Identification of key constituent of sugar-smoking pigment and its photobleaching, antioxidant and antiproliferative properties.

The key constituent(s) of sugar-smoking brown pigments were identified, the chemical and biological properties were subsequently investigated, and the possibility of obtaining it from nature was explored. A pigment was isolated, which was identified as condensation product of 5-hydroxymethyl-2-furfuraldehyde (5-HMF) with glucose: 5-(α-D-glucopyranosyl-(1-6)-α-D-glucopyranosyloxymenthyl)-2-furancarboxaldehyde (5-GGMF). The molecular weight was 450.00. The interaction between pigment with protein on chicken skin was mainly via hydrogen and carbon-hydrogen bonds. It was obtained by caramelization instead of Maillard reaction. Discoloration of sugar-smoking pigments were mainly due to cleavage of chromophores caused by the oxidation reaction followed by photobleaching mechanism. Both radical scavenging and antiproliferative capacity of sugar-smoking pigment were in a dose-dependent manner. However, the IC values for HepG2 and PANC-1 cells differed by more than ten times. Since 5-GGMF is also present in plant resources (like Rehmanniae Radix), it can be obtained as natural additive to produce clean label sugar-smoked meat products.