Anthocyanins are a class of flavonoides
that are soluble in water. They exist in
epidermal and sub epidermal cells and
dissolved in vacuoles or accumulated in
vesicles called anthocyanoplasts therefore
they can leak into the osmotic medium
through the cuticle and skin ruptures of fruit.
Layers of epidermal and subepidermal might
be ruptured during osmosis due to the
osmotic pressure gradient. The anthocyanin
aren’t stable and are affected by pH, light,
heat, oxygen, metal ions like iron, copper
and tin, sugar, electromagnetic waves and
etc. The anthocyanin contents are
also influenced by the parameters of the
osmotic process (sucrose concentrations,
temperature), thus, the anthocyanin contents
might be changed as the result of osmosis
parameters changes.