CaCl2 and Na2HPO4 had significant impacts on rheology of S. macrosiphon hydrocolloid.
► The minimum and maximum consistencies were found at pH 3 and the 9, respectively.
► Among all salts Na2HPO4 had the greatest effect on rheology of S. macrosiphon.
► Among all salts at similar concentration NaCl had the lowest effect on S. macrosiphon hydrocolloid.