Vitamins in foods and how to preserve them
The content of vitamins in the diet can vary and depends on various reasons: the type and type of food, methods and periods of storage, the nature of technological processing of food, food choices and dietary habits. An important role is played by the composition of the food.
Sources of vitamins of plant and animal originVitaminPlant ProductsAnimal productsA
With the prevalence of carbohydrates in the diet, the body needs more vitamins B1, B2 and C. With a lack of protein, the absorption of vitamin B2, nicotinic acid, vitamin C is reduced, and the conversion of carotene to vitamin A is impaired. has usehighly refined products(sifted white flour, white rice, sugar, etc.), from which all the vitamins are removed during processing. Another problem of human nutrition, especially in cities, is the consumption of canned foods.
The methods of fruit and vegetable cultivation currently used in commercial agriculture have led tothe amount of vitamins A, B1, B2 and C was reduced in many vegetable crops by 30%.For example, vitamin E almost completely disappeared from lettuce, peas, apples, parsley. The amount of vitamins in spinach of one crop can be 30 times less than in the greens of another crop. In other words, even a strictly balanced diet can not always meet the body's need for vitamins.
The content of vitamins in foods can vary significantly:
- When boiling milk, the amount of vitamins contained in it is significantly reduced.
- On average, 9 months a year, Europeans eat vegetables grown in greenhouses or after prolonged storage. Such products have lower levels of vitamins compared to vegetables from open ground.
- After three days of food storage in the refrigerator, 30% of vitamin C is lost (at room temperature, this figure is 50%).
- During heat treatment of food, from 25% to 90-100% of vitamins are lost.
- In the light, vitamins are destroyed (vitamin B2 is very active), vitamin A is exposed to ultraviolet rays.
- Peeled vegetables contain significantly less vitamins.
- Drying, freezing, mechanical processing, storage in metal dishes, pasteurization reduce the content of vitamins in the original products.
- The content of vitamins in fruits and vegetables varies greatly in different seasons.
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