Stock?

It gives better flavour and better colour.

Iv'e never seen done before, is there any thing to do with their restriced time they have to add flavour?

No. It's for the same flavors that come from browning in any cooking process.

Maybe some cultures brown vegetables before making a broth or stock, but when I think back to my grandmother's chicken soup, the process was to clean and chop some carrots and celery, put them in a big pot with a halved onion, place a whole chicken in the pot, add water and boil. That stock was pretty tasty.

I wouldn't say browning gives better flavors. It gives different flavors, which many people prefer.

Irish stew is traditionally made with lamb that isn't browned. I should say "was traditionally made". I don't know if anyone makes it that way any more.

I agree with Vinny. There two kinds of chicken stock, for instance--white stock and brown stock. I make both. For white stock, nothing is browned. It's pale and has a milder, more delicate flavor and it's also, well, white. I use it where I want a more subtle flavor, or if the finished dish needs to be pale, such as some white sauces.

I use brown chicken sauce more often because it has a richer flavor. I brown the meat and onions for sure. If I am adding that bag of veggie trimmings from the freezer, I don't brown them, but if I'm adding fresh, raw veggies, I usually do. Except garlic--it can become bitter when browned--and herbs which don't brown well.

For beef stock, I always brown the meat. I want this as rich as possible.

I'd never brown ingredients for fish stock, which I rarely make.

Just for the record, the final was on last night, and the sisters Sammi & Balla did win, jeez these girls can indeed cook!

That process is called the Maillard reaction
http://en.wikipedia.org/wiki/Maillard_reaction
The heat causes a chemical reaction to occur which changes both taste and color.

There are other things that can be going on in browning, castaway_girl, notably caramelization of the sugars e.g. in the onions, carrots, and parsnips. (Or leek, carrot, and parsnip trimmings if you make stock the way I do.)