Food

Out of interest, how?

Here's an article that explains some of it and gives some examples of methods:

http://www.thecitycook.com/cooking/advice/general/000058

There's an umami element in many things and it's easily destroyed by wrong method. I find the most important thing is to cook things well, though. I've often got the same recipe to be umami or not umami just by making or not making mistakes. Of course, we've all had the dishes that didn't work and added some soy sauce at the end to 'rescue' them. :) My first taste of umami was always about tomatoes (often puréed) and garlic, as these were just about the only ingredients with those properties that I knew. It was only much later that I discovered other things.

I cook Indian for a vegetarian audience quite frequently.

I wouldn't apply this to Indian cooking. Umami as such isn't a dominant element in most Indian dishes, and if you're putting any of the ingredients (except perhaps some of the mushrooms) listed in the article into your Indian dishes, you're doing something wrong.