Cut the apple open for a few minutes and it will change color

Apples usually begin to change color within 3-5 minutes after being cut open. The discoloration of apples is mainly related to factors such as oxidation reactions, phenolic content, environmental temperature, tool cleanliness, and variety differences.

1. Oxidation Reaction

When apple pulp is exposed to air, phenolic substances react with oxygen under the action of polyphenol oxidase to produce brown quinone substances. This is the core mechanism that causes discoloration, and peeling or cutting into pieces will accelerate this process.

2. Phenolic Substance Content

Phenolic substances are unevenly distributed in different parts, with higher content near the fruit nucleus. Red Fuji and other varieties change color significantly faster than green apples due to their high content of anthocyanins.

3. Environmental Temperature

High temperature environments can enhance enzyme activity, and the color change rate significantly accelerates above 25 ℃. refrigeration can delay discoloration, but it cannot completely prevent oxidation reactions from occurring.

4. Tool Cleanliness

When cutting with rusty or residual fruit juice tools, metal ions catalyze oxidation reactions. It is recommended to use a ceramic or stainless steel knife and thoroughly clean it.

5. Variety Differences

Yellow Marshal and other browning sensitive varieties show obvious discoloration within 1 minute after cutting, while Australian green apples and other varieties can maintain their color for more than 10 minutes due to their strong acidity. To delay the discoloration of apples, the cut pieces can be soaked in light salt water or lemon water, and the enzyme activity can be inhibited by chloride ions and vitamin C. Using a vacuum preservation box to isolate air is more effective, but it should be noted that soaking for too long can affect the taste. Fresh apples are recommended to be cut and eaten immediately, and should not be refrigerated for more than 4 hours after cutting. In daily life, you can choose varieties with dense flesh and high acidity, and pair them with ingredients with high antioxidant content such as blueberries for consumption.