Changes in Compositions of Ume (Prunus mume Sieb. et Zucc.) Liqueur during Production and Aging

Abstract

Homemade Ume liqueur is made by steeping Ume fruit and sugar in spirits. Changes of compositions during production and aging of Ume liqueur were studied. The results obtained are as followes: (1) At an earlier stage of storage, the flesh weight decreased in contrast with an increase in the liquid volume. The rate of decrease reached a maximum between day 16 and 30, after which the liqueur permeated into the flesh, as shown by the gradual increase in weight. (2) The pH value of the liqueur decreased and its acidity increased until day 30. After that it remained constant. (3) Most of organic acids, malic, citric, formic and oxalic acids, in the liqueur increased to some extent until day 30, and reached a plateau after that time. However, fomic and oxalic acids did not change until day 60, but were hardly detected affer day 90. (4) Asparagine is the major free amino acid, and we detected γ-aminobutylic acid, alanine and asparatic acid etc. Most of free amino acids in the liqueur increased to some extent until day 30, but did not greatly change thereafter. However, glutamic acid was not detected in the liqueur nor the mixture of liqueur and fruit at day 1 in spite of its presence in the fresh fruit. In contrast, γ-aminobutyric acid sharply increased at day 1 which was almost 0 in the fresh fruit.