Validation of a curd-syneresis sensor over a range of milk composition and process parameters

Visible–near-infrared reflectance spectra showing the effect of (a) curd-stirring speed at 3 levels [10 (thin black line), 16 (thick black line), and 22 (gray line) rpm] for one cutting intensity level (8.3 total revolutions) and (b) fat level in milk at 3 levels [0 (thin black line), 2.5 (thick black line), and 5 (gray line) g/100g] for one gel firmness level at cutting (35Pa). Both graphs show the untreated spectra of 3 trials during syneresis at 45min after gel cutting.

Fit of model for yield of whey, Y_w, to (a) the calibration set (experiment 1) and to (b) the validation set (experiment 2). Y_w was determined at 10-min intervals from time (t)=5 to 75min after gel cutting during syneresis, giving n=216 data points in each experiment. Each experiment involves 2 clusters of data points corresponding to t=5min and t>5min, respectively.

Fit of model for yield of whey, Y_w, to (a) the calibration set (experiment 3) and to (b) the validation set (experiment 2). Y_w was determined at 10-min intervals from time (t)=5 to 75min after gel cutting during syneresis, giving n=192 data points in experiment 3 and n=216 in experiment 2. Each experiment involves 2 clusters of data points corresponding to t=5min and t>5min, respectively.

Fit of model for fat in whey, F_w, to (a) the calibration set (experiment 1) and to (b) the validation set (experiment 2). F_w was determined at 20-min intervals between time (t)=15 to 75min after gel cutting during syneresis, giving n=108.

Fit of model for fat in whey, F_w, to (a) the calibration set (experiment 3) and to (b) the validation set (experiment 2). F_w was determined at 20-min intervals between time (t)=15 to 75min after gel cutting during syneresis, giving n=96 data points in experiment 3 and n=108 in experiment 2. Experiment 3 involves 3 clusters of data points corresponding to the 3 fat:protein ratios investigated.