these two products, singly are colorless, however, it is necessary a phenolic compound addition in the medium to develop a colored compound, in this case redness. this technique is firstly mentioned by Roe(1934), with some posterior modifications by Roe et al. (1949), becoming a quick reaction and with stable color. The reaction uses the hydrochoride acid (HCl) for carbohydrates dehydration and the resorcinol is the phenolic compound that reacts with furfural and HMF.