SIMPLIFIED METHOD FOR THE DETERMINATION OF TOTAL GLYCOALKALOIDS IN POTATO-TUBERS

A simplified method for the determination of total glycoalkaloids (TGA) in potato tubers has been developed in which potato tissue is extracted with dilute sulphuric acid and the extract is hydrolysed directly. Analysis is completed in less than 4 h using very simple apparatus and reagents. A colorimetric procedure employing bromothymol blue is used for quantitation. A study of the hydrolysis of α‐solanine and α‐chaconine and the stability of solanidine and solanthrene under hydrolysis conditions, which was made in order to define optimum conditions for the method, showed that hydrolysis time and temperature are quite critical if reproducible aglycone recovery is to be obtained. The results obtained using the method for tubers of fourteen experimental samples with a wide range of TGA contents compare well with corresponding results obtained using a lengthier and more tedious literature method. Its simplicity makes it a suitable method for plant breeders to use to measure the TGA content of new cultivars of potatoes. Copyright © 1979 John Wiley & Sons, Ltd