Abstract
This study was to determine both the contents of chlorophyll (Chl) and potato glycoalkaloids (PGA) in which the cortex tissues (the outer 1-3mm thick), prepared from‘May Queen’ potatoes, were stored at 1°, 5°, 10° and 15°C under white fluorescent light (5, 200-5, 800 lx) or in the dark. Further, the effects of light exposure on changes ofChland PGA contents in the cortex and the pith tissues of potato tubers coated half with aluminum foil were also examined.
1. The cortex tissues stored at 1°and 5°C under light exposure showed no color change and both of theChland PGA contents showed no change throughout the storage period. At 10°C-storage, they turned green from the 4th day accompanied by increases in theChland PGA content. On the other hand, the samples stored at 15°C turned green from the 2nd day. As the storage period was prolonged, the green color of this sample became deeper and the Chl content increased. The PGA content also increased with an increase of theChlcontent. It was found that the light exposure would accelerate the content of α-chaconine and α-solanine and that the increase of the latter compound was particularly remarkable.
2. A lengthwise half of potato tubers was coated with aluminum foil and subjected to light exposure at 15°C for 7 days. TheChlcontent in the cortex tissues of the coated half was fairly higher than that stored in the dark, but it was lower than that of the lightened one. On the other hand, the PGA content in the cortex tissues of the coated half was lower than that of the lightened half, and it was almost the same amount as that stored in the dark.
3. It is desirable to store potato tubers at a temperature of 10°C or below while insulating light as strictly as possible.
