Feasibility study on the use of attenuated total reflectance mid-infrared spectroscopy for the analysis of malt quality parameters in wort

The feasibility of using attenuated total reflectance in combination with mid-infrared (MIR) spectroscopy for the analysis of malt quality parameters in wort, such as free α-amino acid (FAN), apparent attenuation limit (AAL), soluble protein (SP) and viscosity (VIS), was evaluated. The coefficients of determination in cross-validation RCV2 and the standard error of cross-validation were 0.81 and 10.3mgL^-1 for FAN, 0.80 and 1.49% for AAL, 0.78 and 0.18% for SP and 0.69 and 0.13cP for VIS. Good calibration and validation statistics were obtained for AAL. However, for nitrogenous compounds the MIR predictions can only be used as approximate estimates of the true concentrations, for example to rank samples (low, medium, high) in the context of a breeding programme. © 2014 The Institute of Brewing & Distilling.