An application of the barcroft-warburg apparatus to the study of antioxidants in fats

Abstract

Summary The results of the active oxygen method and those obtained with the Barcroft‐Warburg apparatus at 70° C. are in good agreement with storage tests at room temperature on lard to which no anti‐oxidant is added and on lard to which lecithin alone is added. With lard to which d‐isoascorbyl palmitate or d‐isoascorbyl monostearate, in concentrations between 0.01 and 0.10 per cent, is added the results with the Barcroft‐Warburg apparatus are in much better agreement with storage tests than are those of the active oxygen method. The d‐isoascorbyl esters in 0.01 to 0.10 per cent in lard usually behave as antioxidants with the active oxygen method and as pro‐ or antioxidants, depending on their concentration, with the Barcroft‐Warburg apparatus and during storage at room temperature. This study demonstrates that in testing new compounds for antioxidant properties conclusions should not be drawn from results obtained when the experimental conditions of the test are very different from the conditions under which the antioxidant is to be used. It emphasizes the importance of correlating the results of accelerated tests with storage tests.

Effect of storage conditions and antioxidants on the keeping quality of packaged oils

“…It is conceivable that the destruction of catalase during storage would liberate this iron which would then accelerate the oxidation of the oils. The results of Nagy et aL (13) which show ascorbic acid esters to be prooxidants in concentrations above 0.01% in lard stored in the presence of air in the dark differ from other reported findings. The insolubility and taste of many of the antioxidants prevented their successful use in corn or cottonseed oils.…”