Induction of modified atmosphere-related browning disorders in ‘Fuyu’ persimmon fruit

Critical O2 levels which induce modified atmosphere-related browning disorders in ‘Fuyu’ persimmon fruit were determined using controlled atmosphere (CA) storage at two different temperatures. Fruit were harvested at commercial maturity and stored for 4 months under different CA regimes and temperature. In the 2000–2001 season, O2 levels were adjusted to 0.5–0.75 or 0.1–0.3 kPa in combination with 5.0–7.5 and 10.0–12.5 kPa CO2, respectively, at 0 °C. In the 2001–2002 season, two different O2 levels, 0.5 and 0.25 kPa O2, were combined with 9.0 kPa CO2 at −1.0 and 1.0 °C. Incidence of the stylar-end-specific browning (SEB) disorder was almost 0 above the 0.50 kPa O2 level regardless of CO2 concentration, whereas it was noticeable at 0.40–0.50 kPa, indicating that inductive O2 levels for SEB are below 0.4 kPa. Other types of browning such as pitted specks (PS) and pitted blotch browning (PBB) all over the surface occurred at 0.50 kPa O2, and the incidence tended to increase at lower O2 levels. Effects of storage temperature on the incidence of browning disorders were not significant except that lower storage temperature enhanced post-storage development of flesh blotch browning. Incidence of SEB was closely related with internal ethanol content, while incidence of PBB did not show clear relationships with the ethanol contents. Tissue specificity of SEB seemed to be closely related to the accumulation of anaerobic metabolites in the stylar-end part of the fruit.