The method of keeping apples unchanged after peeling

After slicing apples, oxidation discoloration can be delayed by soaking them in salt water, lemon water, or honey water. The discoloration of apples is mainly due to the reaction between polyphenol oxidase in the flesh and oxygen. The use of physical isolation or acidic environment to inhibit enzyme activity can effectively maintain the color.

1. Soaking in Salt Water

Soak peeled apple slices in 3% salt water for 1-2 minutes. Sodium ions can inhibit polyphenol oxidase activity. This method is easy to operate and does not affect the taste, making it suitable for apple slices that require short-term storage. Note that soaking for too long may lead to the infiltration of salty flesh. It is recommended to rinse the surface salt with cold water in the future.

2. Applying Lemon Juice

The citric acid in fresh lemon juice can create an acidic environment, and vitamin C has strong reducing properties. You can directly sprinkle lemon juice on the cut surface of the apple, or dilute it in a 1:5 ratio and soak it. This method can maintain the original flavor of apples and is particularly suitable for making fruit platters. People who are sensitive to acidity can reduce the amount of lemon juice used.

3. Honey water treatment

Soak apple slices in 10% honey water for 3 minutes. The natural antioxidant components in honey can block the oxidative chain reaction. This method can maintain the sweet and refreshing flavor of apples, and the protective film formed by sugar can also reduce water loss. In patients with diabetes, sugar substitute solution can be used instead, but the antioxidant effect will be reduced.

4. Vacuum sealing

Using a food grade vacuum bag to remove air and seal, delaying browning by physically isolating oxygen. This method can maintain the original flavor of the apple and has a longer storage time, making it suitable for scenarios where it needs to be carried out. Attention should be paid to vacuum treatment, which may cause slight deformation of the fruit pulp. It should be used with caution by those who cut and eat it immediately.

5. Low temperature refrigeration

Put the cut apples into a fresh-keeping box and place them in a refrigerator at 4 ℃. Low temperature can significantly reduce enzyme activity. The use of plastic wrap to cover the cut surface yields better results, and can maintain the color for 4-6 hours when refrigerated. It is recommended to consume it as soon as possible after taking it out of the refrigerator, as reheating will accelerate the oxidation process. In addition to the above methods, selecting apples with moderate maturity is more resistant to oxidation, while overripe fruits are more prone to browning due to cell wall damage. Use a ceramic knife to reduce metal ion catalysis during cutting, and avoid direct sunlight after treatment. If long-term storage is required, apples can be mixed with fruits such as pineapples and oranges that contain natural antioxidants for storage. It is recommended to prioritize using lemon juice or honey water treatment for daily consumption, which can maintain nutrition and comply with healthy eating principles.