Changes of Chemical Constituents in Small Mume Fruit during Growth and Maturaion

Abstract

The content of chemical constituents in small mume fruit (Japanese Apricot, Prunus mume Sieb. et Zucc. var. microcarpa Makino, cv. Ryukyo koume and cv. Koshu koume) was determined in relation to growth and maturation in investigations conducted between May 11th to June 22 nd 1981. The following results were obtained. 1) The growth curve of the fruit showed a double sigmoidal pattern like that of stone fruits, the three growth phases were designated into periods rapid growth stage, stagnation stage and rapid enlargement stage. 2) The fruit reached a maximum hardness of 1011±113g/φ in the fruit stagnation stage and decreased about 1/3 of maximum hardness in relation to fruit enlargement. 3) The AIS content of the fruit was 4.65% in the immature stage, and the initial content decreased about 1/2 during growth and maturation. The ratio of total pectin to AIS increased from 16.9% to 29.7% during growth and maturation. 4) An increase was observed in ash, total nitrogen and free amino acid content during the growth of the fruit and a corresponding decrease with its enlargement. 5) The titratable acidity content of the fruit was in the region of 3.1 to 5.5g/100 g. It was observed to increase in the fruit stagnation stage reaching a constant in the fruit enlargement stage. The results were similar to the changes in the soluble solids content. 6) The fruit contained malic, citric, oxalic and succinic acids. The content was in the region of 3478 to 6517mg/100g during growth and maturation. The changes showed similarity to those of titratable acidity content. A significant increase was observed from 8% to 60% in citric acid content during growth and maturation and the malic acid content increased in the stagnation stage, then decreased from 86% to 39% in the fruit enlargement stage. A marked decline was noticed in the ratio of malic acid to citric acid from 10.59 to 0.65 during growth and maturation. 7) The total amount of free amino acid in the fruit increased to a maximum of 340mg/100g with its growth, then the maximum content was observed to decrease about 1/2 in the fruit enlargement stage and increase as it became over-ripe. In all stages of growth and maturation, between 73% to 87% of the total free amino acid in the fruit flesh was occupied by asparagine and when 7-amino butyric acid, glutamic acid, glutamine and aspartic acid were added, this totalled between 93% to 98%. 8) Significant changes in the content of the fruit sugars, sucrose, glucose, fructose and sorbitol were observed in fruit growth and maturation. The composition of major sugar was between 36% to 54% glucose in the immature stage, glucose and sorbitol between 22% to 31% in the stagnation stage, between 33% to 34% sucrose and between 49% to 78% in the enlargement and over ripe satages. Also a decrease was observed in glucose content and the fructose content decreased after an increase, also a decline was noticed in the ratio of glucose to fructose from 4.94 to 0.55 during growth and maturation. 9) The mineral content reached its maximum of 3123 ppm in the fruit stagnation stage, and the maximum content decreased about 78% in the fruit enlargement stage. Between 90% to 95% of the mineral content of the fruit flesh was occupied by K, increasing to 99% with the addition of Ca and Mg.