CHANGES IN SUGARS, ACIDS, AND AMINO-ACIDS DURING RIPENING AND STORAGE OF APPLES (CV GLOCKENAPFEL)

Changes in sugars, the principal acids, and amino acids were monitored in the ethanol-soluble matter of apples (cv. Glockenapfel) during a 6-month period between the beginning of July, while the apples were still on the tree, and January, after storage at 4-degrees-C. Fructose was the principal sugar. Fructose, sucrose, and glucose increased at different rates till harvest, and then the levels remained constant after an initial drop. The sorbitol content did not vary much. Malic acid was the principal acid, and it decreased during growth and storage. Citric acid followed a similar trend. The amino acid content declined steadily during development. All of these changes can be related to the metabolic activity during fruit growth and maturation.