Validation of a curd-syneresis sensor over a range of milk composition and process parameters
Teagasc, Moorepark Food Research Centre, Fermoy, Co. Cork, Ireland. Journal of Dairy Science
(Impact Factor: 2.57).
11/2009; 92(11):5386-95. DOI: 10.3168/jds.2009-2363
An online visible-near-infrared sensor was used to monitor the course of syneresis during cheesemaking with the purpose of validating syneresis indices obtained using partial least squares, with cross-validation across a range of milk fat levels, gel firmness levels at cutting, curd cutting programs, stirring speeds, milk protein levels, and fat:protein ratio levels. Three series of trials were carried out in an 11-L cheese vat using recombined whole milk. Three factorial experimental designs were used, consisting of 1) 3 curd stirring speeds and 3 cutting programs; 2) 3 milk fat levels and 3 gel firmness levels at cutting; and 3) 2 milk protein levels and 3 fat:protein ratio levels, respectively. Milk was clotted under constant conditions in all experiments and the gel was cut according to the respective experimental design. Prediction models for production of whey and whey fat losses were developed in 2 of the experiments and validated in the other experiment. The best models gave standard error of prediction values of 6.6 g/100 g for yield of whey and 0.05 g/100 g for fat in whey, as compared with 4.4 and 0.013 g/100 g, respectively, for the calibration data sets. Robust models developed for predicting yield of whey and whey fat losses using a validation method have potential application in the cheese industry.
Available from: Luigi Calamari
- "c o m / l o c a t e / f o o d c h e m 1998). In other studies the infrared spectroscopy was used to predict syneresis indices during cheesemaking (Mateo et al., 2009) and to predict some of the cheeses sensory quality (Fagan et al., 2007). Although TA is claimed to be measurable by commercial Fourier transform infrared spectroscopy equipment, limited scientific literature is available. "
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ABSTRACT: This study investigated the potential application of Fourier transform mid-infrared spectroscopy (FT-MIR) for the determination of titratable acidity (TA) in cow's milk. The prediction model was developed on 201 samples collected from cows in early and late lactation, and was successively used to predict TA on samples collected from cows in early lactation and in samples with high somatic cell count. The root mean square error of cross-validation of the model by using external validation dataset was 0.09 °Soxhlet-Henkel/50mL. Applying the model on milk samples from cows in early lactation or with high somatic cell count, the root mean square error of prediction was 0.163 °Soxhlet-Henkel/50mL, with a RER and RPD of 23.9 and 5.1, respectively. Our results seem to indicate that FT-MIR can be used in individual milk samples to accurately predict TA, and has the potential to be adopted to measure routinely the TA of milk.
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Available from: Massimo De Marchi
- "instruments using infrared analysis have been used to monitor milk coagulation, curd firming, and syneresis (Payne et al., 1993; Fagan et al., 2007; Mateo et al., 2009). Infrared instruments have been used also to predict the MCP, usually measured with a mechanical lactodynamograph. "
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ABSTRACT: The aim of the present study was to compare milk coagulation properties measured through a traditional mechanical device, the Formagraph (FRM; Foss Electric A/S, Hillerød, Denmark), and a near-infrared optical device, the Optigraph (OPT; Ysebaert SA, Frépillon, France). Individual milk samples of 913 Brown Swiss cows from 63 herds located in Trento Province (Italy) were analyzed for rennet coagulation time (RCT, min), curd-firming time (k20, min), and 2 measures of curd firmness (a30 and a45, mm) using the 2 instruments and under identical conditions. The trial was performed in the same laboratory, by the same technician, and following the same procedures. Extending the analysis by either instrument to 90 min permitted RCT and k20 values to be obtained even for late-coagulating milk samples. Milk coagulation properties measured using the OPT differed considerably from those obtained using the FRM. The average k20 values varied greatly (8.16 vs. 5.36 min for the OPT and the FRM, respectively), as did the a45 figures (41.49 vs. 33.66 mm for the OPT and the FRM, respectively). The proportion of noncoagulating samples for which k20 could be estimated differed between instruments, being less for the OPT. The between-instrument correlation coefficients were either moderate (0.48 for a30) or low (0.24 and 0.17 for k20 and a45, respectively) when the same traits were compared. The correlations between k20 and a45, and milk yield varied among instruments, as did the correlations between k20, a30, and a45 and milk composition, and the correlations between a45 and pH. The relative influence of days in milk on k20 and a45 varied, as did the effect of parity on a45 and that of the measuring unit of coagulation meter on k20 and a30. The RCT estimated by the OPT was the only milk coagulation property to show good agreement with the FRM-derived value, although this was not true for the data from late-coagulating samples.
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