Predicting sediment formation in ultra high temperature-treated whole and skim milk using attenuated total reflectance-Fourier transform infrared spectroscopy

Establishing accelerated shelf-life testing using Fourier transform infrared spectroscopy (FTIR) as a tool for prediction of stability requires pre-assessment of correlations between spectral changes and instability development during storage at room temperature. Comparison of results with those at elevated temperatures would establish appropriateness of accelerated shelf-life testing. UHT skim milk (SM) and UHT whole milk (WM) were stored at 20 °C for 9 months to investigate the feasibility of identifying spectral markers to predict sedimentation (a measure of instability). Marker variables corresponding to changes in structure and interactions of lipids, proteins and carbohydrates successfully predicted sedimentation in SM (R2 = 0.92) and WM (R2 = 0.60). Low predictability in WM may be due to influence of fat. These markers were similar to those observed during accelerated shelf-life testing, hence affirming its application with further work required to develop a model able to forecast sedimentation and other instabilities in UHT milk.