Studies on Glycoalkaloids of Potatoes (Part IV) Changes of Glycoalkaloid Content in Four Parts of a Sprouted Potato Tuber and in Potato Tubers during Storage

Abstract

The concentrations of potato (Solanum tuberosum L. ) glycoalkaloids (PGA) (i. e., α-chaconine and α-solanine) in four different parts of a sprouted ‘MayQueen’ potato tuber were determine by high-performance liquid chromatography (HPLC). The observation of sprouting condition and the changes of both PGA contents of tubers of both ‘Danshaku’ and ‘MayQueen’ during storage at 1°C, 8°C and 20°Cwere also investigated.1. On determining PGA content in four different parts of a sprouted potato tuber, it was found that the PGA concentration was highest in the sprout shoot and in the cortex tissues of the peripheral zone of the shoot. In the pith, however, a small amount of α-chaconine and only a trace amount of α-solanine were detected.2. The sprouting conditions of two cultivars stored at 1°C, 8°C and 20°C were observed during storage. It was found that two cultivars stored at 20°C sprouted about 7-15mm in length after 20 days of storage, whereas in 1°C-stored potatoes sprouting was not observed until 120 days of storage.3. The PGA content of ‘Danshaku’ was found to be lower than that of ‘MayQueen’ and the PGA contents of two cultivars increased with the development of sprout during storage. On the other hand, even in tubers stored under cold temperature, PGA was gradually accumulated in the cortex tissue, while in the pith PGA was not detected.