The Use of a Digital Brix Refractometer to Estimate Cheese-Making Constituents in Ewes’ Milk

Abstract

In this study, 737 individual sheep milk samples were collected to evaluate the relationships between Brix refractometer measurements and milk constituents—particularly, protein and fat percentages—with the aim of verifying the ability of the refractometer to predict milk constituents. The Pearson's simple (rSP) and partial (rPP) correlations between milk constituents were calculated, and several first- and second-order regressions were tested to predict the protein and fat percentages. The results of the forecasts can be considered satisfactory only for the simple regression that predicted the percentage of milk protein through the measurements read with the Brix refractometer (PRT = -2.996 + 0.639*Brix), while the regression that predicted the percentage of fat + milk protein presented a weak forecasting capacity, which was probably due to the absence of partial correlations between the Brix refractometer measurements and the fat percentage.