For gel preparation at pH 7, 0.116 g of pectin powders were
dispersed into 15.21 mL of distilled water and mixed for 120 min
at 20 C, in order to get a complete hydration. The pH was adjusted
to 7.1–7.2 with sodium citrate solution. The pectin solutions were
heated to 85 C, upon which 0.0087 g of calcium chloride dihydrate
(CaCl22H2O), dissolved in 1 mL of water, was added under magnetic
stirring for 5 min. The final pectin concentration was 0.7%
(w/v), while the final calcium concentration was 0.04%.