Prediction of starch pasting properties in barley flour using ATR-MIR spectroscopy

The objective of this study was to evaluate the feasibility of using attenuated total reflectance (ATR) mid infrared (MIR) spectroscopy to predict starch pasting properties in barley flour samples. A total of 180 barley flour samples sourced from the University of Adelaide germplasm collection, harvested over three seasons (2009, 2010 and 2011) were analysed using both ATR-MIR and the rapid visco analyser (RVA) techniques. Calibrations (n = 100) were developed using partial least squares (PLS1) regression and full cross validation. The coefficient of determination (R²) and the standard error in cross validation (SECV) were 0.74 (SECV = 875 RVU) for peak viscosity (PV), 0.63 (SECV = 561 RVU) for trough (THR), 0.80 (SECV = 173 RVU) for breakdown (BRK), 0.74 (SECV = 126 RVU) for setback (STB), 0.77 (SECV = 679 RVU) for final viscosity (FV), and 0.73 (SECV = 0.57 s) for time to peak (TTP). The RPD values (SD/SEP) from the validation indicated that only BRK can be accurately predicted (RPD = 4). We have demonstrated that ATR-MIR spectroscopy has the potential to significantly reduce analytical time and cost during the analysis of barley flour for starch pasting properties.