No abstract

Summary A study has been made of the infrared absorption spectra of autoxidized methyl linoleate in samples ranging from PV 1 to PV 940 m.e./kg. Principal changes occur in the frequency range 3400–3550 cm−1 where bonded−OH groups absorb and at 1650–1775 cm−1 where >c=0 groups absorb. Two maxima were observed in oxidized samples in the −OH absorption range: one sharp and distinct at 3467–70 cm−1 which increased in intensity with increase in PV and a broad band which increased with increasing PV until it resolved into a true maximum at 3430 cm−1. Reduction of typical oxidized samples with KI reagent resulted in disappearance of the 3430 cm−1 band and appearance of a new band above 3500 cm−1. The band at 3430 cm−1 was attributed to −OOH groups associated by hydrogen bridging. The band at 3467 cm−1 and the band appearing above 3500 cm−1 were attributed to −OH groups, the band at the higher frequency resulting directly from reduction of a hydroperoxide. Absorption due to ketone and aldehyde carbonyl groups appeared only as an indefinite shoulder on the band due to the ester carbonyl. These were resolved by using the intensity of the sample with PV 1 as Io and that for the oxidized samples as I. A plot of Log Io/I then revealed three maxima. These indicate the presence of two and possibly three carbonyl containing substances other than the ester carbonyl in autoxidized methyl linoleate. Absorption in the two critical frequency ranges of fractions of autoxidized methyl linoleate eluted from an adsorption column correlate with interpretations made from ultraviolet absorption studies of the same substances.

Summary Butylated hydroxyanisole has been developed as a new and very effective antioxidant for animal fats. It is readily soluble in fats, and practically insoluble in water. It exhibits synergism with acids, hydroquinone, methionine, lecithin, and thiodipropionic acid. It is very effective in protecting foods made with lard against rancidity. In combination with small quantities of hydroquinone or propyl gallate and an acid synergist, it imparts to animal fats high AOM stability and shelf life and is very effective in protecting foods made with lard (crackers, pastry, etc.) against rancidity. Extensive pilot plant and commercial tests have demonstrated the practical usefulness of the antioxidant. Extensive toxicological tests with rats have failed to demonstrate any physiological effects when the antioxidant is used daily in food, even in amounts several hundred times the maximum amount permitted by the regulations of the Meat Inspection Division.