THERMAL STABILITY OF SUBSIDIARY DYES ASSOCIATED WITH FD&C YELLOW NO. 6

Abstract

FD&C Yellow No. 6 and five subsidiary dyes commonly found in commercial samples of this colorant were examined to determine their thermal stability in various model systems. Differences in thermal stabilities were noted for the various subsidiary dyes. Variations in stability for samples processed in neutral and acidic solutions were noted. Samples were also processed in the presence of a reducing sugar. Possible breakdown products are discussed. Studies have shown significant differences in the stability of the major and subsidiary dyes which could have potential significance.

Food colourants

“…61 The stability of individual colours has also been investigated. 62,63 This work showed that the dyes of the FD&C Red No. 2 series (Amaranth) were all less stable than the respective dyes of the FD&C Yellow No.…”

“…The most stable of the commonly used synthetic colours to high temperatures are Ponceau 4R, Allura Red, Sunset Yellow, Tartrazine, Chocolate Brown HT, Green S and Brilliant Blue. [62][63][64][65] Brownley and Lachman 65 reported that Indigo Carmine is not stable to high temperatures. At very high temperatures some carbonisation may occur which will cause colour loss and change of shade.…”