Antioxidant Action of Some Commercial Caramel Colors on Autooxidation of Linoleic Acid

Abstract

The antioxidant action on linoleic acid of four types of caramels which were prepared by different methods (A from glucose, sodium hydroxide and ammonium sulfite; B from glucose and ammonium hydroxide; C from glucose, sodium sulfite and ammonium sulfite; D from sucrose) was investigated. The results obtained are as follows.
1. Caramel B showed the highest antioxdative activity under the various conditions. The relative activities compared with those of BHA were as follows: ca. 1/11 for caramel B, ca. 1/100 for caramel A and C, ca. 1/500 for caramel D.
2. Comparison of the antioxidative activity of dialyzed caramel with that of undialyzed one showed that the latter exhibited higher activity than the former in any type of caramel.
3. By the investigation on the relationship between the antioxidative activity and color intensity, nitrogen content, or reducing power of caramel, it was indicated that, generally, the higher color intensity or nitrogen content, the higher antioxidative activity. But a definite relation was not found between the antioxidative activity and the reducing power.