Stainless steel vacuum flask is not suitable for making green tea with acidic beverages
Yesterday (February 23), the Provincial Quality Supervision Bureau announced a quality analysis report on the risk monitoring of vacuum flask products. Among the 145 batches of sampling samples, 53 batches of products have problems, mainly due to the easy migration of heavy metals from stainless steel vacuum flasks when they contain acidic beverages. Some products use high manganese steel with poor corrosion resistance as the inner material, which is also very easy to Cause heavy metals to exceed the standard.
In the experiment, the quality supervision engineer heated 4% acetic acid as an acid simulant to above 95°C, poured it into the thermos cup to be tested, covered the lid, and kept it at room temperature 20°C for 24 hours. Then pour the acid simulant into a beaker to test the heavy metal content. The experimental results showed that among the 145 batches of samples, 45 batches showed excessive migration of heavy metals such as chromium, nickel, and manganese.
“Juices, fruit teas, fruit powders, carbonated beverages, etc. are all acidic. Once these beverages are filled with stainless steel vacuum flasks, the migration of heavy metals will intensify, and long-term drinking will cause heavy metals to accumulate in the body.” The quality supervision engineer said chromium, chromium, heavy metals such as nickel and manganese are harmful to the human body.
In addition, 10 batches of products were tested and found that the inner container of the stainless steel vacuum flask was made of high manganese steel. “The corrosion resistance of high manganese steel is poor, it is more likely to cause heavy metal migration in acidic media, and the sanitary safety is very poor.” The quality supervision engineer especially reminded that there are 8 batches of product prices in 10 batches of high manganese steel stainless steel vacuum flask products. Below 50 yuan, consumers need to be cautious when buying low-end vacuum flask products.
The quality supervision engineer also took a thermos cup and a glass cup with roughly the same capacity, put the same quality tea into the two cups, and added the same quality of boiling water. After 10 minutes, the tea soup in the glass was lighter and the color in the vacuum flask was darker. He explained: “The tea polyphenols contained in tea have the effects of preventing cardiovascular diseases, lowering blood lipids, preventing strokes, anti-thrombosis, and anti-aging. It is more likely to be oxidized into darker theafuscin under high temperatures.
Therefore, the color of the tea soup is darker. Using a stainless steel vacuum flask with good thermal insulation performance to make tea will accelerate the oxidation process of tea polyphenols to a certain extent, resulting in the loss of tea polyphenols. Therefore, consumers are not recommended to use vacuum cups to make green tea.”