Vegetable cooking tips

How do you keep vegetables in soup a nice bright colour?

Ive made tamarind soup using a knorr packet available at any old asian market. Its *mostly* ok except the colour. I have all these gorgeous vegetables: chinese long beans, japanese eggplant, okra, baby bok choy. I basically added the long beans and the eggplant after the meat is done but while the soup on the heat and cook it for a few minutes. I added the okra and the bokchoy at the very end and turn the heat off immediately since they cook awfully quickly.

When Ive had similiar dishes, not of my own cooking eh, the colours stay vibrant. In my soup pot; however, the eggplant and longbeans are bleh coloured. The veggies aren't overcooked as they are still crisp (except the eggplant) but just bleh looking.

So yeah its too late for this soup pot but any tips for future reference appreciated.

To set a vegetables colour, you blanche them. Basically get a pot of LOTS of water on the boil, and chuck the veg in, then after about 30 seconds, drain the veg and put them in very, very cold water (I just bung them in a colander under a running cold tap). Then cook the veg as normal. Your beans will stay a nice vibrant green, and won't go splurge colour.

Thanks chiefy, I knew TT would have some good answers.