High school students invented trench oil identification method: 8 °C solidification is waste oil
â— High school students invented trench oil identification method online heat transfer
â—Expert: Method has loopholes
Who can borrow our eyes and see if there is any waste in the dish! “Disposal oil condenses at 8°C. Put the edible oil purchased at home into a refrigerator with a temperature of about 8°C. If it is condensed, it means waste oil.†Recently, a method of identifying the oil from the freezing point was widely used in Weibo. For circulation. When we all like to have such a practical and simple identification of waste oil, the rumor mill of the shell network has “poured cold waterâ€. It is possible to identify the oil product by the temperature condensation point alone. "Bad oil.
Heat Passing "Differential Trench Oil" Invention Award
The method of identifying the cooking oil was the entry of the senior student Lin Lizhen from Shanghai Xiangming Middle School in the Beijing Invention Innovation Competition and was awarded the Silver Award. According to the "Beijing Times" report, Lin Lizhen thought of using physical methods to identify waste oil. Most of the waste oil is used repeatedly, and the animal oil content is high. Compared with vegetable oil, the viscosity and freezing point are different. Lin Lizhen uses semiconductor refrigeration chips to design different combinations of structures to identify the composition of the oil through temperature.
"Olive oil is generally less than a dozen degrees Celsius (degrees Celsius) before the condensation, ordinary vegetable oil also has zero degrees, but animal oils, especially waste oil, 7-8 °C that is the condensation." Lin Lizhen said that the use of chemical reagents to test drainage oil is more accurate, but It is impossible to be popularized in the family. Physical authentication is simpler and easier to operate.
Since the cooking oil is more apt to condense than other oils, “put the edible oil purchased at home into a refrigerator with a temperature of about 8°C, such as condensation, that is, waste oil.†This simple and practical method is very fast. Bozhong spread.
Identification of "temperature identification method" is not a panacea
How can waste oil really be seen through so simple? "The truth of eating," author Yun unwittingly wrote in the shell network, pointed out that many of the cooking oil does contain animal oil, which can be solidified at 8 °C or even higher temperatures, "temperature identification method" can "judge" some of the waste oil. However, with the temperature method alone, it is very likely that other normal oils will “pick up†and “leak over†the problem oil.
Cloud unintentionally mentioned that the freezing point of edible oil is mainly determined by the ratio of saturated fat to unsaturated fat in the oil. Vegetable oils are dominated by unsaturated fats and have a low freezing point. Animal oils have a high saturated fat content and a high freezing point. They usually exist in the solid state at room temperature.
There are always exceptions to all things. Palm oil and coconut oil in vegetable oils have a freezing point above 25°C. In addition, there is a category of “harmonic oil†on the market whose solidification temperature is determined by the type and ratio of the oil being blended. It can be imagined that with the temperature method, vegetable oils such as palm oil and coconut oil are directly “killedâ€; if the oil “reconciles†the above two oils, it may also “dead and dieâ€.
In accordance with the principle of "will rather miss, not let go", do not eat high freezing point of vegetable oil, whether it will be able to eliminate the waste oil outside the kitchen? The cloud has no intention of reminding us that the so-called "drainage oil" is not a "standard" commodity, and its connotation varies according to each "district". In the waste oil, the increase in saturated fat content mainly depends on how much animal fat is mixed in. If only the fried dough sticks and fried potato chips are repeatedly fried, there will not be much animal oil “blastedâ€, and the animal oil content will only be high if the cooking oil produced by the hot pot waste or fat and meat waste soup is used.
The freezing point of waste oil is not always at 7-8°C, and the level is even controllable. If the temperature is used to identify, illegal traders can use dilution and other methods to manipulate the solidification point of waste oil away from the “judgment indicatorâ€.
Netizens have something to say
Since the domestic oil is not worried about the restaurant oil difficult to identify
The "temperature discrimination method" that has caused everyone to be excited has been "crushed," and the waste oil is still a big stone that is placed on food safety. A high school student who can pay attention to edible oils and use them to identify them in the school can be praised by netizens regardless of whether the methods are reliable or not.
In the eyes of netizens, the oil bought by oneself is not too worried, mainly because of what kind of oil is eaten under the pavilion. How can we see at a glance that the food served on the side is not waste oil? This is still a chronic problem. “You can't go to the kitchen of the restaurant to freeze the oil and order it again!†“Cup, ah, eat something, you have to experiment first!â€...
In addition to eating out of the restaurant, the netizen “Ginger is old and spicy†also proposed to go to large-scale supermarkets to buy decent oil, save shopping tickets and invoices, and eat out problems that can be traced.
The netizen “He Junqi†is more philosophical. In his view, “drainage oil†is not necessarily a bad thing, but it is misplaced. In fact, gasoline prices have risen again. Can waste oil develop into alternative energy sources? Everything is possible! (Hua Jingyan)
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