Yes, it is helpful to cover your soup pot whenmaking soup. The process of soup-making exposes food to increasedtemperatures over a relatively long period of time. In addition, foodsare usually chopped up or sliced before being added to a soup, and thischopping and slicing increases their exposed surface area. Finally,these chopped and sliced foods with more exposed surface areas getsubmerged into water. This particular combination of factors—large foodsurface areas exposed to water under increased temperature for anextended period of time—is a perfect combination for leachingwater-soluble nutrients from food.
This leaching doesn't happen all at once. But over the time ittakes to cook a soup, some water-soluble nutrients (includingB-vitamins and vitamin C) will be drawn out of the food and into thebroth. There will still be important amounts of water-soluble nutrientsleft in the food, but a varying percentage of these nutrients will havemigrated into the broth.
From among the water-soluble nutrients that have migrated intothe broth, some will become volatile and evaporate in the steam thatrises from the soup pot. These nutrients will be lost into the air. Bycovering your soup pot, you will create a mechanical barrier that willtrap some of these volatile nutrients and cause them to fall back downinto the broth. In this way, your soup broth will stay morenutrient-rich. In comparison to an opened soup pot without a lid,you'll need to turn down your stove burner to achieve a gentle simmerwhen you're making soup in a covered pot.
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发表于 2010-5-27 23:05:18