| dc.description.abstract | Chilling injury symptoms in horticultural products were examined through the dynamic state of water by proton NMR analysis. Cucumber fruits, a chilling sensitive horticultural product, were used as a sample. After harvesting, samples were stored in polyethylene bags at temperature of 50C and 250C for 9 days. T1 relaxation time, weight loss, pH. ion leakage and the occurrence of pitting were measured during the period of storage. For samples stored at 25°C, T1 changed slightty for the first 3 days from 1.25 to 1.29s and increased from 4 days at the range of 1.35 to 1.38s. In contrast to this, at storage temperature of 50C, T1 increased extremely from 1.24 to 1.59s from storage time of 2 to 4 days and after that decreased to 1.38s at 9 days. The change in T1 indicates the change in water movement in cell due to the physical change in membrane permeability. This phenomenon was supported by the change in weight loss, pH and ion leakage. The weight loss of samples for 25 and 5°C was almost the same; therefore. it is considered that the pitting for samples stored at 5°C was due to the impact of low temperature. The increasing tendency of pH was observed for samples slored at 5°C with the value at 9 days was higher than that at 25°C. The increase in pH could be thought as the change in acid content which indicates the occurrence of chilling injury. The rate of ion leakage for samples stored at S °C was higher than that at 25°C. This shows that impact of chilling has changed the membrane permeability. It is concluded that longer T1 relaxation time in chilling temperature indicates the change in the dynamic state of water which is related to the increase in membrane permeability. The dynamic state of water which is showed through the change in T1 could be applied to detect the early symptom of chilling injury before the external symptoms such as pitting can be detected. | en |
