Red cabbage and green cooking water
If you steam red cabbage, the leaves remain red (actually a bluish-red) but the water turns an amazing emerald green - which quickly fades to a rather muddy green-brown. Here are the transmission spectra of the leaf and the water. The absorption band at around 970nm is from the water itself: see www.flickr.com/photos/35652793@N04/5817855446/
The colours are due to an anthocyanin pigment whose colour depends on the pH.
Red cabbage and green cooking water
If you steam red cabbage, the leaves remain red (actually a bluish-red) but the water turns an amazing emerald green - which quickly fades to a rather muddy green-brown. Here are the transmission spectra of the leaf and the water. The absorption band at around 970nm is from the water itself: see www.flickr.com/photos/35652793@N04/5817855446/
The colours are due to an anthocyanin pigment whose colour depends on the pH.