Extracting Water-Soluble Dye from Vegetables & Fruits

RED CABBAGE contains a water-soluble pigment that is purple at neutral pH.  This colouring can be easily extracted from the vegetable by boiling it in water.

The resultant extracted colouring is decanted and/or filtered to remove the cabbage pieces. This purple pigment changes to red when in an acidic solution, and changes to green when in an alkaline (basic) solution.

 
BEET ROOT also contains water-soluble pigment, which can be obtained by removing the skin, cutting it into small pieces and boiling them in water.

Blue pigment can be extracted from the SKIN of BLUEBERRIES by boiling it in water.  If the whole fruit is boiled in water, you end up with jam!  As the fruit is boiled, it softens and sugar from the fresh of the fruit would also dissolve into water. This results in a sweet-smelling, thick mixture (see picture below) that is very difficult to filter.

Footnote:  

• If you feel that the colour is too diluted when you paint it on paper / cloth, you might want to boil off some water to make the colour darker.  However, the colour of the solution might change if it is heated for too long.
• Looking around you for more colourful vegetables, fruits or even flowers and other parts of a plant!
• Read more about the anthocyanins, which is the group of compounds that are responsible for the colourings.