if you tell me the functional group modification in this reaction or molecular structure let me think if I could.

 Mr. Budkevich,

If I have properly understood from [ref. 1], melanoidins have represented a macromolecules with still unknown structures (structural fragments), which have been obtained under heating of some foodstuffs such as for example coffee. However, according to [1], the efforts to identify the structural sub-units of these substances, has yielded to conclusion that melanoidins have consisted of substituted phenols, derivatives of benzoic acids and related. So that, these compounds can be easy determined even quantitatively in the presence of lactulose by IR-spectroscopy. All carbohydrates have relatively common spectroscopic profile. Please pay attention, for example, on [ref. 2]. By contrast benzoic acids and phenols have strongly characteristic, individual, profiles, in fact, within whole mid-IR-region of the spectrum. If you have a spectrum of lactulose, you could apply a reducing procedure towards the IR-spectrum of a melanoidins/lactulose mixture. The method has been described and validated in [ref. 3]. It allows to identify IR-bands of each of the components of a mixture.

But, can you provide a IR-spectrum of melanoidins even in the presence of lactulose?

[1] C. Coelho,M. Ribeiro,A. Cruz, M. Domingues,M. Coimbra,M. Bunzel, F. Nunes, Nature of Phenolic Compounds in Coffee Melanoidins, J. Agric. Food Chem. 2014, 62, 7843−7853

[2] J. Mol. Struct. 879, 2008,30-39, Benzamidinium d-glucuronate: Spectroscopic and structural elucidation, Kolev, T., Koleva, B., Spiteller, M., Sheldrick, W., Mayer-Figge, H.

[3] Talanta, 69, 2006, 822-828, Validation of reducing-difference procedure for the interpretation of non-polarized infrared spectra of n-component solid mixtures, Ivanova, B., Tsalev, D., Arnaudov, M.