Redistribution of minerals in apple fruit during storage. Preliminary investigations with the variety spartan

Concentration gradients of dry matter, potassium, phosphorus, magnesium and calcium across median transverse slices were measured on a fresh matter basis at intervals during the storage of Spartan apples in either air or 2% oxygen (<1% carbon dioxide) at 1°C. Proportions of calcium declined in the core and increased, during the first 4 months of storage, in the cortex where calcium rapidly became less extractable with 75% ethanol. Proportions of potassium increased in the inner cortex while those of phosphorus increased in the inner cortex and, during the first 2 months of storage, in the core. Proportions of magnesium declined steadily in the peel and outer cortex with corresponding increases towards the fruit centre. These changes were mainly independent of storage conditions and differences in dry matter concentrations. Calcium and magnesium moved to the core region when core browning developed, especially in the air‐stored samples, towards the end of the storage period.