Some fruits and vegetables contain natural indicators. Indicators are substances that can detect changes in properties such as pH. Examples of natural edible pH indicators include blueberries, beets, onions, curry and cherries. These indicators change colour depending on the pH of the solution.
My favourite pH indicator is red cabbage. It is easily found in any grocery store and is easy to make. Take a head of red cabbage. The brighter and deeper the colour, the more anthocyanin it contains. Anthocyanin is the pigment that changes colour. In an acidic environment, anthocyanin changes a deep pink. In a basic environment, it changes a bluish green. Its fun to see how variable you can make the indicator.
To make red cabbage indicator, chop up the cabbage and place it in a pitcher. Add some hot water and let it sit. The longer it sits the more anthocyanin gets into the water. WARNING!! Red cabbage indicator has a pungent smell. Some people don’t mind it but some people think it smells like farts.
When the indicator is ready, try out different solutions in your kitchen. It starts as a purple solution but when mixed with other things it changes from pink to blue. Tip: things that are sour are acidic. These are things such as lemon juice and vinegar. Things that are slippery and bitter are basic. These are things like baking soda and soap.
Use the indicator you just made and test out a couple of things in the kitchen. I’ve added lemon juice to my indicator and yes it turns a pink!
Baking soda and indicator turn a blue.
But wait!! What happens when you add vinegar to the baking soda and cabbage juice??
As you notice when the vinegar and baking soda mix, the colour turns from a purple to a pink. When acids and bases mix, they neutralize each other and the indicator turns from a blue back to a purple. Then when the acid surpasses the concentration of base, it turns back to a pink. Neat huh???
Try different solutions like milk, juice and even ammonia! You can get a range of different colours.
When eggs cook, they become basic. I decided to cook my egg in red cabbage to see what it does. I first added the egg to the red cabbage.
The red cabbage should be a strong solution so that the eggs can pick up the colour. Add the eggs and the red cabbage to the frying pan and let it cook. You might notice the colour around the outside of the cooking egg is starting to turn from a purple to a blue.
As it continued to cook, the egg whites pick up the blue colour. I should have left it a lot longer in the red cabbage solution before cooking.
While making the eggs, I thought it looked strangely like green eggs. So why not make green eggs and ham!! I added a bit more green colour by using food colouring.
To make green ham, I mix green food colour with water and then poured it over the meat. (I actually used sliced chicken instead).
I let the meat sit to pick up as much colour as possible.
Check out other recipes on our blog https://eatitnoworeatitlater.com/recipes-list/