Shiny yellow label suspected of being bleached with sulfur?

Thin skin, bright yellow color, thick flesh, as big as lychee,... the giant longan is flooding the markets in Hanoi, making many people suspicious.

It is the season of ripe longan, so for about a month now, in big and small markets as well as on many streets in Hanoi, all kinds of longan have been displayed and piled up on carts and market stalls. Thai longan, Hung Yen longan, native longan,... are priced at 30,000-50,000 VND/kg depending on the type.

Huge longan fruit with bright yellow skin is sold everywhere in Hanoi.

However, there is also a type of longan on the market that is huge, as big as a lychee, with a shiny yellow outer skin that looks very beautiful. This type of longan costs around 45,000-50,000 VND/kg.

According to the seller's advertisement, this new variety of longan is grown in Hung Yen, very attractive to buyers because the longan pulp is quite thick, the skin is thin, and the taste is quite sweet. In particular, because the design and color of the longan skin is very beautiful, many people choose to buy it as a gift for relatives and friends.

Having just bought 3 kg of giant Hung Yen longan at a fruit shop on Nguyen Xien Street (Hoang Mai, Hanoi), Ms. Tran Thanh Nhan in Bac Linh Dam (Hoang Mai) shared: "I saw that the longan had a beautiful yellow color and was big, so I bought it to eat even though it was much more expensive than other types of longan."

However, according to Ms. Nhan, she has a relative from the countryside in Hung Yen who occasionally sends her longan. However, she has never seen a type of longan that is as bright yellow as the one sold at the market today. "The longan sent from the countryside is only half as small, and the skin is also dark, not yellow," she said.

She said she heard rumors that the yellow-skinned longan is dried with sulfur to bleach the skin to make it look more beautiful.

Similarly, Ms. Nguyen Thi Quynh in Nguyen Bieu (Ba Dinh, Hanoi) also said that her family often eats longan, and every year when the season comes, they buy a lot to eat. However, this year when she went to the market, she saw a vendor selling a strange type of longan, with large fruit and yellow skin, different from the type she usually buys.

“The other day I bought some to try and found them quite delicious. Although they are not very sweet, this type of longan has thick flesh and thin skin. However, since the day I tried them, I have not dared to buy any more, because I heard that traders use sulfur to bleach the skin of this type of longan to make it brighter and more beautiful,” said Ms. Quynh.

According to experts, the bright yellow skin of longan is due to the use of sulfur as a drying biochemical method, so the longan fruit will have a much more eye-catching color than its natural color.

Mr. Vu TN, director of a company specializing in organic agricultural products, said that the giant longan fruit currently sold in Hanoi markets is Mien Thiet longan (one of six types of longan grown in Hung Yen).

Regarding the bright yellow skin of longan, Mr. N. admitted that the bright yellow skin of longan is indeed treated with sulfur.

According to Mr. Vu TN, the natural longan skin is usually dark because of mold, but when treated with sulfur, the skin will be cleaner, brighter, and much more yellow. Traders often do it this way to make the appearance and color of the longan more eye-catching.

“This method is widely used in many countries around the world. In Vietnam, the Ministry of Agriculture and Rural Development also allows it. However, when doing it, it is necessary to ensure the correct dosage and a minimum quarantine period of 2 days to ensure the safety of consumers when eating longan,” said Mr. N.

PSG-TS. Nguyen Duy Thinh (Institute of Biology - Food Technology - Hanoi University of Science and Technology) also added that to prevent fresh longan from turning brown, people often put longan in a paper box or basket and burn sulfur at the bottom to create SO2 gas. The gas rises and covers the skin, making the longan brighter and preventing mold and spoilage.

This is a dry biochemical method and sulfur is allowed to be used in food technology.

According to Associate Professor, Dr. Nguyen Duy Thinh, sulfur is not only used to preserve longan but also many other fruits, such as lychee or dried foods.

Mr. Thinh said that the amount of sulfur used is not important, because when used, it is just a gas that only sticks to the outer surface. When the SO2 gas is gone, the longan can be eaten normally, without fear of toxicity.

However, they must be quarantined for at least two days before being sold to consumers to eat. The reason is that SO2 gas sticks to the skin of the longan fruit. If it has not completely evaporated, it will have a slightly pungent smell, causing an unpleasant feeling. Therefore, many people who buy longan and smell a strange smell often suspect that the longan has been preserved with toxic chemicals.

However, Associate Professor, Dr. Nguyen Duy Thinh also noted that in the process of burning sulfur, the SO2 gas sticks to the fruit skin and if you directly inhale this gas, it will be very toxic to your health, your eyes will always feel stinging and watery. Therefore, you should avoid direct contact when burning sulfur./.

According to VOV