How do products change, and what kind of changes with them occur during heat treatment?
Proteins.
Proteins are rich in food such as meat, fish, milk, eggs, legumes. Such proteins are proteins of animal origin. Some of them dissolve in water, others in saline solution, others do not dissolve in either one or the other. When heat treatment should take into account the type of proteins. For example, you make soup. In what water do you put meat or fish to boil - hot or cold? If in a cold, the broth will turn out to be more saturated, stronger, since more protein will be released into the water. If you boil meat for the second dish, it is better to put it in boiling water, so it forms a protective crust, which will not allow juices to flow out of the piece during cooking, and consequently, the meat is cooked juicy, soft, tasty.
The same should be done when frying meat - meat placed on a hot pan loses less of its nutrients and juices.
The change in nutritional value depends on the time of heat treatment. For example, hard-boiled eggs take longer to digest and are difficult to digest in the stomach than soft-boiled eggs, like overcooked meat. Therefore, you need to know the timing
Heat treatment of different products.
Fats.
As is known, in the process of cooking meat loses 40% of the fats contained in it, which turn into broth. Therefore, the fatter the meat, the fatter and fatter will be the meat broth. When cooking fatty meat, it is better not to give a lot of boiling to the broth and, as far as the separation is concerned, remove excess fat from the surface of the broth.
Do not long heat vegetable oil, since the fatty acids contained in it, can oxidize and harm the body. Under the influence of high temperature, the nutritional value of butter is significantly reduced. Therefore, it is better not to use butter for frying, it is better to use it for making sauces or salads.
Carbohydrates.
When heat affects the products, carbohydrates change. This, in turn, affects the taste of the dishes.
Minerals.
Mineral substances practically do not change during heat treatment, but some of them pass into water during washing, cooking. To preserve minerals during cooking, one should know the following rules: vegetables are best cooked steamed or immersed in boiling water; It is necessary to pour vegetables with so much liquid that it floods the entire surface of the vegetables.
Vitamins.
In order to keep as many vitamins as possible during cooking, it should be cooked in aluminum, nickel, enameled vessels, stainless steel vessels. Iron and copper destroy vitamin C, which is in the products.
For cooking salads and cold dishes, vegetables should be cooked in a peel or cooked peeled.
The main reason for the evaporation of vitamins is their interaction with oxygen. Therefore, cook should be under the lid. If you cook vegetables, they should be completely covered with water. the boiling point should be added a new one. Stir the contents of the pan should be carefully, without taking the vegetables out of the water, the water should not boil too violently and continuously.
The knife for vegetables should be made of stainless steel. Before adding carrots, greens and onions to soup or broth, you must pass them in a small amount of vegetable oil, so they will retain more nutrients.
When cooking fish soups, you should follow the sequence of the laying of various products, so as not to disturb their nutritional properties. For example, first lay cabbage, when the broth will boil again - potatoes, and already 10 minutes before the end of cooking - passaged vegetables and spices. So the loss of vitamins will be relatively small.
You should not boil potatoes with sauerkraut, as potatoes in acidic water are boiled and become harsh.