However, since these bands are significantly more intense in the spectra for roasted corn and barley than they are in the spectra for roasted coffee and husks and for spent coffee, they will probably contribute to the discrimination between coffee and

its respective adulterants. Thus, more attention should be given to this region of the spectra. With a prior knowledge that starch is present in both corn and barley and is not present in coffee and its by-products (husks and spent Erastin in vitro grounds) we have studied FTIR spectra for commercial corn starch (not shown) and noticed that these bands are clearly observed in those spectra and are more intense than those present in spectra for coffee, coffee husks and spent coffee grounds. The presence of these bands in the spectra for commercial corn starch may be attributed to the absorption combination bands of bound phenolics (Lopez-Martinez et al., 2009; Omwamba & Hu, 2010), such as ferulic and coumaric acids and their derivatives, or to absorption in the C–O stretching region due to the interaction of starch and the residual gluten in the presence of water. Also, in this same wavenumber range, the water association band (2400–2000 cm−1), attributed to a combination of the bending mode of water molecules with intermolecular vibration modes due to hydrogen bonding between water molecules and between water

and other molecules, may be responsible for part Ku-0059436 supplier of the absorption. In the spectra we obtained for hydrated corn starch (not shown), the absorption in this region was significantly more intense than it was in the spectra for commercial corn starch. Hence, Doxorubicin concentration in our study, the absorption in the range of 2250–1850 cm−1 may be partially associated with a large presence of phenolics bound to non-degraded starch in roasted corn and roasted barley and partially with the hydration water effect on the non-degraded starch in roasted corn and

roasted barley. Low hydration of starch granules stabilizes the starch structure and allows some of the starch granules present in corn and in barley to stay intact during roasting and thus be found in the roasted product, as detected by Amboni, Francisco, and Teixeira (1999) by scanning electronic microscopy. Sharp bands at 1745–1742 cm−1 are evident in coffee, corn and spent coffee grounds spectra. Such bands have been previously identified in FTIR spectra of roasted coffee (Kemsley et al., 1995; Lyman et al., 2003; Reis et al., 2013) and attributed to carbonyl (C O) vibration in esters (triglycerides) and aldehydes. Such literature reports and the fact that these bands are rather weak in the spectra obtained for roasted coffee husks and barley (low lipid content) corroborate our previous assessment (Reis et al., 2013) regarding its association to lipid concentration.