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.     

Determination of air content in dry shortenings

A method of test is described for the determination of dry shortening air content. Liquid mediums are prepared which have identical specific gravity to that of the shortening which is under test. Simple calculation of specific gravity data gives the air content. A distinct advantage to the method lies in the fact that air content can be determined for any shortening sample size.     

The oven test as an index of keeping quality

The Schaal or Oven Test, originally developed by the biscuit and cracker industry to provide a relative rating for stability of various shortenings, has been generally adopted by shortening manulacturers. Advantages as well as limitations of the test are enumerated. It is possible to estimate the Oven Test by determining peroxide development in the test sample after two to four days in the oven. Oven Tests may also be conducted without having determined them organoleptically by observing the color change at the point of extreme rancidity. Peroxide formation occurring in a fat contained in biscuits or crackers when subjected to the Oven Test has been investigated and a simple and rapid method of extracting the fat, without changing its peroxide characteristics, has been devised. Lever brothers company