Use of mid-infrared spectroscopy to predict coagulation properties of buffalo milk

This study aimed to evaluate the feasibility of mid-infrared spectroscopy (MIRS) to predict rennet coagulation time (RCT), curd-firming time (k20) and curd firmness (a30) of buffalo milk. One hundred and sixteen milk samples were collected and analysed using both reference analysis and MIRS. Reference measures of RCT, k20 and a30 were matched with milk spectra information (5,000 to 900 cm-1 wavenumber) and prediction equations were developed for each trait using i) cross-validation on the whole dataset and ii) external validation on a subset of the entire data. The prediction models were evaluated through the coefficient of determination (R2) and the residual predictive deviation (RPD). The most accurate prediction model was developed for RCT (R2 = 0.72; RPD = 1.88) in cross-validation. Models developed for RCT and a30 allowed a quite satisfactory prediction of milk coagulation properties. Nevertheless, the accuracy was not enough to suggest their application in milk payment systems. Instead, they might be interesting for breeding purposes.