How to choose a nitrate-free watermelon at a retail outlet?
The property of melons and gourds with gratitude to accept nitrogen fertilizing and put aside nitrates in reserve is known. But for a person, such a berry can be dangerous. You need to know how to choose a nitrate-free watermelon. These harmful substances are present in any vegetables in small quantities. Watermelons hold the record for the accumulation of nitric acid salts.
Why are nitrates dangerous to humans?
Mild poisoning is expressed by depression, nausea, vomiting, diarrhea. The doctor diagnoses poisoning by an enlarged and dense liver. The danger is higher in children, since they are low in body weight, and there is no enzyme that can convert methemoglobin to hemoglobin. Therefore, a child cannot be given a watermelon to a baby.
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.
WHO has defined as the permissible daily intake of nitrates 3.7 mg, nitrites 0.2 mg per kilogram of human weight. In terms of a weight of 70 kg, this is 350 mg of sodium nitrate.
During heat treatment, in the presence of vitamin C, during storage, nitrates are destroyed. The danger of nitrates in watermelon is great precisely because it is eaten without preliminary processing and in large quantities.
How to determine nitrates in watermelon?
If before the advice was not buy watermelon out of season was the most correct, then modernity makes adjustments. New ultra-early ripening varieties and hybrids appear that ripen early, without accelerators. Such watermelons are small, only 1.5-2 kg, and we were taught not to choose small fruits. This means that if the variety is ultra early, then the watermelon cannot be large.
Therefore, the study of sweet berries must be carried out in aggregate according to a number of signs:
- appearance;
- the structure of the pulp when examined at home;
- use of control methods and devices.
Watermelon research begins at the counter. You cannot buy goods from the roadside collapses. For a day of standing in a gas-polluted environment, the product will gain a lot of exhaust gases, no less harmful than nitrates. On the ground, the crust will become dirty, the grains of sand will injure the shell, and it will not be possible to completely wash such a watermelon. Usually, roadside trade is illegal, there is no sanitary certificate for the product on the content of harmful substances.
It is safe to buy agricultural products, including watermelons and melons, in special places and with a quality certificate.
The watermelon should have a dry tail. It should be carefully examined, a sign that the watermelon was removed green will be a soaked tip or cut with a sharp knife. In addition, this will be a sign that the watermelon has been stale for a long time. And without a tail, you should not take the fruit. This means the seller has something to hide. The tail can naturally dry out in the garden bed of an unripe watermelon, which is specially turned over several times, twisting the tail.
Stripes of dark and light colors should be contrasting, not blurred, the pattern is clear.In a ripe watermelon, you can slightly scratch the skin, and then a white dense layer and a clearly audible watermelon smell will be found below. All this is a sign that the watermelon was recently sitting in the garden.
On examination, you need to check well if there is a puncture in the peel of the watermelon, through which they fed what the watermelon is pumped with for quick redness. And not only watermelon, other melons and tomatoes also get injections from unscrupulous sellers. An injection of nitrate accelerates redness.
You cannot buy a watermelon in black spots on the surface, a small spot of rot, with a crack or dent. You cannot ask to cut a triangle to inspect the middle. A cut fruit with an unwashed crust and a dirty knife can lead to bad consequences.
To find signs of nitrate watermelon at home, research needs to be continued. First omit watermelon in a bowl of water. If the fruit is ripe, it will float. A drowned watermelon can be left unchecked and returned to the owner. After that, wash the watermelon with soap and a brush, dry.
The cut fruit should have a grainy surface, not a smooth, glossy cut. The seeds should be developed and black. There should be no thick yellow strands or nitrogen supply overpasses on the cut. The veins are thin white, this is the normal structure of the fruit. The pulp should not be in the middle of an intense color, but gradually turn yellow towards the periphery. These are signs that there is a lot of nitrogen. Watermelon with nitrates, the photo of which is posted below, shows its inside view.
Finally, put a 20 gram piece of watermelon into a transparent glass and knead in water. If the water becomes cloudy, everything is fine. If colored, it indicates the presence of nitrates. Moreover, the more intense the color, the more impurities in the watermelon.
The instrumental research method is the most reliable. He suggests:
- laboratory analysis;
- examination using test strips;
- using a special device, nitrate meter, or ecotester.
Only a specialist will decide to keep a tripod for titration of a sample and potassium alum at home. But this is how the amount of nitrates in agricultural products is checked in laboratory conditions. There are indicator strips that are inexpensive, do not determine very accurately, approximately. And you can purchase an ecotester device that gives a result, and a warning about the dangerous content of nitrates.
If a dangerous dose is found, you should not eat a watermelon, it is better to part with it. In order for the risk to be minimal, you should wait until mid-August and only then feast on watermelon. But even at this time, vigilance should be observed. Producers are trying to get a large harvest and feeding is always carried out, only during a certain growing period.
How to choose a sweet watermelon?
When buying a watermelon, experts advise to choose "girls". From a scientific point of view, this does not apply to berries. There are no boys and girls among the fruits. However, folk signs show that a watermelon with a flat or slightly recessed top is sweeter and has fewer seeds. "Boys" are considered if there is a small tubercle at the top. Perhaps these are some peculiarities in pollination, but this selection rule is valid.
Another sign of a ripe berry may be a small orange spot where the fruit was lying on the ground. If the filling went quickly, the ground was warm, the spot was small, the berries were tasty. If the spot is large, white, then the taste of the 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 cutting a watermelon, you need to leave 3 cm of pulp near the crust, fertilizers accumulate there. And give the children a piece from the very middle. You don't have to eat a lot of treats in one sitting. Better to stretch the pleasure, eat the fruit in small portions, while listening to the state of the body.
Bon appetit and health!