抄録
Experiments were carried out with hardened coconut oil to find the correlation between crystal growth and hydrolysis of esterifird lower fatty acid at lower temperature.
1) A.V. showed practically no change, both in hardened and non-hardened oils, when stored in anhydrous state, and there was no difference in the values due to storage temperature.
When the oil was saturated with vapor, the values increased in the order of those stored 15 and 5°C, and the tendency was especially marked in hardened coconut oil stored at 15°C.
2) Methyl ester of hardened coconut oil and those dissolved in ethanol, n-hexane and benzen did not show rise in A.V. values even when stored at a low temperature.
3) The fraction obtained by molecular distillation showed less change, even when stored at 5°C, than the original hardened coconut oil. The fact that A.V. was higher in Fraction 2 than in Fraction 1, containing larger amount of lower acids, indicated that when molecules of a same size were collected, more impacted intermolecular space should be presumably produced. This was borne by the fact that electron microscopic observation showed a smooth surface although there were fine single crystals.
