For gel preparation at pH 3, dry pectin powder (0.106 g) was
dissolved in 12.2 mL of citrate buffer pH 3 (citric acid 0.45% and
sodium citrate 0.1%) and stirred for 120 min at 20 C. The mixtures
were then heated, saccharose was added in 3 portions to a final
concentration of 30% and the solution was heated once more
until boiling. Afterwards, 0.026 g of calcium chloride dihydrate
(CaCl22H2O), dissolved in 1 mL of water, was added with a final
concentration of 0.1% and mixed under intense stirring. The solution
was boiled again. The final pectin concentration was 0.7%.