香料ゼラニウム精油の増収機構に関する研究

第I報収油率の変化について

抄録

The percentage yield of the geranium is determined by the weather condition of the seasonn and the hour when the materials are harvested. The temperature, the quantity of sunshine, and the humidity are the meteorological elements which determine the percentage yield of oil. The temperature has an especially close relationship. Using materials of identical leaf-placement and weight taken from P. roseum “Bourbon” (annual and biennial) . I have investigated the fluctuation of percentage yield of oil and have summarized the results as follows:
(1) As for the sesonal ups and downs of the percentage yield of oil from the end of May to the beginning of June and from the end of July to the begining of August, the increase rate is remarkable. From the end of November to December it decreases rapidly. The hour of maximum percentage yield of oil in a day changes by season. In June and September it is about 4: 30 and at other times it is between 11: 30 A. M. and 3: 30 P. M.
(2) It is found that the percentage yield of oil is determined remarkably by the weather condition at the time when the materials are harvested. Even though the temperature is high, if the humidity rises, the percentage yield of oil declines rapidly. There is a high correlation between the percentage yield of oil and the hour and temperature of the harvesting season. There is also an evident correlation between the percentage yield of oil and the accumulated temperature. Temperature of the harvesting season r: 0.760**±0.090, temperature of the harvesting time r: 0.925**±0.032, accumulated temperature r: 0.763**±0.094
(3) The percentage yield of oil rises in proportion to the temperature as far as 25°C. Daily fluctuation can be classified by temperature and the percentage of increase in the amount of collecting oil. At 10°C, it becomes normal distribution type, at about 15°C. middle type, and over 20°C. level distribution type, this suggests that the secretory activity of oil gland reaches a maximum in high temperature.
(4) When the temperature of the leaf is raised artificially, the refining of the oil-drops in the voil glands is hastened and the secrective function becomes excellent. The use of black carbon is then effective.
(5) The percentage yield of oil is determined by the weather condition of harvesting time rather than the drying method of the materials. When the materials are dried for less than ten days, regardless of the drying method, there is no great difference in the percentage yield of oil in comparison with green plant distillation.
(6) In the case of the hanging-dried, the total as alcohol as Geraniol declines a little and the acid value rises a little with the passing of days, but in the case the spreading on ground, there is no difference in the total alcohol as geraniol and the acid value when compared with green plant distillation. In the case of the sundried material, the ketone cont. as isomenthone increases a little.