Composition of Free Amino Acids in Plums Harvested in Japan

Abstract

The composition of free amino acids in the juices from six varieties of plums (Plunus salicina) and their changes during ripening were investigated. The plums were harvested in Yamanashi Prefecture in June-July, 1974 or 1975. The juices contained 124.6 to 272.5mg% of free amino acids and the twenty kinds of amino acids were identified. Aspartic acid and asparagine were the principal amino acids in all juices, occupying 50 to 79% of the total amino acid content. Serine, proline and glutamic acid were 7 to 16%, 4 to 16%, and 2 to 4% of the whole, respectively. The juice from "Ooishi Wase" was especially rich in alanine and isoleucine, and that from "Methley" rich in alanine. Compositional changes in free amino acids in the juices occurred during ripening. Namely, in the case of "Ooishi Wase", the amounts of aspartic acid and proline significantly decreased, and those of alanine and isoleucine increased. In "Sordum", the amount of alanine increased.