Proposed formation mechanism, antioxidant activity and MDA-MB-231 cells survival analysis of two glucose–ammonium sulfite caramel colour melanoidins fractions

Ultrafiltration and gel chromatography were used to isolate caramel colour melanoidins, and elemental analysis and pyrolysis-GC/MS was used to analyze the characteristic of glucose–ammonium sulfite caramel colour melanoidins of various molecular weights. Results indicated that furfuran was the main skeleton of glucose–ammonium sulfite caramel colour melanoidins. And 5-hydroxymethyl-2-furaldehyde might be one of the origins of melanoidins skeleton which was formed via aldol condensation. A proposed mechanism on the formation of glucose–ammonium sulfite caramel colour melanoidins might be that bi-furan derivatives were formed after aldol condensation (part A), and sulfite ion could connect with carbon atom of formyl group, and amidolinks might be formed between aldehyde of furfuran and nitrogen atoms (part B). At last, parts A and B polymerized and formed the possible structure of the glucose–ammonium sulfite caramel colour melanoidins. And the formed melanoidins have a significant radical-scavenging activity, and complex effects on MDA-MB-231 cells survival.