Content of the article:
The property of melon crops to gratefully take nitrogen supplements and reserve nitrates, it is known. But for a man such a berry can be dangerous. Need to know how to choose a watermelon without nitrates. These harmful substances are present in small quantities in any vegetables. Watermelons are champions in the accumulation of nitric acid salts.
How are nitrates dangerous for humans?
In the human body in the large intestine, nitrates are converted into nitrites and absorbed into the blood. In this case, nitrites form the compound methemoglobin. Hemoglobin in the blood is needed to deliver oxygen to the cells. Methemoglobin does not fulfill this function and oxygen starvation begins in the body. At 30% replacement, nitrate poisoning occurs, at 50%, death can occur.
Mild poisoning is expressed by depression, nausea, vomiting, diarrhea. The doctor diagnoses poisoning due to an enlarged and dense liver. The danger is higher in children, because they have a low body weight, and there is no enzyme capable of converting methemoglobin to hemoglobin. Therefore, a baby cannot be given a baby watermelon.
In the human gastrointestinal tract, protein products are broken down, amines and other nitrogenous compounds are present. Combining with salts of nitric acid, carcinogens, nitrosamines are obtained. The
WHO defined as the permissible daily dose of nitrate use of 3.7 mg, nitrite 0.2 mg per kilogram of human weight. In terms of weight in 70 kg, it will be 350 mg of sodium nitrate.
During heat treatment, in the presence of vitamin C, nitrates are destroyed during storage. The danger of nitrates in watermelon is great precisely because it is eaten without pre-treatment and in large quantities.
How to identify nitrates in watermelon?
If before the advice not to buy watermelon off-season was the most correct, then modernity makes adjustments. There are new ultra-fast-growing varieties and hybrids that ripen early, without accelerators. Such watermelons are small, only 1.5-2 kg, and we were taught not to choose small fruitlets. So, if the variety is ultra early, the watermelon can not be large.
Therefore, the study of the sweet berries should be conducted in the aggregate on a number of grounds:
- appearance;
- structure of the pulp during home research;
- use of methods and control devices.
Watermelon research begins at the counter. You can not buy goods from the collapse of the curb. During the day of standing in a gas medium, the product will pick up a lot of exhaust gases that are no less harmful than nitrates. On the ground, the crust becomes dirty, the grains of sand will injure the shell, and it will not be possible to completely wash off such a watermelon. Usually, the roadside trade is illegal, there is no sanitary certificate on the content of harmful substances for the goods.
Buy agricultural products, including watermelons and melons, safely in special places and with a certificate of quality.
Watermelon should have a dry tail. It should be carefully examined, a sign that the watermelon was removed in green will be a crushed tip or cut with a sharp knife. In addition, it will be a sign that the watermelon stale for a long time. And without a tail, the fetus should not be taken. This means the seller has something to hide. Dry tail can naturally on the bed in the immature watermelon, which is specifically turned several times, twisting the tail.
Dark and light stripes should be contrasted, not blurred, pattern is clear. In a ripe watermelon, you can slightly scratch the skin, and then you will find a dense white layer and a clearly audible watermelon smell below. All this is a sign that the watermelon was recently sitting in the garden.
During the inspection, it is necessary to check well whether there is a puncture in the peel of the watermelon, through which watermelon is pumped for quick redness. And not only watermelon, other melons and tomatoes also receive injections from unscrupulous sellers. Accelerates redness injection of nitre.
You can not buy watermelon in black spots on the surface, a small spot of rot, with a crack or dent. You can not ask to cut a triangle to inspect the middle. A cut fruit with an unwashed crust, a dirty knife can lead to bad consequences.
To find signs of nitrate watermelon at home, the study should be continued. First, put the watermelon in a bowl of water. If the fruit is ripe, it will swim. A sunken watermelon can not be checked, returned to the owner. After that, wash the watermelon with soap and a brush, drain it.
The cut fruit should have a grainy surface, not a smooth shiny shine. Seeds must be developed and black. On the cut, there should be no thick yellow bundles, overpasses for nitrogen supply. Veins thin white, this is the normal structure of the fetus. The flesh should not be in the middle of intense color, but gradually turn yellow towards the periphery. These are signs of a large amount of nitrogen. Watermelon with nitrates whose photo is located below shows its inside view. 
Finally, put a piece of watermelon grams for 20 put in a transparent glass and knead in water. If the water becomes cloudy, everything is fine. If stained, it indicates the presence of nitrates. Moreover, the more intense the color, the more impurities in the watermelon.
Instrumental research method is the most reliable. He suggests:
- laboratory analysis;
- study using indicator strips;
- using a special device, nitratomer, or ecotester.
Only a specialist will decide to hold a tripod at home for the titration of the sample and potassium alum. But this is exactly how the amount of nitrates in agricultural products is checked in the laboratory. There are test strips that are inexpensive, not very accurate, approximately. And you can buy the device ecotester, which gives the result, and a warning about the dangerous content of nitrates.
If you find a dangerous dose, you should not eat watermelon, it is better to part with it. In order to minimize the risk, you should wait until mid-August and only then enjoy the watermelon. But at this time, vigilance should be observed. Producers are trying to get a big harvest and feeding always, only in a certain period of cultivation.
How to choose a sweet watermelon?
When buying watermelon, experts advise choosing "girls".Scientifically, this does not apply to berries. It does not happen among the fruits of boys and girls. However, folk signs show that a watermelon with a flat or slightly indented top is sweeter and has less seeds."Boys" believe, if at the top there is a small bump. Perhaps these are some features in pollination, but this rule of choice is valid.
Another sign of a ripe berry may be a small orange spot, this place the fruit was lying on the ground. If the filling went quickly, the ground was warm, the spot was small, the berry was tasty. If the spot is large, white, then the taste of watermelon will be different. This means that the berry lay on the ground for a long time, the ground was cold, so you should not expect sweets from such a berry.
When slicing watermelon, 3 cm of pulp should be left around the crust, and fertilizer will accumulate there. And children give a piece of the middle. No need to eat a lot of treats in one sitting. It is better to stretch the pleasure, eat the fruit in small portions, while listening to the state of the body.
Enjoy your meal and health!
