Physiological, physicochemical and mineral attributes associated with the occurrence of bitter pit in apples

The objective of this work was to identify the physiological, physicochemical, and mineral attributes associated with the occurrence of bitter pit in 'Fuji' and 'Catarina' apples. Fruit were harvested, stored in air at 1 degrees C and 90-95% relative humidity for 120 days, and, then, divided into lots with or without bitter pit symptoms. 'Catarina' apples had higher incidence and severity of bitter pit, in comparison to 'Fuji'. In both cultivars, fruit with bitter pit had higher ethylene production, respiration, and titratable acidity, and lower pH, flesh firmness, skin and pulp textures, and percentage of red skin area. Fruit with bitter pit also had lower Ca content and higher values of K/Ca, N/Ca, (K+Mg)/Ca, and (K+Mg + N)/Ca ratios in the skin and flesh tissues of the blossom-end. Canonical discriminant analysis indicates that the best attributes to discriminate between fruit with or without bitter pit are force to penetrate the flesh and K/Ca ratio in the pulp, in 'Fuji' apples, and titratable acidity and K/Ca ratio in the skin, in 'Catarina' apples.