Abstract
The effects of the maturation and the sodium chloride concentration on the composition of pickled sun-dried ume products ‘umeboshi’ were investigated using ume fruit harvested on May 31 (immature stage, salted in 15.0% sodium chloride), June 7 (stage from immature to just before mature, salted in 15.0% sodium chloride) and June 14 (a stage from mature to slightly ripe, salted in 12.5%, 15.0% and 17.5% sodium chloride). There were no differences in moisture or sodium chloride concentration among the different harvesting dates of fruit which was salted with the same sodium chloride concentration, and the titratable acidity was highest in June 7 fruit and then dropped as the harvesting date advanced due to the original content in the fresh ume. The moisture content increased and acids eluted less when a lower quantity of sodium chloride was used during salting, however, no differences were observed in the final sodium chloride concentration. Therefore, it is concluded that there was no effect on reducing the final sodium chloride concentration even after lower concentration had initially been added. In the NaCl-reduced condition, the concentration of sodium chloride after salting was less, however, a larger volume of moisture evaporated. Sucrose, glucose, fructose and sorbitol increased with the advance of harvesting date, and sucrose dissolved completely, consequently glucose and fructose increased in all samples during salting. Free amino acid content was not influenced by the harvesting date or initially added sodium chloride concentration. Asn, Gln and Glu decreased during salting, and Ala and γ-ABA increased in all samples during the process.
