Vegetable
The vegetables are a group of plants generally grown in orchards or irrigated land, which are eaten as food, either raw or prepared in the kitchen, and which includes vegetables and legumes (broad beans, peas, etc.). Vegetables do not include fruits or cereals.
However, this distinction is arbitrary and not based on any botanical grounds. The Royal Spanish Academy does not recognize this taxonomy, and circumscribes this meaning to crops grown in an orchard.
Composition of the vegetable
- Water. The vegetables contain a lot of water, approximately 80% of its weight.
- Glucids. According to the type of vegetables, the proportion of glucids (or carbohydrates) is variable, being mostly slow absorption. According to the amount of glucids, the vegetables belong to different groups:
- Group A. They contain less than 5 % of carbohydrates (cell, celery, spinach, eggplant, cauliflower, lettuce and radish).
- Group B. They contain 5 to 10 % of carbohydrates (alcachofa, peas, onion, nabo, puerro, carrot and beetroot).
- Group C. They contain more than 10 % of carbohydrates (papapa and mandioca).
- Vitamins and minerals. Most vegetables contain a lot of vitamins and minerals, and belong to the group of regulatory food on the food wheel, like fruits. Vitamin A is present in most of the vegetables in the form of provitamin, especially in carrots, spinach and parsley. The vegetables are also rich in vitamin C, especially bell pepper, parsley, strawberry cabbage and broccoli. Vitamin E and vitamin K are found, although in small quantities, in peas and spinach. As a representative of group B vitamins is folic acid, which is found in the leaves of green vegetables. Potassium abounds in the beet and cauliflower. Magnesium is found in spinach and acelains. Calcium and iron are present in small quantities in the vegetables, and are absorbed with difficulty in the digestive tract. The celery contains sodium.
- Volatile substances. The onion contains dipropyl dysulfure, which is the substance that makes us cry.
- Lipids and proteins. The vegetables have a low content of these macronutrients.
- Dietary fiber. From 2 to 10 % of the weight of vegetables is food fiber (or dietary fiber). Food fiber is pectin and cellulose, which is usually less digestible than fruit, so it is necessary to cook the vegetables for consumption on most occasions. Most vegetables are rich in fiber (berenjena, cauliflower, green beans, broccoli, escarola, peas).
Calorie value. Most vegetables are hypocaloric. For example, 100g of Swiss chard only contains fifteen calories. Most do not exceed fifty calories per 100g, except for artichokes and potatoes. Due to this low caloric value, vegetables should be present in a large percentage in a diet against obesity.
All these properties make it advisable to consume them quite frequently and daily: a portion is recommended at each meal and in the most varied way possible. For this reason, vegetables occupy the second floor, together with fruits, in the pyramid of food. It is worth clarifying that this pyramid is only one of the existing theories in human nutrition: there are other nutritional pyramids, such as those proposed by vegetarianism, veganism or raw veganism.
Preservation and storage
Fresh vegetables must be properly preserved until the moment of consumption. The conditions and duration of storage greatly influence the appearance and nutritional value. Most vegetables must be kept at low temperatures with high environmental humidity, so the greengrocer in the refrigerator is the most recommended place. It is advisable to put them in bags with holes or aluminum foil, and avoid making the container airtight. They can be kept in the refrigerator for a few days, depending on the type of vegetable. For example, spinach, lettuce, etc. should not be kept for more than three days; however, carrots, turnips and beets are less sensitive and keep longer. Some vegetables, such as dried onions and garlic, do not need to be kept in the refrigerator, but rather a dry and ventilated place.
Nutritive value
Vegetables are parts of herbaceous plants that are suitable for human consumption. These edible components of the plant can be stems, leaves, roots, flowers and fruits. The nutritional value of vegetables defines the presence of those essential substances that are important to sustain life. Scientists categorize vegetables as nutraceuticals, because they are a mixture of nutrition and pharmaceuticals: certain chemicals present in vegetables have great medicinal value.
Cleaning
Vegetables must be carefully washed or brushed before being consumed, depending on whether they are leaves, roots or tubers. When they cannot be peeled, they must be cleaned a lot, especially if they have rough or hairy skin. Vegetables to be eaten raw should be soaked in water with a few drops of diluted bleach for about five minutes, and then cleaned under running water. This must be done because the vegetables are sometimes irrigated with non-potable water that can contain numerous bacteria, and the irrigation water comes into contact with the vegetable, which is usually at ground level.
Cooking
Vitamins in vegetables are destroyed by exposure to light, air, and heat. The mineral salts dissolve in the water when cooking the vegetables. In order to benefit from the vitamins, minerals and flavor, it is necessary to cook the vegetables with little water (or, better, with steam) and very quickly, immersing them directly in boiling water. The cooking container should be kept covered and avoid moving it (or moving it as little as possible). The cooking water should be used to make soups, consommés and other types of broths, because the cooking water is where the minerals are concentrated. Cooked vegetables that are not going to be consumed at the moment should be cooled and stored in the refrigerator. Afterwards they can be heated again, but for a short time.