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The Waters in Foods
Lamb nuggets have to be stewed for almost 2 hours to become eatable, but if it’s done to lamb slices, those meat will get uneatable. Why the size difference makes the same meat from lambs have to be cooked in different ways? The answer lies in the waters inside foods.
As we know, every kind of food contains certain percentage of water. However, most may not know that those water exists in one of the two forms of free water and bound water.
Free water refers to the water between the cells with all features of normal water. For example, it boils at 100 Centigrade degree, freezes at 0 centigrade degree and vaporizes easily. Especially important here, it can be removed from foods just by simply heating.
Bound water is the water that is within cells. It binds with other molecules via the attractive force between molecules or via Chemical force between element H (Hydrogen). Bound water is closely bound with food protein molecules. Therefore, it needs more energy to break up the binding. Usually, bound molecules won’t separate until 120 centigrade degree.
What ‘s the relationship between the waters and the methods of cooking? An appropriate method of cooking is the way to make food have good taste and texture.. The taste brings out by the food juice, which is composed largely by free water, while the texture depends on the length of molecule chains. The shorter the chain is, the tender the food tastes. Thus to select a cooking method is to find a good way to let the free water just out easily and molecule chains break up into smaller. Let’s go back to the lamb meat. Compared to the lamb slices, lamb nuggets are much bigger in size, which implicitly tells that protein molecule chains in lamb nuggets are longer than those in lamb slices. It takes more energy to break up the longer protein chains of lamb nuggets into smaller to make the meat taste tender. That’s why we have to stew the lamb nuggets for almost 2 hours. But keep it in mind that overheating will remove too much of free water in foods, which may result in dry foods. Although it breaks up more protein chains, it won’t taste good without juice.
There’s another way to save time when cooking nuggets. Meat tenderizer. There are 2 forms of meat tenderizer. The one is an enzyme in powder. The other is like a kind of small hammer with toothed blade. Before putting the meat into cooker, cover the meat with powder tenderizer or knocking the meat with hammer tenderizer, it can break up the chains chemically or physically.
The water in foods affects the taste and texture of foods, greatly but silently. A good cook should master the skills to balance between keeping free water and breaking up protein chains linked by bound water . |
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发表于 2005-12-21 11:58:19