This browning is caused by the oxidation of phenolic compounds in the pear's flesh. Phenolic compounds are naturally occurring plant pigments that are responsible for the color of many fruits and vegetables. When these compounds are exposed to oxygen, they undergo chemical changes that result in the formation of brown pigments.
The rate at which pears ripen and develop brown spots is influenced by several factors, including the cultivar, maturity stage at harvest, storage conditions, and ethylene exposure. Pears that are harvested at a more mature stage will typically ripen and develop brown spots more quickly than those harvested at a less mature stage. Higher storage temperatures can also accelerate the ripening process and increase the incidence of brown spots. Additionally, exposure to ethylene gas, which can occur during transportation or storage, can also speed up ripening and cause brown spots to develop.
To minimize the development of brown spots during commercial storage, pears are typically stored at low temperatures (usually around 0°C or 32°F) and in controlled atmosphere conditions that limit the concentration of ethylene. These conditions help to slow down the ripening process and reduce the incidence of brown spots. Additionally, pears may be treated with anti-browning agents, such as calcium chloride or ascorbic acid, to help prevent the oxidation of phenolic compounds and the development of brown spots.
It's important to note that some pear cultivars are more susceptible to browning than others. For example, 'Bartlett' pears are known to be more prone to browning than 'Anjou' pears. Therefore, the storage conditions and handling practices may need to be adjusted accordingly to minimize browning in different pear cultivars.
