Normal phenomenon. Many mangosteen have some yellow mucilage on their surfaces, which is secreted by the fruit itself. Generally, mangosteen is damaged during picking, or the fruit is damaged and squeezed during transportation, which leads to the secretion of yellow mucilage and condensation on the surface of the fruit to protect its pulp from being damaged. This yellow pulp will not affect its nutritional value and taste, and it is also harmless to the human body. It is a normal phenomenon. Fresh mangosteen pulp is generally white and tastes sweet and juicy. However, if the pulp of mangosteen turns yellow after peeling, it shows that mangosteen is likely to have deteriorated. The nutrients in the mangosteen have begun to lose and bacteria have grown, which leads to the rotten pulp. It is not recommended to continue eating such mangosteen, otherwise it will have a bad impact on health.