What is the reason for pear blackening

Pear blackening may be caused by oxidation reactions, low-temperature freezing damage, microbial infections, mechanical damage, ethylene ripening, and other reasons. It can be treated by soaking in salt water after peeling, refrigerating, checking for mold, handling with care, and avoiding mixing with ripe fruits.

1. Oxidation Reaction

When pear flesh is exposed to air, polyphenolic substances come into contact with oxygen and undergo enzymatic browning, resulting in a darker color. This phenomenon is similar to the discoloration of an apple after being cut open, which is a normal chemical reaction. Soaking sliced pear pieces in lemon juice or diluted salt water can effectively inhibit oxidase activity. Vitamin C solution can also be used as an antioxidant, but it may affect the taste.

2. Low temperature freezing damage

Pear cells may be damaged by ice crystals when stored in environments below zero degrees Celsius, resulting in browning after thawing. The surface of frostbitten pears will show semi transparent water stains, and the flesh will gradually become soft and black. During winter transportation, it is important to pay attention to insulation, and it is recommended to maintain a temperature of 3-5 degrees Celsius in the refrigeration compartment of household refrigerators. Pears with mild frostbite can still be consumed, but the discolored parts need to be removed.

3. Microbial Infection

Pear skin damage can easily be infected by microorganisms such as Penicillium and Alternaria, resulting in brown spots in the early stages and black mold spots in the later stages. Moldy pears can produce harmful substances such as penicillin, and even if visible moldy parts are removed, toxins may still remain. When purchasing, pay attention to checking whether the fruit stem is blackened. Keeping the environment dry and ventilated during storage can reduce the probability of mold growth.

4. Mechanical damage

Collision and compression during transportation can cause internal cell rupture in pears, leading to the exudation of phenolic substances and the formation of dark bruises. This type of black spot usually appears in irregular patches and is more common in the compressed parts of the fruit. Pears with minor scratches should be consumed first, as severely damaged fruit pulp can ferment and lose its flavor. Choose pears with mesh packaging when purchasing, and avoid stacking them too high when storing at home.

5. Ethylene ripening

The ethylene gas released by ripe fruits accelerates the respiration of pears, leading to softening and browning of the flesh. Mixing pears with bananas, apples, etc. will accelerate this process. The use of ethylene absorbents in commercial storage can delay ripening, and unripe pears can be stored separately in a cool place at home. Fermented pears that have already developed a taste of alcohol are not suitable for consumption and may contain harmful substances such as methanol.

For daily storage of pears, intact and undamaged fruits should be selected, and the cut of the fruit stem should be wrapped with plastic wrap to reduce oxidation. Refrigeration can extend the shelf life, but it should not exceed two weeks. Before consumption, check for any odor or mucus secretion. For pears that have already been cut open, it is recommended to consume them as soon as possible or soak them in honey water to slow down discoloration. If large areas of mold or fermentation are found, the whole piece should be discarded to avoid the risk of food poisoning. Moderate consumption of fresh pears can help supplement dietary fiber and potassium elements, but those with weak gastrointestinal function should control their intake.