What is the reason for the blackening of pear skin

The blackening of pear skin may be caused by mechanical damage, low-temperature frostbite, oxidation reactions, fungal infections, ethylene ripening, and other reasons. When the degree of blackening is light, it usually does not affect consumption. If it is accompanied by pulp decay, it needs to be discarded.

1. Mechanical damage

During the picking and transportation of pears, collision and compression can cause cell rupture, and polyphenols oxidize to form melanin upon contact with air. Slight bumps only cause discoloration of the skin, and the flesh can be peeled for consumption when it has not spoiled. When storing, be careful to handle with care and avoid stacking too high.

2. Low temperature frostbite

When pear is stored in a sub zero temperature environment, the crystallization of cell fluid will damage the cell structure, and brown patches will appear after thawing. Frozen pears have a soft but non-toxic taste and should be consumed as soon as possible. In winter, it is recommended to wrap the pear with foam box to avoid direct contact with the metal frame of the cold storage.

3. Oxidation Reaction

Pear skin is rich in tannic acid, which can cause enzymatic browning when in contact with metal ions from cutting tools or exposed to air for a long time. Peeling with a ceramic knife and applying lemon juice to the incision can slow down discoloration. It is recommended to wrap the cut surface of refrigerated pears with plastic wrap.

4. Fungal infection

Extended infection by pathogenic bacteria such as Penicillium can cause round black spots and gradual depression on pear skin, accompanied by white hyphae. This type of moldy pear may produce toxins such as penicillin, and if mold spots are found, the whole pear should be discarded. Wiping the remaining moisture in the fruit peel with a soft cloth before storage can reduce the probability of infection.

5. Ethylene ripening

When mixed with ethylene releasing fruits such as bananas and apples, pears will accelerate ripening and cause the skin to darken. Pears ripened naturally have higher sugar content, but it is necessary to observe whether they soften synchronously. Storing separately or wrapping in breathable paper bags can control the maturation speed.

When purchasing pears in daily life, choose fruits with green stems and no scratches on the skin, and store them in a humid environment to avoid dehydration. Slightly blackened pears can still be consumed after removing the discolored parts. If the flesh has a wine like taste, transparency, or mold spots, it is not edible. It is recommended to place the pear in a cool and ventilated place to avoid direct sunlight that accelerates decay. Rinsing the skin with running water before consumption can effectively remove some pesticide residues and microorganisms.