Jambolan peels were thawed at room temperature and homogenised
in a high-speed hand blender (Braun, Spain). The pigments
were extracted with ethanol 98% (material to solvent ratio of 1:2,
w/v) under stirring for 1 h, followed by centrifugation at 3552g
for 10 min. Then, the supernatant was collected and the residue
was re-extracted (three times). The supernatants were vacuum-filtered
then concentrated in a rotavapor at 40 C under reduced
pressure to obtain aqueous extract by addition of distilled water.
The monomeric anthocyanin content of aqueous extract was
4.37 mg CyE/mL, determined by the pH-differential methods (Giusti
& Wrolstad, 2001). The total soluble solids and pH values were
11.00 (Brix%) and 3.74, respectively.