Causes of food desiccants to explode in water
One of the most frequently repeated messages in the WeChat circle of friends in recent days is related to food desiccants. It is the phenomenon that food desiccants will explode when they encounter water and cause great harm.
According to media reports, a 5-year-old boy broke open a small bag of desiccant in the seaweed snack, poured into the bottle and joined the water to play, and exploded. One eye was eroded by alkaline fluid and caused blindness. Is the desiccant so powerful? The visitors verified through experiments.
Speaking of desiccants, everyone is no stranger to life, many food, medicine and other packaging bags, boxes have its presence. In many large supermarkets in the city, many food packaging bags are marked with "containing desiccant."
The visitors went to the supermarket to purchase two kinds of different brands of snacks. They discovered that there was a small bag of food desiccant inside and it was in children's food. The children of several years old still could not discern whether it was a food or a desiccant. This brings great health risks to children.
The package of desiccant was marked with the words “inedible, non-playable, non-dampable, non-openable, unapproachable by young children, and if swallowed by mistake, please rinse quickly with plenty of waterâ€.
Desiccant put into bottle of mineral water
In order to verify whether the desiccant will explode when it meets water, the visitors deliberately did an experiment: remove the different desiccant packets in the food bag, pour the desiccant into the water bottle, tighten the cap and shake gently.
After observation, one bottle of desiccant quickly sinks to the bottom of the bottle after entering the water, and there is no temperature change in the bottle. When the other bag of desiccant meets water, the liquid in the bottle turns to milky white, and the bottle body starts to be slightly warm for a while. The desiccant settled to the bottom of the bottle and the bottom of the bottle became hot but did not explode. After a period of time, the water temperature began to cool.
Experts Analyze Lime Desiccant to Release Heat with Water
In fact, the desiccant that explodes in the news report should be a desiccant containing lime, because in general, when lime encounters water, a series of chemical reactions will occur. This reaction will emit a huge amount of heat. When it is dry, explosions are very likely.
Satisfy the conditions of the explosion
One is the sealed space; the second is the generation of a large amount of gas generated by heat.
Li Zongxiao, dean of the School of Chemistry and Chemical Engineering of Baoji University of Arts and Sciences, said that lime is mainly used in the industrial field. Because it is inexpensive and absorbent, it is used as a food desiccant. However, lime desiccant is prone to accidents after reacting with water. In addition to lime desiccants, there is also a silica gel desiccant on the market.
Silica gel desiccant has many advantages such as its non-toxic, odorless, non-corrosive, stable shape, and good moisture absorption capacity. It has been widely used in recent years. Therefore, silica gel desiccant may not be added to the test.
Li Zongxiao said: "In general, the combination of desiccant and water will immediately appear chemical reaction. It will only heat for a while before the experiment. It is due to the addition of curing agent to the lime desiccant. This is a protective measure.
However, this chemical reaction is also related to the amount of desiccant. In the experiment, the water in the bottle was only hot, indicating that the amount of the calcined in the desiccant was not enough. If there is enough lime, the amount of water is slightly less, and an explosion may occur. â€
However, whether it is lime desiccant or silica gel desiccant, as long as it is not damaged, do not touch the water, are relatively safe. In order to prevent it, after purchasing foods with desiccants, citizens should desperately discard the desiccants and avoid contact with children.
How great is the damage of food desiccant?
Puffed food, seaweed, dried fruit, chewing gum ... In a variety of packaged foods that people are familiar with, many desiccants are added to the package to prevent food from getting damp. Although the vast majority of consumers are aware that desiccants in packaged foods are "not edible," they all clearly indicate that the cause is unknown.
In this regard, the Food Safety/Food Engineering Master of the Wageningen University in the Netherlands and the health management teacher Lin Lin introduced that the current food desiccants based on quicklime and silica gel are the most common.
Quicklime, in particular, has been widely used in food desiccants because of its high water absorption, convenient source, and low price and "popularity."
However, quicklime, that is, calcium oxide, is an alkaline substance. When water becomes mature lime, this neutralization reaction process will generate heat or even an explosion. Lime is accidentally eaten or inadvertently enters the eye, and it will damage the digestive tract or the eye conjunctiva. The latter can even cause blindness.
As an alternative to lime desiccant, silica gel desiccant has gradually been favored in recent years. Its main component is silicon dioxide, non-toxic, non-corrosive, stable in character and good in moisture absorption capacity.
Silica gel desiccant is also the only type of desiccant approved in the European Union. Only for food production companies, silica gel desiccants cost more than lime desiccants.
Insiders pointed out that under normal circumstances, food companies will first consider the desiccant from the perspective of safety, followed by cost issues. In particular, the use of lime desiccant is irreversible. Once water absorption becomes hard, it cannot absorb more water. This is one of the reasons that it will gradually be eliminated.
Although it is a small package of desiccant, there is also a great security risk. The occurrence of such incidents also warns the desiccant processing and packaging equipment. The amount of processing must be strictly controlled, and the packaging must be tight. The equipment handling must be more rigorous to ensure the safe and safe use of the desiccant. At the same time, for children's snacks, guardians and processing companies should jointly enhance safety awareness.
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