Reconstruction of humins formation mechanism from decomposition products: A GC-MS study based on catalytic continuous flow depolymerizations

•Humins can be decomposed by hydrogenation or transfer hydrogenolysis to a plethora of products.•Identification of the same classes of products suggests incorporation of these molecules in the humins structures.•Humins structure is more complex than the ones proposed in literature, and will change depending on process.•The occurrence of multiple mechanisms towards the formation of humins was observed.