What constellation is Li _ the meaning of Li's name

The reason is overripe and oxidation.

1. Over-ripening: After plums are ripe, the enzymes in the pulp will decompose the cell wall in the pulp, resulting in the pulp softening and blackening. This usually happens after plums are over-ripe.

2. Oxidation: Enzymes in plum pulp react with phenols in the pulp, and the oxidation products produced will lead to the surface blackening of the pulp. This usually happens because the pulp is exposed to air and comes into contact with oxygen.