source: the results of
experiment showed that the sulfur dioxide content in sample 1 was significantly higher than that of sample 2 and sample 3. Reporter Mu Jing photo "wolfberry a bubble, how sour smell?" Such a medlar dare to eat. Recently, readers of Ms. Xu reflected that the Lycium barbarum bought in the market of farmers' market in the provincial capital was clear with water and sour. Experiments show that the red sulphur wolfberry juice purchased by Ms Xu is 20 times more than sulfur dioxide or smoked with sulphur.
readers reflect: the sour taste of Chinese wolfberry after the water "bought some wolfberry from the farmer's market. I wanted to do the porridge, and I didn't think that a blister of water was an acid odor." In October 23rd, Ms. Xu put a handful of Chinese wolfberry in hot water for a long time.
Ms. Xu introduced that the wolfberry was bought from the farmer's market for a period of time. The owner told her that wolfberry was Ningxia wolfberry. It was 18 yuan a jin of special price. Reporters saw that Miss Xu bought a smaller Chinese wolfberry, the color is very bright, relatively dry, close to smell a faint acid.
Ms. Xu checked the Internet, and Ms. Xu was very worried when she saw that "the bright red wolfberry may have been smoked with sulfur dioxide, and too much to be nausea and vomiting." "Originally wolfberry is a nutritious tonic, but now illegal business, once smoked, has become a poison." Experiment: Red sulphur wolfberry and sulfur dioxide exceed 19 times the color. Is the bright red wolfberry smoked with sulphur? In order to verify this statement, in October 25th, the reporter took the wolfberry bought by Ms. Xu to the laboratory of the Shandong Normal University. In order to compare the results of the experiment, the reporter bought two Jin wolfberry from the farmer's market and the supermarket to carry out a test. Among them, the sample 1 is the wolfberry bought by Xu. The price is 18 yuan per Jin; the sample 2 is the wolfberry bought from the farmer's market, the price is 25 yuan / Jin; the sample 3 is the wolfberry bought from a supermarket on the mountain road. The price is 55 yuan / Jin.
the method used in this experiment is acidification distillation iodide titration, the step is to acidification and heat distillation of the sample in a closed container to release sulfur dioxide, and the release is absorbed in lead acetate solution. After absorption, it was acidified with concentrated acid, then titrated with iodine standard solution, and the sulfur dioxide content in the sample was calculated according to the amount of iodine standard solution consumed. 3 days later, the reporter got the test results.
test results show that the content of sulfur dioxide in the sample 1 is 1000mg/kg, the content of sulfur dioxide in the sample 2 is 61.68mg/kg, and the content of sulfur dioxide in the sample 3 is 57.84mg/kg. According to the relevant national standards, the limit of sulfur dioxide in wolfberry is not more than 50mg/kg, and the Chinese wolfberry purchased by Ms. Xu is 20 times the national standard.
for the results of the experiment, the experiment explained that because the experimental results only measured the content of the reductive substance, it was calculated with sulfur dioxide, and there were other sulfur containing impurities in the sample, which was also calculated, making the result of the test higher than the actual content of sulfur dioxide. But it is certain that the sample 1 is significantly different from the sample 2 and 3, and the sample 1 data is too much. The guess is that it is fumigated with sulphur.
it is understood that sulfur is a chemical raw material, sulfur burning to produce sulfur dioxide, can play the role of bleaching, fresh-keeping, so that the color of the goods is bright and bright. Therefore, illegal traders use Sulphur Fumigation to enhance the appearance of goods and extend the shelf life.
extended survey: Booth owners say that 18 yuan a jin of wolfberry to hot pot restaurant is popular in the market. The reporter then investigated the market of wolfberry in the provincial capital. Most drugstores sell bottles of wolfberry in bottles or bags, while the market sells more wolfberry in bulk.
a drugstore staff told reporters that bulk wolfberry was used for medicinal purposes, and the quality was general. Reporters found that these bottles of wolfberry bottles weighing 150g or 200g, the origin is Ningxia, because manufacturers are different, the price ranges from 39 yuan to 48 yuan. In supermarkets, bags of wolfberry are sold. The price of wolfberry 200g weighs more than 20 yuan.
in a farmer's market in the eastern part of the provincial city, the reporter saw two kinds of medlar before a booth: 18 yuan a Jin and 30 yuan a Jin. 18 yuan a pound of wolfberry is bright red, the particles are dry, smell sour, 30 yuan a jin of wolfberry is jujube red, grain full. Stall owners said that 18 yuan a kilogram of wolfberry was rarely bought, usually in restaurants and chafing dish shops to buy soup and make hot pot bottom.
reporters found that wolfberry here is mostly bulk, and the price of wolfberry in each booth is not very different, maintaining between 18 yuan and 35 yuan. Each stall has two colors of wolfberry: fresh red and jujube red, fresh red wolfberry is cheaper than jujube red wolfberry, one jin of 18 yuan to 20 yuan, and jujube Chinese wolfberry is 25 yuan to 35 yuan a Jin, the bigger the grain, the more expensive wolfberry.
the reporter then asked a few stalls, the stall that the owner of the cheap fresh red wolfberry will ask to buy back to do what to do, but also suggested that the reporter buy a little red jujube Chinese wolfberry. "Cheap will always have a cheap reason to eat more expensive." One of the vendors suggested a reporter. Why Chinese wolfberry presents two colors of fresh red and jujube red, the owner's explanation is that the big Chinese wolfberry is dried after maturing, while the fresh red wolfberry is dried by the wolfberry without maturity. As for how to dry, the owner is not talking about it.
how to choose wolfberry to see that the color of Lycium barbarum which has been smoked or dyed is mostly bright red, while the authentic Chinese wolfberry is mostly dark red. In addition, the natural Chinese wolfberry in the growth of the influence of light and other factors, the color distribution is uneven, there is a partial color, after exposure, the color is dark; if overdose sulphur smoked, the color will be particularly bright and beautiful, and the red is very uniform.
Lycium barbarum, with the highest fruit size, has no black head, and the poor quality wolfberry has many black heads and impurities.
smelling can catch a Chinese wolfberry, cover it with your hand, and smell it in front of your nose. If the smell is more sharp, it is obviously processed with sulphur.
these people avoid eating Chinese wolfberry. It is understood that Lycium barbarum has the effects of nourishing liver and kidney, benefiting essence, improving complexion and improving eye and tranquilizing mind. How do people eat wolfberry? Reporters randomly surveyed several residents, most of whom called wolfberry soup and tea making. In addition to boiling soup and water, wolfberry can also add wolfberry when stewing meat, or add a small amount of Lycium barbarum when beating soya bean milk.
however, wolfberry is not suitable for everyone, and people with weak constitution and poor resistance can eat more. People who have a fever, inflammation, and diarrhea are taboo. Besides, wolfberry should not be consumed with too many hot tonic products such as longan, red ginseng and jujube.