Because the pulp can change color when put in oxygen, it means that the discoloration of the pulp is related to oxygen, but the discoloration of the pulp has nothing to do with carbon dioxide, which means that the pulp will not change color when put in carbon dioxide; the pulp will also change color if it is placed in water for a long time. , the possible reason is that oxygen is dissolved in the water, causing the pulp to change color; nitrogen is chemically inactive and generally does not react with other substances. Research has shown that the discoloration of the pulp is related to oxygen, so in order to prevent the discoloration of the pulp from reacting with oxygen , the fruit can be processed using oxygen isolation, and the fruit juice can be stored in vacuum packaging.
So the answer is:
The discoloration of the pulp is related to oxygen; oxygen is dissolved in the water, causing the pulp to change color; the fruit is processed using oxygen isolation, and the fruit juice is stored in vacuum packaging.