Abstract
Changes in organic acid contents of tomato and Japanese pear fruits vibrated at 1G and 3G for 5 hours were determined during and after vibration. Changes in glutamic acid content of tomato fruit in relation to changes in organic acids were also determined.
In both fruits, the contents of citric and malic acid decreased rapidly during vibration at every intensity, especially at 3G. Citric acid content increased temporarily at the beginning of vibration prior to a rapid decrease during vibration. This was more striking in tomato fruit vibrated at 3G.
When vibrated at 3G, the level of α-ketoglutaric acid in both fruits increased at the beginning of vibration, remained at an elevated level during vibration, and returned to the initial level after the vibration was terminated.
The glutamic acid content of tomato fruit vibrated at 3G remained high during vibration. Changes in, content during and after vibration seemed to follow slightly behind the changes in citric acid content, which increased temporarily and then decreased rapidly.
The results obtained suggest that when vibrated at 3G some metabolic pathway is retarded and subsequently another pathway is activated. As a result, a temporary accumulation of glutamic acid and a rapid decrease in citric acid might be induced during and after vibration.
