Why don't peeled apples turn black

Peeled apples can be delayed from turning black due to oxidation by soaking them in diluted salt water, applying lemon juice, using vitamin C solution, refrigeration, or vacuum sealing.

1. Soaking peeled apples in diluted salt water

Soaking peeled apples in diluted salt water with a concentration of about 3% can effectively inhibit oxidase activity. Sodium ions in saltwater can temporarily disrupt the structure of polyphenol oxidase and delay browning reactions. The soaking time should be controlled within 5 minutes, and after removal, rinse with clean water to avoid excessive saltiness. This method is suitable for apple chunks that require short-term storage, with simple operation and minimal impact on taste.

2. Lemon Juice Treatment

The citric acid and vitamin C in lemon juice have strong reducibility and can preferentially bind with oxygen. Apply fresh lemon juice evenly to the cut surface of the apple, or dilute it in a 1:10 ratio and soak for 2 minutes to form an antioxidant protective layer on the surface. This method will give the apples a slight sour taste and is suitable for use in ready to eat or making fruit salads.

3. Vitamin C Solution

Dissolve 100 milligrams of vitamin C tablets in 200 milliliters of water to make a solution, soak the apple slices for 1-2 minutes. Vitamin C can directly reduce oxidized phenolic substances, causing browning products to fade. This method can maintain freshness for more than 4 hours without changing the original flavor of the apple, making it suitable for occasions with high taste requirements.

4. Low temperature refrigeration

Storing peeled apples in a refrigerator below 4 ℃ can significantly slow down the enzymatic reaction rate. Low temperature environment reduces the activity of polyphenol oxidase. It is recommended to tightly wrap the cut surface with plastic wrap to isolate the air. This method can maintain the color of apples for 2-3 hours, but prolonged refrigeration may cause cell dehydration. It is recommended to use it in conjunction with other antioxidant measures.

5. Vacuum sealing

uses vacuum preservation boxes or vacuum bags to completely isolate oxygen, which can block oxidation reactions from the source. Vacuum treated peeled apples can maintain a white state for more than 8 hours under refrigeration conditions, but specialized equipment is required. This method is suitable for catering batch preparation or situations that require long-term storage. The oxidation and blackening of apples is a natural phenomenon that occurs when phenolic substances come into contact with oxygen. Although it does not affect food safety, it affects the appearance. In addition to the above methods, it is recommended to cut and eat immediately for the best taste. Using a ceramic knife during processing can reduce the catalytic oxidation of metal ions, and choosing apples with moderate maturity can result in slower browning rates. Various anti oxidation methods can be combined in daily life, such as soaking in vitamin C solution and then vacuum refrigerating, which can maximize the freshness of apples. If you need to make a fruit platter, it is recommended to process the apples last and consume them as soon as possible.