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, country 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 longan with a bright yellow color, like the one sold at the market today she just bought. “The longan sent from the countryside is only half the size, 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, 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, big fruit, 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 it, 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 the longan is due to the use of a method of using sulfur to dry the lychee, so the longan 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 sold at Hanoi market today is Mien Thiet longan (one of six types of longan grown in Hung Yen).

Regarding the bright yellow longan peel, Mr. N. admitted that the bright yellow longan peels are indeed treated with sulfur.

According to Mr. Vu TN, natural longan fruit often has a dark skin due to mold, but when treated with sulfur, the skin becomes cleaner, brighter, and much more yellow. Traders often do this to make the appearance and color of the longan fruit 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.

Associate Professor, Dr. 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 has evaporated, 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 buy and eat. The reason is that SO2 gas sticks to the longan skin, and if it has not completely evaporated, it will have a slightly pungent smell, causing an unpleasant feeling. Therefore, many people when buying longan, smelling 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 peel 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