SORBITOL AND FREE SUGAR CONTENTS IN PLUMS

Analytical data are reported for sorbitol and free sugar contents of thirteen cultivars of plums grown in different pedoclimatic areas of Italy. Two chromatographic systems were compared: one using an amino-bonded silica phase (LiChrosorb-NH2) and the other using a polymeric phase (Polypore Pb). The second phase yielded a sharper resolution of sorbitol from the other sugars with better sensitivity and reliability without the problems of loss of resolution due to ageing of the column. On average, the tested cultivars of plums had a sorbitol content higher than cultivars growing abroad, which are reported in the literature. The variability among the cultivars and the interrelationship between sorbitol and sugars are discussed. The sorbitol content should be included in criteria of plum suitability for drying processing.