Some notes on the determination of moisture and volatile matter in fats and oils

Summary

It has been found that the method of moisture determination introduced by Parsons and Holmberg, in which water is evolved from the sample and absorbed on CaCl₂, is absolute and is applicable to all types of oils and fats, except those containing residual solvent. It is particularly suited for the determination of very low percentages of moisture in oils and fats.

Of the methods recommended by the A.O.C.S. for the determination of moisture and volatile in oils and fats, the vacuum oven was found to be the most accurate, except on high-fatty-acid coconut oil.

The hot-plate method gave the highest moisture results when the test was conducted according to the procedure outlined in the methods of the A.O.C.S. When first traces of smoking were observed under a strong beam of concentrated light, resulting moistures approached those obtained by the vacuum oven.

Moisture results obtained by the air oven, if corrected for peroxide absorption, approach those of the vacuum oven.

The percent of residual solvent in extracted soyabean oil, independent of moisture, may be accurately determined by adsorption of solvent vapor on activated charcoal.