Articles
POLAROGRAPHIC pO2-MEASUREMENT IN CRUCIFEROUS VEGETABLES STORED AT STABLE OR CHANGING O2-CONCENTRATIONS
Needle electrodes were used to measure pO2 by polarographic method in the plant tissue held at different O2-concentrations of the atmosphere.
Crops were stored at 2°C for 4 weeks under linearly increasing, decreasing or stable O2-concentrations.
CO2-concentration was kept below 4%.
PO2 in the tissues was measured directly after harvesting, after 2 and after 4 weeks storage time.
In addition respiration rates were measured in air after the storage in CA conditions.
The pO2-values showed significant differences depending on the O2-concen-trations of the storage atmosphere.
The highest values were found directly after harvesting and after storage in air.
The lowest values were measured for the variants between 1% and 5% O2, as well at stable as at changing O2-concentration of the storage atmosphere.
During the storage period of 2 to 4 weeks the pO2-values of the tissues corresponded only partly to decreasing or increasing O2-levels of the atmosphere.
This phenomenon cannot be explained now.
The correlation coefficient (r) of pO2-values in the tissue and O2-concentration in the atmosphere after 2 and 4 weeks was 0,97 for Brussels sprouts and for broccoli.
CO2-production of broccoli was reduced after 4 weeks storage in low O2-con-centrations in comparison to storage in 21% O2. Regarding Brussels sprouts we didn’t observe this effect.