Postharvest 'Forelle' (Pyrus communis) mealiness influenced by canopy position, harvest maturity and storage duration

A preliminary study showed that canopy position is correlated to mealiness development, a dry textural disorder after ripening, in 'Forelle' pears. This study explored whether the differences in the ripening rate of inner and outer canopy fruit, harvested at different harvest maturities, may influence mealiness development. Fruits were harvested at two maturities (optimum and post-optimum) and evaluated immediately and after storage (0, 8, 12, 16 weeks at -0.5 degrees C) and ripening (0, 4, 7, 11 d at 20 degrees C). Maturity indices, mealiness, ethylene and CO2 production were assessed on each evaluation day. The outer canopy fruit was mealier compared to the inner canopy fruit. Inner canopy fruit mealiness remained constant for both harvest maturities regardless of cold storage and ripening duration. Maximum mealiness levels for harvest one pears from the western and eastern outer canopy occurred after different storage and ripening durations, respectively after 8 weeks of cold storage plus 11 d of ripening and 12 weeks of cold storage plus 11 d of ripening. The ethylene production of the inner canopy fruit was generally higher compared to that of the outer canopy fruit. However, the inner canopy fruit never got as mealy as the outer canopy fruit, suggesting that mealiness development may not be related to ripening rate. In conclusion, the outer canopy fruit, that was exposed to direct irradiance and higher temperatures for the most part of the day, were more susceptible to mealiness development. It is uncertain how the large temperature fluctuations and higher irradiance experienced by outer canopy fruit affect fruit metabolism and flesh structure.